Pi ut mu “PUMP IT UP� Responsive Soft-Robotic Architecture Bachelor Thesis
OFIR ALBAG, 795186
Politecnico di Milano, Facolty of Architecture and Society Bachelor in Architectural Sciences
Supervisor: Prof. Ingrid Paoletti Co-Supervisor: Roberto Naboni 2015/2016
להשראה הראשונה והנצחית שלי,
אמא
A
ABSTRACT The constant adaptation and incorporation of new technologies and materials into the architectural realm has long been the core driver of change in the way in which architecture is conceived and the solutions it offers. In this work, the emergent area of soft robotics is taken into scrutiny with an aim to demonstrate a possibility of application into an architectural practice, a task that was only explored in a handful of works before. This challenge is approached by firstly setting a foundation to the topic in a survey of the motivations for the task, the fundamental definitions that constitute Its disciplinary domain, and the prominent projects that set up the state-of-theart ventures into soft-robotic architecture. This foundation is followed by the introduction of a designated design and manufacturing process of a specific kind of soft elastomeric actuator - the “PneuNets� bending actuator, and then culminating in a practical attempt to apply the covered knowledge in the form of a design proposal for an original soft-robotic, meteo-responsive building skin component, to harvest the advantages offered by the innovative technology. Critical observations onto the processes and experimental products reviewed throughout this work attempt to set a frame over the state of the new exploratory territory of applied softrobotic technology in architecture. Although the technology encompasses an almost infinite variety of promising applications for the improvement of existing technological solutions and even for problems that have yet to be answered, it is not gone without notice that the technology in its current state has its downsides and limitations. Whether delimited by its inherent characteristics or by the tools and methods that exist to this date for its design and management, some further research could be done on this exciting technology, to render it more compliant, precise and user-friendly for designers and architects. With these considerations in mind, it seems that soft robotic architecture might be just a step away from being fully and easily implemented in our built environments. Key words: soft robotics, responsive, inflatable, smart, temporary design, shelter, building skin
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NDX
CHAPTER.01 // Introduction
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1.1 Motivation: Why soft robotics in Architecture? 1.2 Objectives and Scope: Developing Meteo-responsive Temporary Structure 1.3 Thesis Outline References
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CHAPTER.02 // Towards a Definition of Soft Architecture
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Abstract 2.1 Inflatable Architecture 2.2 Kinetic Architecture 2.3 Smart Architecture 2.3.1 Interactivity, Responsivity 2.4 Robotics 2.4.1 Soft Robotics References
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CHAPTER.03 // State of Art
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Abstract 3.1 The Ability to Transform. Soft robotics as a new platform for architecture 3.2 Case Studies Review and Critical Aspects 3.2.1 Case Study 1: Adaptive Pneumatics 3.2.2 Case Study 2: Soft Robotics for Architects 3.2.3 Case Study 3: Furl: Soft Pneumatic Pavilion 3.2.4 Case Study 4: Adaptive Solar Facade References
56 59 61 61 64 69 72 77
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CHAPTER.04 // Soft Robotic Actuator
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Abstract 4.1 The Soft Robotic Actuator 4.2 PneuNet Bending Actuator 4.2.1 The Pneumatic Network 4.2.2 Design 4.2.3 Modeling 4.2.3.1 Rhinoceros + Grasshopper + Kangaroo 4.2.3.2 FEM (Abaqus CAE) 4.2.4 Fabrication 4.2.5 Testing 4.3 Sensors and Electronic Control References
82 85 87 87 89 93 93 95 102 111 114 117
CHAPTER.05 // Design Proposal
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Abstract 5.1 Design Brief 5.2 Design Process 5.2.1 Concept 5.2.2 Component to System 5.2.3 Unit Design 5.3 Fabrication Hypothesis 5.4 Prototype References
120 123 127 127 131 137 153 157 163
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CHAPTER.06 // Summary and Discussion
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6.1 Work Summary 6.2 Criticism 6.3 Suggestions and Potentialities References
167 169 173 179
CHAPTER.07 // Conclusion BIBLIOGRAPHY
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LIST OF FIGURES
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ACKNOWLEDGEMENTS
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01
INTRODUCTION
CHAPTER.01
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INTRODUCTION
1.1 MOTIVATION - WHY SOFT ROBOTICS IN ARCHITECTURE? Since the beginning of time architecture was conceived as an entity opposite to the organic, an immutable object that withstands the effects of time. For centuries the keyword associated the most with the construction of buildings was stability, the tendency to stay firm and preserve the same characteristic over a long period of time. This is what people traditionally aspired for in their buildings, leading thus to a certain degree of stagnant predictability.
Nowadays, new ideologies and technologies are being gradually introduced into architecture making a new paradigm prevail for the built environment, in which the guiding keyword is adaptability, the ability to change, transform and react according to the changing needs and environmental conditions (Andresen, 2005). There seems to be an increasing interest in the less known crossroad of fields where architecture meets automation, the point in which architecture becomes a machine. This automation process is aimed to improve our desirable results - the performance of our built spaces. Keywords like optimization, responsiveness and robotics are prominently more present and affecting our lives.
Architects have been and still primarily deal with the classical building materials that help them achieve their goal of defining and enclosing space, which are usually concrete, steel, glass or wood. These traditional materials are familiar and easy, designers could work with empirical data already gained from decades of experience and use advanced methods that provide complex calculations allowing to use these materials in an almost risk-free manner. All of these available methods using wellknown building materials are creating a design leading to more or less foreseeable outcomes.
As a field that tends to be rather inflexible in its nature, with changes and innovations being introduced over the course of decades, it is always challenging to involve new technologies and materials in the architectural design. This is a good reason why it is our job, as participants in the less restricted academic counterpart,
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to identify and investigate a design process dealing with non-conventional materials and technologies. It is in our hands to establish the theoretical background, tools and methods that will push forward and bring about the evolution of architecture. Our built environments might take a completely different shape when one employs a “building material” which is yet to be established in the architectural canon of materials.
solutions and technologies with the conception of bio-inspired ideas, using the principles of biology - decentralization, bottom up control, evolutionary advances (Kelly, 1995), and taking inspiration from biological systems and mechanisms existing in nature. These two latter fields had given birth in recent years to a new exciting field in automation and robotics: soft robotics (Trivedi et. al., 2008). Its original concept is to make all of the components in a robot soft and flexible in order to move and manipulate in very limited spaces and change gaits fairly easily. Using innovative elastic materials to emulate biological structures and mechanisms, inspired by animals such as octopus or starfish, allows for unprecedented advantages over traditional “hard robotics”. Unlike hard robots, that are fabricated from metals and often heavy and expensive to make, flexible robots are relatively cheap and easy to produce, they require simplistic designs and controls to generate a wide range of mobility and they are more resistant, in many ways, than their hard-bodied counterparts to damage from common dangers (Whitesides, 2011).
Recent decades have experienced several small movements in architecture deriving from High-tech architecture, also known as Structural Expressionism. These are showing a shift from fashionable attitudes towards scientifically supported design of the form (Davie, 1988). The constant change of lifestyle and rising awareness to the problem of global warming and sustainability is forcing architects to search for new solutions. Some of these involve familiar materials in new unconventional uses and some exploit the breakthrough in the chemical industry by introducing innovative responsive materials with embedded active properties. The emergence of the field of biomimicry in design and engineering is providing for new
figure 1.1 Soft-robotic actuator produced by FUNL Maker Club Course on Soft Robotics (The University of Nebraska–Lincoln)
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INTRODUCTION
The abovementioned advantages could be harnessed in their turn to develop new typologies of kinetic architecture, produce a new language of aesthetics and push forward the evolution of our built environment.
This thesis is motivated by the idea of a new kind of building, one that is not just a lethargic mass of material, a passive container, but rather one which is alive, it breathes and adapts, it is aware.
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CHAPTER.01
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INTRODUCTION
1.2 OBJECTIVES AND SCOPE The overall goal of this thesis is to explore the possibility of applying soft robotic technologies and principles into an architectural practice. This will be done by introducing the field of soft robotics, its mechanism of work, upsides and downsides over traditional systems, establishing a method of designing and producing soft actuators that could facilitate the incorporation
of such actuators into building technology and architectural design, discussing existing state of the art examples of soft architecture and finally proposing a building skin system design that will manifest the opportunities of this merge of fields.
figure 1.2 Soft-Robotic prototype, developed during the work
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CHAPTER.01
WHY
WHAT
HOW
DESIGN
ROUND-UP & FUTURE
Chapter 1 : Motivation, Objectives and Scope
{
Chapter 2 : A Definition of Soft Architecture Chapter 3 : Studying from State of the Art
Chapter 4 : A Workflow for Soft-Architecture
Chapter 5 : A Meteo-Responsive Proposal
{
Chapter 6 : Summary, Criticism & Future Chapter 7 : Thesis Conclusion
figure 1.3 Thesis outline scheme
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INTRODUCTION
1.3 THESIS OUTLINE The outline of this thesis is represented in the adjacent scheme (Figure 1.3). The introductory section, explaining the “Why” was unrolled in the previous sections of Chapter 1.
introducing the technological solutions such a responsive component should be accompanied with: typologies of sensors depending on the function, and other accessories required in order to demonstrate the responsive capabilities of this technologies that could be implemented in an architectural application.
Chapter 2 is a collection of relevant definitions in the preliminary fields for the topic of soft robotics: inflatable architecture , kinetic architecture, the topic of smart environments, and introduction to the topic of Soft Robotics as a part of bio-inspired ideas.
Chapter 5 goal is to apply studied knowledge in an original architectural proposal hypothesis, comprising of a meteo-responsive shelter design, explaining in detail design and prototyping processes.
Chapter 3 is presenting and discussing the cutting-edge works in the emerging field of soft-robotic architecture, Questioning the potentialities and possible improvements for the future in each of the projects.
Finally, chapter 6 is analysing in detail the advantages and drawbacks of the technology and methods, and suggests future possibilities of application for soft robotics,
Chapter 4 is the “How”. It takes a dive into the practical procedures and knowledge necessary to the design and fabrication of soft-robotic systems. comparing the simulation and design tool alternatives and demonstrating the process of fabrication of a specific soft component, relying on the pneumatic principles. It is also
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INTRODUCTION
REFERENCES Colin D, (1988) High Tech Architecture (paperback). Thames & Hudson Ltd Whitesides G, Shepherda R, Ilievskia F, Choia W, Morina S, Stokesa A, Mazzoa A, Chena X, Wanga M (2011) Multigait soft robot, Department of Chemistry and Chemical Biology, Harvard University. Kevin K (1995) Out of Control: The New Biology of Machines, Social Systems and the Economic World. Addison-Wesley. Trivedi D, Rahn C, Kier W (2008) Soft robotics: Biological inspiration, state of the art, and future research, Applied Bionics and Biomechanics, 5(3), 99-117. Andresen K, Gronau N (2005) An approach to increase adaptability in ERP systems. In Managing modern organizations with information technology: proceedings of the 2005 Information Resources Management Association international conference, San Diego, Idea Group Publishing, Herschey (pp. 15-16).
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02
Towards a Definition of Soft Architecture
The chapter introduces the different fields which pose as a background to the topic of soft robotics in architecture, which will hereafter in the work be entitled the compound name “Soft Architecture�. Each of the relevant topics will be described with some important definitions and notable case studies mentioned, with the scope of forming a common platform of knowledge from which pursuits for an architectural application can be undertaken.
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KINETIC adj., of, relating to, or resulting from motion.
AUTOMATIZATION automatic; adj. (of a device or process) working by itself with little or no direct human control.
INTERACTIVE adj. responding to a user’s input.
RESPONSIVE adj. readily reacting or replying to events or stimuli.
SOFT INFLATABLE “An inflatable is an object that can be inflated with a gas, usually with air, but hydrogen, helium and nitrogen are also used. One of several advantages of an inflatable is that it can be stored in a small space when not inflated, since inflatables depend on the presence of a gas to maintain their size and shape.” (Topham, 2002)
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
The problem of designing and controlling a soft-robotic system requires knowledge from many areas including biomechanics, compliant control, smart materials and flexible robots (Sanan, 2013).
preceding knowledge which is considered as a base of the actual research. Areas of study such as inflatable systems, kinetic and responsive technologies are to be summarised in this chapter together with main definitions from the field of soft robotics, approximating a path towards a new paradigm of bio-inspired design.
Before initiating the exploration of how to apply soft robotic technologies into an architectural practice it is important to clarify
figure 2.1 Scheme - areas of knowledge and their intersection, constituting the definition of pneumatic, Soft-Architecture.
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(A)
(B)
figure 2.2 Diagram: air-inflated (A) vs. air-supported (B)
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
2.1 INFLATABLE ARCHITECTURE “An inflatable is an object that can be inflated with a gas, usually with air, but hydrogen, helium and nitrogen are also used. One of several advantages of an inflatable is that it can be stored in a small space when not inflated, since inflatables depend on the presence of a gas to maintain their size and shape.” (Topham, 2002)
(Figure 2.2). Air supported structures commonly utilize a small pressure differential between internal and external pressure and are continuously replenished with air as they are usually open structures - inflatable roofs and other inflatable structures used in entertainment. (Sanan, 2013) Air inflated structures, on the other hand, usually consist of pressurized air only within the walls of the structure, and not in the occupied space itself, thus eliminating the need for airlocks at access points (in the case of buildings) and requiring less power to pressurize a relatively much smaller volume of air. some examples of commonly used air inflated structures are temporary buildings and pavilions used for military and entertainment, but also vehicles such as airships and boats, emergency equipment such as escape slides and even toys and furniture. (Onate and Kroplin, 2005)
The term ‘inflatable’ origins in the latin language, where the word inflare means to blow into, to pump. Inflatable structure is the pliable-walled structure that can be filled with air and maintains its size, shape and strength due to internal pressure (Graczykowski, 2011) - it is made by using membrane material (can only hold tensile stress). Such structures are a special case of a class known as membrane structures. Based on the method of pressurization, inflatable structures using air can be classified as either air supported or air inflated
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
Inflatable architecture has been around for at least 40 years. In this way, architectural design becomes truly portable. It can eventually fit into a shopping bag, be made smaller or larger. Inflatables have aided technological and other advances and are often used as temporary structures for specific occasions, despite the several disadvantages, namely its durability or wastefulness.
Rakowitz attempted to fuse the inflatable with the existing in his project of ParaSITE. Originally intended as a critical joke about the waste products of human inhabitancy, Rakowitz was using the HVAC exhaust from buildings to inflate a temporary heated shelter structure for the homeless (Figure 2.6). With development of CAD systems and robots came also the ability to cut more precise and complex envelope shapes. Alexis Rochas, an architecture professor at SCI-Arc, created an installation in 2006 (Figure 2.7). He had the idea that in the future we will pack our homes into a regular suitcase, and so he transported his installation over a period of six weeks to different locations to host a variety of functions. Another digitally fabricated notable example is by Kengo Kuma (2005) who created a modern, air inflated form of a traditional japanese tea house on the grounds of a museum in Frankfurt (Figure 2.3).
Since the 1960’s many projects have used air as a medium for shaping enclosures. The idea began in that decade - design by American firm Jersey Devil (Figure 2.4) or by Ant Farm - outdoor installation Cadillac Ranch in 1970 - the most prolific at that time, gearing several projects (Figure 2.5). Those early important inflatables created as “happenings” to host temporary events, standing in contrast with their urban contexts, in between of the classical materials like the stone, glass and grass. On the other hand, later in 1998, the artist Michael
figure 2.3 Kengo Kuma “Tea Haus” , Museums für Angewandte Kunst Frankfurt, 2005
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figures 2.4-5 Jersey Devils,; Inflatables (up) and Ant Farm; Clean Air Pod (down)
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
figure 2.6-7 Michael Rakowitz, paraSITE inflatable shelter (up) and Aeromads - a movable environment by Alexis Rochas (down)
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
2.2 KINETIC ARCHITECTURE Kinetic (adj.) “relating to motion,” 1841, from Greek kinetikos “moving, putting in motion,” from kinetos “moved,” verbal adjective of kinein “to move” (Harper, 2015).
The possibilities for practical implementations of kinetic architecture, or rather, the automized mobilization of larger, more significant building components, increased rapidly in the late 20th century due to technological advances in mechanics, electronics, and robotics (Zuk, 1970). In his 1970 book “Kinetic Architecture”, William Zuk inspired a new generation of architects to experiment and design a broad variety of functioning kinetic buildings. Since the 1980s, thanks to the introduction of new concepts, such as Fuller’s Tensegrity, and by the commercial widespread of robotic systems, kinetic buildings have become increasingly common internationally and in daily use (Salter, 2011).
The concept of kinetic architecture follows a path where buildings are designed in order to allow parts of the structure or envelope to move, without compromising overall structural integrity. A building’s capability for motion can be used to enhance its aesthetic value, respond to environmental conditions, and perform functions that require an easily adjustable, alternating solution, which would be impossible for a static structure (such as blocking and opening an accessway).
figure 2.8 Burke Brise Soleil at the Milwaukee Art Museum, Santiago Calatrava, 2001
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Examples of such kinetic systems put in use in buildings vary from very small component size (usually at a residence environment) to a very large scale (such as for entire building portions or large infrastructural solutions- in the case of kinetic bridges (Figure 2.9), providing solutions to every-day building usage patterns (such as automatic gates, doors, windows and shutters, and even some transport means which are building incorporated as elevators and escalators), or on a special event scale (such as retractable roofs at stadiums).
which make use of kinetic properties primarily for the sake of aesthetic awe inspiring, such as Calatrava’s bird-like Burke Brise Soleil at the Milwaukee Art Museum (Figure 2.8) and the “living skin” theme, which groups together a growing attempt to turn building envelopes into a kinetic element that is able to transform and adapt to varying conditions and needs, as in the way of living organic skins (Salter, 2011). A well-known early example for such a kinetic building skin system is Jean Nouvel’s Institut du Monde Arabe, which features a photo-responsive shutter system inspired by the Islamic Mashrabiya (Figure 2.10).
Some other, more specific themes of kinetic structures that could be distinguished by the early 21st century are fantastic structures,
figures 2.9-10 Lake Shore Drive Bridge, a double-leaf bascule bridge constructed in Chicago 1937 (up), and the kinetic facade at the Institut du Monde Arabe in Paris, Jean Nouvel, 1987 (right)
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
2.3 SMART ARCHITECTURE Although AT&T introduced the “intelligent buildings” concept already in 1982 (Graham and Marvin, 1996), much of the research and development work in this important area is still in its infancy.
How could we frame the general direction of the mentioned above development? How can we define the difference in making architecture mechanically and computationally intelligent? What does it mean for architecture to be called “smart”?
A degree of automation provided by kinetic systems was emerging in last decades thanks to the IT industry fast development. This trend is going beyond mere automation, embracing complex cybernetic processes (the science of control and communication in animals, men and machines) and learned behaviors. Previously to be purely technical, theoretical or predominantly environmental camps have merged and begun to share their concerns under the rubric of smart architecture. (Senagala, 2005)
The main outline of framework for smart architecture connects important conceptual, technological and architectural developments in this direction. We could use the term smart in order to group together all the advanced technological solutions coming from kinetic architecture such as the following fields sometimes referred to as responsive, performative, interactive or adaptive architecture.
figure 2.11 The Al Bahar Towers dynamic external screen, opens and closes in response to the movement of the sun, Aedas, Abu Dhabi, 2012
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2.3.1 Interactivity, Responsivity On one hand, across the many fields touched by interactivity (information science, computer science, human-computer interaction, or industrial design, communication) there is still little agreement over the meaning of that term. In computer science, interactive refers to software which accepts and responds to input from people, for example, data or commands. (Sedig, Parsons, Babanski, 2012)
On the other hand, responsivity differentiates itself from interactive design by not limiting itself to human induced input. Unlike mere interactivity, responsiveness does not require human gesture to take place, and is equipped with the sensibility and set of algorithms to perform on its own.
figure 2.12 Recompose, an interactive system for manipulation of an actuated surface, MIT Media Lab, 2011
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Although low-tech systems that make use of physical mechanism or properties of materials could be considered responsive by certain terms, The main focus of the field is usually dealing with electronic configurations, which allow much greater flexibility of operation.
elements including: a mean of input (e.g. buttons, sensors, cameras), a mean of output (or the manipulated object e.g. light, sound or matter) and a computer or a microcontroller, pre or continuously equipped with a set of algorithms (a program) to bridge between the manipulator source and the manipulated target (Figure 2.14).
Since interactivity could be regarded a branch of responsivity, common features could be drawn for both kind of electronic systems. It could be generally stated that any interactive or responsive system require a set of essential
Responsive architecture attempts to incorporate intelligent and responsive technologies into the core elements of a building’s fabric. The term “responsive architecture� was originally
figure 2.13 Aegis Hyposurface, a faceted metallic surface that deforms as a real time response to electronic stimuli from the environment, dECOi, 2001
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used by Nicholas Negroponte during the late 1960’s at a time when spatial design problems were being explored by applying cybernetics to architecture. Negroponte suggested that responsive architecture is the natural product of the integration of computing power into built spaces and structures, and that better performing, more rational buildings are the result. (Sterk, 2009)
Some core examples of interactive environments include systems that allow for human aided direct manipulation of physical objects, surfaces and spaces. For example, many projects have used a voxelized grid of elements in order to be pushed or pulled by human gestures (see MIT Media Lab ‘s Recompose, Figure 2.12, or the Dynamic Reconfigurable Theatre Stage by Laval’s Robotics Laboratory and LANTISS).
It is an evolving field of architectural practice as well as a field of research. With the introduction of responsive technologies into the structural systems of buildings, architects have the possibility to optimize the shape according to the different parameters coming from the environment (Grünkranz, 2010). It measures actual environmental conditions (via sensors) to enable buildings to adapt their form, color or character responsively (via actuators or other executive devices). Investigation in the field of responsive systems has potential to design with possibility of adaption to the future unforeseen requirements (Basterrechea, 2012).
Since Negroponte’s results, many working examples of responsive architecture have emerged (a noteworthy example for that is the dynamic facade of the Al Bahar tower in Abu Dhabi, Figure 2.11), but not only in a functional way - also as an aesthetic creations or systems that could allow spatial transformations directly at architectural scale. Such example we can find in the works of Diller & Scofidio (Blur), dECOi (Aegis Hyposurface, Figure 2.13) and NOX (The Freshwater Pavilion, NL).
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
INPUT
SENSOR
COMPUTER
figure 2.14 A diagram showing the essential elements of any electronic responsive system,
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
2.4 ROBOTICS Robot: origins in Czech language, derived from word “robota” which means to work - ‘forced labour’. The term was coined in K. Čapek’s play R.U.R. ‘Rossum’s Universal Robots’ (1920). (Zunt, 2007)
Arms of the kind in recent years have stepped outside the industrial realm with applications in transport, construction and even entertainment (Kuka 2015). However the construction or domestic sectors are still left relatively behind. Widespread adoption of robotic technologies within architecture would likely have a major impact on the field, both in how the built environment is constructed and in the way it performs. It is important to continue in the investigation of its compatibility with human natural environments, Nevertheless lack of interdisciplinary knowledge is possibly the main obstacle for designers in adopting robotic technologies into buildings.
Over the last century robots, or automated machines, entered into our lives at an increasing rate, bringing with them significant transformations into our industries and lifestyle, arguably with positive effects. The main advantages of automation is in saving labor, energy and materials and performs with better quality, accuracy and precision (Aramburo and Trevino, 2008). The industrial sector has seen the most integration of robotic systems with the automation of production lines in factories, to the point that nowadays, many of the tasks that were considered too delicate or complex for a machine could be accomplished by a generic industrial robotic arm that could be easily adapted to perform an array of tasks that used to be manual such as handling, assembling, screwing and welding (Figure 2.15). Robotic
Robots are usually rigid machines. Design is following the aim in order to perform a small set of tasks in an efficient way. Adaptation in robotic operation is usually achieved by the software layer, which adds a burden on control systems and planners. (Onal, Rus, 2012)
figure 2.15 KUKA robotic arms spot welding in the automotive industry
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There has been some prior research in combining robotics and Architecture. In his book “e-topia” Mitchell claims that in the near future our buildings will become robots for living in (Mitchell 2000). Most efforts have concentrated on either adding sensory / computational elements to existing buildings - smart architecture (Johanson, Fox, Winograd, 2012), or introducing self-contained robots into existing spaces (Siciliano, Khatib, 2008).
The second approach may appear as a more natural way to introduce robotics into Architecture. However, after all considerations it could be regarded more of a practical approach to involve a tighter coupling of the fields, in the sense of including robotics via (re)programmably moving the mass that forms the core shape of the environment (Kapadia, Walker, Green, Manganelli, 2010). Several researchers have developed projects considering aspects of “robotic environments”- for example Oosterhuis and his real-time configurability in programmable pavilions (Oosterhuis, 2003).
figure 2.16 A PneuNet gripper by Cambridge Soft Robotics, 2014
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
2.4.1 SOFT ROBOTICS Robotics has grown exponentially in the last fifty years and robotic technologies are today very solid and robust, in the accurate, fast, and reliable control of robot motion. Almost all the theories and techniques for robot control, fabrication and sensing, which represent an incredible wealth of knowledge, are based on a funda-
mental assumption and conventional definition of robots: a kinematic chain of rigid links. Recent advances in soft and smart materials, compliant mechanisms and nonlinear modelling, on the other hand, have led to a more and more popular use of soft materials in robotics worldwide. This is driven not only by new scientific para-
figure 2.17 Cross-section of common approaches to actuation of soft-robot bodies in resting (left) and actuated (right) states. Nature, 2015
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digms (biomimetics, morphological computation, and others), but also by many application requirements (in the fields of biomedical, service, rescue robots, and many more), because of the expected capability of soft robots to interact more easily and effectively with real-world environments (Mazzolai et al., 2012; Pfeifer et al., 2012).
generate shape memories and elasticity states (Yokoi, Yu & Hakura, 1999). A variety of typologies of soft robotic actuators were developed, using different actuation mechanisms (e.g. pneumatic actuation, mesh geometry, electroactive polymers) yet all characterized by the use of soft components (Figure 2.17). Among these some of the more prominent are the PneuNets bending actuator (to be thoroughly discussed in chapter 4), fiber-reinforced actuators, pneumatic artificial muscle, dielectric elastomer actuator and multi-module manipulator (De Falco et al. 2014).
Soft robotics is a morphological class of bioinspired robotics. As such, it is greatly drawing it’s inspiration from animals such as octopus or starfish. It’s core concept is to fabricate a robot all made up of flexible and elastic components to grant it with the ability to change gaits easily and maneuver in very limited spaces. We can characterize it as a new research area in the field of developmental robotics, which encompasses flexible structures, control and information processing. In this context soft robotics refers to systems based on the use of shape changing materials and their composites, which
Moreover, it is valuable to mention some new methods and technologies which were developed to integrate into soft-robotic actuators and could extend their applicational range such as elastomer embedded 3d-printed sensors (Muth et al. 2014) and microfluidics to change color or opacity of the actuator (Figures 2.18, 2.19).
figure 2.18, 2.19 A three-layer strain and pressure sensor 3d-printed in a stretched elastomer, Harvard University, 2014 (left) and a microfluidic color-changing soft robot, S. Morin, Harvard University 2012 (right)
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Application areas of practical soft robotic mechanisms include artificial muscles, medical robotics, biomimetic robotics, conformal grippers for pose-invariant, shape-invariant and
delicate grasping (Figure 2.16), and human interaction or human assistive technologies (Figure 2.20). (Trivedi, Rahn, Kier, 2008)
figure 2.20 A soft robotic arm, proposed as a part of a future humanoid caregiver. Siddharth Sanan, CMU’s soft robotics lab, 2014
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TOWARDS A DEFINITION OF SOFT ARCHITECTURE
REFERENCES Topham S (2002) Blow Up: Inflatable Art, München, Prestel Verlag Graczykowski C (2011) Inflatable Structures For Adaptive Impact Absorption. Warsaw. Graham S, Marvin S (1996) Telecommunications and the City. Electronic Spaces, Urban Places. London, Routledge Grunkranz D (2010) Towards a Phenomenology of Responsive Architecture, The University of Applied Arts in Vienna. Retrieved 26 January 2016. Harper D (2005) Online Etymology Dictionary, as accessed on September 5th 2015, websource: www.etymonline.com/index.php?term=kinetic. Johnson B, Fox A, Winograd, T (2002) Inventing wellness systems for aging in place, IEEE Pervasive Computing, vol. 1, no. 2, pp. 67–74 Kapadia, Walker, Green, Manganelli (2010) Architectural Robotics: An Interdisciplinary Course Rethinking the Machines We Live In. Part by an NSF grant IIS-0534423 - the Department of Electrical & and Computer Engineering, Clemson University, Clemson, p. 1 Onal C, Rus D (2012) A Modular Approach to Soft Robots, The Fourth IEEE RAS/EMBS International Conference on Biomedical Robotics and Biomechatronics Roma, Italy. June 24-27, 2012. Oosterhuis, K (2003) Towards an E-Motive Architecture, Birkhauser Press, Basel, Switzerland.
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Salter C (2011) Entangled: Technology and the Transformation of Performance, MIT Press, pp. 81–112. Sedig K, Parsons P, Babanski A (2013) Towards a characterization of interactivity in visual analytics, Journal of Multimedia Processing and Technologies, Special Issue on Theory and Application of Visual Analytics 3 (1): 12–28, Retrieved July 29, 2015. Siciliano B, Khatib O (2008) Springer Handbook of Robotics, Chapter 55: Robots for Education, pp. 1283–1301. Sterk T (2009) ‘Thoughts for Gen X— Speculating about the Rise of Continuous Measurement in Architecture’ in Sterk, Loveridge, Pancoast “Building A Better Tomorrow” Proceedings of the 29th annual conference of the Association of Computer Aided Design in Architecture, The Art Institute of Chicago. Senagala M (2005) Kinetic, Responsive and Adaptive: A Complex Adaptive Approach to Smart Aechitecture. Zuk W (1970) Kinetic architecture, Reinhold Zunt D (2007) Who did actually invent the word “robot” and what does it mean?, The Karel Čapek website, Retrieved 11-09-2015. Trivedi D, Rahn C, Kier W, Walker I (2008) Soft robotics: Biological inspiration, state of the art, and future research, Advanced Bionics and Biomechanics, vol. 5, no. 2, pp. 99–117 Yokoi H, Yu W, Hakura J (1999) Morpho-functional machine: design of an amoebae model based on the vibrating potential method, Robotics and Autonomous Systems 28, pp. 217-236 Mazzolai B, Margheri L, Cianchetti M, Dario P, Laschi C (2012) Soft-robotic arm inspired by the octopus: From artificial requirements to innovative technological solutions, pp.338-339
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Pfeifer R, Lungarella M, Iida F (2012) The challenges ahead for bio-inspired soft robotics, Commun, ACM, 55(11), pp. 76-87 Onate E, Kroplin B (2005) Textile Composites and Inflatable Structures, p. vii Mitchell W (2000) e-topia, Cambridge, MA: MIT Press. Aramburo J, Trevino A (2008) Advancements in Robotics, Automation and Control, InTech. Kuka Industrial Robots (2015) Kuka Industrial Robots - Robocoaster, Kuka Industrial Robots, Retrieved June 12, 2015. Falco I, Cianchetti M, Menciassi A (2014) A Soft and Controllable Stiffness Manipulator for Minimally Invasive Surgery: Preliminary characterization of the modular design, IEEE Engineering in Medicine and Biology Society. Muth J, Vogt D, Truby R, Menguc Y, Kolesky D (2014) Embedded 3D Printing of Strain Sensors within Highly Stretchable Elastomers, Advanced Materials, Volume 26, Issue 36, September 24, 2014, Pages 6307–6312
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The main goal of this chapter is to provide a concise overview of this young stimulating field of Architectural Soft Robotics and discuss the cutting-edge works in its front line. In particular, It will try to identify the potentialities of development and the challenges that enables these technologies of soft robotics, together with the implications and perspectives towards the future.
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“Ligament and membrane, Muscle and tendon, Run between bone and bone; And the beauty and strength of the mechanical construction lie not in one part or in another, But in the harmonious concatenation which all the parts, Soft and hard, Rigid and flexible, Tension-bearing and pressure bearing, Make up together.” — D’Arcy Thompson, 1917
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3.1 THE ABILITY TO TRANSFORM. SOFT ROBOTICS AS A NEW PLATFORM FOR ARCHITECTURE. Form and its ability to transform in nature are the result of a harmonious cooperation among many elements with specific properties. Speaking about the material properties, the human body (illustrated in Thompson’s quote), is neither hard nor soft; however, a combination of muscles, bones, joints, tendons, etc. which make up the complete load-bearing actuation structure that allows us to perform many actions - movements (Thompson, 1992).
and properties and adapting harmoniously to their changing environments. maybe what our architecture lacks is softness, that soft, flexible ligament that operates to constantly adjust the rigid, static parts of the structure. Which could be that missing link, that soft tissue that could revive our buildings, from an anachronistic monument to our own living, breathing skin? Nowadays ‘smart’ and ‘responsive’ systems are in the front line of scientific, engineering research. Despite their fast progress in the previous decades, these systems are mostly working as additional shading and ventilation devices. The majority of cases of these systems are depending on energy-hungry mechanisms (Jerominidis; 2004). The relatively new field of Soft Robotics could just be the solution we were waiting for. It is proposing the concept of a synthetic muscle, formed after biological principles, simple and cheap to fabricate, made in one part that is able to flex itself into countless possibilities of deformation. It might gift our buildings with the ability to transform.
Architecture as we know it is a rigid skeleton, almost always static, it is dead as it only has one physical purpose - to stay still. When we start to ask for more from our buildings, to provide us with a better standard, by turning from a passive shell into an active skin, we have to ask ourselves - how do we give life to this static rigid pile of matter? If we will open our eyes to the existing solutions all around us, that is, to nature itself we might figure out that something is missing in our buildings, and keeps them from having the desired ability to constantly changing form
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3.2 CASE STUDIES REVIEW AND CRITICAL ASPECTS Until this day, in recent years, only a handful of prominent attempts to incorporate the soft robotics domain into an architectural practice have emerged, of which none ever actually extending out of the academic framework. These explorations
of converging the fields, However, often resulted in interesting outcomes and valuable lessons. I will describe some of these efforts, what did they aim for, and what could be learnt and applied from them in further future projects.
3.2.1 CASE STUDY 1: ADAPTIVE PNEUMATICS An early significant research to be underlined is that of “Studio Integrate” called “Adaptive Pneumatics” (2009). Influenced by natural living organisms, the research was initiated to challenge conventional building design and construction methods, which exploit the use of electromechanical devices for the provision of comfortable internal environments.
capacity, manufacturing, assembly and environmental modulation a better built environment can be created. (Gharleghi et al. 2009) “In contrast to traditional engineering and design methods, in biology, adaptation to the environment and structural performance of a system are not opposing terms. They are embedded characteristics of natural systems and contribute for the formation and evolution of organisms with regards to their innate material
By exploring a new approach which integrates form generation, material behaviour and
figure 3.1 Performative soft building skin system, Adaptive Pneumatics, studio Integrate (2009)
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properties. This requires revisions of the traditionally dominant notions of the structural design, which are stiffness and efficiency.” (Gharleghi, Sadeghy 2009)
They devise a deployable skin system to be installed over an existing building which fails to adapt to its local environmental conditions. This system is composed of structural and actuated pneumatic elements so while material complexity is maintained at the minimum with the exclusive use of one material, the adaptability of the material is at its maximum, just like the way nature masterfully demonstrates how particular materials can change their characteristics in accordance to changing environmental or climatic conditions and requirements.
The research aims to utilize the building envelope in order to achieve a new system that is capable of reacting to its climatic conditions, allowing for passive environmental modulations based on changes of temperature. As a relatively early attempt to harness the potentialities of pneumatic actuation, it doesn’t quite directly refer to the field of soft robotics and its by now established methods and techniques.
At first they devised a geometrical system of “four stars-four kites” inflated components, in which at hot summer days a sensitive pressure valve incorporated in each of the components detects the turgor pressure exerted on interior membrane of the components pneumatic cells as a result of direct sunlight radiation. When this happens the valve opens up to allow the inflation of an embedded elastic membrane which in its turn triggers the rotation of the “kite” opening elements, to allow airflow through the skin system - just like the pores in a natural skin
Thus, instead of using elastomer silicones, which came to be the most common materials identified with this branch of robotics, mainly for their highly elastic properties, the designers use non-elastic plastic membranes (PVC, ETFE) which are more conventional materials in the field of pneumatic structures and more familiar to the construction industry. However, the designers still exploit the actuating properties of pneumatic structures.
figure 3.2 Membranic soft actuator prototype, Studio Integrate:,“Adaptive Pneumatics (2009)
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that react locally to cool the body down. On cold winter days, on the other hand, the skin system does not get triggered and hence remains sealed to allow exploiting the thermal insulation properties of the pneumatic cells.
While it seems that this attempt successfully incorporates some biological principles of efficiency and adaptability into an architectural practice, and does so with a viable, deployable, transportable, economically feasible solution, some questions and doubts could be raised:
At a second attempt, to even further simplify the skin system and maximize its performance, they come up with a different actuation method, and thus also a different component shape, which strongly relates to the soft robotics field and to the PneuNets actuators in particular, with their pneumatic inner network structure that allow their actuation. They devise a simpler rectangular cover, organized into smaller air cells which is attached to the inflated structure on one end, to which a smaller deflated membrane is attached, which once triggered, inflates to furl up the cover and allow air exchange, or deflates to furl the cover back down to seal it and insulate when it’s cold (Cianchetti, Licofonte 2014).
How robust is this system and material over the lifespan of a building? Is it really structurally solid enough to not collapse under an unusual environmental conditions? How well does it actually optimize the building’s thermal performance? Is it not a visual obstacle for the building’s users, with their view being blocked or distorted by the skin system? Is it possible to harness these material properties in an additional way, perhaps in order to increase visual comfort, for shading or privacy purposes?
figure 3.3 Soft actuator component, Adaptive Pneumatics, Studio Integrate (2009)
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3.2.2 CASE STUDY 2: SOFT ROBOTICS FOR ARCHITECTS One more recent interesting attempt took place in the form of a one week workshop under the name “Soft Robotics for Architects� at the ETH department of Architecture in Zurich, Switzerland (2014).
course of the workshop managed to mutually enrich each other with their by then gained knowledge in order to render the process more effective and to adjust each stage to the other. The facade design consisted of 24 triangular soft silicon actuator modules (of the PneuNet type), each one subdivided into three separately controlled triangular elements with the center portion of the module used for mounting to the hexagonal grid support structure made of a laser-cut acrylic sheet.
The proclaimed aim of this workshop was to introduce architecture students to the field of soft robotics engineering (Rossi, Nagy, Schlueter 2014). More specifically, the course was aiming to do so by developing a building facade concept that integrated soft robotics, and fabricating a demonstrative prototype. While theoretical background and introduction of the fields were limited to the first half of the first day of the workshop, the rest of the days were entirely dedicated to the development of the concept and fabrication of the facade prototype, due to the short time, gaining familiarity with the design methods and particular fabrication techniques on the go.
The actuators were arranged in such a way that each hexagonal opening in the support structure related to six triangular actuators from six different modules, allowing to completely or partially block the opening, depending on their degree of inflation. The concept is that the control over each opening related actuator, separately or in unison, could allow variation of the building facade’s opacity, hence allowing light in and views out (Rossi et al. 2014).
The final single building facade prototype was the result of a collective work of the students, divided into smaller groups each one corresponding to a different stage of the fabrication process, which eventually over the
The prototype actuation was possible with a compressed air tank, while airflow controlled using an Arduino microcontroller and valves.
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figure 3.4 Structure (red), actuator tiling (dashed black), and actuator detail (solid black) of the soft robotic building facade prototype.
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The interaction with the prototype is with a small, four buttons remote control, connected to another Arduino microcontroller with a wireless radio transceiver, able to send control signals to a radio transceiver mounted on the microcontroller used to trigger the valves, and thus allowing remote control over the airflow and the resulting actuation of the soft modules.
a facade system, with the diagrams of various arrangements of the soft actuators that suggest varying responses to environmental inputs (Figure 3.6) thus extending the possibilities of such facade to the realm of responsive architecture rather than just user controlled. Another interesting aspect of this work was the feedback on the final result from the public, which was studied and mentioned in the article about the workshop. The audience was particularly intrigued by the “body like� changes in the form of the actuators, and said it seemed strangely alive.This aspect is of an important value since this technology is rather new and unfamiliar to the public, and incorporation of it in architecture has to deal with its aesthetic input as well as its functional.
While a rather limited, manual method of control over the facade elements were imposed in the prototype, Some additional attempts to demonstrate the possibilities were taken by the students: Although the manual remote control only allowed for a unison actuation by three different sections and a fourth button to deactivate all sections, A further, more complex possibility was explored in the variation of such
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figure 3.5 Schematic overview of the prototype elements.
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figure 3.6 Diagram of varying actuation configurations.
figure 3.7 View of the final soft robotic building facade prototype.
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3.2.3 CASE STUDY 3: FURL: SOFT PNEUMATIC PAVILION Another example for a project integrating elastomer PneuNet actuators into an architectural use and scale is that of Bijing Zhang and Francois Mangion in their graduate project “Furl: Soft Pneumatic Pavilion” (2014).
almost life-like adaptation of the architectural space to the environment and users’ own very thoughts, made possible with the EEG sensing of of the human brain activities. The result of their research is a “Breathing Pavilion” (computer visualisation and small scale model), consisting of soft and hard architectural elements. The Structure is static and consists of a series of rigid frames, curving in two parts to create an interstitial outdoor space. In its turn this space is inhabited by these mega-scale silicone actuators, fixed with one end to the frames and varying in size and length along the structure, acting as a sort of a shade or a cover (Zhang, et al. 2014). These tentaclelike triangular elements could vary in shape and position depending on the level of inflation, from a vertical to a horizontal position when inflated, depending on their activation through the EEG sensor.
In their work, Zhang and Mangion attempt to create a new platform for a kinetic responsive architecture which can let space interact with users needs and adapt itself to environmental conditions. They do so combining some cutting edge technologies - they propose to use electroencephalography (EEG) as an input source, that allow the measurement and recording of electrical activity in different parts of the brain, and large silicone PneuNets actuators, which they describe as “air muscles”. They mark that the introduction of soft robotics replaces the mechanical principles in interactive architecture through a biological paradigm (Zhang, Mangion; 2014), hence allowing a wider range of deformation patterns to allow for a better, arguably
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This attempt to incorporate soft robotics into an architectural application, more than researching its possible advantages with environmental performance optimization, seems to venture into the realm of the biological experience of architecture, offered by
this new technologies, to establish an intuitive connection between the user and the space, using the architectural biomimetic elements as a viable extension of the human body. However, some doubts and difficulties arise from this project: how viable is this proposal of large scale
figure 3.8 Miniature scale prototype of the soft actuator. The gestures are programmed when the silicone casts are made, predicting how the arm would move if certain air pockets were inflated. But the actual air flow can be controlled via EEG readings. 70
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silicone actuators? taking in consideration their real life weight and size, would they be able to perform as desired and not collapse under the environmental working forces (gravity, wind, solar exposure etc.)?
as they were intended to do (provide shade or protection from precipitation)? Moreover, we can question the need or functionality of such a human brain-architecture interface, as multiple signals from different users could render the idea impossible to put to practice in real life situations, and simpler, more accurate and sensitive environmental sensors could be used to meet the comfort of the users instead.
How about the cost of casting such a one piece big scale silicon actuator? Are these elements in their current form able to sufficiently meet the environmental comfort needs of the users,
figure 3.9 Furl: Soft Pneumatic Pavilion - plan view. The robotic walls morphing according to variety of custom algorithms and the will of its occupants.
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3.2.4 CASE STUDY 4: ADAPTIVE SOLAR FACADE Another worth mentioning, still on-going attempt with integration of soft-robotics into performative adaptive architecture is the “Adaptive Solar Facade” (ASF) by the Architecture and Building Systems Professorship in the ETH university of Zurich (2015).
radiation through the window, the modules can control the light and heat of the internal space and at the same time produce electricity through highly efficient thin-film solar cell modules. The adaptive solar façade is also very lightweight, so in contrast to traditional photovoltaic panels it can be mounted almost anywhere, including on existing buildings.
Unlike former examples, this concept draws perhaps a more practical, and arguably less architecturally radical, industry-oriented line of research and development, suggesting the utilisation of soft robotic actuators as one part of a synthesized system comprised of different materials and technologies. The Adaptive Solar Facade is a dynamic facade of thin film photovoltaic modules with soft pneumatic actuators for solar tracking and daylight control. The research explored novel methods of building integrated photovoltaics within architectural systems that are energetically productive, but also respond to the desires of building occupants, thereby increasing comfort (Schlueter 2015).
By using valves controlled soft actuators it is possible to control each adaptive solar façade module individually and rotate it on two axes, either on its own or in groups. (Jayathissa, 2014) This enables the modules to track the sun’s movement and generate power, use or limit solar power, create privacy or open up the view. An intelligent and adaptive regulator allows the façade to adapt to changing weather conditions and the habits and wishes of the user. (Schlüter, 2014) Without soft actuators, such functionality would be possible only through a complex combination of several mechanical parts. These would be less durable and more heavy and expensive – making it unlikely that they would achieve widespread use in façades. In contrast,
The system consists of individual modules mounted on a cable network on a traditional façade. By adjusting the amount of solar
figure 3.10 The adaptive solar façade is assembled on the south side of the House of Natural Resources.
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figure 3.11 Modules with soft pneumatic actuators for solar tracking and daylight control.
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the soft pneumatic actuator costs only a few francs when produced industrially (Schlüter, 2014). The soft actuator has been proven to be robust in cyclic tests in the laboratory; currently, in order to prove that it is just as effective in the harsh conditions of a building façade, the group assembled a full scale working prototype façade of 50 modules on the south side of the House of Natural Resources at ETH Zurich.
unfamiliar properties, which in the case of soft robotics are quite significant and could propose entirely new aesthetics in the field. The realm of the emotion a new technology induces from the users was completely overlooked, and it seems no significant care was given to the visual experience of the facade system from the interior. Perhaps a more thorough, out of the box attempt could discard the use of various materials and components and try showcasing the soft actuator as both an actuation device and as a shading module.
This attempt seems the most promising to successfully incorporate the use of softrobotic technology into the construction industry mainstream, and offers a truly viable solution. Its promise lies in its pragmatic use of a soft pneumatic actuator to supply with a better alternative to existing rigid-mechanical actuators, and hence allowing for a less complex, cheaper and light weight multi-axial actuation, that can respond more sensitively to environmental and user comfort inputs.
Some technologies for flexible films or even coatings which have photovoltaic abilities are already known, and perhaps could allow the solar energy harnessing of elastic silicone modules. Moreover, The use of a translucent inflatable component could bring about the possibility of active shading through the use of an opacity control smoke, that is, easily changing facade opacity upon need by changing the air mixture pumped into the modules, to include an opaque gas mixture, and in such a way even further expanding the spectrum of solutions offered by the responsive facade.
However, the pragmatic use of soft robotics in this project could also be scrutinized: as often happened in the past with the introduction of new technologies into old industries, there is a tendency to conceal it, avoid to put on display its
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REFERENCES Project Adaptive pneumatic skin (2009) as accessed on May 16th 2015, http://www.studiointegrate. com/pneumatic.html Workshop - Soft Robotics (2014) as accessed on July 20th 2015, http://online.liebertpub.com/doi/ pdfplus/10.1089/soro.2014.0006: International Workshop on Soft Robotics and Morphological Computation (2013) as accessed on July 25th 2015, http://www.softrobot2013.ethz.ch/program/SoftRobot2013_Digest Soft Robotics for Architects (2013) as accessed on July 25th 2015, https://srfa2013.wordpress.com/ Furl shades project (2014) as accessed on May 7th 2015, http://www.fastcolabs.com/3037993/ furl-the-eeg-responsive-soft-robotics-future-of-architecture Quick conversation with one of the creators of Furl (2014) as accessed on May 7th 2015, http://wemake-money-not-art.com/archives/2014/11/furl.php#.Vd3gsPntmko Furl: Soft Pneumatic Pavilion (2014) as accessed on May 8th 2015, http://www.interactivearchitecture. org/lab-projects/furl-soft-pneumatic-pavilion Schlueter A (2015) Adaptive solar facade,ETH Zurich, Institute of Technology in Architecture Project “Adaptive solar facade” (2015) as accessed on June 3rd 2015, https://www.ethz.ch/en/ news-and-events/eth-news/news/2015/06/soft-robotics-for-adaptive-building-facades.html Photovoltaic flexible film and coating (2014) as accessed on June 3rd 2015, http://www. nanoflexpower.com/
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Studio Integrate (2014) Gas-Inflatable opacity, as accessed on June 8th 2015, https://youtu. be/2EB81kxKFT0. Bahramzadeh Y, Shahinpoor M (2013) A Review Of Ionic Polymeric Soft Actuators And Sensors, Soft Robotics, 1(P), 38-52. Gharleghi M, Sadeghi A (2009) Adaptive Pneus, Acadia 09: Reform, Page 111. Jeronimidis G (2004) Biodynamic Morphogentic Design Strategies, Vol 74 No3 May/June 2004, pp. 231-256 Herzog T (1977) Pneumatic Structures: A Handbook For The Architect And Engineer, Crosby Lockwood Staples. Khampanya R (2013) Softbot: The Implementation Of Evolutionary Algorithm In Silicone Gel Robots, pp. 5-21 Koyac M (2013) The Bioinspiration Design Paradigm: A Perspective For Soft Robotics, Soft Robotics, 1(P), pp. 28-37. Majidi C (2013) Soft Robotics: A Perspective – Current Trends And Prospects For The Furture, Soft Robotics, 1(P), pp. 5-11. Negroponte N (1975) Soft Architecture Machines, Cambridges, Ma: Mit Press. Pask G (1969) The Architectural Relevance Of Cybernetics, Architectural Design, 7(6), pp. 494-496. Rossi D, Nagy Z, Schlueter A (2014) Soft Robotics For Architects: Integrating Soft Robotics Education In An Architectural Context, Soft Robotics, Volume 1, Number 2 Thomphson D (1992) On Growth and Form. (J. T. Bonner, Ed.) Cambridge, Cambridge University Press, UK.
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Willmann J, Augugliaro F, Cadalbert T, D’Andrea R, Gramazio F, Kohler M (2012) Aerial Robotic Construction Towards A New Field Of Architectural Research, Int J Archit Comput, 10, pp. 439–460. Advanced Robotics (2012) Volume 26, Issue 7, 2012 (Online), as accessed on July 25th 2015, www. Tandfonline.Com/Toc/Tadr20/26/7#.UoIaDZHfZKs
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SOFT ROBOTIC ACTUATOR
The goal of this chapter is to present a method of designing and fabricating soft actuators together with their sensing and electronic control system that could facilitate the incorporation of soft actuators into building technology and responsive architectural design.
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4.1 THE SOFT ROBOTIC ACTUATOR Soft robotic actuators are critical to be studied and understood if we wish to truly integrate and harness soft robotic technology into our architectural practice. Elastomeric actuators powered pneumatically are of particular interest for soft robotics because they can be lightweight, inexpensive, easily fabricated, and able to provide non-linear motion with simple inputs (Mosadegh, 2014).
elastomeric actuator - the PneuNets bending actuator. The focus on this typology of soft actuator is out of consideration of it’s rather simple and uniform design using exclusively one or two materials, ease of fabrication by commonly available means and materials, and no requirements of extensive preliminary knowledge. However, the intent of this chapter is to provide with the general principles and guidelines to allow the production of a wide array of soft actuators to be employed in the architectural technology and design.
The following paragraphs contain explanations and instructions to support the design, modeling, fabrication and testing of a specific kind of a soft
figure 4.1 A prototype of a PneuNet actuator developed during this work
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∆P = +
∆P = 0
K1<K2 stretchy rigid
air inlet figure 4.2
figure 4.3
Section diagram of a PneuNet actuator. Expansion occurs in the thinnest structures. Soft Robotics Toolkit, 2015
Diagram illustrating the differential strain in an actuator made with materials of different elasticity properties. Soft Robotics Toolkit, 2015
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4.2 PNEUNET BENDING ACTUATOR 4.2.1 THE PNEUMATIC NETWORK A Pneu-Net is a soft actuator that consists of a pneumatic network (hence the name) of small channels in elastomeric materials that is capable of producing sophisticated motions with simple controls (Mosadegh, 2014). It was developed as a part of an ongoing trend which is drawing inspiration from nature to create a new class of robots modeled after simpler organisms that lack internal skeletons, such as worms, squids, and starfish (Harvard Magazine, 2011).
will occur at the thinnest structures (Soft Robotics Toolkit, 2015). This allows designers to pre-program the behavior of the actuator by selecting wall thicknesses that will result in a desired type of motion (Figure 4.2). In addition, It is possible to enable further control over the actuator’s behaviour with the employment and combination of different materials with different elasticity properties. If a PneuNets actuator contains layers of materials with different elastic behavior, the “stretchy” material will expand more than the “rigid” material when the actuator is pressurized. In this type of configuration, we call the more rigid material the “strain limiting layer”, as it restricts the amount of strain that can occur. The “differential strain” effect can be used to achieve useful motions such as bending and twisting (Figure 4.3).
The actuator’s motions are enabled by the inflation of the channels when a fluid is pumped into them and they are pressurized. The nature of the motion is determined by the geometry of the embedded chambers and the material properties of their walls. When a PneuNets actuator is pressurized, expansion occurs in the most compliant (least stiff) regions. For example, if the PneuNet is composed of a single, homogenous elastomer, most expansion
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Some interesting current day applications of the PneuNets actuator, helpful to demonstrate some of the capabilities of the PneuNets actuator, comprise of a soft gripper, actuated by compressed air, capable of lifting an unboiled chicken egg (Harvard University, 2011), a soft pneumatic quadruped robot capable of multiple modes of locomotion and squeezing through narrow openings (Shepherd 2011, Figure 4.4), and soft robotic fingers that can bend in just 50 milliseconds to hit keys and play a simple tune on a piano (Ceurstemont, 2014).
In this chapter I will focus, in sake of simplicity, on the methodology for the design and fabrication of a specific PneuNets bending actuator. However many of the methods used here could be easily adapted to produce other kinds of PneuNets actuators and also the part dealing with sensors and control is regarded as general and could be applied to almost any kind of pneumatic or soft actuator. This introduction served to explain the variety that such a PneuNet actuator could take, whether by employing different shapes, thicknesses and materials, and to provide with the general principles of workings of such an actuator.
These examples demonstrate some of the groundbreaking advantages of these soft actuators which enable for a more gentle maneuvering of fragile objects, deforming their shape to adapt and fit to different environments, displacing with a non-conventional, biologically inspired movements that donâ&#x20AC;&#x2122;t require wheels, joints or other moving parts, and even able of doing so with an impressing speed, and remarkable durability (Ceurstemont, 2014).
figure 4.4 soft quadruped robot that is capable of locomotion in multiple gaits. Harvard University, 2011
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4.2.2 DESIGN The PneuNet actuator I chose to describe here is a combination of varying in wall thickness elastomeric series of chambers with a strainlimiting layer embedded in the elastomer layer which consists their base. The small chambers are arranged in a row, and their walls vary in thickness in such a way that the thinnest wall sections are those which face each other, between each chamber and the next (Figure 4.5).
make use of fabrics, fiberglass or even more rigid silicone elastomers for the low strain layer in the actuatorâ&#x20AC;&#x2122;s base and lead to varied actuator behavior. The mechanism of actuation is such, that when the main body is inflated, its thinner walls are bulging out to the point of pushing against each other, and thus the chambers aspire to expand in the axial direction along the device. However, due to the inextensible layer embedded in the base, this axial expansion is limited and a bending deformation is achieved in its place. In order to fabricate this actuator the two parts are cast separately with the use of three 3D printed molds (Figures 4.7, 4.8): two of which for the main body and a simple rectangular tray
The actuator is made in two parts; the main body, a silicone elastomer structured in chambers, which expands axially when pressurized, and a thick elastomeric base in which the inextensible paper layer (strain-limiting) was embedded (Figure 4.6). Other variations of this actuator
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for the base. It is important to bear in mind the fabrication process in order to come up with a successful design for the actuator and create its 3D model in such a way to be compatible with the fabrication process. For bigger component scales, for example, a CNC milling machine could be used to fabricate the different parts of the molds.
quality detailed print (usually slower extrusion rate) in order to avoid future imperfections and difficulties in the casting process of the elastomer. Some important details to note in the design and printing phases of the molds are the correct position of the two-part main body mold over each other in order to achieve the desirable hollow chambers with thin inner walls (a rim and handles could be helpful as an addition to the mold design to allow an accurate easy fixing of the parts together, and to allow for an easy dismantle of the molds in order to safely extract the main body part, after it was casted.) Other very important detail in the bottom mold of the main body, is the thin air
Of the digital 3D model of the actuator the three-part mold should be designed digitally in such a way to be compatible with the 3D printing machine. 3D modelling programs such as SolidWorks, Rhinoceros and Sketchup could be utilized for the task and the models of the molds are to be eventually exported for printing as an â&#x20AC;&#x153;.stlâ&#x20AC;? format. While setting up the machine for printing it is suggested to allow for a high
figures 4.5-6 The inner structure of a PneuNet soft actuator, while deflated and inflated (left) and the parts and layers that constitute the PneuNet soft actuator (right), Soft Robotics Toolkit, 2015
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channel placeholder, which is going along the chambers. It is important to take care of the scale of this element so itâ&#x20AC;&#x2122;ll not be skipped or result imperfect in print. Another detail of the main body bottom mold, which serves to the phase of gluing together the two casted silicone parts, is that of the series of cavities made to form small bumps for bonding, on each strut between two chambers, on both sides along the air channel. These elements should be carefully managed as they are small and easy to be skipped upon in the printing process and they are essential to keep the air channel continuous and clear, while the body and base parts are glued together, to ensure the adequate inflation of the PneuNet chambers.
The resulting behavior of the actuator is determined by its materials and morphology. Different combination of materials and different design of the chambers will result in varied actuation. The stiffness of the selected elastomeric materials will affect how much applied pressure is required for a certain increase in volume and, in combination with the properties of the strain-limiting layer and the chambers amount, size and wall thickness, itâ&#x20AC;&#x2122;ll affect to what degree the actuator will bend. Even without applying a different material, the stiffness of different parts of the actuator could be adjusted by varying its shape - as more material results in greater stiffness (e.g. a thicker wall is stiffer than a thinner wall of the same material).
figures 4.7-8 The main body of the PneuNet actuator is cast in a two-part mold, while the base of the actuator is a simple rectangular plate (left) and the 3d printed mold parts on the printerâ&#x20AC;&#x2122;s print bed (right)
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A general rule of thumb to be followed in the design and material selection of the actuator is that while more elastic actuators are less capable to apply as much as force and move slower than their stiff counterparts, they are less resources-hungry and could be operate at greatly lower pressures.
this actuator. The following Modeling section is presenting useful tools to help with the task of predicting the behavior of the actuator. These tools could be used alternately during the design phase, in order to check our hypothesis about the design and optimise its function to our needs.
When dealing with elastic materials it is difficult to accurately predict the effects of our design decisions due to their nonlinear behavior, especially when given the complex shape of
figure 4.9, 4.10 A 3d mesh volume before (up) and after (down) inflation simulation in Kangaroo for Grasshopper.
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4.2.3 MODELING When approaching the task of designing a soft actuator, It is useful to have an understanding of how the design decisions we take, the materials, morphology and geometry of our actuator, are affecting the behaviour of the device once inflated. In this section I will introduce some general, more accessible tools for architects to simulate the behaviour of inflated elements using the programs Rhinoceros and Grasshopper, and a less accessible for architects, yet much more accurate tool to model and analyse the physical behaviour of a design through the Finite Element Method (FEM), using the Abaqus software, which is more recommended in the design of PneuNet actuators. However it is advised to bear in mind that similar other software and solutions might be useful for the task, even if not mentioned in this paper.
not accurate by any standard and still lacks some important features in order to be successfully replacing the need to refabricate and retest the actuator in order to optimize the design (such as the ability to assign the properties of physically accurate materials to the geometry, for instance), It is useful to mention it, first as it is done using tools and software which are familiar to users coming from the field of architecture and as such itâ&#x20AC;&#x2122;ll usually pop up as a natural selection for the simulation, and second because it currently allows getting some easy and basic sense about the relationship between geometry and behaviour and it could be used to simulate the principle of inflation and soft actuation. I will present what in my search, and by the time this paper was written, I found to be the current state of ability of this method, with hope that this introduction might push forward the abilities of simulating accurately inflatables and soft actuators with these common tools.
4.2.3.1 Rhinoceros + Grasshopper + Kangaroo Although the following method, using Rhinoceros 3D modelling program and its parametric plug- in Grasshopper together with its physical simulation extension Kangaroo, is
As this software is not adapted to the simulation of complex elastomeric actuators but rather a much more simplified 3D volumes
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with no thickness, in sake of simplicity of this overview, I will deal with the latter.
definition acting on a triangle) as the 3 different point of the generic triangular face on which the pressure force is to act upon. Then, the fourth property of the pressure level is defined by a numerical slider and a “PressureLevel” component and fed to its corresponding inlet in the pressure component.
Starting with a 3D volume enclosed by a triangulated mesh (Figure 4.9), the mesh is then imported to Grasshopper (Figure 4.11) where it is decomposed in vertices afterwhich to be connected between themselves in order to create a 3d network of lines that will outline the 3d volume. All the resulting curves are being fed as a “connections” to a “Springs” component in which they are attributed a length in rest, stiffness factor and a damping constant. This will define the resistance of the membrane-like material to the inner pressure force of inflation which we will now apply.
Now, we set up the Kangaroo physics engine component: both the springs and pressure components are fed to the flattened “Force objects” inlet, the original mesh is fed to the geometry inlet, a toggle is fed to the “SimulationReset” inlet and a timer for the interval in which we desire the physics engine to work is fed to the bottom of the “KangarooPhysics” component. Placing another mesh component in the “GeometryOut” outlet allows for the preview of the inflated mesh (Figure 4.10). Then in order to start the simulation the toggle must be switched on.
The same decomposed vertices of the mesh, assorted in 3 groups according to their relative position on the triangular mesh face, are being fed to a “Pressure” force component (by
figure 4.11 The Grasshopper definition for the inflation simulation of a 3d closed mesh using Kangaroo.
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This method allows for a general yet far from accurate understanding of how geometry behaves and deforms when in pressure. In some examples it could be used to get a rough prediction of a soft actuator’s behavior, like suggested in the series of simulations by Berend Raaphorst (Raaphorst, 2014).
paragraphs will briefly describe how to perform FEM analysis of the discussed PneuNet actuator using the Abaqus software suite. Starting with the 3D digital model of the actuator, it is recommended to simplify its geometry and omit some unnecessary features for the simulation, such as the bonding ridges and bumps, in order to speed up the process and save valuable computational resources.
Due to its limited abilities, this method is not adapted for simulation of more complex structured elastomeric actuators of the PneuNet type. Other, more precise simulators should be sought.
Once simplified, the geometry is ready to be exported from the 3D modeling program as a “.STEP” file (in our case 3 different files, one for main body, and two other for elastomer layers at the bottom, Bottom Layer A and B). Import the parts as “solids” into Abaqus, right-clicking the “Parts” menu under “Model-1”. The “Parts” menu should now display the 3 imported parts of your model.
4.2.3.2 FEM (Abaqus CAE) The second and more important approach to accurately predict the behavior of the soft actuator is the Finite Element Method (FEM). This method requires a software which is not commonly used by architects and is more complex to handle, yet it offers a great deal of physical accuracy, and could come in as significantly handy in the design process of a soft actuator, expectantly sparing the need to refabricate and retest actual prototypes in order to optimize the design. The following
Since in our case we deployed two different materials in our design, the silicone elastomer and an inextensible layer of paper, we should now model a 4th part to represent the embedded paper. In order to do that we will simply duplicate the upper surface of the most bottom silicon layer: under “Bottom Layer B”
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enter “Surfaces” and create a new surface for the paper selecting the top rectangular surface of the layer.
Under the sections menu create sections for the created materials according to their morphology in your model: Elastosil as a homogenous solid and the paper sheet as a homogenous shell with a 0.1 mm thickness (in our case). Finally we will assign the different material sections to the corresponding parts of our model: under the tree of each model part, using “Section Assignments”, select the part’s geometry (region) and assign the proper material section (e.g. “Main Body” - Elastosil section).
Next we will create the materials to be used and then assign them to the appropriate parts of the model. In the model tree select “Materials” and create a new material. In our case we have Paper (Density= 750 Kg/m3 , Elastic: Young’s Modulus= 6.5 GPa, Poisson’s ratio= 0.2) and “Elastosil” elastomer (Density=1130 Kg/m3, Hyperelastic: Strain energy potential= Yeoh; coefficients: C10= 0.11, C20= 0.02, Isotropic). Create in this way all materials and assign their physical properties.
figure 4.12 The assembled and merged model of the actuator.
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In order to assemble the different parts into their correct configuration in the actuator, the parts should now be positioned correctly relative to one another (this could be done using the face-to-face tool while fixing one element each time). Finally, select all parts and merge them together using the “Merge Instances” tool. Choosing the “Retain” option in the pop-up window will keep the intersecting boundaries inside the model. A new part in the model tree for the merged parts will appear (Figure 4.12).
under “Bottom Layer B” (using the display group manager tool) and select it to create the skin. Then, under “Section Assignments” for the merged part, assign the paper section by selecting the isolated top surface and choosing the paper section (Figure 4.13). The next step is to create the physical loads for the simulation to consider. Other than the inflation pressure load we must not forget real-world loads, such as gravity, if we wish the result to be realistic. First we must define which model surfaces will receive what load. We must select all the faces of the inner cavity of the actuator that will be subjected to inflation (chambers and air channel) in order to apply the
In order to finalize the creation of the inextensible paper layer, we must go under this new “Merged” part and create a new “Skin”. Isolate the surface created beforehand
figure 4.13 The inextensible paper layer (red).
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pressure load. This could be done by creating a new surface under the merged part menu and selecting all inner cavity faces using the “View Cut Manager” tool to cross section the actuator with the Y plane, then reverse the view to add to the selection the other faces of the cavity (Figure 4.14). A new surface of the inner cavity should be created under the “Merged” part.
the pressure value to be applied to the cavity (in our case 0.055 MPa). Now we proceed to define the important physical interaction that causes our geometry to actuate. When a PneuNet actuator is inflated it starts to extend in a furling movement, partially due to its special structure in which the adjacent chamber walls come into contact with each other when under sufficient pressure. Abaqus needs to be informed of the significance of this interaction in our simulation, in order for it not to overlook it and leave the walls to simply intersect with each other, producing a poorly realistic modeled result (Figure 4.15).
Now, under “Steps” in the model tree we create the acting forces. Create the first step which is the gravity acting upon our actuator (step’s properties: “Static, General” procedure type, Nlgeom on). Under the gravity step created, create a new “Gravity” load with the value -9810 on the Y axis (Component 2). Finally define the fixed end of the actuator by creating a new boundary condition (BCs) under the Gravity step. Select the option “Symmetry/ Antisymmetry/Encastre” and then click on the face of the model that is going to be fixed and select “Encastre”.
In order to define this interaction we proceed to create a new “Contact” interaction property, using “Interaction Properties” under the model tree, then add a mechanical, tangential behavior to the interaction and render it frictionless. Next we define the location and way in which our contact interaction will apply: under “Interaction” in the model tree create a new standard selfcontact interaction to apply during the pressure step (the step in which the actuator is inflated and the chamber walls touch). Finally select all faces that will be in contact, that is the facing chamber walls.
Next we create the pressure load step with “Static, General” procedure type again. This time however, we create a pressure type load under the pressure step. We assign the load to the internal cavity by selecting the predefined inner cavity surface (using the “Surfaces” button on the bottom right). Finally we define
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figure 4.14 Selecting all surfaces of the inner cavity (red) using the view cut manager.
figure 4.15 Adding contact interaction to adjacent chamber walls will avoid this poorly realistic result of walls passing through one another. Soft Robotics Toolkit 2015
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The next step is meshing. When we finally finished to set up our model for simulation, we must mesh its geometry according to our available computing resources: a detailed mesh will produce more accurate results however it will consume more computing capacities and time. In order to do so we open the “Mesh” option under the merged part in the model tree. Using the “Mesh Controls” tool we then select all parts of the model and define a tetrahedral (Tet) element shape for the mesh. Using the “Seed” tool define the size of the mesh and then mesh the part.
In order to finally run the simulation we must create a new job under the “Jobs” section in the model tree, then submit the job (Right-click on job - Submit). Once completed, it is possible to view the results and perform analysis (Rightclick on job - Results). In order to observe the different simulation stages of the actuator under the applied loads, use the “Plot Deformed Shape” tool, using the navigation arrows to view the actuation steps. Other useful tools to mention are “Plot Contours on both shapes” that allows to superimpose the initial and final states of actuation, as well as to color-code the mesh by stress (Using “Contour Options” to adjust the color-coding scale to be visible on the hyperelastic parts of the model, Figure 4.17).
Since we are dealing with a hyperelastic material that could stretch, a hybrid element type for the mesh is required. This could be done using “Element Type” option under the “Mesh” menu in the toolbar. Select the 3 elastomeric parts (paper layer not included) and tick the “Hybrid Formulation” option (ensure geometric order is quadratic). Now do the same for the inextensible paper layer by isolating it (using Display Group Manager), and defining its element type (quadratic geometric order). Now the model is properly meshed and ready for the simulation (Figure 4.16).
To conclude we can observe how the FEM approach using the powerful Abaqus software could provide with an accurate physical simulation that could allow for a rapid and easy optimization of design by effortlessly adjusting material, morphological and geometrical parameters and in such way may constitute a significant tool in the design process of soft robotic actuators.
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figure 4.16 The meshed model. A detailed mesh will produce more accurate results.
figure 4.17 Simulated initial and final state of actuation, with stress color-coding
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4.2.4 FABRICATION The fabrication process of a soft actuator strongly varies with its material selection. Generally, when dealing with mostly elastomeric actuators, such as in the case of the discussed PneuNets actuator, the fabrication process tends to be similar and is greatly revolving around the preparation of the molds and casting of the elastomers. In the this process a great deal of care should be given to the quality of molds as any change of detail will produce a different result in the casted elastomer, as well as to the assembly phase of the different casts, so important delicate details, such as the air channel, will not get blocked with the gluing material, a mistake that could render the entire actuator unfunctional. With the notion that other fabrication processes may exist and especially should be looked into when dealing with different materials other than elastomers, in the following section I will focus solely on the fabrication steps required for the production of a PneuNets bending actuator type (Figure 4.18).
within. This separation to parts is only true for the molding phase of the fabrication as following to this stage the parts will proceed to be assembled together to form the final unified actuator. In this way the two parts are molded separately, pouring the liquid elastomer into the prefabricated molds, and then glued together with the same elastomer material. In the method presented here, the molds are 3D printed from a digital 3D model file in 3 separate parts (Figure 4.19), two of which are then assembled to form the main bodyâ&#x20AC;&#x2122;s mold and the third is a simple rectangular plate and is used to cast the bottom part of the actuator. When printing the mold parts in the 3D printer it is recommended to set up a high quality settings for the print so it will not skip any important detail that will then not show correctly on the casted elastomeric part. In FDM plastic extrusion printers, which is the method recommended for the printing of these molds, this usually means slower filament extrusion rate with longer overall printing time, and it is strongly advised to use the recommended extrusion head temperature for the type of filament in order to get optimal results. Some other important notes about the
As mentioned before, the PneuNets soft actuator is a synthesis of two parts: a main elastomeric body consisting of a network of air chambers, and an elastomeric rectangular base with an inextensible paper layer embedded
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The elastomer mix is cast into the molds. The main body mold is filled completely, while the bottom mold is filled to its half, and then placed with a paper layer on top.
Both parts are cured, and the main body is demolded.
Bottom mold is filled to the top with new elastomer.
The main body of the actuator is merged into the uncured elastomer layer on the bottom mold.
The merged parts are left to cure.
The final actuator is extracted from the bottom mold.
Tubing is inserted to connect the actuator to air source. figure 4.18 The PneuNet actuator fabrication overview.
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figure 4.19 The 3 separate 3d printed molds.
figure 4.20 The assembled molds.
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preparation of the 3D printed molds could be found in the previously discussed â&#x20AC;&#x153;Designâ&#x20AC;? section of this chapter.
and cast, so a certain amount of care to this matter is advised. In our case, the material in use is Elastosil and the mixing ratio is 1:9 in order to achieve a hardness of 28 Shore A (e.g.for 80g of material we need 8g of curing agent over 72g of silicone rubber).
Once the 3D printed molds are ready and assembled (Figure 4.20), we can start prepare the elastomer to be molded. Usually elastomer silicone rubbers come in a twopart configuration, where the gel in the bigger container (usually colorless) is the silicone rubber base substance and the liquid in the smaller container is the curing agent and is typically the one to contain the color pigment, if exists.
We measure the substances using mixing cups with the appropriate measure scale and we mix them in a third container. Although the mixing process could be done manually, for better results it is recommended to use a professional centrifugal mixer if it happens to be under your reach. The same applies to the other steps of the fabrication process that could be perfected using some more dedicated tools such as a mass scale for measurements of the substances for mixing, a vacuum chamber for the thorough removal of bubbles trapped in the casted silicone and a professional lab oven to help speed up the curing process of the cast. All of these tools are not exclusively necessary for the fabrication of the actuator, that could be also done manually, however they contribute for an easier faster work with a reduced risk for unwanted results.
In order to prepare the silicone to be casted and cured the two parts must be mixed. The mixing ratio between the two substances is usually few percent of curing agent for every portion of silicone rubber gel. It is highly recommended to follow the manufacturerâ&#x20AC;&#x2122;s instructions about the ratio as it depends on the type of silicone chosen and may vary from one brand to another and according to desired hardness of the resulting silicone cast (measured in Shore A scale). It is generally useful to know that a bigger percentage of curing agent will produce a higher hardness in the outcome and will tend to cure faster, which might render the material difficult to manage
Next, we pour the mixture into the molds. In the main body mold make sure all chambers are filled and that any excess elastomer is removed
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figure 4.21 The elastomer casted into the molds.
figure 4.22 The strain-limiting paper layer is placed over the silicone.
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from the top of the mold, especially from the plastic ridges that divide each chamber from another, which should be visible and clear from excess material to ensure the proper separation between the chambers (Figure 4.21).
base silicone layer (Figure 4.22) and we leave the molds to cure in room temperature (usually over several hours, according to manufacturer’s instructions, or rather the process could be speeded up to several minutes using a preheated lab oven at about 65°C). After the molds have finished curing, ensure the level of elastomer in the main body mold did not critically drop (more than 2mm in this design, due to leaking). If it did, pour some more of the mixture to make sure the chambers roof is not too thin, and allow it to cure.
As a first step, the base mold should be filled only partially with the elastomer mixture, only up to about a half of its depth, in order to create the bottom silicon layer on which the paper layer will later be placed. After making sure the elastomer is spread evenly over the bottom of the mold we proceed to the removal of air bubbles that are trapped in the elastomer (this could be done using a vacuum chamber to bring the bubbles up to the surface and then manually popping the bubbles with a spatula).
The next step is where we remove the main body from its mold and we assemble it with the bottom part for final curing. When trying to extract the cured elastomer from the mold try to slowly disconnect the two parts of the main body mold from each other and from the silicone cast. It could be useful to use some pointed tools for the task, but it is important to make sure it is not piercing through the component’s structure or causing any other harm.
This step is recommended, although not crucial, because eventual trapped air bubbles may cure in this form and create “air bridges” in the component through which the air can escape when inflated (as well as to damage the component’s aesthetic appearance). However this scenario is not probable to occur and mostly popping up manually the visible bubbles on the surface should provide with a satisfactory result.
Try to not break the mold as it could be useful for another future casting. If the mold ended up slightly deformed, it could be easily returned to its original shape by heating it up a bit to soften it and then placing it under some flat surface
Next we place the strain limiting paper layer (precut to fit the base mold) over the casted
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with a weight. Once main body is extracted from its mold (Figure 4.23), proceed to gluing it together with the bottom part. While still in its mold, pour some extra mixture material on the bottom mold to fill it up, then spread it out to obtain an approximated flat surface. While still uncured, place the main body directly on top and slightly press its rim to submerge it inside the material (Figure 4.24). This is important in order to ensure a satisfactory adhesion to avoid any possible air leakage, however it is also important not to submerge the main body too deep in such a way that will block the air channel in its bottom (this is also the reason for the bonding bumps discussed in the design section). Leave it to cure for some minutes in the oven or several hours in room temperature.
air source. This is done by piercing carefully one end chamber of the actuator and inserting a narrow plastic tubing within it, that will facilitate the air provision into the actuatorâ&#x20AC;&#x2122;s internal cavity (In our case a plastic pneumatic tubing of about 3mm in outer diameter was used). The piercing could be done using a thin metal rod and should be done in an angle and such extent that itâ&#x20AC;&#x2122;ll pierce through the center of the chambers outer wall and will lead towards the bottom of the inner cavity chamber, where the air channel starts.Extra care should be given not to accidently pierce through the other side of the component, through the other chamber walls or through the bottom layer- It is immensely important that no hole would be formed in the bottom layers as this could allow air to penetrate and separate between the silicone and paper layers during inflation and will render the actuator unfunctional.
After the mold has finished to cure we could finally proceed to remove the complete actuator body from the bottom mold (Figure 4.25). Check closely to ensure no defect such as holes or bubbles is there that could become a weak spot in the actuator- If necessary cover these with some extra elastomer mixture.
After successfully piercing to create the air supply hole, insert the tubing, possibly over a thin metal rod to reinforce it while pushing it through and securing its position inside. When done, remove the metal rod, and connect the tubing to a air source such as a syringe or an air
Finally, to complete the actuator and prepare it for inflation, it is necessary to connect it to an
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figure 4.23 Main actuator body extracted from its mold.
figure 4.24 Main actuator body submerged in the bottom part.
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pump. The actuator could be finally inflated for the first time and inspected for defects and air leakages.
or rather thereâ&#x20AC;&#x2122;s an air leakage, in which case you could try to track the source of leakage by inspecting the component or placing it under water inside a clear container. If found an air bridge, it is possible to patch the location with some of the mixture material, let it cure and test the actuator again.
If the actuator does not correctly inflate and bend, it is possible that the main air channel was blocked during the assembling phase of the two parts, In which case thereâ&#x20AC;&#x2122;s nothing to do,
figure 4.25 The complete actuator demolded from the bottom mold.
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4.2.5 TESTING Performing different kinds of tests on your actuator is useful in order to characterize its behavior and to guide you through the optimization process of its design. These tests may also be helpful to validate the results of your modeling and simulation phase and check for eventual discrepancies.
The force delivery capability (Pelygerinos et al. 2013) is another test designed to measure the force capacity of the actuator. Again, the actuator is rigidly fixed on one end, while the actuator is being gradually pressurized in 1 psi increments. The tip of the actuator is as a result pressing a prefixed 6-axis force/torque sensor on a short rod in which it was brought into contact. The force exerted by the actuatorâ&#x20AC;&#x2122;s tip is then recorded and compared to the FEM simulation data (Figure 4.28).
A series of possible empirical tests that could be employed into testing the behavior of PneuNets actuators exists in the literature. The bending curvature estimation test (Polygerinos et al. 2013) is a test where the actuator is in one end rigidly fixed then inflated in order to track the trajectory of its tip. The actuator is pressurized and depressurized three times in front of a HD video camera, using a checkerboard pattern in the background to align the camera and a small ruler next to the actuator for pixel-to-length conversion. Then, post processing using a video analysis software (Kinovea) it is possible to obtain a series of x and y coordinates, translating into the trajectory of the actuatorâ&#x20AC;&#x2122;s tip. The results could then be compared to the FEM simulated trajectory to check for inconsistencies (Figures 4.26, 4.27)
Another useful test to be mentioned is the actuator morphology to pressure requirements correlation test (Mosadegh et al. 2013). Essentially, this test investigates the effect of varying actuator morphology on the pressure required to achieve full bending. This is done by pressuring one-end-fixed variety of actuators that differ only by their morphology, but not in length and materials. Only parameters such as pneumatic chambers number, wall thickness, and chamber height is varied in each actuator in order to then record the pressure required to fully bend the actuator and compare it with that recorded for the other variations (Figure 4.29). This is a useful test to understand the effect of different morphology parameters on
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the pressure, or the eventual energy, required to operate the actuator. A similar test could be employed to test the effect of other parameters, such as material variation, and help to optimize the soft actuator’s design.
for evaluation purposes 07 as a platform to carry out the tests (which together with other electronic control board configurations will be further described in the subsequent “Sensors and Electronic Control” section), however they could also be done manually using an air pump or a syringe, with the correct set up.
All of the above examples make use of the “Soft Robotics Toolkit” control board, modified
-200
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43 kPa
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figure 4.26, 4.27 The bending curvature estimation test and its results compared in a FEM / experimental data graph, Polygerinos et. al, 2013
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-200 1.4 1.2 Force (Newtons)
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FEM DATA Experimental Data
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figure 4.28 The force delivery capability test results compared to a FEM in a graph, Polygerinos et. al, 2013
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0 2 4 5 8 10 12 Height of Chambers (mm)
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Pressure (KPa)
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0 5 10 Number of Chambers
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figure 4.29 The Effect of Actuator Morphology on Pressure Requirements test, variation comparison, Mosadegh et. al, 2013
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4.3 SENSORS AND ELECTRONIC CONTROL In the process of prototyping soft actuators, and especially when culminating to the point of setting up the designed soft robotic system, a platform is needed that can be used to operate and control fluidic soft actuators, such as the PneuNets Bending Actuator, in a non-manual way.
platform, generally contains all the elements needed to control fluid-operated soft robots and as such could be customized to fit any specific purpose and design (Figure 4.30). It’s main components include: an electric pump (to pressure fluid through the system), a set of valves (to control flux of fluid in the system), pressure sensors to allow tracking of the system’s behaviour, and finally, a set of switches or an Arduino microcontroller, to manually or automatically control the board. The controlled timing of the valves is used to regulate the pressure in the system using a Pulse-Width Modulation (PWM) (Soft Robotics Toolkit, 2015).
Some self devised solutions are possible using different components available on the market, however it is helpful to look into some easier open-source solutions offered online, such as the Fluidic Control Board developed by Harvard University, and based over it, the Paradox Robotics Fluidic Control Board Kit, which offers an all-in-one set with all necessary components (Soft Robotics Toolkit, 2015).
When testing several physical parameters of a prototype, or when sensibility is required for acquiring a responsive soft robotic system, It could be useful to incorporate a variety of sensors to the control board. Sensor components could be purchased from
The Harvard university Soft Robotics Fluidic Control Board, on which I’ll focus here for it is an easily accessible open-source hardware
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independent sources however some built-in sensors could be used, that are already adapted to the microcontroller in use, as in the example of Arduino and its accessory components. Some example of the sensor variety that could be incorporated in the fluidic control board are EGlan sensors, which allow to record strain, TakkTile sensors to detect physical contact
with the elastomeric component in which they could be embedded, Stretchsense sensors can measure either stretch, bend, shear, or pressure in soft structures, and finally many other sensors could be incorporated to use in an array of applications, such as photodetectors, temperature, humidity and motion sensors (Mengßç et al. 2013)
figure 4.30 The components of the Soft Robotics Fluidic Control Board , Soft Robotics Toolkit, Harvard University, 2015
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REFERENCES “Soft” Robots: The Starfish Variation (2011) Harvard Magazine, as accessed on September 20th 2015 http://harvardmagazine.com/2011/12/soft-robots-starfish-variation Mosadegh B, Polygerinos P, Keplinger C, Wennstedt S, Shepherd R, Gupta U, Shim J, Bertoldi K, Walsh C, Whitesides G (2016) Pneumatic Networks for Soft Robotics that Actuate Rapidly, Advanced Functional Materials, Volume 24, Issue 15, pp. 2163-2170. Soft Robotics Toolkit (2015) Harvard University, as accessed on September 20th 2015, http:// softroboticstoolkit.com/home Polygerinos P, et al. (2013) Towards a soft pneumatic glove for hand rehabilitation, Intelligent Robots and Systems (IROS), IEEE/RSJ International Conference, pp. 1512–1517. Menguc Y, et al. (2013) Soft Wearable Motion Sensing Suit for Lower Limb Biomechanics Measurements, in IEEE Int. Conf. on Robotics and Automation, Karlsruhe, Germany. Multigait soft robot undulating under a glass obstacle (2011) Shepherd R, 2011, as accessed on September 3rd 2015, https://www.youtube.com/watch?v=QpnLj-rzjIo Soft Robotic Gripper Based on PneuNets (2011) Whitesides Group, Harvard University, as accessed on September 15th 2015, https://www.youtube.com/watch?v=csFR52Z3T0I Rubbery robot fingers play piano faster than a human (2014) Article by Ceurstemont S, New Scientist journl, as accessed on September 15th 2015, https://www.newscientist.com/article/ dn24874-rubbery-robot-fingers-play-piano-faster-than-a-human/ Raaphorst B (2014) Inflation Simulations, as accessed on September 10th 2015 https://www. youtube.com/watch?v=tsndIJAZ-n4
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Drawing on the lessons of last chapters, this chapterâ&#x20AC;&#x2122;s goal is to put into practical test the overviewed knowledge in an original architectural design hypothesis; a meteo-responsive temporary study shelter. The experimental proposal outlines a soft-robotic envelope system that could allow it to transform radically from an open to enclosed and thermally insulated space, and thus to improve climatic and energetic performance and comfort. With the support of drawings and schemes, the study capsule design process is layed out, together with its speculative realization procedure and implications, with a particular focus on its soft robotic components and control system. Finally, a miniature prototype of the component is fabricated as a proof of concept.
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5.1 DESIGN BRIEF GENERAL FRAMEWORK, REQUIREMENTS AND SPECIFICATIONS
Before approaching the design itself It is fundamental to define its goals and requirements, to ensure we achieve a desired outcome. Since the requirement to implement soft robotic technology in the design was preliminary stated, the design process is by its nature a bottom-up strategy, which focuses firstly on the developent of the soft component, and only then developes an overall design to complement it. With this in mind, in the following section was prepared to help explain the chosen case study for the implementation of the technology.
The existing situation in many public university campuses, and specifically in Politecnico di Milano campus Leonardo, is that of insufficient free study spaces. Even though some efforts were put by the university in past years to supply with additional, temporary study spaces, these efforts most often fail to meet their goal, especially due to the fact these spaces are usually located in outdoor areas of the campus, and without proper measures are not able to provide with adequate comfortable study conditions, particulary in summer and winter (Figure 5.2).
figure 5.1 Focus on the deformation of a miniature scale model of the soft component under pressure.
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figure 5.2 Example of an existing outdoor study space in Politecnico di Milanoâ&#x20AC;&#x2122;s Campus Leonardo. The structure is unable to provide with comfortable study conditions.
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In the following table (Figure 5.3) I set out the goals, requirements and specifications for the design of a new outdoor, temporary study space, that could intentionally offer better conditions and greater comfort for students. Key Features to be Considered
Commentary
Function • Where? The structure is to be located in the outdoor free spaces of university campuses. • What? To provide a comfortable, temporary study or work space, supplementary or independently to indoor spaces.
The structure should be generally designed to be placed at any flat outdoor space, without the need for a proper foundation or preparation of the site. It should not be permanent and as such should be relatively easy to assemble, disassemble and transport.
Performance • How? The shelter is to provide a proper cover, illumination and study equipment (desks, chairs, electrical plugs) that are necessary for studying. Moreover, climatic comfort should be provided using an active climatization device together with a cover that responsively provide with several configurations adapted to various weather conditions (meteo-responsive) and lets natural light in during daytime,
The responsive envelope system should incorporate soft-robotic technology, to allow flexibility of configurations with a relatively simple skin system, to facilitiate assembly procedures on site. The envelope is to function without human intervention, making use of a set of sensors and a custom-made algorithem for optimal climatic and energetic performance.
Purpose Market • Who? The structure is to be used by students that seek for a study/work space, individually or in a small group. It is to be employed by universities, schools or independent educational entities that urgently need adittional study spaces.
It is not however intended to be used as a lecture hall or any sort of frontal teaching. It could also be employed by companies or organizations that require urgent temporary office space.
figure 5.3 Design Brief Analysis
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Key Features to be Considered
Commentary
Quantity • How many users? A single structure unit should provide enough space for 15 people, a standard 1.8 m2 for each student (overall standard of 27m2). • How many units? The number of units in which the structure is to be produced could vary from a single couple to several dozens per campus.
The modular use of this study capsule allows flexibility to locate it in big or small outdoor spaces. One unit by itself will doubtly provide the required amount of study spaces (in campuses), however the position of a series of units could meet the demand.
Quality • Comfort. The study space should be optimized to study comfort, with the adequate acoustic, thermal, and light conditions. Privacy from external distractions is also advised.
For the case of acoustic comfort, all eventual machinary should be properly located or insulated to avoid any annoyances in the space. Bright daylight should be allowed in during the day and proper artificial lighting at night. The skin envelope should provide adequate thermal insulation and protection from the elements when needed.
• Efficiency. Advantage comfortable natural conditions to the maximum, and reduce artificial solutions to the minimum required. The kinetic systems employed should act independently from human control and sensitively to the climatic conditions (responsive).
Another aspect of comfort and efficiency is the requirement for an open space, that is with no obstacles that could pose as annoyances , and with relative flexibility of the interior’s arrangement for various functions other than study, and that might require a continous interactions with the outside (e.g. events, info point, etc.).
• Transportability. The proposed solution, due to its temporary urgent nature, should be easy and quick to fabricate, assemble and disassemble, light-weight, simple with minimal parts, • Cost. As a temporary solution, it is required that costs for the realization of these study spaces be kept to minimum without significantly degrading the quality. figure 5.3 Design Brief Analysis
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5.2 DESIGN PROCESS 5.2.1 CONCEPT The concept for the design of the meteo-responsive study capsule and itâ&#x20AC;&#x2122;s soft-robotic envelope are described in the following scheme (Figure 5.4).
Independent meteoresponsive study capsule for 15 people. Required ability to transform from an openair to closed insulated space A dome, ideal volume per surface area ratio - minimal heat transfer with the exterior. Wind aerodynamic
Rosebud - a natural kinetic enclosure system with identical actuating components. transforms from a fully enclosed to a fully open space, without substructures figure 5.4 Design Process
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Upside down rosebud two planar cuts
Octagonal dome composed of 8 identical actuator sides. Minimal operational 3m central height, standard 28 sqm study area for 15 students
Unroll actuator side surface
Extrude surface for silicone elastomer thickness. Added internal pneumatic network cavity (PneuNet) for actuation under air pressure
figure 5.4 Design Process
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Double sided PneuNet structure with an intermediate connective layer. Allows for a bidirectional actuation for opening and closing.
Actuator component layers assembly. Left-over solid area on narrow side for component fixation to support structure
Run FEM simulation for the component to perfect parameters such as PneuNet configuration, layer thicknesses and required pressure load, while simulating inflation under gravitational conditions
When arranged in a system, the skin actuator components allow to fully enclose the study space and adapt to climatic conditions to provide maximal comfort. Inflation allows for the actuation of the skin system to take place while providing additional thermal insulation
figure 5.4 Design Process
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5.2.2 COMPONENT TO SYSTEM As desribesd in the previous section, the general form and scale of the soft-robotic component that was devised as part of this design proposal was inferred from the overall morphology of the envelope, which consists of identical 8 faces of a dome-like configuration with an octagonal section (Figure 5.4).
compactness and ease of fabrication). A possible solution for these issues are other typologies of PneuNets actuators, that were designed specifically to create a series flat, compact soft robots that could easily manipulate and squeeze through narrow spaces (see figure 4.3, chapter 4).
Inspiring from the biological kinetic aperture example of the rosebud, this component is required of two kind of motions: furl up and down; from an open to fully encolsed space.
These compact, flat versions of actuators have the same mechanism of work, through the pressurizing of a series of adjacent internal chambers, however they embed all chambers in a flat configuration entirely inside the outlines of their slender bodies; instead of having the chambers projecting up from the main air channel, they keep the same thickness as the channel and spread sideways from it (Shepherd et al. 2011).
In order to achieve this sort of motion we look into an existing solution in soft robotics, the PneuNets actuator, previously introduced in this work. As described earlier, the PneuNets allows for a variety of curling motions, alternating by tweaking the configuration of the embedded pneumatic network.
Nevertheless, unlike the PneuNet actuator typology described in chapter 4, this kind of actuators usually does not make use of a strain limiting layer to achieve its furling deformation, but of variation in elastomer thickness instead, with a thicker layer of silicone on the inner side (Figure 5.6).
However, in the specific case of this building skin component, some specifications have to be met; The component has to have the ability to curl in both oppsite directions, as well as to be morphologically simple, thin and with a flat smooth surface (for reasons of maintenance,
figure 5.5 Focus on the internal structure of a miniature scale model of the soft component.
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figure 5.6 Sections of flat PneuNet actuatorsâ&#x20AC;&#x2122; chamber, with actuation due to material thickness variation.
figure 5.7 Section example of a double-sided flat PneuNet actuator, when deflated and when each side is pressurized.
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This previously desribed properties of the compact PneuNet typology answer the need for a flat component with a smooth surface for the component design, but not the need for an opposite, double-sided curling actuation.
a flat, compact, bidirectional actuator, with the binding layer, together with the thickness of the deflated PneuNet on the opposite side, acting as a strain-limiting layer, to create a furling motion (Figure 5.7).
In order to answer that last specification we could look into a compound version of the compact PneuNet actuator. When attaching two embedded pneumatic networks in an opposite configuration, back to back, we receive
Applying these principles on our skin component surface will result in a wing-like flat membrane that is able to adjust up or down, thus responsively controlling the enclosure of the space (Figure 5.8).
mirrored PneuNet layer
elastomeric binding layer
embedded pneumatic cavity
figure 5.8 Exploded axonometry of the soft-robotic componentâ&#x20AC;&#x2122;s layers.
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figure 5.9 FEM modeling and strain analysis for a scale model of the soft component in full and sectioned view (right).
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Once identified the right typologies of soft actuators to implement in our responsive envelope design and modeling the component in a 3d software, we can proceed to the physical simulations in FEM analysis software (as desribed previously in chapter 4).
After we have finalized the design of our softcomponent, we can move our attention to a bigger scale, to the meteo-responsive skin system. As previously stated in the brief, there is a requiremnet for a skin system that responsively provides with several configurations adapted to various weather conditions (meteo-responsive). Now that we obtained our soft component design we can implement it back on the surface of the exagonal sectioned dome to get a view of the different possible adaptive configurations of the envelope (Figure 5.10).
With the simulations results we could predict how our design will react to different pressure input and under gravitational load; which deformation will it develop and what motion trajectory (Figure 5.9). This is helpful in order to then tweak some design parameters and optimize the results.
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Fully enclosed space activated in the cases of heavy precipitation or uncomfortable climatic conditions (percieved too hot or cold).
Open covered space activated in the cases of thermally comfortable conditions, however light precipitation or excessive solar radiation.
Fully open space activated in the case of a thermally comfortable clear day.
Entrance door is activated using a proximity sensor, and Customized space is possible in the case of special events or needs, with an interactive or manual interface.
figure 5.10 Some of the main different configurations of the meteo-responsive skin system.
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5.2.3 UNIT DESIGN Once completed the design of the meteoresponsive envelope system and its possible configurations, we proceed to the design of the rest of the study capsule: the structure (including the support system for the envelope), the fittings and the finshing. The following schemes and diagrams are
aimed to explain the structure design evolution, considering different aspects of performance and costs, and the technical plan, sections and details of the final design. Finally some possible location and general layout for the study units is proposed for Politecnico di Milano campus Leonardo.
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figure 5.11 Different alternatives explored for the structure design; with a central support plan (1), lateral support for an open flexible space (2), a flat pack economical solution (3) and the final design (4)
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TOTAL AREA: 31,29 sq. m
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figure 5.12
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figure 5.13
AC UNIT AC - inlet, outlet AC UNIT actuators, open configuration Silicone
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figure 5.14 Section B-Bâ&#x20AC;&#x2122; - closed and open configuration
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B
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AC UNIT AC - inlet, outlet Silicone actuators, closed configuration
Wooden deck flooring Studying circular table for 15 people + 0,000
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Studying circular table for 15 people + 0,000
Ecoflex Silicone actuator
Section B-B'
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figure 5.15
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Elevations; front, back and lateral
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Top ceiling cap contains climate sensors and HVAC fan exhaust Ecoflex Silicone soft-robotic envelope fixed to ceiling, actuated by air pump in support base and regulated by microcontroller and climate sensors
Soft-Robotic pneumatic skin system
HVAC system
envelope component fixing frame, connected with tubing to solenoide valves set Air-pump & microcontroller
Steel support structure Modular fiberglass tables Support base Accessible sound-proof fiberglass box; Contains air pump and microcontroller. underfloor air pump inlet
Bottom ceiling cap contains artificial lighting and HVAC air circulation opening Wooden deck flooring Thermally insulated Support fiberglass shell Covering steel structure. Contains all air tubing and electrical fittings Concrete slab base
figure 5.16 Exploded axonometry of the structure, soft-robotic envelope and technological systems
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Design Specifications • Weight and size of component 3.5 m × 1m ×2m × 10 cm ~100 kg • Required air pressure per wing 0.2-0.3 MPa • Materials Ecoflex silicone envelope, steel structure with hollow fiberglass finishing and a wood deck • Envelope sound absorption Indicated by the Ecoflex Gel properties; Attenuation: α(dB/MHz cm ) = 1250.0 0.547 f ^1.278 Speed of Sound: v s ( m/s)= 1250.0 • Thermal Insulation Ecoflex Thermal conductivity 0.16 Wm^-1K^ -1 • Est. manufacturing & assembly time 3-4 weeks prefabrication 1 week assembly • Total cost estimate ~15,000 € (of which ~60% for the silicone)
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TOP CAP
BOTTOM CAP
figure 5.17 Detail 1: exploded axonometry of the actuator to structure fixing detail
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mm fiberglass galvanizedsheet steel sheet 1010mm
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AC AC outlet - condenser fan outlet
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cavity for lighting AC - air circulation opening
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figure 5.18 Detail 1: Section detail of the skin component to structure fixing and technological systems
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figure 5.19 Proposed location and layout for a meteoresponsive study capsul in campus Leonardo.
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figure 5.20 Proposed location for study capsule, campus Leonardo open green space.
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5.3 FABRICATION HYPOTHESIS This section deals with the speculative proposal for the real-life fabrication of the soft-robotic skin component discussed in previous sections.
The following scheme (Figure 5.24) suggests a possible workflow for the fabrication of the discussed component.
Unlike small-scale soft actuators, whom had their manufacturing process explained in detail in chapter 4, the case for large scale actuators is rather different and requires the deployment of different technologies, especially for what regards with the fabrication of the molds.
figures 5.21-23 Perspective exterior views of the meteoresponsive study capsule in an open (5.21) and closed (5.22) configurations, and an Interior, closed configuratoin (5.23)
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Prepare nesting file with all the molds parts for the CNC cutting machine
Cut all parts for molds using a CNC plastic or metal cutting machine
Assemble all molds parts with specific caution to avoid eventul leaks of elastomer through unsealed slits in the casting phase
figure 5.24 Soft componentâ&#x20AC;&#x2122;s fabrication hypothesis scheme
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Cast premixed two parts of silicone elastomer into the molds
Leave elastomer to fully cure
Assemble two casted PneuNet layers together with the intermediate binding layer in two stages (each side seperately) using a thin layer of uncured elastomer. Caution not to block the air channels is advised
Once fully cured, the soft actuator is now almost ready.
figure 5.24 Soft componentâ&#x20AC;&#x2122;s fabrication hypothesis scheme
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A metalic cap, made to fit the fixing end of the silicone actuator, is to be attached to the component using elastomer to metal binder. The purpose of the cap is to allow dry fixation to the structure while spreading the loads on a wider area of the elastomer
Insert tubing into the end of each PneuNet layer
On site, mount the soft component into the support by dry fixing its cap into the designated frame. Insert the tubings to their corresponding valves openings.
After setting up all systems, the supportâ&#x20AC;&#x2122;s top cover could be sealed.
figure 5.24 Soft componentâ&#x20AC;&#x2122;s fabrication hypothesis scheme
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5.4 PROTOTYPE While experimenting with the design of soft-robotic system, it is useful to create physical prototypes to test your designs and compare with simulations for any discrepancies. In the case of the discussed design for the meteoresponsive skin system, it should be sought to fabricate some 1:1 scale prototypes to help optimize the design, correct any unforeseen failures, and better understand which is the right fabrication procedure for the design. figure 5.25 Fabricating the molds with a Delta 3d printer
However, due to the limited scope of this work, I will display in the following section the fabrication and setting up of a miniature scale component, based on the design of the meteo-responsive skin, to hold as a proof of concept for the design and the possibilities described during this thesis. The following images and captions desribe this process (Figures 5.25-33).
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figures 5.26-27 Once the 3d printed molds are ready (5.23), prepare the silicone for casting by mixing parts A and B (5.24)
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figure 5.28-29 Pour the silicone mixture into the molds (5.25), demold parts when fully cured (5.26)
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figure 5.30-31 Glue the cured PneuNet layer with the binding layer using some uncured silicone (5.27), do for both sides to get the final actuator (5.28)
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figure 5.32-33 Set up the fluidic control board with a sensor, microcontroller and an air pump and insert tubing to actuator (5.29) activate the system (5.30)
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REFERENCES Shepherd R, Ilievski F, Choi F, Morin S, Stokes A, Mazzeo A, Chen X, Wang M, Whitesides G (2011) Multigait Soft Robot, Proc. Natl. Acad. Sci. U.S.A., vol. 108, no. 51, pp. 20400â&#x20AC;&#x201C;20403.
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6.1 WORK SUMMARY This work provided an overview of important definitions, methods and tools necessary to the implementation of soft robotics into built environments, culminating in the application of the covered knowledge in the form of a proposal for an original component of a softrobotic skin system, to harvest the advantages offered by the innovative technology.
of inflatable structures, the functional aim of responsive architecture, and the bio-inspired technological principles of soft robotics. Chapter 3 was presenting and discussing some contemporary cutting-edge works that incorporate soft-robotic elements into the architectural design, in the aim of defining a more detailed domain of the new “Soft Architecture”, Questioning each case study’s prospective and suggesting possible weak points and improvements.
In the first introductory chapter, the fusion of these two areas, soft robotics and architecture, was motivated taking on the ongoing evolution of architectural form and practice by the incorporation of new innovative technologies and materials.
This chapter widened the perspective to a variety of different materials (ETFE, PVC, Silicone rubber), typologies and morphologies of application, ranging from a visible extensive use of the technology (Studio Integrate), to a hidden specific implementation as part of a greater design (ETH Zurich). It is apparent that all proposals settle in the interactive-responsive realm, for the obvious abilities of the technology, and especially all attempt in one way or another to improve the building’s energy and climatic performance. Chapter 4 provided a detailed overview of the designated workflow for soft architecture,
Chapter 2 was a collection of fundamental definitions and brief overview of relevant fields towards a new definition of soft-robotics in architecture- “Soft Architecture”. Some preliminary fields such as inflatable architecture, kineticism and responsivity, together with a deeper introduction to the topic of soft robotics - were converged to draw a framework of the form soft-robotic architecture could take. It is emerging as an approximation of all the fields reviewed; taking the forms and transience
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explaining the working principles in the design of a soft PneuNet actuator, comparing the simulation and design tools alternatives (Of which the FEM software proved more adequate for its accuracy, in comparison with the more architect-familiar Grasshopper+Kangaroo) and demonstrating the process of fabrication of such an elastomeric actuator, which involves a precise mold design, to be fabricated using an additive or milling manufacturing.
from a preliminary knowledge in physics, material properties, informatics and electronics. Chapter 5 goal is to apply and examine studied knowledge in an original architectural proposal hypothesis, a meteo-responsive temporary study shelter, composed in a shape of a dome with a responsive skin system of 8 soft-robotic wings that allow it to transform radically from an open to enclosed and thermally insulated morphology. Accompanied by drawings and schemes explaining its design, proposed fabrication and functioning configurations, it allowed to demonstrate how this technology could be implemented into answering a persistent quotidian need for a climatically comfortable, energy efficient supplementary study space, together with an estimation of its real-life realization implications.
Furthermore, the chapter explained the technological solutions that could manage and amplify the function of such a component: a microcontroller (such as Arduino), system of valves, a variety of sensors depending on the function and other accessories required in order to carry out the responsive capabilities of this technology that could be implemented in an architectural application. This design and manufacturing process proves to be benefiting
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6.2 CRITICISM To name some crucial aspects that were brought up to attention during the work, that could help us assess the compatibility of softrobotics in an architectural application, we could look into some of the following issues.
facilitate both the design, manufacturing, assembly and maintenance of such responsive systems. A greater durability is also suggested over traditional systems, as silicone elastomers or polymeric membranes are waterproof, and not as affected by the elements (humidity, temperature, precipitation) and donâ&#x20AC;&#x2122;t suffer as much from corrosion and decay, and so together with their thermal insulation properties (especially in elastomeric and pneumatic actuators) are optimized to be directly involved in building skin systems. Another property of soft systems is that they could generally be considered as more user-friendly, as they are composed of relatively light weight, soft materials which constitute less user hazard.
In this research are introduced the many new possibilities which could be offered by soft robotics; by the use of non-conventional elastic materials to create soft actuators architects and designers could realize kinetic and responsive systems which emulate biological structures and mechanism and offer visible advantages over traditional â&#x20AC;&#x153;hard roboticâ&#x20AC;? systems. The technology offers high adaptability for responsive and interactive related applications, namely for its inherent robotic flexibility, offering a great variety of actuations, deformations and motions, to propose a multi-scenario solution.
As to the pneumatic typologies of soft actuators, especially of the membranous morphology, possible integration and enhancement of existing inflatable designs are an imminent application. Soft actuators, for their simplicity and materials, generally offer lower costs than existing rigid jointed robotic systems, especially
Some of these suggested advantages, reviewed in this work include greater motility of the kinetic component, an inherent characteristic of soft-robotics, which also offers lesser complexity with a mostly uniform onepart actuator (unlike multi-part rigid jointed mechanisms), a feature that could drastically
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in the case of membranous actuators or small scale elastomeric components (e.g. arranged in modular systems). Moreover, these typologies of soft actuators offer greater, more facilitated transportability, for their light weight and greater compactness over rigid systems (especially in the case of membranous systems, that just like common inflatable structures could be significantly reduced in volume when deflated and folded).
for engineers) and as such its user interface is not very adapted to users coming from these fields; It not compatible with the interface of architectural commonly used software, and could not be directly plugged into any of the common use modeling software. Another major drawback of the tools currently existing for designing and fabricating soft systems is that Preliminary knowledge is strongly required in order to optimize and render efficient the design process. Such knowledge could possibly eliminate the need for recursive prototyping using the trial-anderror method, for example, the FEM software could be used more efficiently and accurately to produce more realistic simulations, and so could reduce eventual time and costs required for the process.
Another arguable advantage of soft robotic technology is its often resulting unordinary, organic-like aesthetics. In architecture and other design-related applications, this could mean a new aesthetic vocabulary, that could be used to identify projects with some specific traits, social-economic group or a philosophy, as often happens with the introduction of new aesthetics.
Preliminary knowledge is significantly useful in order to devise and fully understand the functioning of the the soft actuator (knowledge in material properties, fluid dynamics and hyperelastic solid mechanics) and its control system (robotics, electronics, informatics), for example in order to set up efficiently the fluidic control board, with all its electronic components and to code a designated software for its function. From the design experience recounted
On the contrary, some major shortcomings of the technology in its current state could be drawn from the work as well. In the design process of the PneuNet soft robotic actuator, the main tool for simulating the actuation of the component under pressure and gravity was the â&#x20AC;&#x153;Abaqusâ&#x20AC;? software which is a FEM analysis tool. This tool was not intended to be used mainly by architects and designers (but rather more
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in this work, some significant difficulties were encountered when discrepancies between FEM simulation and prototypes came up. This is very plausible due to the difficulty to achieve physical accuracy in simulation results using currently existing tools, for example, when setting up pressure load in Abaqus, the pressure is set to load evenly on all inner cavity surfaces even though in real-life prototype it is larger on the airsource inlet point, at the end of the tubing. This inaccuracy resulted in an unforeseen bulge in the pressurized prototype and a drastically different deformation trajectory of the component.
Costs could also be a point for improvement as most of the pavilionâ&#x20AC;&#x2122;s costs estimation is made up solely of the cost of the silicone elastomer itself. The soft elastomeric component, although more durable on some aspects (as mentioned earlier in this chapter), might also be less durable on some others, for example, it is plausible to suppose that the pressurized silicone actuator would be sensitive to sharp objects and could even constitute a hazard of explosion. As for the fabrication of such bigger scale elastomeric actuator components, we could point out the possible difficulty that could be encountered when setting out to fabricate the molds required for the casting of the component, especially when dealing with more morphologically complex actuator designmaybe CNC machines could not be sufficient for the task, and other technologies should be sought after.
Other noteworthy issues, that came up during the design experiment, are those having to do with the properties of the soft componentâ&#x20AC;&#x2122;s material itself or of its fabrication process. For example acoustic properties of the elastomer are not optimized for the use (study) and acoustic performance could be improved. Also, due to the preliminary requirement to be a temporary shelter, the transportability of the skin components could be improved, for instance by changing to a lighter-weight material or using a design with smaller component scale.
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figure 6.1 Origami soft actuators, with compact length when deflated. Martinez et al. 2012
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6.3 SUGGESTIONS AND POTENTIALITIES Drawing on the emerging conclusions throughout the work, as described in the last section, some possible implications and suggestions are proposed in the following paragraphs for further future investigation.
Additionally, some tools for the design and simulation of folding patterns could be investigated to be employed in the future design of soft systems (for example in the research of Martinez et al. 2012, Figure 6.1), to achieve maximal compact deflated volume when folded (in the case of membranous actuators), with specific focus on the unfolding of the geometry and allocation of seams (e.g. Mantis add-one for Grasshopper).
Design and Fabrication Tools As for the tools available for designing and fabricating soft robotic components, the task of designing such components could be significantly facilitated by the development of a more dedicated tool for designers and architects, especially when dealing with FEM analysis software, that will eliminate the need for extensive preliminary knowledge, could provide for a more accurate and realistic results, and preferably has integrated interface to architecture programs commonly in use (for example, a plug-in for Grasshopper).
When dealing with fabrication of large-scale elastomeric soft components, It could be useful to further investigate the tools alternatives to facilitate the molds fabrication, especially for more complex morphologies of actuators, maybe by using big-scale additive or milling machines (e.g. Kuka robotic arm 3d printer).
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Other properties of the component such as transportability and lightness could be improved as well, possibly by using different, lighter materials, a different component scale, or even changing the actuator’s typology (e.g. to membranous).
Materials and Performance Some material properties of elastomeric soft actuators could be improved in order to optimize them for an architectural use. For example, the acoustic performance of a soft skin system enclosing an interior space could be improved by an embedded texture in the molding phase, layering or introduction of sound absorbing materials on the component or in the space (such as the “Scale” acoustic component, Figure 6.2) .
Costs, Variety and Availability Costs of fabrication and assembly are a major issue if we aspire to apply new technologies into a widespread architectural use. The cost of actuators of the elastomeric type could be
figure 6.2 “Scale”- sound absorbing modular wall, Layer 2015
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reduced, specifically in bigger scale components (which usually require more material, which in the case of silicone could get quite expensive), by the employment of cheaper materials or typologies (e.g. PVC membrane is cheaper than silicone and its typology requires less material).
Customization and Complementary Technology Due to its nature as a new field of robotics, soft robotics have yet to enjoy an extensive body of research or broad experimental portfolio. The handful existing works on the subject mainly applied the technology in the realm of climatic and energy performance, however other designated areas of architectural application that could make good use of the particularities of this technology are yet to be fully identified or experimented with.
Possibly in the future, a variety of soft robotic actuator typologies and scales could be commercially manufactured and readily available, which could help for an instant application in architecture, just like ready-made rigid components are widely available today. this could shorten the design process and save time and money.
Identifying target architectural fields and specific problems that could benefit from soft robotic technology, more than existing solutions, could widen its application range and possibly result in many new architectural typologies. For instance, some possible application of soft robotics could be used in fairs and entertainment, temporary and disaster relief shelters, military structures,
As for the control systems of such soft components, affordable, open-source parts already in use today could democratize responsiveness, for instance, the possibilities in use of Arduino microcontroller platform (with its relatively easy-to-use interface), cheap sensors, valves and more.
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floating structures (air and water), and even could benefit commercial prominence, due to its unconventional aesthetics and attention drawing motility.
solid structures); for example, rapid variation in typologies and function (typology on demand), or an extension of existing functionality. In the case of instantly changing typologies, it could be useful to examine the possibility for the load bearing capacity of such soft-robotic building elements,for example, to create a retractable balcony, or an entire building floor or section.
It is interesting to investigate the possibility to develop a series of customized soft actuator typologies that could be used in more and more specific architectural implementations. Some other, specific architectural applications that could be investigated are: building systems for instant protection against injury (in hospitals, kindergartens, elderly residences etc.), room partitions, interactive passageways and transformable walls and furniture for maximal usage of spaces, rapidly maneuvering circulation flow elements (e.g. queue lines), transformable architecture (enhancing the kinetic and responsive possibilities and functionality of pneumatic and conventional
Finally, some supplementary technologies, that were already introduced to soft robotics, could potentially also offer extended functionalities for soft-actuators in architecture, such as 3d printed embedded electronic circuits and sensors (Muth et al. 2014), and microfluidic principles for soft sensing, color or opacity change of a soft component (e.g. for shade or privacy) and even to camouflage the structure, make it glow, or change its temperature (Morin et al. 2012, Figure 6.3).
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figure 6.3 Luminescent soft robotic quadruped. Harvard University, 2014.
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REFERENCES Martinez R, Fish C, Chen X, Whitesides G (2012) Elastomeric Origami: Programmable PaperElastomer Composites as Pneumatic Actuators, Advanced Functional Materials, Volume 22, Issue 7 April 10, 2012, pp. 1376–1384. Pedretti M, Pedretti A, Steingruber P, Luchsinger R (2004) First applications of Tensairity Muth J, Vogt D, Truby R, Menguc Y, Kolesky D (2014) Embedded 3D Printing of Strain Sensors within Highly Stretchable Elastomers, Advanced Materials, Volume 26, Issue 36, September 24, 2014, pp. 6307–6312 Morin S, Shepherd R, Kwok S, Stokes A, Nemiroski A, Whitesides G (2012) Camouflage and Display for Soft Machines, Science, vol. 337, no. 6096, pp. 828–832.
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CHAPTER.07
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This work is an attempt to explore whether soft-robotic technology could be practically applied into architecture.
aptness of actuator typology to desired function, the unoptimized material properties and difficulty in fabrication of complex, larger scale components are all obstacles in the way of the designer, which are still waiting to be resolved.
As unfolded in this thesis, soft robotics offers some promising applications in architecture and responsiveness. The advantages it holds over traditional rigid robotic systems includes its relative simplicity, flexibility, mobility, safety, and lower costs.
Additional future research and experimentations could hopefully bridge these gaps and allow for a broader, more facilitated implementation of the technology in our built environments. With further ventures into this underexplored realm, an established soft robotic framework for architects and designers could be set up and enable to fully harvest the advantages of this exciting technology into unconventional and everyday design solutions.
However, some difficulties still prevent it from thoroughly being integrated into the building industry. The insufficient accuracy and compatibility of existing design tools and necessary multidisciplinary knowledge, the insufficient
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CHAPTER 1 Figure 1.1 Soft-robotic actuator produced by FUNL Maker Club Course on Soft Robotics (The University of Nebraska–Lincoln) Figure 1.2 Soft-Robotic prototype, developed during the work Figure 1.3 Thesis outline scheme CHAPTER 2 Figure 2.1 Scheme - areas of knowledge and their intersection Figure 2.2 Diagram: air-inflated (A) vs. air-supported (B) Figure 2.3 Kengo Kuma “Tea Haus” , Museums für Angewandte Kunst Frankfurt, 2005 Figure 2.4 Jersey Devils,; Inflatables Figure 2.5 Ant Farm; Clean Air Pod Figure 2.6 Michael Rakowitz, paraSITE inflatable shelter Figure 2.7 Aeromads - a movable environment by Alexis Rochas
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Figure 2.8 Burke Brise Soleil at the Milwaukee Art Museum, Santiago Calatrava, 2001 Figure 2.9 Lake Shore Drive Bridge, a double-leaf bascule bridge constructed in Chicago 1937 Figure 2.10 the kinetic facade at the Institut du Monde Arabe in Paris, Jean Nouvel, 1987 Figure 2.11 The Al Bahar Towers dynamic external screen, opens and closes in response to the movement of the sun, Aedas, Abu Dhabi, 2012 Figure 2.12 Recompose, an interactive system for manipulation of an actuated surface, MIT Media Lab, 2011 Figure 2.13 Aegis Hyposurface, a faceted metallic surface that deforms as a real time response to electronic stimuli from the environment, dECOi, 2001 Figure 2.14 A diagram showing the essential elements of any electronic interactive system Figure 2.15 KUKA robotic arms spot welding in the automotive industry Figure 2.16 A PneuNet gripper by Cambridge Soft Robotics, 2014 Figure 2.17 Cross-section of common approaches to actuation of soft-robot bodies in resting (left) and actuated (right) states. Nature, 2015 Figure 2.18 A three-layer strain and pressure sensor 3d-printed in a stretched elastomer, Harvard University, 2014
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Figure 2.19 A microfluidic color-changing soft robot, S. Morin, Harvard University 2012 Figure 2.20 A soft robotic arm, proposed as a part of a future humanoid caregiver. Siddharth Sanan, CMUâ&#x20AC;&#x2122;s soft robotics lab, 2014 CHAPTER 3 Figure 3.1 Performative soft building skin system, Adaptive Pneumatics, studio Integrate (2009) Figure 3.2 Membranic soft actuator prototype, Studio Integrate:,â&#x20AC;&#x153;Adaptive Pneumatics (2009) Figure 3.3 Soft actuator component, Adaptive Pneumatics, Studio Integrate (2009) Figure 3.4 Structure (red), actuator tiling (dashed black), and actuator detail (solid black) of the soft robotic building facade prototype. Figure 3.5 Schematic overview of the prototype elements. Figure 3.6 Diagram of varying actuation configurations. Figure 3.7 View of the final soft robotic building facade prototype. Figure 3.8 Miniature scale prototype of the soft actuator. The gestures are programmed when the silicone casts are made, predicting how the arm would move if certain air pockets were inflated. But the actual air flow can be controlled via EEG readings.
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Figure 3.9 Furl: Soft Pneumatic Pavilion - plan view. The robotic walls morphing according to variety of custom algorithms and the will of its occupants. Figure 3.10 The adaptive solar façade is assembled on the south side of the House of Natural Resources. Figure 3.11 Modules with soft pneumatic actuators for solar tracking and daylight control. CHAPTER 4 Figure 4.1 A prototype of a PneuNet actuator developed during this work Figure 4.2 Section diagram of a PneuNet actuator. Expansion occurs in the thinnest structures. Soft Robotics Toolkit, 2015 Figure 4.3 Diagram illustrating the differential strain in an actuator made with materials of different elasticity properties. Soft Robotics Toolkit, 2015 Figure 4.4 soft quadruped robot that is capable of locomotion in multiple gaits. Harvard University, 2011 Figure 4.5 The inner structure of a PneuNet soft actuator, while deflated and inflated (left) Figure 4.6 The parts and layers that constitute the PneuNet soft actuator (right), Soft Robotics Toolkit, 2015 Figure 4.7-8 The main body of the PneuNet actuator is cast in a two-part mold, while the base of the actuator is a simple rectangular plate (left) and the 3d printed mold parts on the printerâ&#x20AC;&#x2122;s print bed (right) Figure 4.9-10 A 3d mesh volume before (up) and after (down) inflation simulation in Kangaroo for Grasshopper.
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Figure 4.11 The Grasshopper definition for the inflation simulation of a 3d closed mesh using Kangaroo. Figure 4.12 The assembled and merged model of the actuator. Figure 4.13 The inextensible paper layer (red). Figure 4.14 Selecting all surfaces of the inner cavity (red) using the view cut manager. Figure 4.15 Adding contact interaction to adjacent chamber walls will avoid this poorly realistic result of walls passing through one another. Soft Robotics Toolkit 2015 Figure 4.16 The meshed model. A detailed mesh will produce more accurate results. Figure 4.17 Selecting all surfaces of the inner cavity (red) using the view cut manager. Figure 4.18 The PneuNet actuator fabrication overview. Figure 4.19 The 3 separate 3d printed molds. Figure 4.20 The assembled molds. Figure 4.21 The elastomer casted into the molds. Figure 4.22 The strain-limiting paper layer is placed over the silicone. Figure 4.23 Main actuator body extracted from its mold.
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Figure 4.24 Main actuator body submerged in the bottom part. Figure 4.25 The complete actuator demolded from the bottom mold. Figure 4.26-27 The bending curvature estimation test and its results compared in a FEM / experimental data graph, Polygerinos et. al, 2013 Figure 4.28 The force delivery capability test results compared to a FEM in a graph, Polygerinos et. al, 2013 Figure 4.29 The Effect of Actuator Morphology on Pressure Requirements test, variation comparison, Mosadegh et. al, 2013 Figure 4.30 The components of the Soft Robotics Fluidic Control Board , Soft Robotics Toolkit, Harvard University, 2015 CHAPTER 5 Figure 5.1 Focus on the deformation of a miniature scale model of the soft component under pressure. Figure 5.2 Example of an existing outdoor study space in Politecnico di Milanoâ&#x20AC;&#x2122;s Campus Leonardo. The structure is unable to provide with comfortable study conditions. Figure 5.3 Design Brief Analysis Figure 5.4 Design Process Figure 5.5 Focus on the internal structure of a miniature scale model of the soft component.
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Figure 5.6 Sections of flat PneuNet actuators’ chamber, with actuation due to material thickness variation or the incorporation of more rigid elastomers. Figure 5.7 Section example of a double-sided flat PneuNet actuator, when deflated and when each side is pressurized. Figure 5.8 Exploded axonometry of the soft-robotic component’s layers. Figure 5.9 FEM modeling and strain analysis for a scale model of the soft component in full and sectioned view (right). Figure 5.10 Some of the main different configurations of the meteo-responsive skin system. Figure 5.11 Different alternatives explored for the structure design; with a central support plan (1), lateral support for an open flexible space (2), a flat pack economical solution (3) and the final design (4) Figure 5.12 Plan - closed and open configuration Figure 5.13 Section A-A’ - closed and open configuration Figure 5.14 Section B-B’ - closed and open configuration Figure 5.15 Elevations; front, back and lateral Figure 5.16 Exploded axonometry of the structure, sodt-robotic envelope and technological systems
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Figure 5.17 Exploded axonometry of the actuator to structure fixing detail Figure 5.18 Section detail of the skin component to structure fixing and technological systems Figure 5.19 Proposed location and layout for a meteoresponsive study capsul in campus Leonardo. Figure 5.20 Proposed location for study capsule, campus Leonardo open green space. Figure 5.21-23 Perspective exterior views of the meteoresponsive study capsule in an open (5.21) and closed (5.23) configurations, and an Interior, closed configuratoin (5.22) Figure 5.24 Soft componentâ&#x20AC;&#x2122;s fabrication hypothesis scheme Figure 5.25 Fabricating the molds with a Delta 3d printer Figure 5.26-27 Once the 3d printed molds are ready (5.23), prepare the silicone for casting by mixing parts A and B (5.24) Figure 5.28-29 Pour the silicone mixture into the molds (5.25), demold parts when fully cured (5.26) Figure 5.30-31 Glue the cured PneuNet layer with the binding layer using some uncured silicone (5.27), do for both sides to get the final actuator (5.28) Figure 5.32-33 Set up the fluidic control board with a sensor, microcontroller and an air pump and insert tubing to actuator (5.29) activate the system (5.30)
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CHAPTER 6 Figure 6.1 Origami soft actuators, with compact length when deflated. Martinez et al. 2012 Figure 6.2 â&#x20AC;&#x153;Scaleâ&#x20AC;?- sound absorbing modular wall, Layer 2015 Figure 6.3 Luminescent soft robotic quadruped. Harvard University, 2014.
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ACKNOWLEDGEMENT
Firstly, I would like to thank my supervisors at ACTLAB, who opened this opportunity to me and inspired me to explore and experiment with innovative technologies and creative ideas. Special thanks to Prof. Ingrid Paoletti for the time and the helpful guidance during the last critical period of this work., I couldnâ&#x20AC;&#x2122;t be more grateful. To all fellow ACTLABers, friends from school, who are always willing to help or just chat To Chris for the valuable support, and to Rani for the good company in times of dispair A mia famiglia Italiana, al B&B, per essersi presi cura di me da quando ero in Italia To my dear friends Elpi, Gabriella and to Martin, for always being right besides me, in best and worst, I simply could not do it without you. And finally, to my family, To my relatives, that turn a place into a home To my three charming nieces To my grandparents, who I only hope to make proud To my beloved siblings Matan, Liron, Shachar and Ortal To my Father, whoâ&#x20AC;&#x2122;s an infinite source of tranquility and wisdom And last but never least to my eternal inspiration my mother, Yael Tugendhaft Albag this work is merely a continuation of your life-long invincible spirit, aspirations and achievements and so it is dedicated in your loving memory
Ofir
