Tom Vandebroek
Mechatronics Engineering Portfolio December 2022
Technology enthousiast with a PhD in Mechanical Engineering,
I want to participate in building the next era in medical care.
My core interests lie within innovation and cutting-edge technologies. Working on a new product fuels me with tremen dous excitement and motivation.
I specialised in medical robotics because it couples developing challenging products and improving people’s lives.
I believe my strengths to be my high-drive, self-criticism and my ability to conduct a project from idea to production, working either individually or within a team.
My formation provided me with a high range of skills, a deep analytical mind and methods allowing to start a project on the right foot, avoiding many early mistakes and conduct it through its end.
2 Introduction
3 Table of Content 4 GiftSurg Design and development of a novel robotic platform for single-port access fetal surgery. 10 PreSlice Design and development of a steerable, Da Vinci Xi compatible CO2-laser fibre add-on for Transoral Robotic Surgery. 14 Axo-Suit Developing and prototyping of a novel compact and lightweight shoulder mechanism for an assistive exoskeleton. 20 Leg’s Go Design and development of a running knee prosthesis more efficient and cheaper than marketed prosthesis. 26 BioDrop Bio-inspired solution to passively reduce humidity in basements or bathrooms.
4 GiftSurg Multi-arm robot for Single Port Access Surgery • Context: PhD • Duration: Jan 2017 - Jun 2022 (5.5 years) • Design team size: 1 member
GiftSurg - Multi-arm robot for Single Port Acccss Surgery
Problem definition
Open spina bifida (OSB) is one of the most common birth defects. OSB is due to an incomplete closing of the neural tube and often results in severe motor and neurodevelopmental impairment. Fetal surgery has shown promising results compared to the established post-natal surgery. However, open fetal surgery is associated with a high risk of complications. To reduce these risks, minimally-invasive procedures are investigated. These procedures are however extremely challenging to perform and still have high rates of complications due to the multiple incisions fragilising the uterine wall.
Project objective
Gynecologists studied the uterus membranes properties and concluded that operating through a single small incision of 12mm or less would strongly reduce these complications rates. This contribution to the GiftSurg project aims to develop such small diameter multi-arm robot to perform OSB repair.
Design Challenges
:
5
PhD - KUL
COMPACTNESS MINIATURISATION DYNAMIC ACTUATION COMPLEXITY
GiftSurg - Multi-arm robot for Single Port Acccss Surgery
DESIGN & DEVELOPMENT
1. Investigation of surgical requirements - A set of design requirements were established by attending surgeries, discussing with surgeons, investigating the litterature and experimentally measuring critical metrics such as the required suturing forces.
2. Surgical platform design - Comparing many backbone and actuation principles suitable for miniature surgical robots, a macro-micro approach was selected. This approach combines a stable macro triangulation platform based on concentric tube robots and a micro highly flexible distal bending segment; actuated by an embedded dynamic miniature fluidic muscle.
3. Robotic drive development
6 Jan 2017 - Jun 2022
V2 V4 V6
Hybrid gripper/needle-driver design - Instrumentation for continuum robots is challenging due to miniaturisation, as well as the fact that any force applied on the instrument will affect the robot’s pose. The designed gripper requires a low input force thanks to the 3-bar mecha nism and can secure a needle thanks a 3-points contact form closing at the base of the jaws.
(a) Hybrid gripper/needle-driver showing the cross-section plane (green). (b) Cross-sectional view of the three-point contact for needle locking (0.4mm OD needle). (c) Same with a 0.8mm OD needle.
Gripper
prototyping - Each design iteration was first 3D printed in plastic before being 3D printed in stainless steel. The small parts dimensions were flirting with the limits of the machine so acid etching was necessary to bring the parts dimensions back down to nominal.
7 Initialdesign Optimiseddesign PhD - KUL
& OPTIMISATION
GiftSurg - Multi-arm robot for Single Port Acccss Surgery INSTRUMENTATION MODELLING
(b) (c) (a) y x g = gap L = beam length p = pattern spacing c = cut depth a = beam width h = rigid section height lR = rigid length top section lm1 lm2 s1 s2 s3 s4 OD2 OD1 α2 lc2 lc1 α1 y0,1 x0,1 y1,1 x1,1 y1,2 x1,2 ξ
Θ1 Θ2 h1 h2 h3 y0,2 x0,2 y x Θ3
(xT,yT) Section2 y0,3 x0,3 y1,3 x1,3 x0,j y0,j Section j T To μdN dN β a) b) T > To Rf,j Tj cable o 0,j 3,j o0,j 2,j o0,j3,j+1 β f N Tj+1 o 0,j 4,j
l3 θ1 θ2 γ y x l4 J1
J3
Kinematic model - Two different models are necessary for this robot. First, a piece-wise constant curvature can be used for the triangulation platform. Second, a large deformation model of the bending segment taking into account gripping actuationt was derived. Optimisation of laser-cut flexure stiffness - An anisotropic flexure pattern is optimised in order to have both a wide bending range in a direction using the limited input force of a miniature McKibben muscle and a sufficient stiffness to apply suturing forces in the other direction.
Fgrip (xA,yA)
Fv,2 Fh,2
Optimisation parameters Fm Fg F0,1x F2,0x F2,0y F1,2x F2,1x F2,1y F1,2y B C A M1,2 M2,0 y x l1 l2
J2
(a) (b)
V5
V1 V2
8 PROTOTYPING & CONTROL VALIDATION 0 0.5 1 1.5 2 2.5 3 3.5 4 Pressure [bar] 60 80 100 120 140 160 180 Angle [deg] 0.5Hz 1Hz 2Hz 3Hz 4Hz 5Hz BENDING SEGMENT BENDING MUSCLE GRIPPING MUSCLE MARKER BENDING LOADCELL GRIPPER GRIPPING LOADCELL PNEUMATIC TUBE Jan 2017 - Jun 2022 GiftSurg - Multi-arm robot for Single Port Acccss Surgery Prototyping - A total of 6 design iterations were prototyped. Each prototype offered a lot of insight on design flaws and improvements for the next version. Control - Various sensors were implemented on the robotic drive to track the different robot DOFs and enable teleoperation. The robot is controlled with a 3DS Touch device through LabVIEW. Characterisation - Prototypes were characterised to validate the design requirements through various self-design benchmarking experiments. End-effector hysteresis at different frequencies Bending force characterisation Validation - The kinematic model and the gripper design were experimentally validated. Markers for image tracking of the bending segment
GiftSurg - Multi-arm robot for Single Port Acccss Surgery
Knee Prosthesis
RESULTS
The 6th and final design of the multi-arm robot was tested on a skin phantom and was able to perform running sutures.
The sutures were performed through real-time bi-manual teleoperation using two 3DS Touch devices. An embedded chip-on-tip camera provides a view upon the surgical site.
The robot moves dextreously and with a high resolution. The drive unit provides the required force and stiffness to drive concentric tube robots. A novel non-permanent clamping mechanism allows to drive multiple concentric tube robots in close proximity while keeping the drive unit compact (450x240x170mm); which is a first for the state of the art. The robot design is modular, allowing to remove and replace robotic arms within a minute.
9 Academic year 2014-2015
PhD - KUL
PreSlice
Laser add-on for da Vinci Xi • Context: PhD • Duration: Oct 2016 - Jun 2021 (4.5 years) • Design team size: 1 member
PreSlice - Laser add-on for da Vinci Xi
Problem definition
Oropharyngeal cancer is often treated surgically. Transoral Robotic Surgery (TORS) using the da Vinci Xi allows to significantly reduce the invasiveness of the procedure. Electrocautery is the most commonly used cutting tool for TORS as it prevents bleeding efficiently. However, when compared to a CO 2 laser, electrocautery causes significantly more collateral tissue damage, complicating margin assessment. It also causes more tissue coagulation on the instrument that needs to be removed.
Project objective
The PreSlice project objective is to add lasering capabilities to the currently established da Vinci Xi robot without replacing the cauterisation tool, which is important for quickly stopping bleeding; while minimally increasing its instrument workspace
11
PhD - KUL
Design Challenges
COMPACTNESS LIGHTWEIGHT DYNAMIC ACTUATION EMBEDDED ACTUATION
:
CONCEPTUALISATION
Concept I : Direct cable pulling
A guide tube is attached on the da Vinci instrument through which the laser is protracted/ retracted proximally. Cables attach to the outer wall of the laser fibre at different points along its length; allowing to steer the fibre tip in various directions. This concept is simple and comprises a small number of parts but might lack robustness.
Concept II : Flexible notched Nitinol tube
The laser fibre is nested inside a flexible, notched Nitinol tubes. Instead of driving the laser fibre directly, the Nitinol tube is translated and bent in two directions by artificial McKibben muscles. These muscles can be external or internal depending on the diameter requirements.
Concept III : Concentric tube robot (CTR)
By mounting a CTR onto the Endowrist, a dexterous and low distal profile concept could be realised. A CTR has a natural lumen to slide the laser through. While CTR have a low distal footprint, their actuation unit is usually complex and bulky.
Concept IV : Intrinsic actuation
The last concept relies on coupling the laser fibre to the Endowrist using guide rings and utilising the Endowrist DOF to steer the fibre simultaneously. The elegance of this approach is that the only DOF that needs to be added to the laser fibre is retraction/protraction for switching between the cautery tool and the laser. This actuation could be provided by a McKibben muscle and a return spring.
12
Oct 2016 - Jun 2021 RESEARCH & PRE-DESIGN
Workspace & constraints evaluation Design brief CLIPPED ONTO INSTRUMENT CO2 LASER CLIP-ON MODULE PATIENT SURGEON MASTER CONSOLE SAFETY NORMS / REGULATION CLEANING / STERILISATION EQUIPMENT IN-BODY CONDITIONS ENERGY SOURCE GAS SUPPLY POWER TRANSMISSION END OF LIFE REPAIR OTHER INSTRUMENTS ASSISTANTS TECHNICIANS SF2 SF9 SF6 SF11 SF7 SF5 SF10 SF4 PF1 CF13 CF14 CF12 Ident. Type Weight Wording Criteria Level Flex. Remarks PF Prim. 100 The laser can swiftly be switched with the main tool by the surgeon Speed Proximity to the main tool Protraction distance <1sec <10mm ~20mm F2 F2 F2 Proximity distance main axis to main axis at the default configuration, wait for workspace investigation SF Sec. 100 The laser cuts the patient tissues under the surgeon direction. Cutting speed Cutting depth Tissue variety mm/s mm X F1 F1 F2 How does the laser behave on different tissues (depending on water % ?) how much parametrisation there SF Sec. 100 The laser is steered in situ by the surgeon controle of the master console Accuracy Speed Range of motion Error <2mm Max. 1cm/sec DOFS F1 F2 F0 The DOFS are rotations the laser and translation relative the cautery unit SF Sec. 70 The laser module must be easily and securely attached & removed by the staff Fastening time Learning time <30sec Short (intuitive) F2 F2 The clipping should not take longer than the time takes to dock tools on the da vinci SF Sec. 100 The laser focusses the ignited CO2 into an energy beam Power Density(spot size) max 40W 500µm Th is performed by an external machine. SF7 Sec. 90 The laser must be maintainable or recyclable by the staff Amount of parts Durability <10 X number of use F1 F1 Depending wether it single use or re usable SF Sec 80 The laser firing & main tool movement are powered by the energy source Volt/amp Reactivity <50ms SF10 Sec. 100 The laser motion is controlled by the command via the power transmission Resolution Reactivity steps <1mm <100ms F1 F1 SF11 Sec. 50 The flexible laser is cleanable & sterilisable by the staff. Ease of cleaning Learning Rounded/closed geometry No specific tool F0 F2 The geometry should have the least amount of small openings small angles making reg cleaning difficult CF12 Cons 100 The laser module must respect all security norms of surgical instruments Y/N Absolute respect Look up surgical robot tools norms CF13 Cons 100 The laser module must be compatible to use simultaneously with other instruments. Protection from clashes Size Rigid sheath Increase instr. Size <50% F0 F1 During TORS, at least instruments are inserted simultaneously in the oral cavity CF14 Sec. 70 The module must resist in body conditions (especially re usable) Humidity Temperature Corrosion Dirtiness Workspace [0 100] [10 50°C] Spotting at max Impervious it in 45 50x60mm space with other instr. F0 F0 F1 F0 irt cannot penetrate the tool in manner that would jeopardise cleaning or proper function Flexibilities: Non negotiable F0 Very flexible F3 PreSlice - Laser add-on for da Vinci Xi PF1 The laser can swiftly be switched with the main tool by the surgeon TF 1.1 Create tool proximity TF .1.1 Do large displacements together TF 1.1.1.1 Attach one tool to the other one TS 1.1.1.1 Clip/fastening mechanism 1.1.2 Minimise axis axis distance TF 1.1.1.2 Embed the laser the main tool housing 1.1.1.2 Groove fitting (partially ?) the laser TF 1.2 Protract/retract the module TF .2.1 Linear relative movement TS 1.2.1.1 Linear glider/rail TS .2.1.2 Actuation for the m ement: Cable pulling with levers Linear drive DC motor pulley Rack & pinion Pneumatic muscle pulling spring return TF .2.2 Rotate the tools TF 1.2. Fold back the flexible structure OR OR
TORS workflow analysis
DEVELOPMENT & PROTOTYPING
Final version CAD - After 5 design iterations, the final version components are displayed here.
Operating room validation - Each iteration was tested on various phantoms to evaluate the add-on performance and identify potential issues.
Early mechanism prototype - A McKibben muscle and an antagonistic spring allow to translate the laser fibre back and forth.
Final prototype - Mounted on a monopolar spatula endwrist & protected by a steel cover.
Control interfaces - Several interface options were tested, from sensorised glove to foot pedal.
13 (3)
(2)
(1)
(8)
(6)
(9)
(4)
(5)
(7)
Tip ring
Spring ring
Pneumatic ring
Laser fibre
Return spring
Fibre-muscle connector
McKibben muscle
Pneumatic supply line
Instrument shaft
PhD - KUL
Laser
PreSlice -
add-on for da Vinci Xi VALIDATION
Cadaver trials - The final prototype was tested against traditional TORS on two cadavers performing a total of four surgical procedures. The add-on performed better than traditional TORS according to NASA-TLX metrics.
AXO-Suit Shoulder Exoskeleton • Context: Second year of MSc in Mech. Eng. Master thesis • Duration: Feb 2016 - Jun 2016 (5 months) • Design team size: 1 member
AXO-Suit - Shoulder Exoskeleton
Problem definiion - Due to an ageing society, the demand for care of elderly or physically weak individuals is rising. Exoskeletons propose a supportive frame that would be able to help these people regain independence in their activities of daily living, such as walking or cooking. However, most exoskeletons developed so far are either too bulky and/or heavy to be portable, preventing to reach commercialisation stage.
Project objective - The AXO-Suit project aims to build the first widely commercialised full-body supportive exoskele ton. This work consisted in developing a novel compact and lightweight mechanism concept for a three degrees of freedom exoskeleton shoulder joint and integrate it to the AXO-Suit.
15
Master Thesis - DTU
Design Challenges
COMPACTNESS LIGHTWEIGHT COMPLEXITY OF THE SHOULDER JOINT HIGH RANGE OF MOTION
:
16 Spring semester 2016 RESEARCH PRE-DESIGN
environment Anatomy & Anthropometry data Design brief Shoulder torques during ADL (Activies of Daily Living) FAST Diagram Pilot Clothes Power transmission Energy source Maintenance Safety measures Time Weather conditions Rest of the Axo-Suit Axo-Suit shoulder joint FS6 FS4 FS11 FS5 FS2 FP1 FC8 FC8 FC8 Ident. Type Weight Wording Criteria Level Flex. Remarks FP1 Prim. 100 The shoulder allows the pilot to move the arm of the exoskeleton smoothly. ROM Reaction time Friction 180 180 180 <0.3s <0.1 F1 F2 F1 Reaction time to be validated by control team Friction very low because extra power = extra weight FS2 Sec. 40 The shoulder functions in indoor climate and light rain conditions Humidity Temperature Dirtiness 100% 10 + 50 C None F3 F3 F3 No emphasis on dirt resistance, meant to use indoor mostly. FS4 Sec. 100 The shoulder is actuated via a sufficient energy source and transmission. Cabling Lifespan Short, fewest X mins F1 F2 Possibility of wireless control Investigation on the battery life will be made by Aalborg University FS5 Sec. 50 The shoulder maintenance is easily achievable by a tierce person. Nbr. of parts Assembly Min. Simplest F2 F2 FS6 Sec. 100 The shoulder actuates the arm movement thanks to the motors/cables. Back drivability Backlash Possible None F0 F1 FC8 Cons. 30 The shoulder resists time and use degradation. Time Corrosion X days of lifetime 1.5 hours/day F2 F2 Specifications have to come up from the AXO Suit executives FC9 Cons. 100 The shoulder is safe for the pilot. Y/N Absolute respect F0 FS10 Sec. 60 The shoulder is light and compact to not burden the user and complicate actuation Weight Size <1kg As small as possible F1 F2 Without the motors FS11 Sec. 50 The shoulder is able to be worn and function over clothes. Sharp edges Dirtiness None Limited F1 F2 Flexibilities: Non negotiable F0 Very flexible F3 FP1 The shoulder allows the user to move the exoskeleton arm smoothly FT 1.1 Match human movement FT 1.1.1 Implement control system FT 1.1.1.1 Acquire information AND FT 1.1.1.2 Produce output ST 1.1.1 PCB FT 1.1.2 Matching human ROM ST 1.1.2 Mechanism design FT 1.2 Articulate joint smoothly FT 1.2.1 Enable fast response ST 1.2.1 Optimised control FT 1.2.2 Smooth relative motion FT 1.2.2.1 Match contact surfaces ST 1.2.2.1 Robust design FT 1.2.2.2 Minimise friction ST 1.2.2.2 Bearings FT 1.3 Connect to the rest of the skeleton FT 1.3.1 : Chest connection AND FT 1.3.2 Arm connection ST 1.3 Bolted assembly FT 1.4 Actuate the shoulder FT 1.4.1 Actuate active joints ST 1.4.1 DC motors FT 1.4.2 Compensate passive joints ST 1.4.1 Springs & cables AXO-Suit - Shoulder Exoskeleton
State of the Art review of upper body exoskeletons Defining the
Shoulder Exoskeleton
CONCEPTUALISATION DEVELOPMENT
Materials Selection
Concept I : Double Parallelogram Mechanism
Two actuators are connected via a double parallelogram linkage resulting in three degrees of freedom. This concept is compact, lightweight, high stiffness, large range of motion free of singularities, minimised collisions with the pilot, all the weight is kept close to the body
Consulting material library CES and analytical performance index (P.I.) derivation regarding the
Motor & Gearset Selection
Selection of DC motors & harmonic gearsets corresponding to the needs in torques and speed.
Concept II : DPM + Passive elevation
This concept tries to compensate misalignment between the human joint axis and the mechanism axis which occurs mainly due to shoulder elevation/depression.
A tilted linear rail system was studied to allow for passive adjustment of the mechanism.
Concept III : DPM + Active rotation
Another solution found in the litterature is to add a fourth degree of freedom behind the scapula to approximate the misalignment trajectory by an arc of radius Ls.
An appropriate motor was selected for the task.
Motor Mounting Design
Interface design to connect the motors to the scaffolding parts and the gears.
DPM & Scaffolding Design
Dimensioning & CAD drawing in CATIA V5 of the four bar mechanism and the connec tions from the shoulder to the back.
Finite Element Analysis
Resistance and deformation analysis in the various most stressful scenarios followed by a refinement of critical dimensions & material choices.
17
AXO-Suit
Master Thesis - DTU
-
MANUFACTURING & CONCLUSION
The various parts were toleranced accordingly to functional requirements, blueprints were drawn and an assembly & machining strategies were proposed.
A prototype was conceived by 3D printing and assembled with threaded rods & nuts.
In conclusion a fully functional exoskeleton spherical shoulder joint mechanism was designed, smaller and lighter than the State of Art.
The design brief was well respected and the AXO-Suit team was overall happy with the result.
AXO-Suit - Shoulder Exoskeleton Spring semester 2016
19
Running Knee
• Context: First year of MSc in Mech. Eng. Integrated Project in Mechanics • Duration: 09/2014-06/2015 (10 months) • Design team size: 3 members
Leg’s Go
Prosthesis
Leg’s Go - Running Knee Prosthesis
Problem definition
This project was proposed by LucHuberty, Belgian paratriath lete pursuing the objective of participating to Olympic Games. His current prosthesis does not bring him satisfaction as the knee is a simple hinge without any braking mechanism. This demands a long learning period to addapt. In addition to the risk of falling, this simple prosthetic knee is highly expensive (above 10,000€).
Project objective
The objective of the project was to design and manufacture an innovative concept of prosthetic knee providing a shorter lear ning period and reduced costs while conserving a low weight.
21
IdP - Université de Liège
CHALLENGES PROBLEM RESEARCH PRE-DESIGN ANALYSIS IDEATION SOLUTION SELECT & DEV PROTOTYPING
Running Knee Prosthesis
RESEARCH IDEATION
Luc founded the Leg’s Go foundation to collect funds in order to offer other amputees the possibility to run again, realising how much it helped him recons truct his life after his accident. The first phase of the project consisted in researching the State-of-Art in knee prosthesis, anatomy, running biomechanics and several meetings with Luc to clearly establish his needs as well as a ses sion in our Human Movement Analysis Laboratory.
Concept I : Mechanical hydraulic knee
The blade is connected to the knee via a piston and a spring. When the blade makes contact with the ground, the piston plunges and compresses the fluid, pushing the braking pads onto a disk mounted onto the rotule (hollow shaft).
Concept 1I : Mechanical cable knee
The core idea is similar to Concept I, except that the force transmission is now achieved via cable pulling, improving the manufacturability and diminishing the system complexity. The lever must be augmented to compensate for the mechanical advantage that was obtained by section differences in the hydraulic pistons.
Concept III : Electromechanical knee
A force sensor triggers the penetration of a pin through the disk, locking the knee into position. A spring and an electromagnet allow for fast release and repositioning.
22 Academic year 2014-2015
-
FRONT VIEW INSIDE-SIDE VIEW Leg’s Go
Running Knee Prosthesis
DEVELOPMENT PROTOTYPING
Materials Selection
Consulting material library CES and analytical performance in dex (P.I.) derivation regarding the desired material behaviours.
Dimensioning & CAD drawing
Hand resistance calculations based on research and measurements allowed for a first dimensioning of the parts. They were drawn in CATIA V5.
FEM Resistance simulations
Most stressful scenarios were evaluated in CATIA to improve dimensions and check resistance of critical parts.
Other components Selection
Off-the-shelf parts were selected according to functional requirements and strength. It allowed reducing the manufacturing costs.
The parts were toleranced loosely for non-critical dimensions and strictly for functional dimensions. Blueprints were drawned and the different parts were manufactured using CNC machining, welding, sawing, milling, turning, rectification and peening. Other components were ordered from various suppliers.
Go -
Leg’s
IdP - Université de Liège
Running Knee Prosthesis
RESULTS
As a result, we conceived a quite lightweight prosthesis (592gr. vs 682gr.) with higher performance and security as well as reduced costs by an order of magnitude compared to Luc’s original prosthesis. The prosthesis was not field-tested as we did not design the connexions to the blade and socket due to lack of time. The simulations and laboratory experiments conducted however were very promising.
Thanks to the security factors chosen during the development, the braking performances were even higher than predicted. Luc was very pleased by the final result, answering his hope for a better running knee.
24 Academic year 2014-2015
*Conceptual image
-
From left to right : Tom Vandebroek, Luc Huberty, Corentin Dantine, Thomas Minisini
Leg’s Go
25
BioDrop
Humidity harvester
• Context: Second year of MSc in Mech. Eng. Course project in Biomimetics & Bio-ins pired design • Duration: 01/2016 (4 weeks) • Team size: 4 members
BioDrop - Humidity harvester
Problem definition
High humidity in basements or bathrooms can be proble matic for the infrastructure and indoor climate. Mold can appear and propagate to the entire house, damaging the materials and putting in jeopardy the inabitants’ health.
Project objective
The aim of this project was to find a low tech and low en ergy solution for lowering the humidity or moisture in a fashion inspired by functional principles found in nature
Week 1 Define and search Week 2 Understand, focus and generate concepts Week 3 Design, built and experiment
Choice of Moist Absorption
Choice of problem
Research results
Investigating the topic of Moist Absorption by bio-brainstorm and four box method.
Field trip and research of the problem - bio phenomenon - technical solution
Selected bio pheno menon is worked out as bio cards. Concept is generated.
of bio-function & concept Choice of experiment Proof/disproof of concept
Choice
Selected bio-pheno menon is invested as an experiment.
Experiment is tested and refined. Further work is described in final report.
27
project- DTU
Course
The phenomena relevant to our problem were then selected and transcripted into the format of ‘Bio-Cards’. These cards extract the functional principle of the organism to allow usage in technology.
Namid desert beetle fog harvesting
Biocard A09
Initial biocards
To start the research on relevant biological phenomena, keywords had to be generated from the selected challenges : Mold and Unhealthy indoor environment. Using these keywords on Asknature.org, at the University Library and at the Bla Planet, the found phenomena were classified into five categories :
Sensing humidity
Absorbing moist/water
Encapsulation
An inclined surface composed with hydrophilic valleys (covered with hexagonal microstructure) and smooth hydrophobic bumps is exposed to fog. Water starts to nucleate in the valleys and will drift of to the bottom of the surface, guided by the bumps.
Osmosis in Leaf-Cells
Eight rounds of brainstorming with the initial problem statement ‘Lowering relative humidity in air’ led to many concepts and ideas.The final idea was chosen based on its experimental feasability and possible future prospects.
Organism Plantae
Biological Phenomena
Plant leaves absorb water by the common principle of osmosis. The membrane of each cell in the leaf is semiper meable, where water can transport though but not polar molecules or particles. The cell attracts the water molecules by creating solutes inside each cell. the outer water intensity and the cells solutes is unbalanced, water trans
Milwid, M., Rubner, M. F., Cohen, (2006). Patterned superhydrophobic surfaces: toward synthetic mimic of the Namib Desert beetle. Nano Letters, 6(6), 1213–7.
port through the membrane by pressure differential either hypertonic or hypotonic. The membranes creates an elastic grid between the cells, which can expand or decrease according to the fluid level in each cell.
Functional Principle
Biocard A07 Structures of elastic membranes allow change in volume.
Tick moisture absorption
Biocard A05
GROUP 17 Responsible: Anna Fliid, s112944 Picture: Jon Sullivan (PD Photo.org) References: Article: Scovazzo, P., Burgos, Hoehn, A., & Todd, P. (1998). Hydrophilic membrane-based humidity control. Journal of Membrane Science, 149(1), 69–81. doi:10.1016/S0376-7388(98)00176-8
Organism Rhipicephalus sanguineus
Biological Phenomena Functional Principle
The brown dog tick possesses an ability to rehydrate itself without drinking water (or blood from a host) and survive for multiple months. It detects micro-regions of high humidity and then secretes a hydrophilic solution to attract the humidity and absorb it. This adaptation allows the tick to extract water from the atmosphere ranging from vapor close to saturation down to 41% relative humidity.
Responsible: Tom Vandebroek, s150493 Picture: https://en.wikipedia.org/wiki/Rhipicephalus_sanguineus References: http://www.asknature.org/strategy/f777a0792ad3bc95a91c2b42ae61bab4 https://en.wikipedia.org/wiki/Rhipicephalus_sanguineus
(1) A hygroscopic solution is exposed to the atmosphere from a container. (2) The solution dries at low ambient humidity leaving crystalline substance. (3) When the relative humidity is above (RH) 41%, the substance absorbs humidity, dissolves and is absorbed back in the structure.
28 BioDrop - Humidity harvester Winter semester 2016
Group 17 - Moist absorption Brain mapping Function mean tree Group 17 - Moist absorption Function mean tree Date: 22.01.16 Appendix nr. A08 1/1 Page:
PROBLEM ANALYSIS & RESEARCH CONCEPTS GENERATION Brain mapping
Group 17 - Moist absorption Initial brainstorm Date: 21.01.16 Appendix nr. A03 1/1 Page: Categories:
•
•
•
•
•
Protection/barries
Water transportation/filters
Organism Stenocara gracilipes Biological Phenomena Functional Principle The Namib desert beetle is able to harvest fog to hydrate itself during long dry periods. It is able to collect
GROUP 17 Responsible: Tom Vandebroek, s150493 Picture:
References:
T., & Dacke, M. (2010). Fog-basking behaviour and water collection ciency Namib Desert Darkling beetles. Frontiers in Zoology, 7(1), 23. Zhai, L., Berg, M. C.,
C., Kim, Y.,
dew from 55% relative humidity.
http://www.biomechanics.bio.uci.edu/_html/nh_biomech/namib/beetle.htm
Nørgaard,
Cebeci,
Experiment main hypothesis: A Bio-inspired
pattern made of (super-)hydrophobic
material
printed on a glass window helps precipitate and collect condensed water from vapour faster.
Experiment I : Bathroom simulation
A glass plate placed inside a plastic box separates a boiling water bowl and an ice of bag, simulating a window. A stripe of absorbing cloth is placed under the glass panel to collect the condensed vapor. Various hydrophobic patterns are printed on the glass and the water collected is weighted to compare their efficiency.
Experiment II : Spraying water
The first experiment taking quite some time, it is difficult to obtain statistically significant results due to the course timeframe. The patterns were then further tested simply by spraying water onto them and seeing how fast the water precipitated at the bottom of the plate.
29
- Humidity
Course project- DTU
BioDrop
harvester
EXPERIMENTS Experiment - setup 1 Input Output Clean glas test Pinecore inspired pattern Leaf inspired pattern Beetle inspired pattern Feather inspired pattern Group 17 2.0 g 0.2 g 3.2 g 3.4 g 3.9 g Experiment - setup 2 Input Output Clean glas test 95 Pinecore inspired pattern 127 Leaf inspired pattern 116 Feather inspired pattern 42 Group 17 (# of squeezes) (ef�icacy to evacuate water drops)
30 Contact Thank you for your time www.linkedin.com/in/tom-vandebroek tvandebroek@hotmail.com +32497805428 in
