Dynamic Force

DYNAMIC FORCE Digital Future 2013

Team: Sen Dai, Yuchuan Chen, Chunyang Zheng, Mei Zhang, Ying Ju Supervisor: Neil Leach, Philip.F.Yuan, Qi Su, Biayna Bogosian

Dynamic Force Tensegrity has always been viewed as a very brilliant structure, because it has two attributes, namely, its elegant form and the intelligent way it distribute load. Many engineers artists have done studies on tensegrity, however most of these studies are based on the analysis of the structure’s static geometry form, omitting to tell people how it works. DYNAMIC FORCE, on the other hand, wants to reveal the inner essence of tensegrity. Through the changes of the brightness of the LED installed in the structure, people can easily understand the changes of load applied on each truss. We want to bring people an interesting space experiment as well as some insights about the structure.

Studio: Tongji-USC-SCUT workshop, Jul-Aug 2013 Teammates: Yuchuan Chen, Chuanyang Zheng, Mei Zhang, Ying Ju Position(Team Leader and Chief Designer): Research, Design, Programming, Fabrication Tutor: Neil Leach, Philip.F.Yuan, Qi Su, Biayna Bogosian

Tensegrity Geometry After research of Kenneth Snelson’s tensegrity sculpture, we discover a basic rule to generate different form of tensegrity unit. There are two kinds of unit structure – basic structure and double structure. Letter a represent the number of truss while b represent the number of rubber band.

Plexiglas

Kenneth Snelson’s tensegrity model

Rubber band

Basic Structure 3a=b a=number of truss b=number of band

a=3 b=9

a=4 b=12

a=5 b=15

a=6 b=18

Double Structure 4a=b a=number of truss b=number of band

a=6 b=24

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Photos Produced by Sen Dai, Ying Ju

a=8 b=32

a=10 b=40

a=12 b=48

Tensegrity Flexibility Replacing the rubber band with elastic string, we change the unit structure into a flexible prototype, which has been the basic element of our installation. As pictures showed below, the structure will change shape to adapt the stress.

Lobster hooks Elastic string with lobster hooks String lockers

Joints

PVC pipe with circle hooks

Elastic string

Basic Structure

Double Structure

SMA Test for Flexibility We endowed the prototype with self-flexibility using shape memory alloy (SMA), which will stretch when it is cool and shrink when it is heated.

Changing some of the elastic string into SMA, the prototype can change shape when electrified. We use electric current to heat the SMA and through manipulating the electric current we can manipulate the shape of the installation.

For videos, please visit: http://vimeo.com/daisen/sma-test

Photos Produced by Ying Ju, Sen Dai

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Mock up - Interactive Unit

LED Strip Metal Hooks

SMA Spring Plexiglas Tube

100%

80%

60%

40%

20%

We choose the first double structure, which has a=6 and b=24, to be the form of interactive unit.

Equipped with LED strip in the Plexiglas tube and SMA spring instead of elastic string, the interactive unit can demonstrate the inner change of the pressure on each truss by the brightness of LED when its shape transformed owing to the contraction of SMA.

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Diagrams Produced by Chunyang Zheng, Sen Dai, Yuchuan Chen

The Combination of Ten Interactive Units The shape of the interactive unit can be abstracted into a variant of regular icosahedron, which can be combined with each other in eight directions. Diagrams below shows the combination of ten interactive units arranged in an order from compact to sparse.

Interactive Unit

Unit Abstraction

Connection Direction

Diagrams Produced by Sen Dai

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Deformation To make the installation stable, we deform the shape of tensegrity form. Pictures above shows the deformation of one interactive unit.

A sparse combination of ten interactive units

Deformation

Tensegrity form

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Diagrams Produced by Sen Dai

The Design The final design of the installation consists of ten deformed interactive tensegrity units on each of which two SMA springs were equipped (red lines on the diagrams below show the position of SMA). When people waving hands in front of the sensor fixed on the end of each SMA, the shape of the installation would change to feed back the action, meanwhile the real-time analysis of pressure on each truss by computer will regulate the brightness of LED to demonstrate the change of force.

Diagrams Produced by Sen Dai,Yuchuan Chen

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Assembly Group For the convenience of transportation, we divide the installation into four parts.

Group 4

Group 1

Group 3 Connection Lines

Connection Lines

Connection Lines

Group 2

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Original Shape of Group 1

The Movement of Group 1

LED Brightness of Group 1

Original Shape of Group 2

The Movement of Group 2

LED Brightness of Group 2

Original Shape of Group 3

The Movement of Group 3

LED Brightness of Group 3

Diagrams Produced by Sen Dai

Circuit Design

AC-DC 220V-12V

AC-DC 220V-12V

AC-DC 220V-12V

DC-DC 12V-5V

DC-DC 12V-5V

DC-DC 12V-5V LED Control

LED Control

LED Control

Data Output

Data Output

Data Output

Data Output

Data Input Data Output

SMA Control

SMA Control

Sensor Control

Photocell Sensor

AC-DC 220V-5V

AC-DC 220V-5V

Diagrams Produced by Sen Dai

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Fabrication

August 6th Fabrication

August 7th Fabrication

August 8th Test

August 9th Exhibition,Shanghai

October 26th Assembly

October 27th Exhibition, Beijing

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Exhibition Interactive Shanghai, Tongji University, Shanghai, Aug 2013

Dada Digital Infiltration, 751 D_Park, Beijing, Oct 2013

For videos of this project, please visit: http://vimeo.com/daisen/dynamic-force

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The Lamp The lamp is one of the derivative product of Dynamic Force. It can interact with people with code embedded in Arduino.

Sensor ST188 (reflective infrared photoelectric sensor)

Shape Memory Alloy

Plastic Tube (with one blue LED and one white LED strip)

Elastic Rubber Band

Control Box

Circuit Design The whole control system was integrated into the control box which had provide the portability of the lamp. On the other hand, I use two arduino boards to complete the computation process in order to ensure that the transformation of shape and the brightness change can take place simultaneously.

DC-DC 12V-5V

AC-DC 220V-12V

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Diagrams Produced by Sen Dai

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