Material Transformation
Designing Shape Changing Interfaces Enabled by
Programmable Material Anisotropy
Jifei Ou
Dipl. Design, Offenbach University of Art and Design (2012)
Submitted to the Program in Media Arts and Sciences,
School of Architecture and Planning,
in partial fulfillment of the requirements for the degree of
Master of Science in Media Arts and Sciences
at the Massachussetts Institute of Technology
June 2014
© 2014 Massachusetts Institute of Technology. All Rights Reserved
Author
Certified by Accepted by
Jifei Ou
Program in Media Arts and Sciences
May 24, 2014
Hiroshi Ishii
Jerome B. Wiesner Professor of Media Arts and Sciences
MIT Media Lab
Pattie Maes
Associate Academic Head,
Program in Media Art and Science
Material Transformation
Designing Shape Changing Interfaces Enabled by
Programmable Material Anisotropy
Jifei Ou
Submitted to the Program in Media Arts and Sciences,
School of Architecture and Planning, on May 30th, 2014
in partial fulfillment of the requirements for the degree of
Master of Science in Media Arts and Sciences
at the Massachussetts Institute of Technology
ABSTRACT
This thesis takes a material perspective on designing transformable interfaces. The structure of material and mechanical properties such as stiffness, can determine not only
its static performances, but also, with the help of external forces, support dynamic shape change. By encoding
structural or stiffness distribution in the actuated materials, we can partially offload the shape-changing control
from actuators (digital) to the material itself (analogue),
in order to achieve expressive transformations that current modularized actuation system cannot easily provide.
The implementation of this thesis will be three series of
material primitives and three application prototypes that
demonstrate the real world potential of this research.
Thesis Supervisor
Hiroshi Ishii
Jerome B. Wiesner Professor of Media Arts and Sciences
MIT Media Lab
3
Material Transformation
Designing Shape Changing Interfaces Enabled by
Programmable Material Anisotropy
Jifei Ou
The following people served as readers for this thesis:
Thesis Advisor
Thesis Reader
Thesis Reader
Hiroshi Ishii
Jerome B. Wiesner Professor of Media Arts and Sciences
MIT Media Lab
Neri Oxman
Assistant Professor of Media Arts and Sciences
MIT Media Lab
Sangbae Kim
Assistant Professor of Mechanical Engineering
MIT Department of Mechanical Engineering
4
CONTENTS
ABSTRACT03
ACKNOWLEDGEMENTS11
INITIAL REMARKS
Chapter 1. INTRODUCTION
1.1 Motivation17
1.2 Thesis Aims19
1.3 Thesis Contribution21
1.4 Thesis Outline21
Chapter 2. MACHINE TO MATERIAL TRANSFORMATION
2.1 Mythology of Shapeshifting24
2.2 Transformable Machine24
2.3 Programmable Matter & Claytronics
28
2.3 Shape Changing Interfaces 29
2.5 Smart Materials32
Chapter 3. MATERIAL, FORCES AND INFORMATION
3.1 Transformation in Nature35
3.2 Material Computation38
3.3 Model for Material Transformation
40
Chapter 4. PNEUMATIC ACTUATION PLATFORM
4.1 Inspiring Works
4.1.1 Soft Robotics44
4.1.2 Tunable Stiffness with Jamming
45
4.2 Principle of Layer-jamming
46
4.3 Control Systems
4.3.1 Inflation for Deformation
47
4.3.2 Vacuum for Tunable Stiffness
48
Chapter 5. PROPOSED DESIGN SPACE
5.1 Parameter
5.1.1 Deforming Forces52
5.1.2 Programmable Material Anisotropy 54
5.2 Design Space56
5.3 Transformation Primitives
5.3.1 Type A
Primitive A57
Primitive B58
Fabrication60
5.3.2 Type B
Primitive C61
Primitive D63
Fabrication66
5.3.1 Type C
Primitive E67
Chapter 6. APPLICATIONS AS EVALUATION
6.1 Design Principles70
6.2 HelighX
Design70
Sensing71
Fabrication72
6.3 PLYABLES
Design72
Extention of Application75
Sensing73
Fabrication75
6.4 JamBot
Design76
Sensing and Motion Control76
Fabrication77
Chapter 7. A STEP FORWARD...
7.1 Morphing Vehicle79
7.2 Beyond Transformation
7.2.1 Illumination81
7.2.2 Sensing82
7.2.3 Construction82
7.2.4 Nano-Actuator Distribution83
Chapter 8. CONCLUSION85
APPENDIX87
BIBLIOGRAPHY91
ACKNOWLEDGEMENTS
I would like to thank Lining Yao, my dearest friend, and
smartest collaborator. Without you, none of the projects
would become tangible. Thank you for all the help, trust,
fight, and laugh. Thank you for walking me through the
transition from being a designer to a researcher.
My deepest gratitude goes to my role model, my advisor
Prof. Hiroshi Ishii. Thank your for your appreciation when I
was still in Germany. Thank you for constant modifying and
debugging my brain. Thank you for making me believing in
vision that transcends life and spirit.
Thank you Prof. Neri Oxman and Prof. Sangbae Kim, for
your unique thoughts, comments, and suggestions. Thank
you for trusting me and being extremely supportive. I am
fortunate that such brilliant and inspiring people surrounded me. Without your help this thesis would not have
been possible.
My collaborators: Daniel Tauber, Ryuma Niiyama, Juergen
Steimle. I could never thank you enough. The works would
never become solid without you.
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Thank you Daniel Leithinger and Sean Follmer for your
pioneer work on Jamming UI. I truly appreciate all the discussions, suggestions and tolerance in the past two years.
Thank you Xiao Xiao, for sharing philosophical thoughts,
for creating MirrorFugue, which inspires and moves me all
the time.
Thanks to All the TMGler: Tony Tang, Felix Heibeck, and
Philipp Schoessler for the discussion, support and help.
Basheer Tome, you are an amazing designer. I hope we
could collaborate more in the future. Thank you Leonardo Bonanni and Amanda Parkes for the appreciation and
encouragement.
Prof. Pattie Maes, Prof. Ethan Zuckerman, Prof. Tod Machover and Elliot Hedman, thank you for your valuable suggestions and critics during the crit-day of my thesis.
Thanks to Linda Peterson and Keira Horowitz for making
sure that all papers wen to the right place with the right
signature at the right time. You make every students enjoying the life in the lab more.
I want to give the special thank to my former advisor Prof.
Frank Zebner, my friend Prof. Jussi Ängeslevä and my former employer Joachim Sauter. Thank you for teaching me
how to think and act as a designer. Thank you Prof. Achim
Menges and Steffen Reichert from my former university, for
your extraordinary vision and works that have been inspiring me ever since I know you. I learned more than I could
imagine from you.
Thank you Pragun Goyal, Carlos Gonzalez Uribe, Valentin
Heun, for debating, joking, and meditating with me. We
spent two wonderful years together in the lab.
Thank you Dhairya Dand, Gershon Dublon, Nan Zhao, Jie
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Qi, Anirudh Sharma, Robert Hemsley, Jared Laucks, Travis
Rich, Daniel Novy and Sujoy Kumar Chowdhury, for the
laughs, late nights, critical discussions and just about everything that made the last two years in the lab possible.
Thank you Steven Keating, Samuel Calisch, William Langford, Markus Kayser for being so awesome. I am so proud
to be your friend. Thank you for all the help. Thank you
Nathan Linder, Philippa Mothersill, Jennifer Jacobs, Matt
Hirsch, David Mellis, for the brainstorming and helping.
Thanks to all the UROPs who helped the design, fabrication and documentation process: Grace Lee, Erica Green,
Clark Della Silva, and Kaleb Ayalew. You guys showed me
how smart an MIT undergrads should be.
Foremost, I am thankful to my aunt, my father and my
brother. Thank you for being supportive, understanding
and loving all the time.
Thank you grandma.
- Jifei
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Initial Remarks
Physical materials usually are considered having the
opposite characteristics of digital information. They are
static, passive, and permanent, etc. What you are about
to read, is my effort to augment physical materials with
characteristics of digital information: dynamic, active,
and programmable. The characteristics are embodied by
the capability of physical transformation. The new materials with such abilities could be used to construct a more
responsive living environment; accelerate the process of
design and making; and enhance our existed interaction
with products or information, etc.
Under this vision, this thesis presents a combination of
two intertwining research thread. The first one is a methodology framework of designing physical transformation
by learning from the optimized way of how Mother Nature
form and transforms living materials. The second looks at
different application scenarios in which transformable materials can be applied to support future human-computer
interaction (or human-material interaction).
Hopefully this thesis will inspire ideas, suggest new directions and guide the development towards a future where
atom and bits are truly integrated.
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INTRODUCTION
As a negotiation between computation and physical
material, Tangible User Interface (TUI) leverages the metaphor of physical object and human bodily experience with
physical inert materials to build an intuitive experience
with digital information (Ishii, 2008). This is the core concept of “Tangible Bits”. Today, we are standing at a point
where “Tangible Bits” is transforming into “Radical Atom”
(Ishii, et al.). It is a vision that questions our fundamental
experience with physical material: What if inert materials
become dynamic as pixels on the screen? How can such
materials make sense to us?
To embody such concept, TUI expands it focus from passive to actively transformable materials. Such materials
should not only be able to change physical shape, but also
other properties (color, stiffness, refractive index, etc.)
The transformation should be able to be controlled, programmed, and even synchronized with digital information.
At its core, Radical Atoms seeks integration, instead of
negotiation between bits and atoms.
As we pursuing the vision of Radical Atoms, we are encountering a new range of design problems: how do we
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prototype such physical processes of transformation?
Pioneer works have been focusing on designing transformable machines using hard mechanics. They gave us
an exciting preview of future human-material interaction.
Yet this approach of designing “machine” is limited by the
size, weight and energy consuming of actuators. How can
we scale the transformation up or down for different usage? Without scalability, Radical Atoms cannot truly reveal
its potential in real-world application. How can we design
materials that transforms? While designers have numerous techniques and tools to improve the appearance of
objects, similar method for creating ways to model material transformation are lacking.
If we want to depict a convincing picture of future Radical
Atoms, we need to find an ecological way of designing
transformable materials that can creates numerous real
world applications. Proposed here is an alternative method of constructing future shape-change interfaces. This
approach looks at how can we shift our attention from
programming the actuator (force) to the structure (material). Rather than repetitively patching actuators (be it gear
motors or smart materials) on the material, then connecting them to a global controller, we should directly encode
transformation information into the inert materials. By
giving them different energy sources (forces), they should
accomplish a reversible shape-change as encoded.
a
b
Figure 1. (a) The camouflage behavior of octopus. (b)
A octopus changes the size of chromatophore cells to
adjust the skin color .
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In the natural world, the phenomena of property-change
are always conducted on the material level. Nature utilizes
both forces (internal or external) and material anisotropy
to create amazing material transformation through space
and time. Anisotropy means direction dependent. It is
the heterogeneous distribution of material. The octopus’
camouflage phenomenon is a result of adjusting the size
of chromatophore cells on the skin; wooden veneer curves
directionally based on the directional structure of its fiber
when absorbing environmental humidity (Menges & Re-
ichert, 2012). Materials’ structural anisotropy play a significant role in those transformation processes. In this thesis, I propose that, if we are going to build materials that
have dramatic and scalable transformation, we should
learn from nature’s optimized way of building formation
and transformation by leveraging material anisotropy. It
is not about bio-mimicry design. Nature’s examples only
provide us a perspective. The material’s anisotropy can be
also encoded or programmed to archive complex transformation.
However, programming materials anisotropy does not
suggest giving up on controlling the force. In this thesis, I
also draw a spectrum of deforming forces: computational,
manual, and environmental. The controllability/programmability decreases in such order. This is another parameter of designing Material Transformation. Together with
programmable material anisotropy, I propose a design
space in which six types of transformation are described. I
then present a serial of physical shape-change primitives
based on the type of transformation, which evolve to three
prototypes as real-world applications.
Aims
This thesis postulates that the ability to design, program
and prototype the shape changing interfaces is becoming
increasingly important as the programmability is shifting
from digital to physical world. The thesis aims to create
design framework for programmable material transformation by examining the relation between material anisotropy and deforming forces. I aim to establish two main
parameters of the framework:
1. Deforming Forces
Computational: External computationally controllable actuator connected to the interfaces causes their transforma19
tion. Air pressure is selected the prototypes in this thesis.
Manual: Human body’s direct action upon the physical
interfaces causes their transformation. Such as bending,
pressing, pushing, etc.
Environmental: Natural forces acting upon physical interfaces cause their deformation. Such as gravity, wind, etc.
2. Programmable Material Anisotropy
Encoded Stiffness Distribution: location, density and direction of material stiffness distribution can be designed and
fabricated.
Dynamic Tunable Stiffness: a dynamic material stiffness
changing can be achieved by using jamming technique.
By pairing those parameters, I aim to show a wide design
space for material transformation.
Figure 2. The Design Space of Material Tranformation for this thesis.
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Contribution
This thesis offers the following contributions:
1. An integrated framework of designing shape-change interfaces. Material anisotropy should be added to the agenda of designing shape-change interfaces in Human-Computer Interaction (HCI). It could help us build expressive
transformable objects more easily.
2. A pneumatic actuation platform that allows material
change shape and stiffness.
3. Application prototypes show how transformable material can be used in everyday life.
4. Provide a material perspective for interface designer to
play with smart materials beyond shape-change. The old
“patching” approach leaves designer little space for creation. By introducing programmable anisotropy, designers
could maximize the creativity with limited technology.
Thesis Outline
the following chapters describe the evolution of ideas in
this thesis:
Chapter 2: introduces a context and previous work on designing physical transformation. I distinguished Machine
and Material Transformation and pointed out the interests
shift from machine to material.
Chapter 3: gives a series of examples of how nature transform organism by encoding information in the material
structure. Nature weaves energy, material and information
together to create complex transformation. Yet man-made
shape-change interfaces tend to isolate them.
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Chapter 4: describes a pneumatic platform for designing
material transformation. a pneumatic system can be used
to deform a soft body and change their stiffness.
Chapter 5: presents a design space with primitives of
transformable material. Sis types of Material Transformation are explained. The chapter also presents three of
those types with physical shape-change primitives.
Chapter 6: offers three application prototypes as an evaluation of the framework. They are HelighX, PLYABLES and
JamBot.
Chapter 7: discusses how the programmbale anisotropy
can be extended beyond shape transformation. How can
designers utilize it for other perspective of interface design, such as property-change, self-assembly, etc.
Chapter 8: concludes the thesis with a summary.
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Machine to Material Transformation
To consider transformable materials in design practice
first we need to establish a context of human controllable
physical transformation. Mark Weiser once envisioned:
“The most profound technologies are those that disappear. They weave themselves into the fabric of everyday
life until they are indistinguishable from it.” (Weiser,
1999) As human beings have been designing, building
and improving machines that can transform by using hard
mechanics (linkages, gears, etc.) since long, now we are
standing at a point, where materials that change shape
are desired. For instance, instead of constructing sophisticated mechanical structure for foldable furniture, now
imagine a piece of clay that actively changes its shape
from one to another.
As it is radpidly developing, man-made technology is
shifting from focusing on machine transformation to material transformation. Here, machine refers to human-scale
mechanical structures that support transformation. Material refers to wood, fabric, polymer, etc that can deform
under certain stimuli. Certainly material transformation is
a result of material structure (atomic, molecular ) change.
In this chapter, I will go through several examples of phys23
ical transformation design to demonstrate the interests
shfift from transformable machine to material. This shift
has also influenced the development of Shape Changing
Interfaces in HCI.
Mythology of Shapeshifting
From ancient Greek to ancient China, if we look back at human mythology and literature, it is not difficult to find the
origin of human’s desire and fascination with transformable material. Although they are pure imagination of the
physical world, they depict scenarios of how human would
interact with those transformable matter.
Figure 3. An illustration of Ruyi Jingu Bang and
Monkey King
One of the most famous transformable objects is Ruyi Jingu Bang (Chinese: 如意金箍棒). It is magical staff wielded
by the Monkey King Sun Wukong in the 16th-century classic Chinese novel <Journey to the West>. Anthony Yu translates the name simply as “The Compliant Golden-Hooped
Rod,” It is described as being made out of black iron, with
gold bands on the ends. It has the ability to shrink to the
size of a needle, as Monkey King stores it in his ear when
not using it, and grow back to the size of staff as weapon.
(Figure 3)
Transformable Machine
In reality, human beings have been building kinetic machines in the context of transformable objects or architecture. The machines are usually constructed with homogenous materials. Through a set of mechanical principles
they can be assembled together to exhibit certain transformation ability.
The Expanding Geodesic Dome by Hoberman Associate,
opens from a 1.5-meter cluster to a 6-meter structural
dome when pulled open from its base. When deployed it
has the same shape and triangulated pattern as Buckminster Fuller’s static, geodesic dome. This movable lattice is
24
formed from the edges of the icosidodecahedron, a cross
between the dodecahedron and the icosahedron. Under
the similar design principle, one can develop a ring, a
sphere, even a curved surface that can expand or shrink.
Figure 4. The Expanding Geodesic Dome by Hoberman Associate. 1991
Similarly, many designer have been developing transformable furniture to meet different need in domestic scenarios. The table and bench combination by Uwe Fischer and
Achim Heine, can be extended and retracted by means
of numerous folding grilles and is therefore variable in
length. The rollable tabletop is constructed like a rolling
blind and adapts to these movement. It can be stored in
a crate-like container together with the grilles. This work
inspired other future development oon transformable
furniture design.
Figure 5. The table and bench combination by Uwe Fischer & Achim Heine, 1987
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Beyond scaling the volume of physical objects, some
artists interpret transformation as assembly and disassembly. Arthur Ganson’s famous kinetic sculpture “Cory’s
Yellow Chair” decomposes a wooden chair model into
several pieces, which are connected to the ends of a large
mechanical system. The gears in the system rotate to
move the wooden pieces away from each other. After a cycle they can be brought back together to form the original
shape of the chair.
Figure 6. Cory’s Yellow Chair by Arthur Ganson. 1997
Max Dean, in collaboration with roboticist Raffaello D’andrea, created a robotic chair that can self assemble and
disassemble. It is not only a piece of technological work,
but also a design prototype that envisions how future furniture could be, and proposes a question of how we could
interact with such object. The Robotic Chair looks like a
generic wooden chair. Unlike most chairs, however, this
one falls apart and puts itself back together. The Robotic
Chair is guided by an overhead vision system and controlled over a wireless network by an external computer.
Various algorithms govern the chair’s behavior, while the
software is structured in such a way that the system can
learn from its environment. The Chair keeps its controls
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and technology hidden under a simple wooden veneer,
making it high-tech in the most unassuming way.
Figure 7. The robotic Chair by Max Dean & Raffaello D’andrea assembles and disassembles by itself. 2006
More recently, designers also look at mechanical systems
with high controllability that facilitate abstract physical
transformation. The kinetic sculpture by Art+Com is a commercial work for BMW. The sculpture uses 714 metal balls
that are individually suspended one barely visible string,
creating an seemingly weightless, amorphous mass. Each
ball lowers and retracts independently, which allows them
to approximate different forms, from simulating water
wave to construct the fluid surface of a car.
Figure 8. The Kinetic Sculpture by Art+Com. 2008
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Programmable Matter & Claytronics
Art works express our desires to a physical world that can
be rapidly transform. In the field of robotics, much effort
has been made to realize such desire. Programmable
Matter (supported by DARPA and the Wyss Institute, Harvard) is a new concept for reconfigurable systems based
on self-folding or self-assembly. One example is the
Self-folding Sheet by MIT Distributed Robotics Lab (Figure
9). These sheets are constructed from smart materials
that embed actuation, computation, communication, and
sensing. Embedded actuators are used to self-assemble
flat sheets into 3D robots with specified functionality.
Figure 9. The Self-folding Sheet by Daniela Rus’ Distributed Robotics Lab, MIT. 2007. (a) A 4 by 4 units of self-folding sheet. (b) Folded into a
table. (c) Folded into a pinwheel.
Another example, the self-reproducing machines demonstrated here are essentially modular robots. Their modules
have electromagnets that selectively weaken and strengthen connections, determining where the structure breaks
and joins. Each module is a 10cm cube, split into two
halves along the plane. One half of the cube can swivel
relative to the other half in increments of 120 degree, each
time cycling three faces of the cube. Connected cubes can
both form and change into arbitrary arrangements
However, the challenges lie between Programmable Matter
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and the reality are not only the high energy consuming for
the transformation, but also the physical limitation of the
size, weight and dimension of the electronic components
as they need to be all “patched“ on the passive materials.
Thus so far the Programmable Matter remains difficult to
scale up.
Figure 10. Self-reproduction of a physical, three-dimensional 4-module robot. 2005 (a) A basic module and an illustration of its internal actuation mechanism; (b) Three snapshots from the first 10 seconds showing how a 4-module robot transforms as its modules swivel simultaneously.
Claytronics, as an emerging vision, seeks to achieve higher freedom and precision of physical transformation by
embedding miniature sensors, actuators and controllers
into a single unit. Just as computer screen is composed by
numerous pixels that change colors, Claytronics envisions
a world that is composed with numerous such physical
units. Each unit can sense where the others are, and
change its position correspondingly to form the desired
macro shape.
Shape-changing Interfaces
Deeply influenced by the kinetic art and robotic field,
recent research in Human-Computer Interaction (HCI)
looks beyond static, rigid physical interfaces, and explores the rich transformability of input/output devices
[12]. Shape-changing Interfaces is a vision that future
physical objects can be deformed and adapted to any
non-planar surface [29]. Enabled by different technology,
29
Shape-changing interfaces investigate the dynamic interaction that derives from actively changing forms of interfaces.
Figure 11. Recompose allows user to control the transformation of a surface by hand
gestures. 2010
Figure 12. inForm by Daniel Leithinger & Sean Follmer consists of 900 individually
controllable pins that can lift up and down, MIT Media Lab, 2013
Recompose (Figure 11) and inForm (Figure 12) look at how
30
we could interact with 2.5D Shape display. Similar to the
kinetic sculpture by Art+Com, Recompose and inForm have
a matrix of plastic pins that can lift up and down. User can
use gesture or direct manipulation to change the shape of
the surface. As the physical 2.5D model is synchronized
with its digital model, the surface actively deforms itself,
too. However, like other robotic system, such interface
requires a large set of motor control, which limit its scalability.
Figure 13. Shutter by Marcelo Coelho. MIT Media Lab, 2008
Shutters takes another approach of constructing shapechange by compositing Shape Memory Alloy (SMA) into
soft fabric. As one examples of his Thesis, Marcelo showed
the potential of using SMA as a substitute of gear motors
to deform soft flexible material. As SMA has a smaller
dimension than usual gear motor, it can be easily attached
on the surface that one wants to deform, and gives people
a perception of material transformation, instead of machine transformation.
Similarly, morePhone is a prototype of future cellphone
that bend its shape to give users a silent yet visual cue of
an incoming phone call, text message or email
A set of SMA is attached on a flexible display to archive
the bending. It shares the similar construction principle as
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Shutters.
Figure 14. morePhone, Queen’s University Human Media Lab, 2013
Smart Materials
The emerging interests on SMA bring our attention to the
deployment of Smart Materials in HCI. A smart material
refers to a highly engineered material that responds intelligently to their environment (Addington & Schodek, 2005).
The response can be mechanically or optically, etc. The
figure below lists out some of the current popular smart
materials by comparing the relationship between input
stimulus and output response.
Figure 15. Stimulus-response matrix for selected materials, Modified from Textiles Future
In this thesis, we focus on the mechanical output, which
allows material transformation. Recently, more and more
researches in HCI utilize smart materials to leverage input,
output, power storage and communication for interface
design. As the project Shutters demonstrated, smart
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materials shift our attention from machine to material
transformation, from hard to soft mechanics. Smart materials, like SMA, Ferro fluid, Electro-Active Polymer, enables
interface/product designers to think about physical transformation from material perspective.
However, most current attempts to implement smart materials in interface/product design simply propose smart
materials as replacement or substitutes for more conventional materials or actuators. Smart materials are typically
patched atop an existing structural system. It still follows
a paradigm, in which actuators and actuated materials
are separated, isolated. Take Shutters for example. If we
change the fabric to another soft material (e.g. rubber), its
topological transformation will stay the same (although
the degree of bending might vary based on the substrate’s
Young’s Modulus.)
Such patching strategy remains still repetitive assemblies
and difficult to scale up as it is typically maintained by
global control, just as modularized gear motor system. If
we want to construct complex three-dimensional transformation, this “patching” approach would result numerous
cable attached on the material surface and high energy
consuming. It is difficult to demonstrate a real world application with that.
So the question I would like to propose is: Can we propose
an alternative design approach to achieve more expressive material transformation that current modularized actuation system cannot easily do? Can we partially offload
the shape-change control from actuators (digital) to the
material itself (analogue)?
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Material, Forces and Information
“Above all we must remember that nothing that exists or
comes into being, lasts or passes, can be thought of as entirely isolated, entirely unadulterated. One thing is always
permeated, accompanied, covered or enveloped by another. It produces effects and endures them.”
— Johann Wolfgang von Goethe
Transformation in Nature
It has been commonly agreed that Nature creates solution with maximal performance using minimal resources.
Nature’s inventions have been also inspiring human activities and inventions. Now let’s slow down the speed of
chasing new enabling technologies of actuator, and look
at how nature transforms things. In the natural world, the
phenomena of shape-change are always conducted on the
material level. The octopus’ camouflage phenomenon is a
result of adjusting the size of chromatophore cells on the
skin; wooden veneer curves directionally based on the directional structure of its fiber when absorbing environmental humidity [1]. Materials’ geometry and structure play a
significant role in that transformation processes. However,
35
they have been neglected in man-made shape-changing
interfaces.
Take a close look at dry leaves. When leaves are alive,
they are all flat. After they dry out, the surface curves up in
different angle and degree to form varies shape. Where the
leaf veins are thick, it stays flat; where veins are thin, the
surface bends. The end form is an equilibrium state after
constant negotiation between gravity and the distribution
of veins. The leaf vein serves as a material constraint that
contributes to the end shape.
Figure 16. Diagram of a transverse section through a tree trunk illustrating the
deformations that result when blocks of secondary xylem (wood) are taken out and
allowed to try. the in situ geometry of each block of wood is shown by solid lines;
the bent outline of each block, once it is removed from its original location, is shown
by dotted lines
Another example of the transformation of natural material is the wooden veneer and its hygroscopic behavior
(Niklas, 1992). When a piece of wooden veneer is taken
36
out of the tree trunk and let to be dried, the veneer will
curves up to different direction due to its very fibrous
structure. Figure 16 shows the relation between deformation and fiber orientation. The property of directional
dependency is termed as Anisotropy. It implies the ununiformed distribution of physical material that causes heterogeneous mechanical properties. As core of this thesis,
I will discuss later how to design material anisotropy to
control its transformation.
Figure 17. Diagram of a transverse section through a tree trunk illustrating the
Chrysochroa fulgidissima (the Japanese Jewel Beetle). (a) The elytra and the
ventral side of this beetle display bright and iridescent colors that show a strong
angular dependence. (b) A multilayer stack with appropriate thicknesses and refractive index of the constituent films causes interference of light and strong spectral selectivity for the reflected color, scale bar 400 nm. Irregular deformations of
the multilayer - (c) optical micrograph, scale bar about 100 um, and (d) scanning
electron micrograph, scale bar 10 lm - assure scattering and the visibility of the
color over a wide angular range. All pictures are taken from <Photonic Structures
Inspired by Nature>.
Not only transformation, Nature constructs functionality through material structure and geometry. While pigment-based colors feature in the most abundant techniques used to create color stimuli in nature, the brightest
37
and most intense colors result from the interaction of light
with complex structures on the micro- and nanoscale. The
shell of Japanese jewel beetle shows a remarkable metallic iridescence on its elytra1 and on its ventral side (Figure
17a). a multilayer arrangement in the epicuticle layer of
the beetle shell is the responsible structure for the bright
iridescent colors.This layer structure is made up of 20
alternating layers with refractive index n1 = 1.5 and n2 =
1.7. Irregular structures on the surface of the beetle shell
(Figure 17d) assure that the beetle’s strong color appears
not only in the direction of specular reflection but can also
be observed from other angles (Kolle, 2011).
Through the cases presented above, we can see that
Nature creates function and transformation by combining
pre-defined structure and passive force, instead of pre-defined force and passive structure. The heterogeneous
distribution of material (a pre-defined structure) gives us
the opportunity to shift the controllability from the environmental forces to the material construction.
Material Computation
Architects have been learning from Nature to build responsive artifacts that leverage the heterogeneous material
structure. The emerging field of Material Computation in
Architecture explores how material properties; micro-scale
structures and behavior can now be seen as information
that can be processed (compute) (Ahlquist & Menges,
2011). As active design generators, they can be calculated,
arranged, and fabricated to archive certain functionalities.
Carpal Skin is a prototype for a protective glove to protect
against Carpal Tunnel Syndrome, a medical condition
in which the median nerve is compressed at the wrist,
leading to numbness, muscle atrophy, and weakness
in the hand. Carpal Skin is a process by which to map
38
the pain-profile of a particular patient—its intensity and
duration—and to distribute hard and soft materials to fit
the patient’s anatomical and physiological requirements,
limiting movement in a customized fashion. It is an example of designing material distribution to archive desired
material performance.
Figure 18. Carpal Skin by Neri Oxman maps the pain distribution on human hands
to the local thickness change of material.
Figure 19. HygroScope is a prototype that changes permeability as environmental
humidity varies.
39
HygroScope explores a novel mode of responsive architecture based on the combination of material inherent
behavior. Inspired by the pinecone that opens and closes
to release seed based on the humidity change, this work
utilizes the directional instability of wood, as described
previously, in relation to moisture content is employed to
construct a climate responsive architectural morphology.
Suspended within a humidity controlled glass case the
model opens and closes in response to climate changes
with no need for any technical equipment or energy.
Model for Material Transformation
The journey to the Nature gives us an opportunity to reflect
how can we design and construct next generation shapechange interfaces with expressive transformation in an
ecological way. Nature not only operates difference forces to deform materials (Just as we use motors or SMA to
actuate interfaces), but also creates material structure to
assist formation and transformation.
We can then define three factors that are essential for a
transformable system (machine or material).
Material: The physical matter, soft or hard, that
performs the transformation.
Forces: The operation of energy, internal or external, that actuates the material.
Information: The instruction of how the transformation should be.
The abovementioned approach of design Machine Transformation can be conclude as a model below:
40
Figure 20.
If machine transformation looks at how encoded energy
distribution can actuate materials directly, material transformation focuses on how the transform information can
be offloaded to the material structure. As Nature encodes
the shape-change information in the material instead of
forces, Similarly, We can either encode the Information in
the Force or Material to design next generation of transformable interfaces.
Figure 21.
41
Pneumatic Actuation Platform
“The finest workers in stone are not copper or steel tools,
but the gentle touches of air and water working at their
leisure with a liberal allowance of time.”
— Henry David Thoreau
The previous chapter provides a conceptual model of
constructing transformable material. To embody such
model, a serial of transformable primitives and designs
were made. This chapter serves as a technical support
for the design primitives and applications for the next
chapters. It describes a pneumatic platform that allows
deforming a soft body and change stiffness of thin sheet
(Ou, et al., 2014). Pneumatic actuation is chosen because
air is a lightweight, compressible and environmentally
benign energy source. A Pneumatic platform comprises
with a combination of solenoid valves, a vacuuming and
an inflation pump. They can be programmed to deform
or change stiffness of a soft body. For this chapter basic
concept and principle of how pneumatic control for deformation and jamming will be explained. In the next chapter
I will describe the fabrication of the soft body, in which we
can encode material distribution to archive desired transformation.
43
Inspiring works
Soft Robotics
Soft robotics is an emerging domain that is dedicated
to robots comprised of soft components including soft
actuators, flexible sensor/circuits, and soft bodies. In
contrast to other techniques for shape change, such as
spatial arrangement of actuated modules, self-foldable
chains, self-foldable surfaces, soft robotics often focuses on pneumatic actuation of elastomeric channels and
bladders. The elastomeric channels are designed in a way,
so that when inflated, the soft body can perform a series
of locomotion (Ilievski, Mazzeo, Shepherd, Chen, & Whitesides, 2011).
Figure 22. Multigait Soft Robot, Harvard Whitesides Group, 2011. The locomotion
is enabled by the air inflation and deflation.
While a primary focus of soft robotics is the improvement
of the robot’s performance and the exploration of the
bio-inspired mechanism itself, there is a large space to
introduce soft robotic technology in constructing shape
changing interfaces. One design space is to explore not
44
only isotropic, but also anisotropic deformation with
soft composite materials: an elastomer by itself deforms
uniformly under stress; however, by compositing different
structural layers with various mechanical properties, the
orientation of deformation can be controlled. More detail
will be explained in the coming Chapter.
Tunable-Stiffness With Jamming
Stiffness-changing material and mechanism have been
explored in mechanical engineering to construct robotic
manipulators, such as medical robotics, gripping arms
(Cheng. et al. 2012). Particle jamming has been explored
recently. Granular jamming system can switch from fluid
state to solid state when air pressure gets low. Externally
actuated snake-like manipulators (i.e. those with actuators integrated into the structure) utilize this stiffness
changing mechanism to deform and lock to different
shape states.
a
b
Figure 23. Stiffness tunable material enabled by jamming. (a) Particle jamming for
robotic gripper. (b) Layer jamming for robotic arm
45
However, particle jamming has unique disadvantage as
it can only work in a relatively large volume system, thus
it cannot be used to construct thin and light surface/
wall with tunable stiffness. To solve this issue, layer jamming was developed very recently (Kim, Cheng, Kim, &
Iagnemma, 2012). Layered jamming system includes an
airtight envelope with multiple thin layer jamming flaps
(i.e. sketch paper) inside. It utilizes a negative air pressure to amplify the friction between each jamming layer.
Layer jamming has been used to construct the wall of
robotic manipulators in hollow tubular shape, which can
be deformed and actuated to grasp objects. Orthoses and
protective equipment that can be shaped and fitted to the
body shape in an optimal way have been developed
Principle of Layer-jamming
Layer-jamming systems can be composed of an airtight
envelope with multiple thin layers of “flaps” (e.g., paper)
inside. As with particle jamming, the system utilizes negative air pressure to vacuum-pack the thin layers of material
to amplify the friction between each layer. As illustrated in
Figure 2, where S, P, n and μ represent the overlapped surface area, the pressure applied on the surface, the number
of layers present, and friction coefficient of the thin layers
respectively, the maximum resisting tensile force (F) can
be calculated as follows:
F = μnPS.
Depending on the direction of applied external loads, the
flexural stiffness of the jamming layers can also be important. If the direction of an applied external force is not
parallel with all the flaps, then the layered flaps can be
subjected to bending forces. That is the reason why even
sheet materials with high friction coefficients do not nec46
essarily result in a layer-jamming system with significant
bending stiffness.
Figure 24. Layer jamming effects are dependent on both maximum resisting tensile
force and compressive bending force
Control system
Inflation for deformation
To deform a soft body, a large-sized stationary air compressor (Silent Aire Tech., Super Silent compressor 50)
and a vacuum pump (Rocker Scientific, Oil-Free Pump
300) were used for experiments. However, typical tethered
pneumatic systems with a stationary air compressor limits
use in portable applications. Therefore, we developed a
a
b
Figure 25. (a) Basic pneumatic circuit for single air bag; (b) Self-contained pneumatic system
miniature pneumatic control system with small solenoid
47
valves (SMC, Series S070), a pump used as both supply
and vacuum (Koge Electronics, Series KPV), and lithium
polymer battery (3.7V, 110mAh). The system indicates
feasibility of a further mobile application. The noise levels
of the systems are 40dB and 72dB for the stationary air
compressor and the miniature pump used in the portable
in the portable system, respectively (catalog value).
Vacuum for Jamming
In a jamming control system, air can be either vacuumed
out of or pumped into the jamming envelope. A layer-jamming control circuit can be composed of two 3-port
solenoid valves and one air pump for a single jamming
envelope. For most of our tests and applications, we built
a portable control system composed of an Arduino mini
Pro, mini Arduino FET shield, SMC s070c-sdg-32 solenoid
valves and AIRPO mini D2028 air pump (Figure 6b). There
are three modes to control the airflow in and out of the
layer-jamming envelope: exhaust, supply, and close.
The exhaust/supply is the mode to deflate/inflate an air
bag, respectively. The close mode stops the airflow to
maintain the system at a certain air pressure and therefore
a degree of stiffness (Figure 26).
a
b
Figure 26. Layer-jamming control system: (a) Basic pneumatic circuit for single air
bag; (b) Portable pneumatic system
48
For the deformable furniture application, a large stationary vacuum pump instead of a small portable air pump
is used, due to the large volume of air that needs to be
removed for the application. The stationary version of the
layer-jamming control system can achieve greater jamming
and inflation speeds, as well as larger negative pressures
when jamming. This is crucial since a higher jamming stiffness is desired for the furniture application.
49
50
Proposed Design Space
Proposed here is a framework of constructing future
shape-change interfaces. This approach looks at how can
we shift our focus from programming the actuator (force)
to the structure (material). Rather than repetitively patching actuators (be it gear motors or smart materials) on
the material, then connecting them to a global controller,
we could also directly encode transformation information
into the inert materials by controlling the material heterogeneous distribution. The approach of encoding transformation information in materials is called Programmable
Material Anisotropy. By giving them different energy sources (forces), they should accomplish a reversible shapechange as programmed.
As demonstrated in Chapter 3, material’s anisotropy can
be utilized to archive complex transformation. However,
programming materials anisotropy does not suggest giving
up on programming the force. I also draw a spectrum of
transforming forces: computational, manual, and environmental. Their controllability/programmability decreases in
such order. This is another parameter of designing Material Transformation. Together with programmable material
51
anisotropy, I outlined a design space in which materials’
transformation can be designed to meet different demands and applications.
This framework is both analytical and generative. Some of
the existing works can fit into it. I attempt to complete the
whole spectrum with either physical prototypes or design
sketches. Hopefully it will server as an inspiration for new
inventions for interfaces design.
Parameters
Deforming Forces
“The form of an object is a diagram of forces
-- D’arcy Thompson”
From stones eroded by the wind; to human hands shaping
materials into products; to motor-controlled high-precision movement, all things change shape by the force that
act upon it. A force shapes formation or transformation of
physical matter.
Figure 27. The transformation of crustacean
carapaces through the deformation of a flexible
Cartesian coordiation
52
In his book <On Growth and Forms>, D’arcy Thompson
defined the abstract mathematical systems which underlie
organic structural form and their transformations. (Thompson, 1992) Thompson sought to define form through the
understanding of how physical forces produced structure
and pattern. The attempt was to devise the underlying set
of geometric laws, which shape form in relation to external
force. Such force can be from external like wind, gravity or
human intervention; or from internal like thermo, chemical
forces. No doubt that force is a parameter of shape-change
system. If we want to program transformation, we need to
consider the programmability of the deforming forces. Apparently, the environmental forces, such as wind or gravity
are difficult to be controlled.
Three types of deformation forces are introduced in this
framework. They are
Computational force: External computationally controllable
actuator connected to the materials causes their deformation. Air pressure is selected in this thesis. It can be also
hydraulic actuation or smart material such as SMA.
Manual force: Human body’s direct action upon the physical materials causes their deformation. Such as bending,
pressing, pushing, etc.
Environmental force: Natural forces acting upon physical
materials cause their deformation. Such as gravity, wind,
etc.
Figure 28. Three types of deforming Forces for designing transformable interfaces.
The rationale of such categorization is the programmability: how easy we can embed instruction in such force.
The computational force can be precisely instructed as we
programming in the microcontroller; Manual force can be
controlled by our body, but not as precise as computationally control; The environmental force is the most difficult to
be influenced. However, we can still control the materials
transformation by programming material anisotropy. As
53
mentioned, not only forces shape the structure of natural
materials, but also, together the structure of materials,
they can form unique transformation.
Programmable Material Anisotropy
“The book of nature is written in characters of geometry
--Galileo”
As Neri Oxman suggested (Oxman, 2010), Nature’s approach of creating maximum form diversity by using minimum resources is through material anisotropy. Nature
utilizes material anisotropy to achieve expressive formation and transformation. Generally speaking, anisotropy
is the property of being directionally dependent. It can be
defined as a difference of material’s physical properties
(stiffness, refractive index, density, etc.), when measured
along different axis. It implies the ununiformed distribution of physical material that causes heterogeneous
mechanical properties. As mentioned above, wood is a
naturally anisotropic material. Its properties vary widely
when measured with the growth grain or against it. That is
why when dried, they deform in different orientation.
In the field of Material Science and Engineering, the concept of anisotropy is tightly linked to a material’s microstructure defined by its grain growth patterns and fiber
orientation. However, beyond such scales anisotropy can
be utilized as a general design strategy for human-scale
shape-change interfaces.
In this thesis, the material anisotropy is specified as the
heterogeneous stiffness distribution, for the stiffness is
more relevant to the physical transformation. When external forces act upon the material, the stiffness of the
material defined the degree of deformation. The stiffer
the material is, the smaller the deformation is. If we can
54
encode the stiffness distribution across the material, a
desired transformation can be archive.
Two types of Programmable Material Anisotropy are defined here:
1. Anisotropy in Space: Encoded Stiffness Distribution
The material has different stiffness across the region.
For example, the material can be wood or paper, and the
notches or indentations may be cut or engraved by a laser
cutter to form a more flexible region. As “Programmable”
indicated, three basic parameters of stiffness distribution
are defined:
Location: controls where should deform;
Density: controls how much should deform;
Orientation: controls the direction of deformation.
a
b
C
Figure 29. Basic parameters of Programmable Material Anisotropy. (a) Location, (b)
Density, (c) Direction.
2. Anisotropy in Time: Dynamic Tunable Stiffness
Unlike static pre-defined stiffness distribution, material’s
overall stiffness can be dynamically controlled via the
pneumatic system. This enables a dynamic transformation. As explained in the last chapter, the parameter that is
55
crucial to the stiffness changing in time is the negative air
pressure in the jamming bag.
Design space
Once we have the parameters, we can now draw a design
space for material transformation. By matching the Deforming Forces and Programmable Material Anisotropy
together, we have six different type transformations, which
can be programmed in different ways. They are:
i. Pre-defined Stiffness distribution with Computa-
tional Deformation;
ii. Pre-defined Stiffness distribution with Manual
Deformation;
iii. Pre-defined Stiffness distribution with Environmental Deformation;
iv. Dynamic Tunable Stiffness with Computational
Deformation;
v. Dynamic Tunable Stiffness with Manual Deformation;
vi. Dynamic Tunable Stiffness with Environmental
Deformation;
Some of those transformations have been widely studied
before or they have lower programmability. For example,
Pre-defined Stiffness distribution with Manual Deformation is about origami and foldable structure design, which
has been studied quite widely. Their transformations do
not response dynamically, neither.
Therefore in this thesis, I will focus on type B, D, E. I will
56
also leave the type F in the future work due to complexity of conducting real-world experiment. For each type, I
present series of transformation primitives to proof the
concept.
Figure 30. A design space of transformable material for Shape Changing Interfaces.
Transformation primitives
Type A
Dynamic Tunable Stiffness × Manual Deformation
This material primitive examines at how a tunable stiffness
would affect manual deformation of a thin sheet material.
A tunable stiffness enables a dynamic material constraint
when user manually deforms the interface. A user can
easily change the shape of the interface when it is soft and
quickly lock the shape by tune it to stiff.
Primitive A is a simple plan sheet with tunable stiffness.
57
It contains 12 layers of 80-gram sketch paper. The figure
31 shows that as the air pressure inside the jamming bag
drops, the sheet exhibits higher stiffness.
Figure 31. Dynamic Tunable Stiffness with Manual Deformation. The stiffness of the sheet varies as the negative
air pressure changes inside the airtight envelop.
Primitive B looks at a weaving structure of two jamming
sheets can determine the bending orientation of the woven piece. We can weave multiple jamming units to modify
the stiffness of layer jamming. In the test, we design a
jamming unit, which has twelve layers of eight strips. By
cross-weaving the two and applying different air pressures
on each, we can define the directional bending behavior.
When only vacuuming the horizontal jamming unit, the
whole piece can be only bent up and down; when only vacuuming the vertical one, the whole piece can be only bent
left and right.
58
Figure 32. Two jamming bags woven together. It constrain the bending direction, up / down or left / right.
Alternatively, we can also add the stiffness control to each
strip. Figure 33 shows a 5 by 5 weaving structure. Each
strip’s stiffness can be tuned individually. The weaving
structure enables a more free addressable control of surface stiffness.
Figure 33. Five jamming bags woven together. Each one can be individual controlled.
We can envision that, with more sophisticated weaving
structures or higher resolution of stiffness control, tunable
stiffness would allow more type of interaction with physical material be programmed or defined, such as the degree of rolling, the direction of stretching, etc. (Schumach59
er, et al, 2010). Those interactions can be computationally
enabled or constrained as the stiffness changes.
Figure 34. Interactions with sheet shape material.
Fabrication
All primitives are fabricated with heat seal machine. As
figure 35 showed, two pieces of transparent vinyl were cut
into the identical size. One of them has an air connector
attached on. We sealed first three sides of the two vinyl
pieces together. After that put the jammable materials in.
They can be sketch paper, fabrics, cardboard or sandpaper. A detailed performance comparison of those materials can be found in the appendix. Finally we sealed the
last side to create a completely airtight jamming unit.
60
Figure 35. The fabrication process of stiffness changing sheet
Type B
Pre-defined Stiffness distribution × Computational Deformation
These material primitives examine at how a pre-defined
material stiffness distribution would affect computational
controlled deformation. Here, an elastomer by itself deforms uniformly under controllable air pressure; however,
by compositing different structural layers, the orientation
of deformation can be pre-defined.
Primitive C, This transformable primitive includes three
layers, a silicon layer with embedded airbags connected
with air channels, a paper layer with crease patterns, and
a thin silicon layer at the bottom to bond and protect the
paper layer. While soft actuators have been introduced
before, this one focuses on introducing paper composite
with various crease patterns to control the bending behavior. When inflated, the inner airbags function as actuators to generate elongation and force the surface to bend
towards the opposite direction.
Figure 36. Structure of the composite
In this case, dynamic control of the curvature is deter61
mined by two factors: air pressure and crease pattern.
First, airpressure can control the degree of curvature. Our
experiments show how pumping additional air will make
a single bending turn into a curling with continuous bending. Secondly, the design of paper crease patterns will
affect the deformation. As mentioned above, three parameters of crease patterns are defined in the experiments:
density, location and direction. Figure 37 also indicates
how density affects the sharpness of bending. Lower
density creases enable sharper bends and by varying the
location of crease, we can control the bending location on
the surface. Laying out the crease lines diagonally generates helical shapes instead of curling on a single plane.
Figure 37. The bending behavior changes as the lovation, density and direction of the crease pattern varies
Wood has been also test in this experiment. Figure 38
demonstrates a variation of on-surface pattern cuts on
thin pieces of wood instead of paper. It shows similar
bending and curling behaviors.
Figure 38. Crease patterns on thin wood.
62
To apply the aforementioned approaches of dynamic
control of shape changing states, we test how specifically
designed crease patterns and respective control of airbags
can make a flat circular shape morph into different spatial
structures with three stands (Figure 39). We also show a
progressive transformation from a line to a square.
Figure 39. Specifically designed crease patterns and respective control of airbags
enabling dynamic transformation of shapes.
In Primitive D, the appearances of surface bumps are
determined by air pressure and cut pattern. Elastic fabric (Spandex) was chosen due to its compliance under
stress when composited with silicon. The difference in the
Young’s Modulus of fabric compared with silicon creates
multi-state deformation (Figure 40). We demonstrate that
the same surface will deform from macro to micro level as
air pressure is increased (Figure 41).
a
b
Figure 40. (a) Structure of composite material. (b) Fabric constraints of deformation in local areas of surface.
One advantage of a fabric-elastomer composite is the ease
of designing and fabricating different patterns. Rather
than making customized molds for textures, patterns can
be quickly designed and cut with digital fabrication meth63
ods, such as laser cutting. Figure 14 shows a variety of
texture patterns we have explored.
a
b
Figure 41. (a) As the increase of air pressure, the surface deform from global to local region. (b) Different textures
are generated due to different cut patterns on the fabric composite layer.
Alternatively, the surface of a multi-state shape change
may comprise more than three layers. For example, the
surface may comprise a “sandwich” of four elastic layers.
A first central layer of the “sandwich” may be stiffer than
a second central layer of the “sandwich”, and both central
layers may be stiffer than the inner and outer layers of
the “sandwich”. Holes in the second central layer may be
surrounded by holes in the first central layer (when viewed
from a perspective normal to the central layers). This
four-layer “sandwich” can produce at least three levels of
bumps. For example, during an initial stage of inflation of
the multi-state inflatable device, the overall shape of the
display may have only a single bump. In a later stage of
inflation, a second level of bumps may form on the initial single bump. During an even later stage of inflation,
a third level of bumps may form on the second level of
bumps.
64
Figure 42. multiple “sandwich“ structure.
Figure 43. Visualization of three-stages inflation.
Beyond bending or surface texture, we can envision a basic syntax of shape-change (Rasmussen, et al., 2012) can
be achieved just by the encoded material constraints. We
can also envision that by combining syntax together, we
may be able to create a more complex transformation with
less actuator.
Figure 44. A syntax of shape changing.
65
Figure 45. Fabrication process
Fabrication
The fabrication process of these primitive are molding and
casting. The major soft body is molded and casted with
Silicone Rubber ((EcoFlex 00-30, Smooth-on, Inc). All primitives are layered composite materials. In order to create
a nicely performed composite, we used oven to accelerate
the curing process of Silicone Rubber. After pouring the
liquid Silicone Rubber in the mold, we put it in the oven
for 10 minutes. It becomes solid but still not completely
cured. We can then put another half-cured piece on top of
it to let them bond naturally in the oven for 2 hours. Since
paper cannot bond with Silicone Rubber, we coated the
whole surface of the paper with the same type of Silicone
Rubber so that it can bond with the air bladder.
Figure 46.Molding & casting for Primitive C
66
Type C
Dynamic Tunable Stiffness × Computational Deformation
As I showed in Type B, A pre-defined structure can support
a two-stages shape-change. In this part, I exam a hypothesis with a sketch, that a tunable stiffness as a material
constraint could support a multi-stages shape-change.
Here, a weaving structure of jamming is composite together with an airbag. By tuning the stiffness at certain
regions, the surface can deform differently each time we
inflate the airbag.
The Primitive E is to be implemented in the future work.
Figure 49. Reversible multi-stages transformation.
67
68
APPLICATIONS AS EVALUATION
“As structural, chemical and computational properties are
integrated at nano-, micro- and macro-scales, even the
most traditional material might become dynamic.
— Ramia Mazé”
No technological exploration is complete without real
world application that can give form to abstract framework, push the limits of what is technically feasible today
and how can it make send to people’s imagination. With
that in mind, I have developed three application prototypes: HelighX, PLYABLES, and JamBot. Each focuses on
one transformation type that I outlined in the previous
chapter, respectively Pre-defined Stiffness distribution
with Computational Deformation and Dynamic Tunable
Stiffness with Manual Deformation. These application
prototypes serve as the evaluation of the Material Transformation framework from last chapter, where I mentioned
that the framework could be used as a generative source
to create real-world applications.
69
Design Principles
There are two design principles in designing these two
applications.
1. Combining material anisotropy and computational control.
Material constraints can be either pre-programmed stiffness distribution, and/or real-time tunable stiffness; computational control can be shape-changing actuation and/
or stiffness-changing control. As a proof of the framework,
the application should demonstrate that by programming
material anisotropy, we could archive an expressive transformation that facilitates new type of interaction.
2. Combining sensing capability and output in a form of
properties changing.
As an interface, it must be able to take input directly from
outside world and response with its physical property
changing. As this thesis focuses on shape transformation,
the sensors are directly patched in/on the transformable
material. In the future, I will look at how to integrate sensing and actuation as a single material.
HelighX: Shape-shifting Lamp
Design
This lamp supports large deformation from a straight strip
shape to a rounded bulb shape. Users can pull the strip
like pulling the chain of a conventional lamp. The strip is
the illuminating light itself and it starts to curl and light
up. This demonstrates Shape-changing combined with
optical properties (Figure 50).
70
a
b
c
d
e
f
g
Figure 50. (a, b) Lamp in straight state capable of user input by pulling the entire body. (c) Silicon with
embedded liquid metal as pulling sensor. (d, e, f, g) Lamp in bulb state by curling.
Sensing
Soft robotic engineers have shown how to construct elastic sensing surfaces by injecting conductive liquid metal
(eGaIn) into inner channels of elastomer [1]. The resistance
of liquid metal changes in response to the deformation of
the channels (Coelho, 2008).
71
Figure 51. The resistance of liquid metal sensor changes in response to the deformation of the elastomeric channels through pulling.
We adapt this sensing technique to fabricate the top layer
of the composite material. It can sense surface deformation through both direct manipulation and air actuation.
These conductive channels can also be used for capacitive
sensing to detect human touch.
Fabrication
The construction of the lamp is inspired by one type of
shape changing primitives: the curling behavior under curvature change on surfaces. Silicon with embedded liquid
metal is fabricated as pulling sensor, which is attached to
the top of the lamp stip. Soft lithography is adapted for
fabricating the shape-shifting lamp. Before the casting
process, surface mounted LEDs are soldered on top of flexible copper strips. We then bond the copper strips with a
paper substrate with angular cut patterns. The two layers,
paper layer and air channel layer, are bonded together
with half cured silicon.
Figure 52. The Expanding Geodesic Dome by Hoberman Associate. 1991
PLYABLES: A Deformable Furniture
Design
We design a portable chair that resembles a flat, flexible
carpet in its unjammed state, such that it can be folded
and carried easily . When users transform the flat sheet
72
into the shape of a chair by creating two folds where the
sensors are embedded, the system will automatically start
the jamming process after three seconds. Once jammed,
the carpet will become stiff enough to maintain the chair
shape and support up to a load of up to 55 kilograms. The
carpet can be formed into other 3D shapes as well, such
as a table board, or a free-formed lounge.
Figure 53. Deformable Furniture: (a) Unwrapping a flexible carpet. (b) Vacuuming the carpet. (c) Carpet becoming stiff. (d) Carpet becoming
soft again and conformed to the shape of the box. (e) Carpet turning into a chair. (f) The chair holds weight up to 55kg.
Figure 54. Deformable Furniture: (a) Unwrapping a flexible carpet. (b) Vacuuming the carpet. (c) Carpet becoming stiff. (d) Carpet becoming
soft again and conformed to the shape of the box. (e) Carpet turning into a chair. (f) The chair holds weight up to 55kg.
Sensing
PLYABLE can be embedded with sensing layer. In order to
73
proof the concept, a serial of prototypes have been made.
The way to construct thin pressure and bending sensors
with off-the-shelf materials has been introduced. We
construct our pressure sensor and bending sensor with
one layer of copper tape, one layer of 3M velostat, and
another layer of copper tape. As the sensor are pressed
or bent, the copper tapes will make more contact with the
velostat. Thereby the electrical resistance between the
three layers will be reduced. This behavior allows us to
detect the amount of force applied on the sensor. In our
material samples, pressure sensors are constructed as
round shapes and can be attached to any area that need
pressure detection (Figure 54a-c).
Figure 55. Embedding sensors in the jamming units: (a-c) pressure; (d-f) Bending;
(g-i) Mutual capacitance.
Bending sensors are constructed in rectangular shapes
and can be attached to the hinges at which bending needs
to be detected (Figure 54d-f). As a preliminary exploration,
our current sensors have discrete sensing points. In the future, a more generic sensor network can be constructed as
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well. For example, instead of four pressure sensor points,
the entire layer can sense pressure at any given point.
Mutual capacitive sensing is also explored as an approach
to detect proximity between two folding surfaces (Figure
54g-i). Similar to bending sensors, we can also construct
a more complex sensing network to detect more complex
shape deformation.
Fabrication
We use 25 layers of 800-grit sand paper as jamming flaps
to build the entire jamming unit. Each flap has a dimension of 45 × 152 cm. The total thickness of the unit is 8.5
mm. For the jamming envelop, we use a heat sealable 70
Denier Nylon Taffeta fabric (rockywood.com). It is a nylon
fabric, which has PVC laminate on one side, which provides the possibility to heat seal. The Nylon fabric provides nice visual aesthetic and smooth haptic sensation.
The sealing processing is similar to the primitives as described above. We added one layer of mesh fabric to help
the air flow evenly, as the jamming surface is much bigger
than the primitives.
Figure 56. Flexible arm cast.
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Extension of application
Based on the similar fabrication process, we build another strip whose stiffness can be also dynamically tuned.
The strip has a dimension of 10 *120 cm. It is designed as
a reconfigurable rehabilitation cast. Patient can wrap it
around neck, arm or leg when need. The strip can change
its stiffness through time as the patient recovers.
JamBot
Design
To demonstrate the potential of combining Dynamic tunable Stiffness and the computational controlled actuation,
we built a soft robotics that can change its stiffness. The
robot can crawl across the floor like other soft robot when
it is soft. After jamming, its body stiffens to resist higher
pressure or load. For this prototype the jamBot can take
about 400 grams vertical load. (Figure 57)
Figure 57. JamBot uses pneumatic actuation
The design of the jamBot is inspired by the deep-sea animal sea cucumber. It is an echinoderm that can change its
skin stiffness to resist under water storm. We envision that
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the future stiffness-changing robot can be use for rescue
in disaster.
Figure 58. The robotics increases its stiffness to take more load
Figure 59. The control and pneumatic circuit.
Sensing and motion control
Two electrodes are embedded on the back of the jamBot.
They can sense human’s touch as a trigger of stiffening.
The motion control system includes a jamming and an
inflating system (see chapter 4). As current prototype is
limited by its own dimension, we did not attach the whole
control system on the soft body.
Fabrication
The jamBot has a dimension of 0.5 by 5 by 25 cm. It comprises with two layers: a jamming layer and an actuation
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layer. Two layers are glued together by common super
glue. The jamming layer contains 18 layers of sand paper.
The ends of the sand papers were cut into a structure to
archive high flexibility. The actuation layer includes two
non-flexible airbag. While inflated, the airbags behave like
the biceps (the muscle to pull the arm up), and compresses themselves to cause the jamming layer to bend. The
inflation of non-elastic airbags happens on the same side
as the surface bends towards (Figure 60). For more information about compression for bending, please refer the
paper. (Yao, et al., 2013)
Figure 60. Surface bending can be determined by the compression of airbags with low elasticity.
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A STEP FORWARD...
Morphing Vehicle
Figure 61. The concept drawing of morphing wings
If we utilize Programmable Material Anisotropy as one
parameter of designing future transformable object, we
might then be able to rethink some of the big (both scale
and technical wise) design challenge in the real-world
applications of transformable material. Morphing Wings
have been on the top list of future transformable objects.
The development of morphing wings can potentially enhance the aircraft maneuver. For example, the wing twist
could be adjusted throughout the entire flight in order to
maintain a shape giving optimal lift-drag ratio for maximum range. It could be also as a means of roll control.
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If we could utilize material with Dynamic Tunable Stiffness to construct the wings, we could possible leave the
shape-change task to the environmental wind, let it form
the wings to a desired shape as we adjusting its stiffness.
Similarly, we could adopt this approach to design transformable car or sail. This is the Type F transformation that
described in chapter5.
Beyond transformation
Previous chapters demonstrated that programming material anisotropy in space and time provides an alternative
way of designing Material Transformation in the context of
HCI. Yet the full potential interpretation of anisotropy as a
method of controlling material organization remains still
less explored for interface designer. In the field of Material
Science, engineers find inspiration from natural anisotropy
to design new smart material that can dynamically change
properties in response to manual deformation (figure
62). It is therefore crucial for interface designers to adopt
the concept of designing anisotropy across scales to fully
discover the potential of new actuators, smart materials or
sensors.
Figure 62. Material properties.
Through this thesis, I hope to inspire designer to look at
interaction design from a material perspective. As Neri
Oxman stated: “ anisotropy is without a doubt one of the
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most important properties for a designer operating at the
heart of contemporary design culture. “ Beyond Material
Transformation, what else can we do with Programmable
Material Anisotropy?
Illumination
In HCI, illumination is usually designed with electronic
components such as LED or light bulb. Inspired by the
work from Matthias Kohl, we could also design illumination change by designing dynamic material anisotropy
change. Another of my on-going project optiElastic looks
at how can we fabricate multi-layer elastic optical waveguide with elastomers, which have different refractive
index. Such layered structure allows guiding a certain
wavelength, red for example. When stretched, however, it
guides another wavelength, green for example. The color
change needs no longer electronic I/O transducer, but just
the material’s structure change.
Figure 63. Customized elastomeric waveguide with cladding.
Sensing
As interface designers are increasingly encountering new
type of sensors to build novel applications, how can one
design with it beyond simply patching it? Again, we can
look at how the distribution of the sensor can be designed
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in response to human input. For example, we can embed
a type of touch sensor on an elastomeric surface, so that
when user stretch the surface, the gap between the sensors would change to facilitate another sensing modality
(from swipe to precise touch).
a
b
Figure 64. Visualization of deformabale sensor. Sensing modality changes from (a)
swiping to (b) accurate selecting.
Construction
The future of constructing physical world lies in the smarter material, not just smarter machines. If we could design
material parts with a programmed heterogonous structure,
so that we could assemble them in a particular sequence,
we could create a macro-scale material that can perform
self-assembly. Inspired by how DNA performs self-assembly in the cell, Skylar Tibbits provides an approach of
embedding assembly information in the material. He designed material part based on the computer logic so that
then can self-assemble to a desired shape under a passive
force. (Tibbits, 2010)
Figure 64. Digital simulation of Logic Matter self-assembling to a sphere.
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Nano-Actuator Distribution
It has been shown in earlier work (Chen, 2014) that the
Bacillus subtilis spore can be used to bend and release a
thin sheet substrate, due to this spore’s hygromorphic behavior. Inspired by these results, we could also introduce
the anisotropy to the deposition of those nano actuators
onto substrate geometries to achieve a wide variety of
shape transformations. Orientation of spore deposition
define the orientation of bending, position defines location of bending, and density defines degree of bending.
By combining different parameters, we can achieve finely
tuned curvatures on thin strips and larger surfaces.
a
b
Figure 63. (a) SEM scanning of bacillus subtilis natto spores applied on a latex substrate. (b) Bacillus Subtilis
Natto under microscope.
a
b
Figure 63. (a) Controlling the final bending curvature by depositing spores with different densities. (b) Bending
in different orientations defined by the orientation of lines printed out of Bacillus spores.
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CONCLUSION
Physical transformation is by no mean new idea in HCI, but
it remains largely unexplored due to its technical challenges and scalability. Inspired by how natural material changes shape based on its microstructure, this thesis takes a
material perspective on designing transformable interfaces. The structure of material and mechanical properties
such as stiffness, can not only determine its static performances, but also, with the help of external forces, support
dynamic shape change.
By introducing Programmable Material Anisotropy into the
design process, the thesis aims to contribute an alternative way of prototyping shape-change interfaces, which
exhibits expressive property-change, in an ecological and
rapid way. We could partially offload the shape-changing
control from actuators (digital) to the material itself (analogue), to achieve more types of shape-change that current modularized actuation system cannot easily do.
As contribution, the thesis explores:
1. An integrated framework of designing shapechange interfaces. Material anisotropy should be added
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to the agenda of designing shape-change interfaces in
Human-Computer Interaction (HCI). It could help us build
expressive transformable objects more easily.
2. A pneumatic actuation platform that allows material change shape and stiffness.
3. Application prototypes show how transformable
material can be used in everyday life.
4. Provide a material perspective for interface designer to play with smart materials beyond shape-change.
The old “patching” approach leaves designer little space
for creation. By introducing programmable anisotropy, designers could maximize the creativity with limited technology.
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APPENDIX
Jamming evaluation
Based on the aforementioned calculation of layer jamming’s maximum resistance to tensile loads, stackinglayer materials with high friction coefficients can achieve
a higher stiffness while the system is jammed. However,
some materials, which have high friction coefficients,
cannot achieve a considerable stiffness when jammed due
to their own softness. Therefore the material selection is
not trivial anymore. For this paper, we have surveyed 32
types of thin sheet materials (Figure 13) that are that are
relatively inexpensive, commercially available materials,
and conducted bending torque comparison tests between
normal and jammed states to quantify a material’s stiffness change. The purpose of this test is to provide designers and researchers with an overview of what materials are
suitable for layer jamming and to compare and extrapolate
relevant and desirable properties (thickness and weight)
for different applications.
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Figure 67. Samples of materials tested for layer jamming
Figure 14 shows the test setup. A standard layer-jamming
test sample is 12 flaps of targeted materials (20cm by
20cm) sealed in Vinyl-Pane clear plastic (Warp Bros). In
the test, we bend a test sample from 0° to 30°. The lever
arm is 15.2 cm. Based on the measured bending force,
the bending stiffness (jammed or unjammed state) of a
sample can be roughly calculated as: torque = 0.152 × F ×
sin30º, where F is the measured bending force.
Figure 68. Test setup of jamming samples’ torque
Figure 15 and 16 present examples of the normal and
jammed bending torque ratios of five types of materials
as a function of weight and thickness, respectively. As
indicated in figure 17, we have also tested the bending
stiffness changes based on the change in air pressure in
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the jamming envelope in order to understand how the negative air pressure influences the jamming performance.
These graphscan be useful for designers to select jamming
materials based on thickness and weight criteria.
Figure 69. Materials’ distribution in weight and torque.
Figure 70. Materials’ distribution in thickness and torque.
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