30-05-2013, 12:55 PM
Claytronics: A Scalable Basis For Future Robots
[attachment=54491]
INTRODUCTION
Claytronics is a form a programmable matter that takes the concept of modular robots to a new extreme. The concept of
modular robots has been around for some time. (See [14] for a survey.) Previous approaches to modular robotics sought
to create an ensemble of tens or even hundreds of small autonomous robots which could, through coordination, achieve
a global effect not possible by any single unit. In general the goal of these projects was to adapt to the environment to
facilitate, for example, improved locomotion. Our work on claytronics departs from previous work in several important
ways. One of the primary goals of claytronics is to form the basis for a new media type, pario. Pario, a logical extension
of audio and video, is a media type used to reproduce moving 3D objects in the real world. A direct result of our goal
is that claytronics must scale to millions of micron-scale units. Having scaling (both in number and size) as a primary
design goal impacts the work significantly.
The long term goal of our work is to render physical artifacts with such high fidelity that our senses will easily accept
the reproduction for the original. When this goal is achieved we will be able to create an environment, which we call
synthetic reality, in which a user can interact with computer generated artifacts as if they were the real thing. Synthetic
reality has significant advantages over virtual reality or augmented reality. For example, there is no need for the user to
use any form of sensory augmentation, e.g., head mounted displays or haptic feedback devices will be able to see, touch,
pick-up, or even use the rendered artifacts.
Claytronics is our name for an instance of programmable matter whose primary function is to organize itself into the
shape of an object and render its outer surface to match the visual appearance of that object. Claytronics is made up of
individual components, called catoms—for Claytronic atoms—that can move in three dimensions (in relation to other
catoms), adhere to other catoms to maintain a 3D shape, and compute state information (with possible assistance from
other catoms in the ensemble). Each catom is a self-contained unit with a CPU, an energy store, a network device, a video
output device, one or more sensors, a means of locomotion, and a mechanism for adhering to other catoms.
A Claytronics system forms a shape through the interaction of the individual catoms. For example, suppose we wish
to synthesize a physical “copy” of a person. The catoms would first localize themselves with respect to the ensemble.
Once localized, they would form an hierarchical network in a distributed fashion. The hierarchical structure is necessary
to deal with the scale of the ensemble; it helps to improve locality and to facilitate the planning and coordination tasks.
The goal (in this case, mimicking a human form) would then be specified abstractly, perhaps as a series of “snapshots”
or as a collection of virtual deforming “forces”, and then broadcast to the catoms. Compilation of the specification into
local actions would then provide each catom with a local plan for achieving the desired global shape. At this point, the
catoms would start to move around each other using forces generated on-board, either magnetically or electrostatically,
and adhere to each other using, for example, a nanofiber-adhesive mechanism. Finally, the catoms on the surface would
display an image; rendering the color and texture characteristics of the source object. If the source object begins to move, a
concise description of the movements would be broadcast allowing the catoms to update their positions by moving around
each other. The end result is the global effect of a single coordinated system.
Hardware
Even with our design principles, the space of possibilities is enormous. It is helpful to observe, however, that there are
several discontinuities in the design space, as summarized in Figure 1. Of interest are three regimes: macro, micro, and
nano scale catoms.
At the macro-scale, catoms have a diameter > 1cm and weigh many tens of grams. In light of the design principles
stated above, the only viable force that can be used to move and adhere catoms is magnetic; which sets a lower limit on
the size and weight of a catom as the magnets have considerable weight and volume. Furthermore, the circuitry needed
for the high currents necessary to switch the magnets increases the weight. At this scale, it may not be possible to adhere
to the “no static power” design principle. Our current prototype, as shown in Figure 2, is a system composed of catoms
that only operate in two dimensions. In this case gravity holds the individual catoms to a surface and we do not have to
deal with the adhesion problem.
Software
The essence of claytronics—a massively distributed system composed of numerous resource-limited catoms—raises significant
software issues: specifying functionality, managing concurrency, handling failure robustly, dealing with uncertain
information, and controlling resource usage. The software used to control claytronics must also scale to millions of
catoms. Thus, current software engineering practices, even as applied to distributed systems, may not be suitable. We are
just beginning to explore the software design principles needed.
We have broken down the software issues into three main categories: specification, compilation, and runtime support.
Our goal is to specify the global behavior of the system in a direct and descriptive manner. The simplest model we
are investigating with respect to specification is what we call the Wood Sculpting model. In this model, a static goal
shape is specified. We are investigating two alternative compilation methodologies, both of which fit into the general
category of single-program-multiple data (SPMD) programming models. In the first, we are compiling the specification
into a planning problem.
Conclusions
Claytronics is one instance of programmable matter, a system which can be used to realize 3D dynamic objects in the
physical world. While our original motivation was to create the technology necessary to realize pario and synthetic
reality, it should also serve as the basis for a large scale modular robotic system. At this point we have constructed a
planer version of claytronics that obeys our design principles. We are using the planer prototype in combination with our
simulator to begin the design of 3D claytronics which will allow us to experiment with hardware and software solutions
that realize full-scale programmable matter, e.g., a system of millions of catoms which appear to act as a single entity, in
spite of being composed of millions of individually acting units.
[attachment=54491]
INTRODUCTION
Claytronics is a form a programmable matter that takes the concept of modular robots to a new extreme. The concept of
modular robots has been around for some time. (See [14] for a survey.) Previous approaches to modular robotics sought
to create an ensemble of tens or even hundreds of small autonomous robots which could, through coordination, achieve
a global effect not possible by any single unit. In general the goal of these projects was to adapt to the environment to
facilitate, for example, improved locomotion. Our work on claytronics departs from previous work in several important
ways. One of the primary goals of claytronics is to form the basis for a new media type, pario. Pario, a logical extension
of audio and video, is a media type used to reproduce moving 3D objects in the real world. A direct result of our goal
is that claytronics must scale to millions of micron-scale units. Having scaling (both in number and size) as a primary
design goal impacts the work significantly.
The long term goal of our work is to render physical artifacts with such high fidelity that our senses will easily accept
the reproduction for the original. When this goal is achieved we will be able to create an environment, which we call
synthetic reality, in which a user can interact with computer generated artifacts as if they were the real thing. Synthetic
reality has significant advantages over virtual reality or augmented reality. For example, there is no need for the user to
use any form of sensory augmentation, e.g., head mounted displays or haptic feedback devices will be able to see, touch,
pick-up, or even use the rendered artifacts.
Claytronics is our name for an instance of programmable matter whose primary function is to organize itself into the
shape of an object and render its outer surface to match the visual appearance of that object. Claytronics is made up of
individual components, called catoms—for Claytronic atoms—that can move in three dimensions (in relation to other
catoms), adhere to other catoms to maintain a 3D shape, and compute state information (with possible assistance from
other catoms in the ensemble). Each catom is a self-contained unit with a CPU, an energy store, a network device, a video
output device, one or more sensors, a means of locomotion, and a mechanism for adhering to other catoms.
A Claytronics system forms a shape through the interaction of the individual catoms. For example, suppose we wish
to synthesize a physical “copy” of a person. The catoms would first localize themselves with respect to the ensemble.
Once localized, they would form an hierarchical network in a distributed fashion. The hierarchical structure is necessary
to deal with the scale of the ensemble; it helps to improve locality and to facilitate the planning and coordination tasks.
The goal (in this case, mimicking a human form) would then be specified abstractly, perhaps as a series of “snapshots”
or as a collection of virtual deforming “forces”, and then broadcast to the catoms. Compilation of the specification into
local actions would then provide each catom with a local plan for achieving the desired global shape. At this point, the
catoms would start to move around each other using forces generated on-board, either magnetically or electrostatically,
and adhere to each other using, for example, a nanofiber-adhesive mechanism. Finally, the catoms on the surface would
display an image; rendering the color and texture characteristics of the source object. If the source object begins to move, a
concise description of the movements would be broadcast allowing the catoms to update their positions by moving around
each other. The end result is the global effect of a single coordinated system.
Hardware
Even with our design principles, the space of possibilities is enormous. It is helpful to observe, however, that there are
several discontinuities in the design space, as summarized in Figure 1. Of interest are three regimes: macro, micro, and
nano scale catoms.
At the macro-scale, catoms have a diameter > 1cm and weigh many tens of grams. In light of the design principles
stated above, the only viable force that can be used to move and adhere catoms is magnetic; which sets a lower limit on
the size and weight of a catom as the magnets have considerable weight and volume. Furthermore, the circuitry needed
for the high currents necessary to switch the magnets increases the weight. At this scale, it may not be possible to adhere
to the “no static power” design principle. Our current prototype, as shown in Figure 2, is a system composed of catoms
that only operate in two dimensions. In this case gravity holds the individual catoms to a surface and we do not have to
deal with the adhesion problem.
Software
The essence of claytronics—a massively distributed system composed of numerous resource-limited catoms—raises significant
software issues: specifying functionality, managing concurrency, handling failure robustly, dealing with uncertain
information, and controlling resource usage. The software used to control claytronics must also scale to millions of
catoms. Thus, current software engineering practices, even as applied to distributed systems, may not be suitable. We are
just beginning to explore the software design principles needed.
We have broken down the software issues into three main categories: specification, compilation, and runtime support.
Our goal is to specify the global behavior of the system in a direct and descriptive manner. The simplest model we
are investigating with respect to specification is what we call the Wood Sculpting model. In this model, a static goal
shape is specified. We are investigating two alternative compilation methodologies, both of which fit into the general
category of single-program-multiple data (SPMD) programming models. In the first, we are compiling the specification
into a planning problem.
Conclusions
Claytronics is one instance of programmable matter, a system which can be used to realize 3D dynamic objects in the
physical world. While our original motivation was to create the technology necessary to realize pario and synthetic
reality, it should also serve as the basis for a large scale modular robotic system. At this point we have constructed a
planer version of claytronics that obeys our design principles. We are using the planer prototype in combination with our
simulator to begin the design of 3D claytronics which will allow us to experiment with hardware and software solutions
that realize full-scale programmable matter, e.g., a system of millions of catoms which appear to act as a single entity, in
spite of being composed of millions of individually acting units.