11-04-2011, 09:39 AM
PRESENTED BY:
N.sudharson,P.
B.Visnu Bharat
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Abstract:
This Paper discusses about creating physical, three dimensional replicas of people or objects by the application of claytronics. This would eliminate the need for virtual reality gear and overcome the viewing angle limitations of most existing 3-D applications. There are two steps involved:
capturing a 3D image and rendering it as a physical object. Much work have been done in 3D image capture. The Major challenge is to develop 3D replicas. The basic unit of claytronics is referred as CATOMS(claytronic atoms).Replicas will be formed from the ensembles of catoms.
Catoms will have four capabilities: computation, motion, power and communication.
I. INTRODUCTION
Claytronics is an emerging field of engineering concerning reconfigurable Nanoscale robots(‘claytronic atoms’or ‘catoms’)designed to form much larger scale machines or mechanisms.The Catoms,also known as “programmable matter”,will be sub-millimeter computers that will eventually have the ability to move around,communicate with each others, change color, electrostatically connect to other catoms to form different shapes. The forms made up of catoms could morph into nearly any object, even replicas of human beings for virtual meetings. Claytronics is the integrated application of modular robotics, system nano technology and computer science to create dynamic,3-Dimensional display of electronic information.
The main goal is to give tangible, interactive forms to information so that a user’s senses will experience digital environments as though they are indistinguishable from reality.
II. DYNAMIC PHYSICAL RENDERING (DPR)
In a hospital in Houston, two surgeons appear to be performing a difficult procedure on a cardiac patient.
In fact, only one of the doctors in the room is real. The other is a replica-a lifelike physical model whose shape, appearance and movements precisely mimic those of a specialist in Tokyo who is performing the actual work. This scenario may seem like a science fiction, but this wonder can happen with the help of claytronics.
A. Creating the replicas
At a high level, there are two steps in dynamic physical rendering:
1) Capturing a 3D image: Researchers have developed technology that points set of cameras at an event and enables the viewer to virtually fly around and watch the event from variety of positions. Similar approach could be used to capture physical, moving 3D replicas.
2) Rendering as physical object: The major challenge for the DPR researchers is how to reproduce images as physical, moving replicas. Replicas will be created from a form of programmable matter-a kind of high-tech modeling clay. Catoms can be formed into different shapes, and it can change color, through light-emitting diodes on its surface. Embedded photo cells will enable it to sense light, so that a human replica can "see." Claytronics might even simulate the texture of the person or object being replicated.
A replica will have computing capabilities, but these will be accessed through touch, voice, or another natural interface rather than a keyboard or mouse.
III. HARDWARE
A. Claytronic atoms (Catoms)
The basic unit of claytronics is referred as CATOMS. Replicas will be formed from ensembles of tiny catoms. Catoms will be as close to spherical as possible to support multiple packing densities. An ensemble might contain millions or billions of catoms, which must coordinate and cooperate in order for the ensemble to function. So researchers must consider both the function of individual catoms and their behavior as part of an ensemble. Each catom will have the minimum combination of computation and actuation needed to contribute to the ensemble. To support scaling, the researchers are looking for algorithms whose running times are proportional to the longest diagonal of the ensemble. If the algorithms require more running time than this, they will quickly become intractable. In addition to programming individual catoms, researchers are focusing on developing programming models which can facilitate the task of coordinating massive numbers of catoms, all of which are simultaneously executing within an ensemble. From a hardware standpoint, researchers are striving to minimize the complexity of each catom. This will reduce its cost and improve manufacturability. And with fewer parts that could break, simple catoms will be more robust.
1)Capabilities of Catoms:
i)Computation: Researchers believe that catoms could take advantage of existing microprocessor technology. Given that some modern microprocessor cores are now under a square millimeter, they believe that a reasonable amount of computational capacity should fit on the several square millimeters of surface area potentially available in a 2mm-diameter catom.
ii)Motion: Although they will move, catoms will have no moving parts. This will enable them to form connections much more rapidly than traditional micro robots, and it will make them easier to manufacture in high volume. Catoms will bind to one another and move via electromagnetic or electrostatic forces, depending on the catom size.
Imagine a catom that is close to spherical in shape, and whose perimeter is covered by small electromagnets. A catom will move itself around by energizing a particular magnet and cooperating with a neighboring catom to do the same, drawing the pair together. If both catoms are free, they will spin equally about their axes, but if one catom is held rigid by links to its neighbors, the other will swing around the first, rolling across the fixed catom's surface and into a new position.
iii)Power: Catoms must be able to draw power without having to rely on a bulky battery or a wired connection. Under a novel resistor-network design the researchers have developed, only a few catoms must be connected in order for the entire ensemble to draw power. When connected catoms are energized, this triggers active routing algorithms which distribute power throughout the ensemble.
iv)Communications: Communications is perhaps the biggest challenge that researchers face in designing catoms. An ensemble could contain millions or billions of catoms, and because of the way in which they pack, there could be as many as six axes of interconnection.
Another unique feature of catom networks is that catoms are homogeneous. Thus, unlike cell phones or other communications devices, the identity of an individual catom is sometimes (but not always) unimportant. An application is more likely to care about routing a message to the catoms comprising a specific physical part of an ensemble (for instance, the catoms comprising a "hand") rather than sending the same message to specific catoms based on their serial numbers.
Furthermore, catoms may be in motion periodically, as the shape of the ensemble changes.
To address these challenges, researchers are investigating new routing techniques that focus on the location and function of the catoms at a given point in time. They are also focusing on building communications highways within ensembles, to limit the complexity of the routing problem.
IV. SOFTWARE
In domain of research defined by many of the greatest challenges facing computer scientists and roboticists today, perhaps none is greater than the creation of algorithms and programming language to organize the actions of millions of sub-millimeter scale catoms in a Claytronics ensemble. So it is necessary to develop a complete structure of software resources for the creation and operation of the densely distributed network of robotic nodes in a claytronic matrix. A notable characteristic of a claytronic matrix is its huge concentration of computational power within a small space. For example, an ensemble of catoms with a physical volume of one cubic meter could contain 1 billion catoms. Computing in parallel, these tiny robots would provide unprecedented computing capacity within a space not much larger than a standard packing container. This arrangement of computing capacity creates a challenging new programming environment for authors of software.
A. Programming Languages
Researchers in the Claytronics project have also created Meld and LDP. These new languages for declarative programming provide compact linguistic structures for cooperative management of the motion of millions of modules in a matrix. The center panel above shows a simulation of Meld in which modules in the matrix have been instructed with a very few lines of highly condensed code to swarm toward a target.
i) Meld:
Meld addresses the need to write computer code for an ensemble of robots from a global perspective, enabling the programmer to concentrate on the overall performance of the matrix while finessing the resource-consuming alternative of writing individual instructions for every one of the thousands to millions of catoms in the ensemble. This form of logical programming represents a heuristic solution to the challenge of controlling the action of such a great number of individual computing nodes.
From a resource standpoint, as measured in many fewer lines of code, Meld is a language whose programs produce results comparable to programs that are from 20 to 30 times longer when written in C++. This efficiency yields a substantial economy of scale in the operational time and reliability of the matrix. It also reduces the time a programmer needs to write the code.
Meld provides a reliable paradigm for efficiency in the actuation of cooperative motion among millions of Nano-scale robots. It does this by declaring positions that individual robots achieve within clusters by common rules for direct contact. Meld manages motion as a continuous process of rule-solving. Each robot engages its contacts until it satisfies all rules it can declare about its physical relationship.
ii) Locally Distributed Predicates:
While Meld approaches the management of the matrix from the perspective of logic programming, LDP employs distributive pattern matching. As a further development of program languages for the matrix, LDP, which stands for Locally Distributed Predicates, provides a means of matching distributed patterns. This tool enables the programmer to address a larger set of variables with Boolean logic that matches paired conditions and enables the program to search for larger patterns of activity and behavior among groups of modules in the matrix.
While addressing variable conditions related to time, topology and the status of modules, LDP triggers specific actions in parallel with other expressions governing local groups of modules. A reactive language, LDP grows from earlier research into the analysis of distributed local conditions, which has been used to trigger debugging protocols. From this base, LDP adds language that enables the programmer to build operations that can be used for more general purposes in the development of the shape of the matrix.
LDP shares with Meld the achievement of dramatically shorter code, the automatic distribution of the program through the matrix and automatic messaging about conditions in the matrix.
As it originates in the research to evaluate conditions throughout the ensemble, its strength is in detection and description of distributed conditions. From this perspective, it programs locally, focusing upon a bounded number of modules in contact groups while basing its predicates upon Boolean (if, then) expressions, which expand the basic set of variables that the programmer can manage throughout the matrix.
B. Integrated Debugging
In directing the work of the thousands to millions of individual computing devices in an ensemble, Claytronics research also anticipates the inevitability of performance errors and system dysfunctions. Such an intense computational environment requires a comparably dynamic and self-directed process for identifying and debugging errors in the execution of programs. One result is a program known as Distributed Watch Points, represented in the snapshot in the right panel below.
C. Shape Sculpting
The team's extensive work on catom motion, collective actuation and hierarchical motion planning addresses the need for algorithms that convert groups of catoms into primary structures for building dynamic, 3-dimensional representations. Such structures work in a way that can be compared to the muscles, bones and tissues of organic systems. In claytronics, this special class of algorithms will enable the matrix to work with templates suitable to the representations it renders. In this aspect of claytronics development, researchers develop algorithms that will give structural strength and fluid movement to dynamic forms. Snapshots from the simulation of these studies can be seen in the right-side panel at the top of this column and in the left-side panel below.
i) Lifting Catoms into the 3- Dimension:
A Claytronics designer might demonstrate the complexity of this challenge of forming 3- dimensional objects from millions of robotic catoms, each less than a millimeter in diameter, by presenting an ensemble of these tiny spherical devices laid side-by-side on a flat surface. This arrangement would present a 2-dimensional square, approximately a meter on each side. This is the organized position that an ensemble could assume before the application of any external forces.
With a flow of power into the ensemble, the sensors of adjacent catoms could induce an electrostatic alignment or latching effect to increase the hold of one Catom to another across this million-member network of distributed computing devices.
With the fine grain particularity of each individual Catom, the charge in the ensemble might enhance colors and shadings across the pixilated surface of each Catom to induce subtle lines and surface perspectives that would appear with the activation of the individual voxels -- in much the same way that pixels activate images on a video screen.
In this state, moreover, each Catom would possess sufficient micro processing capacity to implement algorithms that instruct the device to localize its position in relation to other catoms. This information would enable each Catom to initiate motion and change its alignment with adjacent catoms until the tiny spheres reach other locations. Thus, the ensemble would reshape as it creates a new contour in a boundary line or opens a void inside its boundary while still lying flat.
ii)Ensemble Rise:
All of these changes in form depend for visual effect upon the number of catoms actuated across the length and width of the ensemble. Yet the state of actuation described thus far, even as it demonstrates important advances in distributed computing, nanotechnology and modular robotics, would also highlight the greater challenge of attaining a 3-dimensional perspective -- in which catoms would rise from the flat surface to represent not only the outline but also the volume and motion of a fully-shaped object, animal or person.
To gather height and volume from the array of a million catoms lying alongside each other within a level plane, the ensemble must not only overcome the resistance of local inertia but also mass sufficient internal force to oppose gravity -- perhaps the most difficult challenge facing claytronic algorithm designers.
D. Localisation
The software researchers are also creating algorithms that enable catoms to localize their positions among thousands to millions of other catoms in an ensemble. This relational knowledge of individual catoms to the whole matrix is fundamental to the organization and management of Catom groups and the formation of cohesive and fluid shapes throughout the matrix. A pictorial context for examining the dynamics of localization is represented by the snapshot of the elephant simulated in the center panel of images below.
One of the first tasks for a modular robot is to understand where its modules are located relative of one to another. This knowledge is very useful: For example, motion planning and control will often shift many modules from one location to another, and knowing the module locations helps robot properly allocate the resources.
The knowledge of module locations will also be useful to identify a human user.
In order to determine their locations, the modules need to rely on noisy observations of their immediate neighbors. These observations are obtained from sensors onboard the modules, such as short-range IR sensors. Unlike many other systems, a modular robot may not have access to long distance measurements, such as wireless radio or GPS. Furthermore, the robot's modules will often form irregular, non-lattice structures. Therefore, the robot needs to employ sophisticated probabilistic techniques to estimate the location of each its module from noisy data.
E. Dynamic simulation
As a first step in developing software to program a claytronic ensemble, the team created DPR-Simulator, a tool that permits researchers to model, test and visualize the behavior of catoms. The simulator creates a world in which catoms take on the characteristics that researchers wish to observe. The simulated world of DPRSim manifests characteristics that are crucial to understanding the real-time performance of claytronic ensembles. Most important, the activities of catoms in the simulator are governed by laws of the physical universe. Thus simulated catoms reflect the natural effects of gravity, electrical and magnetic forces and other phenomena that will determine the behavior of these devices in reality.
DPRSim also provides a visual display that allows researchers to observe the behavior of groups of catoms.
In this context, DPRSim allows researchers to model conditions under which they wish to test actions of catoms. At the top and bottom of this column, images present snapshots from simulations of programs generated through DPRSim.
