Claytronics

The researchers at Carnegie Mellon University have developed various prototypes of catoms. These vary from small cubes to giant helium balloons.[5] The prototype that is most like what developers hope catoms will become is the planar catom. These take the form of 44 mm diameter cylinders. These cylinders are equipped with 24 electromagnets arranged in a series of stacked rings along the cylinder's circumference. Movement is achieved by the catoms cooperatively enabling and disabling the magnets in order to roll along each other's surfaces. Only one magnet on each catom is energized at a time. These prototypes are able to reconfigure themselves quite quickly, with the uncoupling of two units, movement to another contact point, and recoupling taking only about 100 ms. Power is supplied to the catoms using pickup feet on the bottom of the cylinder. Conductive strips on the table supply the necessary power.[6]

In the current design, the catoms are only able to move in two dimensions relative to each other. Future catoms will be required to move in three dimensions relative to each other. The goal of the researchers is to develop a millimeter scale catom with no moving parts, to allow for mass manufacturability. Millions of these microrobots will be able to emit variable color and intensity of light, allowing for dynamic physical rendering. The design goal has shifted to creating catoms that are simple enough to only function as part of an ensemble, with the ensemble as a whole being capable of higher function.[7]

As the catoms are scaled down, an onboard battery sufficient to power it will exceed the size of the catom itself, so an alternate energy solution is desired. Research is being done into powering all of the catoms in an ensemble, utilizing the catom-to-catom contact as a means of energy transport. One possibility being explored is using a special table with positive and negative electrodes and routing the power internally through the catoms, via “virtual wires.”

Another major design challenge will be developing a genderless unary connector for the catoms in order to keep reconfiguration time at a minimum. Nanofibers provide a possible solution to this challenge.[8] Nanofibers allow for great adhesion on a small scale and allow for minimum power consumption when the catoms are at rest.

Meld is a declarative language, a logic programming language originally designed for programming overlay networks.[10] By using logic programming, the code for an ensemble of robots can be written from a global perspective, enabling the programmer to concentrate on the overall performance of the claytronics matrix rather than writing individual instructions for every one of the thousands to millions of catoms in the ensemble.[11] This dramatically simplifies the thought process for programming the movement of a claytronics matrix.

LDP is a reactive programming language. It has been used to trigger debugging in the earlier research. With the addition of language that enables the programmer to build operations in the development of the shape of the matrix, it can be used to analyze the distributed local conditions.[12] It can operate on fixed-size, connected groups of modules providing various functions of state configuration. A program that addresses a fixed-size module rather than the entire ensemble allows programmers to operate the claytronic matrix more frequently and efficiently. LDP further provides a means of matching distributed patterns. It enables the programmer to address a larger set of variables with Boolean logic, which enables the program to search for larger patterns of activity and behavior among groups of modules.[2]

Performance errors for thousands to millions of individual catoms are hard to detect and debug, therefore, claytronics matrix operations require a dynamic and self-directed process for identifying and debugging errors. Claytronics researchers have developed Distributed Watchpoints, an algorithm-level approach to detecting and fixing errors missed by more conventional debugging techniques.[13] It establishes nodes that receive surveillance to determine the validity of distributed conditions.[14] This approach provides a simple and highly descriptive set of rules to evaluate distributed conditions and proves effective in the detection of errors.

Two important classes of claytronics algorithms are shape sculpting and localization algorithms. The ultimate goal of claytronics research is creating dynamic motion in three-dimensional poses. All the research on catom motion, collective actuation and hierarchical motion planning require shape sculpting algorithms to convert catoms into the necessary structure, which will give structural strength and fluid movement to the dynamic ensemble. Meanwhile, localization algorithms enable catoms to localize their positions in an ensemble.[15] A localization algorithm should provide accurate relational knowledge of catoms to the whole matrix based on noisy observation in a fully distributed manner.