Implementation of a Decentralized Adaptive Control System for the 12-TET Walker

The purpose of the tetrahedral walker (Tetwalker) project is to extend current space exploration into regions currently inaccessible by traditional wheeled or humanoid robots. The Tetwalker consists of arms, or struts, that join at nodes to form a tetrahedron. The struts will be able to lengthen and shorten, thereby giving the Tetrahedron shape-shifting abilities. The robot will move by changing the strut length to change its center of mass, causing it to tumble. Another benefit of such a robot is that when multiple units are combined, it is able to assume more complex shapes. This project focuses specifically on the third generation Tetwalker (the 12-Tetwalker), which consists of twelve tetrahedral robots combined to form a cube with the ability to carry a payload in the center. The intention is to use this robot for the exploration of extreme environments, such as the Martian and Lunar surfaces. The focus of this subset of the project was to implement Homayoun Seraji´s decentralized adaptive controller (DAC) to the robot. This would lessen the need for a centralized brain that would control each strut, which would be very complicated and impractical to implement for such a device. The DAC would allow each strut to independently extend to its proper position in the current gait. The DAC was to be implemented in MATLAB as well as in C for the PIC18F6627 microcontroller. The DAC would be tested by using the PUMA 560 model presented in Seraji´s paper. After this initial testing of the DAC, the DAC will be tested on a model for the 12-Tetwalker.