Locomotion With A Unit-Modular Reconfigurable Robot

A unit-modular robot is a robot that is composed of modules that are all identical. In this thesis we study the design and control of unit-modular dynamically reconfigurable robots. This is based upon the design and construction of a robot called Polypod. We further choose statically stable locomotion as the task domain to evaluate the design and control strategy. The result is the creation of a number of unique locomotion modes. The exciting aspect about a modular robot like Polypod is that it does not only describe one robot, but also presents the building blocks from which many different types of robots can be formed. Dynamic reconfigurability adds a new dimension to the capabilities of the robot. To gain insight into these capabilities in the domain of locomotion, we first build a general, functional taxonomy of locomotion modes. We show that Polypod is capable of generating all classes of statically stable locomotion, a feature unique to Polypod. Next, we propose methods to evaluate vehicles under different operating conditions such as different terrain conditions. We then evaluate and compare each mode of locomotion on Polypod within each class. This study leads to interesting insights into the general characteristics of the corresponding classes of locomotion. Finally, since more modules are expected to increase robot capability, it is important to examine the limit to the number of modules that can be put together in a useful form. We answer this question by investigating the issues of structural stability, actuator strength, computation and control requirements.