| This dissertation is a study of peristalsis, the method of locomotion earthworms use, and how to best achieve this in a robotic platform. A technique is presented that uses a braided mesh exterior to produce smooth waves of motion along the body of a worm-like robot. This braided mesh can be powered by a one degree-of-freedom cam mechanism, which is demonstrated, or by several independent motors. A new analytical model of peristalsis is presented and predicted robot velocity is compared to a 2-D simulation and a working prototype. It has been often assumed that this motion requires strong anisotropic ground friction. However, our analysis shows that with uniform, constant velocity waves, the forces that cause accelerations within the body sum to zero. Instead, transition timing between aerial and ground phases and the ability to generate strain play a critical role in the final robot speed. Lastly, we present a soft-body controller that uses simulated neuronal populations. This controller is designed for the next generation of soft, hyper-redundant systems and can intrinsically generate waves of a desired behavior while smoothly incorporating large amounts of simulated sensory input. |
