2600m, DYNAMIC MOTION CONTROL FOR COMPLIANT FRAMED WHEELED MODULAR MOBILE ROBOTS

In this dissertation, a distributed robust controller, a motion control and sensing architecture, and a terrain feature localization are studied to solve general navigation problems for Compliant Framed wheeled Modular Mobile Robots (CFMMR). This type of wheeled mobile robot uses rigid axles coupled by compliant frame modules to provide both full suspension and enhanced steering capability without additional hardware. First, a distributed nonlinear damping controller is developed for single-axle unicycle type robots. The controller is then extended to multiple-axle CFMMR configurations and is robust to disturbances created by modeling errors, especially highly nonlinear frame forces caused by axle interaction. In particular, the controller considers time-varying reference velocities and allows the robot to perform posture regulation, path following, or general trajectory tracking. In order to achieve improved motion control of CFMMR, a distributed cooperative motion control and sensing architecture is developed by combining a kinematic controller for motion coordination and providing reference commands, dynamic motion controllers to follow these commands and reject disturbances, and a sensor fusion system to provide accurate posture estimates. Requirements for each subsystem and their respective interconnections are defined to optimize system performance.