A COMPUTER SIMULATION STUDY OF OMNIDIRECTIONAL SUPERVISORY CONTROL FOR ROUGH-TERRAIN LOCOMOTION BY A MULTILEGGED ROBOT VEHICLE

This dissertation presents motion planning algorithms to provide omnidirectional control of a multilegged robot vehicle over rough-terrain using a three-axis joystick. The algorithms have been developed through computer simulation using a graphics device. They are based on the development of the kinematics of legged locomotion over rough terrain. The hexapod vehicle model used is for the Adaptive Suspension Vehicle (ASV) which is presently under construction at The Ohio State University.; In order to implement periodic gaits for omnidirectional control, the notion of the constrained working volume has been introduced on the basis of reachability of the leg. The optimal cycle period is selected in such a way that at least one leg fully utilizes its constrained working volume.; For control of the body motion over rough terrain, the local terrain surface is estimated by using six points of estimation based on the measurements from the six legs. Also, a simple body regulation plan has been designed which results in the body attitude adjusting to the terrain slope and the body height decreasing with greater slope. In order to control the leg motion in the transfer phase, a simple parallelogrammatic type of foot trajectory has been developed. It allows the proximity sensors to detect the potential footholds and to control the footlift height during the transfer phase. Also, the adjustment of the position and dimensions of the constrained working volume to increase the stability of the vehicle over sloped terrain has been implemented.; The algorithms have been implemented in PASCAL on the PDP-11/70 minicomputer. The evaluation of the control algorithms for the ASV is also given.