The servo-control system for an omnidirectional mobile robot

The authors describe the design and implementation of a motor drive control system for an omnidirectional wheelbase, the Ilonator platform, developed at the Robotics Institute at Carnegie Mellon University. The experimental mobile platform is mounted on four omnidirectional wheels which permit a full three degrees of freedom (3 DOF) in the plane. The distributed servo-control system is coordinated by onboard computer which converts 3-DOF acceleration commands into individual velocity commands for the four wheels. Four HCTL-1000 motor control chips close the velocity-control feedback loops for the wheels. Details of the platform kinematics and motion command structure, servo hardware design and implementation, software for command and joystick control, and the experimental tuning of the controller parameters are presented