Generalized proportional integral observer based control of an omnidirectional mobile robot

This paper presents an observer based trajectory tracking control system design for an omnidirectional mobile robot with MY wheel-II. MY wheel-II is a switch wheel mechanism. Switch wheeled omnidirectional mobile robots are complicated autonomous switched nonlinear systems. In this paper, the complicated switching dynamics, unmodeled dynamics and input-output cross-couplings are considered as an unknown time-varying perturbation input vector, which is online estimated by means of a generalized proportional integral observer. The original switched nonlinear multi-input multi-output system is then reduced to three decoupled double integrators in an approximate manner. Traditional proportional derivative controllers are then applied to the decoupled double integrators. In addition, only part of the robot model information is used in the control system design. Simulation and experimental tests illustrate the effectiveness of this practical control method.