Analysis and control of an omnidirectional mobile robot

In this paper, the control system design is presented for an omnidirectional mobile robot based on MY wheels-II. First, the MY wheel-II mechanism and prototype platform are briefly introduced. Then the detailed dynamic model is derived, which shows the robot is a switched nonlinear system. To deal with the difficulties and challenges in the controller design for the switched nonlinear system, a simple but robust control system design, based on active disturbance rejection control framework, is proposed. The proposed control system requires very little robot information. The basic idea is to estimate the unknown internal changing dynamics of the robot and external disturbances by the extended state observer, and then to actively compensate them by the control signal in real time. In addition, the stability properties are also analyzed based on the previous analysis results. Simulation results show the effectiveness and strong robustness of the proposed control method.