Modeling and Robust Control of Ballbot Robot with Improved Power Transfer Mechanism

In this paper, modeling and dynamic analysis and robust control of a Ballbot Robot are examined. Because these robots are under actuated, their control is more challenging than their counterparts, such as humanoid and Segway robots development of control theories for these robots is less taken into consideration and issues such as robust stability analysis less attention has been. One of the most significant issues in these robots is how to apply force to the ball. The omnidirectional wheels used in Ballbot have only one point of contact with the ball and practically limits the amount of force applied. To resolve this issue, students of Amirkabir University of Technology have designed a new omnidirectional wheel that increases the surface of the contact points of the ball and has caused more force on the ball before sliding and has improved the performance of the robot. For this reason, in this paper, taking into account the parametric uncertainty in dynamics, robust control algorithm is suggested. In addition, in order to show the performance of this controller, a PID controller is utilized to make a comparison. In the following, a robust stability analysis of linearization of the proposed control algorithm is undertaken based on Lyapunov's theory and it is shown the closed loop system is robust with suitable selection of gains. In the end, by presenting the simulation results obtained from the applying of the proposed control algorithm on a Ballbot Robot, the performance of the proposed control algorithm is evaluated.