Kinematic Model-based Integral Sliding Mode Control for a Spherical Robot

Spherical rolling robots are an interesting topic for both control theory and robotic applications. This type of mobile robot shows plenty of outstanding advantageous properties which have been increasingly attracting researchers. Several platform versions of the spherical robot have been developing for these decades. In this paper, a design of a two-wheeled spherical robot attached a counter mass inside is presented along with its kinematic model. To maintain stable posture while the robot is moving, it is necessary to handle the uncertainties and disturbances that arise from changes of surface and friction conditions. A robust integral sliding mode controller, which focuses on the rolling motion control of the robot, is developed based on the established kinematic model. The designed closed-loop controller guarantees the accurate motion of the robot with maintenance of small angles of the main body and the outer shell. Experiment results are provided to investigate the efficiency of the entire operation.