De-Coupled Dynamics Control Of A Spherical Rolling Robot For Waypoint Navigation

In this paper, the decoupled control of a nonholonomic spherical rolling robot capable of waypoint navigation over planar surfaces is investigated. The robot consists of an external spherical shell driven by an internal two-wheeled differential drive cart fused with odometry and IMU sensors. We derived the robot dynamic model under roll and spin locomotion using Lagrangian, and studied its performance under independent control of these two modes of locomotion. Experiments are conducted to evaluate the control performance on a rectangular waypoint trajectory, captured using an optical motion capture system. The result showed that with our implemented sliding mode controller of the cart's pitch and PD controller of the cart's yaw, the spherical robot can follow the desired set of waypoints effectively.