Design and Control of SKATER: A Wheeled-Bipedal Robot With High-Speed Turning Robustness and Terrain Adaptability

This article presents the design, control, and implementation of a novel wheeled-bipedal robot: SKATER. The design of the wheeled-leg structure and joint actuators is introduced and a hardware control architecture is developed for state perception and servo control of the robot. A distributed dynamic modeling strategy is employed to reveal the force transfer relationship between the torso and the wheeled-leg system. Furthermore, a hierarchical control framework based on model predictive control is proposed, with the incorporation of centrifugal force compensation (CFC) and terrain adaptation control strategies into the whole-body controller to enhance the high-speed turning robustness and terrain adaptability of the robot. The robustness to disturbance and high-speed small-radius turning are verified by antidisturbance and CFC turning experiments. In addition, the robot exhibits active compliance and adaptability when facing unstructured terrains, as evidenced by the performance in continuous step-down and down stairs with single-leg experiments.