4SWLR: A Switched System and Skid Steer Integrated Whole-Body Control Framework for Wheeled-Legged Robots

摘要

ABSTRACT Inspired by mammalian locomotion and vehicle skid‐steering principles, this paper proposes a real‐time motion planning and tracking control framework for wheeled‐legged robots, integrating the obstacle‐crossing capability of legged robots with the skid‐steering mechanism of wheeled platforms. Unlike conventional wheeled‐legged robot control methods that rely on external swing joints, the proposed framework leverages differential wheel actuation while comprehensively accounting for the robot‐environment coupling effects under high‐speed conditions, enabling efficient and stable high‐speed steering. First, a hierarchical wheel‐terrain contact dynamics model and a skid‐steering kinematics model are established for wheeled‐legged robots with skid‐steering. By combining switched‐system skid‐steering kinematics with refined wheel–environment interaction dynamics, the framework effectively addresses active wheel torque control during high‐speed steering. Second, a skid‐steering‐based motion paradigm is introduced, which co‐optimizes legged dynamics and wheeled skid‐steering kinematics, eliminating the need for continuous leg‐lifting maneuvers to generate lateral forces and ensuring smooth high‐speed steering. Finally, extensive experiments conducted in challenging environments—including staircases, trenches, ramps, single‐side bridges, and unpaved terrains—validate the robustness and efficacy of the proposed approach. Comparative studies with state‐of‐the‐art wheeled‐legged control methods further demonstrate the superior mobility performance and enhanced wheel–terrain interaction dynamics achieved by our framework.