Whole-Body Motion Response to Abrupt Acceleration Changes: Rapid CoM Motion Mapping, Compensation and Tracking for Wheel-Legged Humanoid Robot

Center-of-Mass (CoM) motion control is key for wheel-legged humanoid robots to perform flexible movement on rough terrains and resist disturbances in order to maintain stability. During rapid movement, collisions and external disturbance, the robot’s acceleration will undergo abrupt changes. However, the challenge of rapidly adjusting and precisely tracking the CoM motion under such conditions to achieve stable movement has not been well solved, resulting in unsatisfactory performance in tasks such as rapid start/stop and payload adaptation. To this end, we propose a novel CoM tracking and compensation controller (CTCC), which integrates CoM motion mapping and compensation with whole-body motion optimization. Based on user commands and the robot’s state, CTCC can optimize the desired CoM motion under abrupt acceleration changes using the motion planner and compensator, and optimize the desired motion of the joints using the whole-body tracking controller while maintaining balance. In terms of flexible movement and disturbance resistance, CTCC enables the BHR-W to rapidly start or stop according to user commands, and also allows it to adaptively adjust when unknown payloads are applied, swiftly restoring stability. Finally, experiments confirm that CTCC significantly reduces acceleration and deceleration times during robot movement and enables swift posture adjustments to restore stability under various payloads, demonstrating excellent effectiveness and stability for precise CoM tracking under abrupt acceleration changes.