Wheeled bipedal robots have the capability to execute agile and versatile locomotion tasks in unknown terrains, with balancing being a key criterion in evaluating their dynamic performance. This paper focuses on enhancing the balancing performance of wheeled bipedal robots through innovations in both hardware and software aspects. A bio-inspired mechanical design, inspired by the human barbell squat, is proposed and implemented to achieve an efficient distribution of load onto the limb joints. This design improves knee torque joint efficiency and facilitates control over the distribution of the center of mass (CoM). Meanwhile, a customized balance model, namely the wheeled linear inverted pendulum (wLIP), is developed. The wLIP surpasses other alternatives by providing a more accurate estimation of wheeled robot dynamics while ensuring balancing stability. Experimental results demonstrate that the robot is capable of maintaining balance while manipulating pelvis states and CoM velocity; furthermore, it exhibits robustness against external disturbances and unknown terrains.

翻译：轮式双足机器人能够在未知地形中执行敏捷且多变的运动任务，其中平衡能力是评估其动态性能的关键指标。本文聚焦于通过硬件与软件两方面的创新，提升轮式双足机器人的平衡性能。受人类杠铃深蹲动作的启发，提出并实现了一种仿生机械设计，使负载高效分布至肢体关节，从而提升膝关节扭矩效率，并有助于控制质心（CoM）分布。同时，开发了一种定制化平衡模型，即轮式线性倒立摆（wLIP）。该模型通过更精准地估计轮式机器人动力学特性并确保平衡稳定性，超越了其他替代方案。实验结果表明，该机器人能够在操控骨盆状态与质心速度的同时维持平衡；此外，其对外部干扰及未知地形展现出良好的鲁棒性。