Wheeled bipedal robots (WBRs) have the capability to execute agile and versatile locomotion tasks. This paper focuses on improving the dynamic performance of WBRs through innovations in both hardware and software development. Inspired by the human barbell squat, a bionic mechanical design is proposed and implemented as shown in Fig. 1. It distributes the weight onto its hip and knee joints to improve the effectiveness of joint motors while maintaining a relatively large workspace of the base link. Meanwhile, a novel model-based controller is devised, synthesizing height-variable wheeled linear inverted pendulum (HV-wLIP) model, Control Lyapunov Function (CLF) and whole-body dynamics for theoretically guaranteed stability and efficient computation. Compared with other alternatives, as a more accurate approximation of the WBR dynamics, the HV-wLIP can enable more agile response and provide theory basis for WBR controller design. Experimental results demonstrate that the robot could perform human-like deep squat, and is capable of maintaining tracking CoM velocity while manipulating base states. Furthermore, it exhibited robustness against external disturbances and unknown terrains even in the wild.

翻译：轮式双足机器人具备执行敏捷且多样化运动任务的能力。本文聚焦于通过硬件与软件开发的创新，提升轮式双足机器人的动态性能。受人类杠铃深蹲动作启发，提出并实现了一种仿生机械设计（如图1所示）。该设计将重量分配至髋关节与膝关节，在保持基座连杆较大工作空间的同时，提高了关节电机的驱动效能。同时，设计了一种基于模型的新型控制器，该控制器综合了高度可变轮式线性倒立摆模型、控制李雅普诺夫函数以及全身动力学模型，从而在理论上保证了稳定性并实现了高效计算。与其他方案相比，高度可变轮式线性倒立摆模型作为对轮式双足机器人动力学更精确的近似，能够实现更敏捷的响应，并为控制器设计提供理论依据。实验结果表明，该机器人能够执行类人深蹲动作，并在调控基座状态的同时保持对质心速度的跟踪。此外，即使在野外环境下，机器人也表现出对外部干扰与未知地形的鲁棒性。