This paper introduces a new approach to studying bipedal locomotion. The approach is based on magnetically actuated miniature robots. Building prototypes of bipedal locomotion machines has been very costly and overly complicated. We demonstrate that a magnetically actuated 0.3~gm robot, we call Big Foot, can be used to test fundamental ideas without necessitating very complex and expensive bipedal machines. We explore analytically and experimentally two age old questions in bipedal locomotion: 1. Can such robots be driven with pure hip actuation. 2. Is it better to use continuous or impulsive actuation schemes. First, a numerical model has been developed in order to study the dynamics and stability of a magnetically actuated miniature robot. We particularly focus on stability and performance metrics. Then, these results are tested using Big Foot. Pure hip actuation has been successful in generating gait on uphill surfaces. In addition, complex tasks such as following prescribed gait trajectories and navigating through a maze has been successfully performed by the experimental prototype. The nature and timing of hip torques are also studied. Two actuation schemes are used: Heel Strike Actuation and Constant Pulse Wave Actuation. With each scheme, we also vary the time duration of the applied magnetic field. Heel Strike actuation is found to have superior stability, more uniform gait generation, and faster locomotion than the Constant Pulse Wave option. But, Constant Pulse Wave achieves locomotion on steeper slopes.

翻译：本文提出了一种研究双足运动的新方法，该方法基于磁驱动微型机器人。以往构建双足运动机器原型成本高昂且过于复杂。我们展示了一种名为Big Foot的0.3克磁驱动微型机器人，可在无需复杂昂贵双足机器的情况下验证基础理论。通过分析与实验，我们探讨了双足运动中两个经典问题：（1）此类机器人能否仅通过髋关节驱动实现运动？（2）连续驱动与脉冲驱动哪种方案更优？首先建立数值模型以研究磁驱动微型机器人的动力学与稳定性，重点关注稳定性与性能指标，随后利用Big Foot验证这些结果。实验表明，纯髋驱动可成功在上坡表面生成步态，且实验原型成功完成了循迹穿越迷宫等复杂任务。同时研究了髋关节力矩的性质与时序，采用两种驱动方案：脚跟撞击驱动与恒定脉冲波驱动，并针对每种方案改变磁场施加时长。结果表明，脚跟撞击驱动在稳定性、步态均匀性与运动速度方面均优于恒定脉冲波驱动，但恒定脉冲波驱动在更陡峭斜坡上仍可实现运动。