Leg Mechanics for Dynamic Locomotion

这项研究将朝着满足并超过人类行走和跑步的敏捷性、效率和健壮性的步行和跑步机器人迈进。具体地说，这项研究将解决腿部物理设计背后的基本原则，包括描述关节、弹簧和其他组件的配置，以最好地实现腿部运动。这项工作属于广泛的跨学科努力，以了解腿的功能和动力学，并将在机器人学、动力学和生物力学社区中产生实用和影响。在这里启动的基础性设计指南将使机器人能够到达动物和人类去过的任何地方，以及许多他们不能去的地方，比如核电站灾区和着火的建筑物。同样的基础将使假肢和外骨骼与人类腿部的自然动力相匹配，而只需一次电池充电就可以跑一整天。这项研究将加强对腿部系统设计与其在触地、站立和挥杆过程中的动力学之间的相互作用的理解，重点放在设计的三个关键方面：第一，腿部的惯性分布，重点是质量位置、连杆数量和腿部运动学的“冗余”元素(例如，将膝盖指向“上”或“下”)如何影响系统在触地时感受到的冲击和在摆动阶段的动力学。其次，电机与连杆的耦合，重点研究驱动和机构自由度之间的不同映射如何导致电机分担负载或相互战斗。第三，弹簧功能和布置，包括用于缓解冲击和摆动相位振铃的理想非线性，主刚度轴与机构自由度的对准，以及允许依赖于配置的弹性的传动。该研究方法借鉴了生物学和以前建造的机器人的例子，利用了应用力学的数学工具，并建立在实验行走和跑步机器人先前工作的基础上。

This research moves towards walking and running robots that will meet and exceed the agility, efficiency, and robustness of human walking and running. Specifically, the research will address fundamental principles behind the physical design of legs, including describing configurations of joints, springs, and other components to best enable legged locomotion. This work falls within a broad, interdisciplinary effort to understand leg function and dynamics, and will have utility and impact among the robotics, dynamics, and biomechanics communities. The foundational design guidelines initiated here will enable robots that can go anywhere that animals and humans go, and many places they cannot, such as nuclear power plant disaster areas and burning buildings. The same foundation will enable prosthetic limbs and exoskeletons that match the natural dynamics of a human leg, while running all day on a single battery charge. This research will enhance understanding of the interaction between the design of a legged system and its dynamics during touchdown, stance, and swing, focusing on three key aspects of the design: First, the inertia distribution in the leg, with an emphasis on how mass placement, number of links, and "redundant" elements of leg kinematics (such as pointing the knee "up" or "down") contribute to the impact felt by the system at touchdown and the dynamics during swing phase. Second, the motor coupling to the linkages, focusing on how different mappings between actuation and mechanism degrees of freedom can lead to the motors either sharing loads or fighting against each other. Third, spring function and placement, including desirable nonlinearities for mitigation of impacts and swing-phase ringing, alignment of principle stiffness axes with mechanism degrees of freedom, and transmissions that allow for configuration-dependent elasticity. The research approach draws on examples from biology and previously constructed robots, utilizes mathematical tools from applied mechanics, and builds on prior work with experimental walking and running robots.