NRI: Rethinking Multi-Legged Robots: Passive Terrain Adaptability through Underactuated Mechanisms and Exactly-Constrained Kinematics

长期以来，有腿的车辆一直让我们着迷，因为它承诺可以像动物一样敏捷地移动，优雅而快速地到达有轮子的车辆无法到达的地方。然而，尽管取得了许多成功，但目前的腿式机器人大多无法穿越崎岖的地形，机械设备复杂，需要复杂的硬件和控制，操作时间短。该项目的工作将调查多腿机器人的开发，这些机器人利用自适应电机和传动装置，以降低复杂性和成本，同时允许腿适应崎岖的地形。这些腿部机器人设计将通过OpenRobotHardware.org免费提供，并将能够通过快速原型技术轻松且廉价地制造。该项目采用了一种新的腿部机器人方法，提出了一种新的体系结构，通过应用欠驱动机构来减少闭合运动链中与地面的过度约束-为机器人配备腿，这些腿被动地适应地形粗糙度的巨大变化，对身体的干扰力最小。这种被动适应性的结果是，机器人能够在崎岖的地形上找到稳定的立足点，而不需要任何感知或规划：腿只需落在适当的位置。此外，机构的适应性还使腿部施加在车身上的力和扭矩能够被被动调节，以最大限度地减少可能导致车辆不稳定或导致其失去航向的干扰。这种能力将极大地简化腿式机器人系统的控制，极大地提高功率效率和对地形变化的鲁棒性，并降低生产和维护成本。

Legged vehicles have long intrigued us with the promise of moving with animal-like agility, gracefully and swiftly going where wheeled vehicles cannot. Despite numerous successes, however, current legged robots are mostly unable to traverse rough terrain, and are mechanically complex, requiring elaborate hardware and control, and having short operation-times. Work on this project will investigate the development of multi-legged robots that utilize adaptive motors and transmissions, to reduce the complexity and cost, while also allowing the legs to adapt to rough terrain. These legged robot designs will be made freely available through OpenRobotHardware.org, and will be able to be easily and inexpensively fabricated with rapid prototyping techniques.The project takes a new approach to legged robots by proposing new architectures that reduce over-constraint in the closed kinematic chains with the ground by applying under-actuated mechanisms - equipping robots with legs that passively adapt to large variations in terrain roughness with minimal disturbance forces to the body. As a result of this kind of passive adaptability, the robot is able to find a stable footing on rough terrain without any sensing or planning: the legs simply fall into place. Furthermore, adaptability in the mechanism also enables the forces and torques applied by the legs to the body to be passively regulated so as to minimize disturbances that would tend to destabilize the vehicle or cause it to lose its heading. This ability will drastically simplify the control of legged robot systems, greatly increase power efficiency and their robustness to terrain variations, and decrease production and maintenance costs.