Anisotropic compliance of robot legs improves recovery from swing-phase collisions
Anisotropic compliance of robot legs improves recovery from swing-phase collisions
复制标题
机器人腿的各向异性顺应性提高了从摆动阶段碰撞中的恢复
DOI：
10.1088/1748-3190/ac0b99
复制
发表时间：
2021
影响因子：
3.4
通讯作者：
N. Gravish
中科院分区：
文献类型：
--
作者：
Henry Chang;Justin Chang;G. Clifton;N. Gravish
自然环境中不平坦的地形通过诱导不稳定性和引起肢体碰撞来挑战腿部运动。在摆动阶段，肢体从地面释放并向前弧形移动以瞄准下一个安全的立足点。在自然环境中，腿部-障碍物碰撞可能发生在摆动阶段，这可能导致不稳定性，并且如果发生碰撞，则可能需要接触感测和轨迹重新规划。然而，碰撞检测和响应通常需要计算上和时间上昂贵的控制策略。受小昆虫和奔跑鸟类的低刚度肢体可以通过障碍物的启发，我们研究了一种克服摆动碰撞的被动方法。我们在机器人腿中实现了虚拟顺应性控制，使我们能够系统地改变肢体刚度，并最终改变其对环境中障碍物碰撞的响应。除了在挥杆运动期间应用标准位置控制之外，我们还开发了两种虚拟顺应性方法：（1）各向同性顺应性，其中x和y方向上的扰动产生相同的刚度响应，以及（2）垂直各向异性顺应性，其中向上y垂直肢体刚度的降低使腿部能够更自由地向上移动。虚拟顺应性的方法略有增加变化沿着肢体的计划路径，但各向异性的顺应性控制提高了70%以上的成功谈判的步骤障碍物相比，各向同性的遵守和位置控制方法。我们证实了这些研究结果在模拟和使用自推进的双足机器人行走沿着线性轨道在颠簸的地形。虽然肢体顺应性的立场相互作用的重要性已经知道，我们的研究结果突出了如何在摆动阶段肢体顺应性可以提高行走性能在自然环境中。
Uneven terrain in natural environments challenges legged locomotion by inducing instability and causing limb collisions. During the swing phase, the limb releases from the ground and arcs forward to target a secure next foothold. In natural environments leg–obstacle collisions may occur during the swing phase which can result in instability, and may require contact sensing and trajectory re-planning if a collision occurs. However, collision detection and response often requires computationally- and temporally-expensive control strategies. Inspired by low stiffness limbs that can pass past obstacles in small insects and running birds, we investigated a passive method for overcoming swing-collisions. We implemented virtual compliance control in a robot leg that allowed us to systematically vary the limb stiffness and ultimately its response to collisions with obstacles in the environment. In addition to applying a standard positional control during swing motion, we developed two virtual compliance methods: (1) an isotropic compliance for which perturbations in the x and y directions generated the same stiffness response, and (2) a vertical anisotropic compliance in which a decrease of the upward y vertical limb stiffness enabled the leg to move upwards more freely. The virtual compliance methods slightly increased variability along the limb’s planned pathway, but the anisotropic compliance control improved the successful negotiation of step obstacles by over 70% compared to isotropic compliance and positional control methods. We confirmed these findings in simulation and using a self-propelling bipedal robot walking along a linear rail over bumpy terrain. While the importance of limb compliance for stance interactions have been known, our results highlight how limb compliance in the swing-phase can enhance walking performance in naturalistic environments.
DOI：
10.1115/1.1372322
发表时间：
2001-06-01
影响因子：
1.7
作者：
Kuo, AD
通讯作者：
Kuo, AD
影响因子：
3.4
作者：
Ernst, M.;Geyer, H.;Blickhan, R.
通讯作者：
Blickhan, R.