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arXiv 2202.01628cs.RO
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足式机器人的可行扳手集计算

Feasible Wrench Set Computation for Legged Robots

University of Twente(特温特大学)

Ander Vallinas Prieto, Arvid Q. L. Keemink, Edwin H. F. van Asseldonk, Herman van der Kooij

摘要:

在运动过程中,足式机器人通过顺序地建立和断开接触与地面相互作用。由接触产生的交互扳手用于操纵机器人质心(CoM),并拒绝使系统偏离期望轨迹并经常使它们掉落的扰动。给定控制目标(所需的CoM扳手或加速度)的可行性取决于接触点分布、地面摩擦力和致动极限。在这项工作中,我们开发了一种方法来计算一组可行的扳手,足式机器人可以施加在其CoM通过接触。所提出的方法可以用于任何数量的非共面接触,并考虑到驱动限制和库仑摩擦的非弹性接触模型的基础上的限制。这是用一个平面的站立模型与脚在不同的高度举例说明。利用接触模型的假设,我们解释了如何计算一组扳手,是可行的CoM时,接触保持在适当的位置,以及那些是可行的,当一些接触被打破。因此,该方法可以用来评估在实现给定控制任务的同时,接触配置的开关是否可行。此外,该方法可以用于识别系统未被致动的方向(即,扳手不能在这些方向上施加)。我们展示了如何有一个关节被致动或被动可以改变非致动扳手方向的机器人在给定的姿势使用的空间模型的下肢外骨骼。因此,该方法也是系统设计阶段的有用工具。这项工作提出了一个有用的工具,用于腿系统的控制和设计,扩展到目前的最先进的。

英文摘要:

During locomotion, legged robots interact with the ground by sequentially establishing and breaking contact. The interaction wrenches that arise from contact are used to steer the robot Center of Mass (CoM) and reject perturbations that make the system deviate from the desired trajectory and often make them fall. The feasibility of a given control target (desired CoM wrench or acceleration) is conditioned by the contact point distribution, ground friction, and actuation limits. In this work, we develop a method to compute the set of feasible wrenches that a legged robot can exert on its CoM through contact. The presented method can be used with any amount of non-co-planar contacts and takes into account actuation limits and limitations based on an inelastic contact model with Coulomb friction. This is exemplified with a planar biped model standing with the feet at different heights. Exploiting assumptions from the contact model, we explain how to compute the set of wrenches that are feasible on the CoM when the contacts remain in position as well as the ones that are feasible when some of the contacts are broken. Therefore, this method can be used to assess whether a switch in contact configuration is feasible while achieving a given control task. Furthermore, the method can be used to identify the directions in which the system is not actuated (i.e. a wrench cannot be exerted in those directions). We show how having a joint be actuated or passive can change the non-actuated wrench directions of a robot at a given pose using a spatial model of a lower-extremity exoskeleton. Therefore, this method is also a useful tool for the design phase of the system. This work presents a useful tool for the control and design of legged systems that extends on the current state of the art.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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