Force Sensing for Multi-point Contact Using a Constrained, Passive Joint Based on the Moment-Equivalent Point
Force Sensing for Multi-point Contact Using a Constrained, Passive Joint Based on the Moment-Equivalent Point
复制标题
DOI：
10.1007/978-3-030-01370-7_31
复制
发表时间：
2018-06
期刊：
影响因子：
--
通讯作者：
Shouhei Shirafuji;J. Ota
中科院分区：
文献类型：
--
作者：
Shouhei Shirafuji;J. Ota
本文介绍了一种用力矩等效点（MEP）分析受限关节的方法，MEP表示机器人机械臂两端关节所施加的力矩与与环境接触的平面多点接触所产生的力矩之间的平衡。通过构造，表示压力中心（CoP）上的反作用力总和的矢量将始终通过MEP。MEP的一个重要特征是，如果在每个关节上施加的扭矩的比率保持不变，则它相对于连接两个关节的连杆是固定的。因此，如果机器人有两个受机械约束的被动关节，使得每个关节的扭矩比恒定，则可以将MEP视为单个接触点。因此，我们可以将机器人的行为建模为只与环境中MEP上的一个点接触，即使实际接触是在平面上的多个点上。这种机械约束的被动关节和MEP的概念导致了一种介于标准多点接触和标准单点接触之间的接触运动学方法。基于MEP考虑机器人与环境之间的力平衡的一个优点是，施加在接触面上的切向力可以仅从CoP位置和CoP处的法向力计算出来。实验结果表明，仅通过测量施加在足部的法向力就可以估计出机器人足部的切向力。
In this paper, an analyzing method of a constrained joint using the Moment-Equivalent Point (MEP) is introduced that represents the balance between the torques exerted by two end joints in a robotic manipulator and the torque created by multiple-point contact of the flat surface that is in contact with the environment. By construction, the vector representing the summed reactive forces on the center of pressure (CoP) will always pass through the MEP. An important characteristic of the MEP is that it is fixed with respect to the link connecting the two joints if the ratio of the torques exerted at each joint is held constant. Therefore, if the robot has two passive joints that are mechanically constrained such that the ratio of the torques at each joint is constant, the MEP can be treated a single-contact point. Thus, we can model the robot’s behavior as if contacts only with a point on MEP in the environment, even if the actual contact is over multiple points on the flat surface. Such mechanically constrained passive joints and the concept of the MEP result in an approach that is midway between the standard multi-point contact and standard single-point contact in terms of the contact kinematics. One advantage of considering the balance of forces between the robot and the environment based on the MEP is that the tangential force applied to the contact surface can be calculated just from the CoP position and the normal force at the CoP. Experimental results indicate that the tangential force at the foot of the robot can be estimated by measuring only the normal forces applied at the foot.