多关节欠驱动机器人手爪包络抓取稳定性分析与仿真

研究了欠驱动手爪包络抓取稳定性.定义了抓取构形,推导了关节数和抓取构形之间的关系,采用抓取构形之间的转移难度作为表征抓取稳定性测度指标,给出了抓取不稳的主要原因以及影响包络抓取稳定性的主要因素.通过仿真对抓取不同形状物体时的稳定性,及影响稳定性的主要因素进行了对比分析和验证.结果表明:理论分析和仿真研究结果是一致的,欠驱动手爪包络抓取时存在多种抓取构形是影响抓取稳定性的直接原因,稳定抓取取决于物体形状和初始的抓取姿态,其中物体凸边的线接触的长度是决定抓取稳定的最重要的因素,物体越是接近圆形稳定性越差,当物体和抓取构形比较吻合时,并且都是以线接触相互作用,抓取稳定性最好.

Analysis and simulation of enveloping grasp stability of the multi-phalange underactuated robot hand

The grasp stability of underactuated robot hand is discussed. The definition of grasp configuration is proposed, and the relationship between the numbers of phalanges and grasp configuration is deduced. The transition difficulty in grasp configuration is employed to evaluate the stability of enveloping grasp. The main factors which influence the grasp stability are investigated. Some cases of stimulation are given to validate the evaluation when the underactuated robot hand grasps different objects. The results show that the theory is in accord ance with the simulation, and the multi-grasp -configurations are the primary reasons that lead to unstable grasp.Stable grasp is decided by object shape and initial posture, among which the length of the convex contact line is the most important factor for the grasp stability. The grasp is most unstable when the object shape resembles circle, while the grasp is the most stable when the object shape wholly conforms to the grasp configuration convex with long margin line. The longer the line is, the more stable the grasp is.