平夹自适应欠驱动手的参数优化与稳定性分析

Parameters Optimization and Stability Analysis for a Parallel and Self-adaptive Underactuated Hand

针对欠驱动多模式抓取问题,提出了一种具有平夹自适应复合抓取模式的8自由度机械手(PASA手).为了研究PASA手的抓取性能,提出了抓取姿态与稳定性分析模型.根据被抓取物体的位置、尺寸和大小的不同,PASA手能够执行平夹(PA)用于精确抓取,自适应包络用于力量型抓取,或者像人手那样既能平夹又能自适应抓取(PASA).不同抓取模式之间的切换是自动且自适应的.详细讨论了PASA手的运动、抓取力分布和在不同外力下基于势能的抓取稳定性分析.对各种状态下手指接触力进行了测量,并对不同的物体进行了抓取实验.尽管被抓取对象形状、大小各异,PASA手均能牢固抓取.实验结果表明PASA手具有可靠性和广泛适用性.

An 8 degrees of freedom(DOFs) robotic hand with parallel and self-adaptive(PASA) hybrid grasping modes is proposed to realize hybrid-mode underactuated grasping. Models of grasping postures and stability analysis are proposed to study the grasping performance of the PASA hand. Depending on the location, dimension and size of different objects, the PASA hand executes a parallel pinching(PA) mode for a precise grasp, a self-adaptive(SA) enveloping mode for a powerful grasp, or a PASA mode to imitate a human hand. The switch among different grasping modes is automatic and self-adaptive.Detailedly, the kinematics and the force distribution of the PASA hand are described, and also the grasping stabilities under different external forces are analyzed based on potential energy. Finally, different objects grasping experiments are conducted,while the contact forces are exactly measured in different states. Though the shapes and sizes of the objects are various, PASA hand can grasp tightly. Experimental results verify the reliability and the versatility of the PASA hand.