基于广义刚度的多指手抓持稳定性分析

Multi-finger hand grasping stability analysis based on generalized stiffness

近年来,仿人灵巧手成为热门的研究方向,大量学者对灵巧手抓持稳定性进行了研究。刚度是影响灵巧手抓持稳定的一个重要因素,本文基于旋量理论综合研究了灵巧手关节刚度和接触刚度与扰动力作用下的被抓持物体位姿变化的关系,在旋量空间中得出了广义刚度。并针对扰动力造成的软指与物体间的滚动情况,提出了一种等效接触切向刚度的方法。在广义刚度的基础上提出了扰动力椭球的概念,并以此定义了一种抓持稳定性指标。最后,设计了一个三指灵巧手对建立的理论模型进行了实验验证,证明了理论模型的有效性。

In recent years, humanoid dexterous hands have become a popular research direction, and many scholars have studied the grasp stability of dexterous hand. Stiffness is an important factor that affects the grasp stability of dexterous hand. In this paper, the relationship between the joint stiffness and contact stiffness of dexterous hands and the change of the location of the grasped object under the action of disturbance force is comprehensively studied based on the screw theory. The generalized stiffness is obtained in the screw space. A method of equivalent tangential contact stiffness is proposed for the rolling between the soft fingertip and the object caused by disturbance force.This paper also put forward a concept of disturbance ellipsoid based on generalized total stiffness and defined a grasping stability index based on this. Finally, a three-finger dexterous hand is designed to verify the theory and prove the validity of the theoretical model.