Analysis of contact localization of dexterous robot hand using force/torque measurement

It is important to detect the position of contact points between the grasped object and the fingertips of dexterous hand. The method using force/torque sensor mounted at fingertip is simpler and easier than the tactile sensor to get the contact position. However, there are two problems held back the application of the former when the sensing data is contaminated with disturbance. First, when the hard finger contact model is used to calculate the points, the solution may not exist. This paper investigates the problem under the contact models of hard finger and soft finger respectively. Mathematical verification is developed to find the existence condition of solutions. A simple criterion is provided to determine which contact model must be selected for calculating contact points. The next problem is accuracy. The error of soft finger contact model is analyzed. Some strategies are given to improve the accuracy of the contact localization. Simulations and experiments show that the reliable and precise measurement of contact points can be achieved by the proposed approaches.