CONTROL OF A COUPLED TENDON-DRIVEN MULTIFINGERED ROBOT HAND

Abstract

The issues related to the low level and stiffness control of a multifingered robot hand with coupled tendon-driven transmission are discussed. The hand, which is called POSTECH Hand II, is composed of two fingers, where the thumb includes two joints and the index finger includes three joints with one degree of kinematic redundancy. Each tendon is actuated by a direct current (DC) torque-controlled servomotor with harmonic reducer, where specially designed tendon tension sensors are attached to the nearest point of the joint to perform tension feedback control. All the controllers are fully digitally implemented to endow flexibility in implementations and simplify its hardware. At first, low level tension and joint torque control algorithms are developed and experimentally verified in a separately designed, one-finger test bed. In a high level control, a stiffness controller is implemented, and also, a stiffness control method for the kinematically redundant finger is implemented.