High stiffness and low slew drag in an antagonistic control system

An antagonistic controller which is to be used in tendon-driven master/slave end-effectors is described. High stiffness was achieved by developing a control law which eliminates one local force loop in the flexion/extension control loops. One force loop maintains tendon cocontraction, while the other force loop is eliminated when the tendon tension is greater than cocontraction. In order to minimize the input impedance or slew drag caused by inertia and intrinsic damping of the system, force compensations were implemented according to the characteristics of the actuators. These techniques have been implemented experimentally on both electromechanical and electrohydraulic systems. A computer analysis of an electromechanical antagonistic control system is included. Servostiffness equations are derived from the transfer function of the electromechanical system