The authors propose the force control of a robot manipulator without a force sensor. The proposed force control system is realized by both the acceleration controller and the force observer. Both systems are designed by the mixed-sensitivity H/sup infinity / design method. The acceleration controller regulates the actuator of the robot manipulator by the acceleration control command. The force observer estimates the reaction force from the target environment. The experimental results showed that the response of the proposed force control system without a force sensor coincided with that of the force control system with a force sensor.>

A decentralized manipulator joint control is proposed, based on the model-following acceleration control system which is constructed using only the information from a rotary encoder. When each joint of the robot manipulator is regulated by the proposed acceleration control system, it is not affected by its dynamical nonlinearity and is controlled independently. A continuous-path tracking method for fast-motion control is also designed using the acceleration control. Experimental and numerical examples show that the proposed acceleration control method is valid for multi-degree-of-freedom robot manipulators.>