H∞ observer based force control without force sensor

The authors propose the force control of a robot manipulator without a force sensor. The proposed force control system is realized by an H^∞ acceleration controller and a H ^∞ force observer. The H^∞ acceleration controller regulates the actuator of the robot manipulator by the acceleration control command ω^cmd. The H^∞ force observer estimates the imposed force to the actuator. Both H^∞ systems are designed by the mixed sensitivity H^∞ control design method. The experimental results show the response characteristics of both the force sensor feedback force control and the H^∞ force observer based force control. It is shown that the system regulates force well