Enhancement of Operability by Admittance Control Using High Dynamic Range Six-Axis Force/Torque Sensor

Abstract

In human-robot interaction, the passivity is important. With high dynamic range (HDR) six-axis force/torque sensors, which can measure about 0.1N force while maintaining the same rated values as comon force sensors for industrial purposes, impedance parameters of admittance controllers can be set to smaller values to improve the passivity. When a large external force is applied, however, speed command of admittance control abruptly increases because of small impedance parameters. In this research, this problem solves by applying an arctangent function to the speed command; by the saturation with the arctangent function, manipulators can achieve both enough passivity and safety. We comfirmed the effectiveness of the proposed methods in experiments.