Abstract
We have developed semi-active assist mechanisms and their control method. The semi-active assist mechanism uses the restoring force of elastic materials as an assist force, and the mechanism can control the restoring force by adjusting the equilibrium point of the elastic materials by using an actuator. The control method for sinusoidal motions were developed for power assist and skill assist in previous study. The power assist means to decrease operator's load, and the skill assist means to correct operator's motion. The method was realized both assist by only using the phase difference of forces between the operator and the assist device. In this paper, we analysed the effects of the phase difference for the power assist and the skill assist from viewpoint of impedance control.
