Power-assist control switching from adaptive nonstationary servo control to force sensorless nonstationary impedance control

Abstract

Many power-assist systems for industrial uses possess simple power-assisting function only. The authors studied on the positioning method of a cart using a smooth switching from the servo access control for the conveyance function to the force sensorless impedance control (FSLIC) for the power-assisting function. The nonstationary optimal control method and the nonstationary impedance control law were applied. However, the optimal control method requires the offline calculations for generating time-varying feedback gains. For actual problems including parameter variations, this characteristic is inconvenient. From such a point of view, this study investigates the use of the adaptive nonstationary servo control (ANSSC) technique instead of the optimal control method. Therefore, this paper discusses the control method switching from ANSSC based access to FSLIC based power-assist. The effectiveness of this method is verified experimentally.