Motion control of precision positioning systems using adaptive compensation

In this paper, an adaptive motion control method is proposed for high-accuracy positioning systems with nonlinear friction and parameter uncertainties. Based on the control input redesign framework for disturbance compensation, a unified control structure of an adaptive compensator and feedback motion controller is designed. Adaptive control which can reduce the uncertainties of system parameters is proposed to remedy the defects of the typical disturbance compensation method with fixed gains. The feedback motion controller is integrated to the adaptive controller to meet the given performance specification. Through stability analysis, the adaptive law is obtained and it is shown that parameter adaptation is performed based on the internal-model following error defined in the adaptive compensator and feedback error defined in the feedback controller. Simulations are carried out to verify the performance of the proposed controller. The results show the marked performance improvement thanks to the inherent structural feature of the proposed controller.