Mode Switching Feedback Compensation Considering Rolling Friction Characteristics for Fast and Precise Positioning

This paper presents a mode switching feedback (FB) compensation methodology based on rolling friction models for the fast and precise positioning of table drive systems. Rolling friction in the table drive mechanisms behaves as a nonlinear elastic component in the micro displacement region and deteriorates the position settling performance with slow responses. Effects of the rolling friction on the positioning, therefore, should be compensated to provide the desired control performance. The authors have already proposed a rolling friction model-based friction compensation scheme to improve the slow settling responses. The conventional approach, however, could not suppress vibratory settling responses due to unknown model errors and/or plant perturbations, and there still remains the performance deterioration in the positioning accuracy to be solved. In this research, therefore, a novel mode switching FB compensation considering the rolling friction properties is applied to provide the desired settling performance with well-suppression of both vibratory response and slow response. The feature of the proposed approach is that the vibratory and slow responses at the settling are handled as an initial value response of the FB control system in the micro displacement region and can be suppressed in a mode switching control manner on the basis of initial value compensation frameworks utilizing the elastic characteristic of the rolling friction. The proposed approach has been verified by numerical simulations and experiments using a prototype of industrial table positioning devices.