Analytical examinations and compensation for slow settling response in precise positioning based on rolling friction model

This paper presents a rolling friction model-based friction compensation in the precise positioning of linear motor-driven table systems. The rolling friction in mechanisms behaves as a nonlinear elastic element in the micro displacement region and deteriorates the positioning performance due to slow settling responses. In this research, therefore, the rolling friction characteristic is mathematically formulated to examine the slow responses in the settling region, and the rolling friction model is adopted to controller design to improve the settling performance. In the analytical examinations, a rheology-based rolling friction model is introduced to construct a precise simulator and clarifies the mechanism of the slow settling response. In the compensator design, on the other hand, the rolling friction model is adopted to a friction compensator to suppress effects of the rolling friction on the precise positioning at the settling region. The proposed examinations and friction compensation for the slow settling response have been verified by simulations and experiments using a prototype of industrial positioning devices.