Modeling and creep compensation control of bellow-driven positioning stage

In order to characterize hysteresis properties of the bellows-driven stage, PI model is established. The parameters of PI model are identified based on the experimental data. The feedback control scheme based on inverse PI model is designed. Creep characteristic of the stage are analyzed, the symmetry logarithmic model is established for the creep effects, and the different creep compensation control schemes are designed for point positioning and trajectory tracking. Two kinds of control schemes are used in the positioning stage with sawtooth signal input, and experimental results show that the max tracking error is 2.18μm, and the average tracing error is 0.96μm with the compounding control scheme based on inverse PI model. The max tracking error is 1.61μm, and the average tracing error is 0.63μm with the creep compensation control scheme. The results show that the creep compensation control scheme is useful for improving positioning accuracy, and the positioning stage can meet the requirement of the ultra-precision positioning.