Design and cooperation control analysis of a coarse-fine dual stage drive positioning system

The coarse-fine dual stage drive mode has been widely applied in high precision positioning systems with long stroke. This paper describes a dual stage positioning system driven by a linear motor and a piezoelectric actuator. The mechanical design and cooperation control strategy of the two stages are considered. The prevailing cooperation control strategy is based on the concept that the fine stage dynamically compensates the position error of the coarse stage, which causes considerable large positioning error band in nanomanufacturing. To cope with this problem, we propose a new cooperation control strategy based on the model prediction, which includes the step signal compensation mode and ramp signal compensation mode. According to the theoretical analysis, simulation and experiment, the new cooperation control strategy can suppress the positioning error band effectively. In addition, an optimal error band reduction method is developed for the step signal compensation mode.