Multistage Rule-Based Positioning Optimization for High-Precision LPAT

This paper proposes a multistage rule-based precision positioning control method for the linear piezoelectrically actuated table (LPAT). During the coarse-tuning stage, the LPAT is actuated by coarse voltage schemes toward the target of 20 μm at a higher velocity, and during the fine-tuning stage, it is steadily and accurately driven by the fine voltage scheme to reach the target position. The rule-based method is employed to establish the control rules for the voltages and displacements of the two stages using statistical methods. The experimental results demonstrate that the proposed control method can quickly reach steady state, and the steady-state error can be reduced to less than or equal to 0.02 μm for small travel (±0.1 μm) and large travel (± 20 mm).