Two-stage rule-based precision positioning control of a piezoelectrically actuated table

Abstract

This article proposes a two-stage rule-based precision positioning control method for the linear piezoelectrically actuated table (LPAT). During coarse-tuning stage, the LPAT is actuated by coarse voltages towards the target of 20 µm at a higher velocity; and during fine-tuning stage, it is driven by fine voltage steadily and accurately 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 reach steady state quickly, 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).

Keywords:

• piezoelectrically actuated table
• two-stage control
• rule-based method
• intelligent control
• expert systems