Design, modeling, and control of a monolithic compliant x-y-θ microstage using a double-rocker mechanism

This paper reports the design, modeling, and control of a novel three-degrees-of-freedom piezoelectric compliant microstage by introducing a new double-rocker mechanism. The double-rocker mechanism combines a first (leverage) amplifier and a second (rocker) amplifier for double-stage displacement amplification and parasitic motion reduction. An analytical model is established to calculate the deformation behavior of the microstage, and the model is verified using finite-element analysis (FEA). An improved Prandtl-Ishlinskii (PI) model is proposed to describe piezoelectric hysteresis characteristics by optimizing the threshold selection. Then, a composite control strategy is designed to achieve precision trajectory control . The control strategy consists of a hysteresis-based feedforward controller and a proportional-integral feedback controller . A prototype of the microstage is manufactured, and an experimental system is established. Several open-loop and closed-loop experiments are conducted, and the experimental results validate the effectiveness of the proposed microstage and the designed control strategy.