Self-Sensing 2-DOF Positioning System With Hysteresis Compensation for Microscale Applications

This paper presents the development and experimental validation of a two-degree-of-freedom (2-DOF) positioning system that integrates mechanical structure, electronic circuits, and control strategies to address displacement feedback challenges. Space limitations in compact precision devices often make traditional displacement sensors impractical, hindering accurate feedback control. To overcome this limitation, the proposed system leverages self-sensing actuation (SSA) technology, enabling piezoelectric (PZT) stacks to function as both actuators and sensors. The motion principles of the parallel-structure mechanism are analyzed and validated through finite element analysis (FEA). A double closed-loop control strategy, combining charge-based feedback and voltage regulation, suppresses hysteresis and enhances trajectory tracking accuracy. Experimental results demonstrate a motion range of 73.37 × 72.30 µm², with hysteresis reductions of 57.63% and 56.22% in the x and y directions. By extracting displacement signals directly from the PZT electrodes, the system eliminates external sensors, simplifying integration and improving reliability. This study demonstrates that SSA-based positioning systems can effectively address feedback challenges in microscale applications, providing a viable solution to enable the widespread adoption of complex multi-DOF positioning systems.