Closed-loop control of microgripper system based on compliant mechanism

Abstract

A three-stage displacement amplification microgripper system based on compliant mechanisms was designed for microassembly and microoperation tasks. The static mechanical models of the microgripper system were established, and the mechanical characteristics of the output displacements, stresses, and strains of the microgripper system were comprehensively simulated and analyzed. It was demonstrated that the microgripper system demonstrated excellent leveling performance, with the stresses and strains being concentrated at the flexible hinges. Subsequently, the tracking control experiments of the finger displacement and gripping force of the microgripper system were conducted using sinusoidal signals, variable amplitude signals, and frequency signals. It was clearly illustrated that the dynamic performances of the microgripper system are remarkable, and the standard deviation of the tracking error of the finger displacement is no more than 0.2 µm, while that of the gripping force is 0.35 mN under closed-loop conditions. The designed microgripper system achieves accurate control of displacements and gripping forces, effectively fulfilling the requirements of high-precision microassembly tasks.