Design and Analysis of a Compact Piezo-Actuated Microgripper With a Large Amplification Ratio

This article presents a piezo-actuated microgripper characterized by large amplification ratio and compact structure size. The microgripper is actuated by a piezo-stack actuator that is integrated with a two-stage displacement amplifier to achieve large travel range. A new design methodology “flexure hinge individualized design” (FHID) was proposed to realize large amplification ratio. According to this methodology, each flexure hinge was designed personally based on force condition of the piviot to reconfigure the motion stiffness of the compliant microgripper so that the parasitic motion and displacement loss could be eliminated. Consequently, a 52-amplification ratio amplifier was obtained. The developed microgripper was modeled via kinematics and Castigliano’s displacement theorem, respectively. Finite element analysis and the experimental studies were conducted to evaluate the characteristics of the microgripper. The results show that the motion stroke of the gripper tip is 917 μm, and the structure dimension is 62 mm × 42 mm × 12 mm. The design methodology FHID is generic and can be extended to other compliant mechanisms.