Novel design of a piezoelectrically actuated compliant microgripper with high area-usage efficiency

Abstract

Microgrippers act as an end effector in micromanipulation systems, completing the pick-transport-release operations during the working process. This paper presents the design, modeling, optimization, simulation, and experiment of a novel piezoelectrically actuated compliant microgripper for micromanipulation and microassembly. Considering the space and cost constraints of the micromanipulation system, the area-usage efficiency and piezoelectric actuator utilization efficiency are introduced to evaluate its performance. A three-stage amplification mechanism based on bridge-type and leverage mechanisms arranged in series is introduced to achieve a large jaw displacement. The displacement amplification ratio of the microgripper is analyzed via the pseudo-rigid-body model approach. Optimization based on response surface analysis was conducted to determine the structural parameters of the compliant mechanism. Finite-element analysis is performed to evaluate the gripper performance. Moreover, a gripper prototype was fabricated for the experimental test. The investigation results indicate that the gripper allows a maximum gripping displacement of 548.42 μm, a first natural frequency of 334 Hz, and a motion resolution of ±0.75 μm. In comparison with previous designs, the reported microgripper has the advantages of a larger displacement, higher area-usage efficiency, and better PEA utilization efficiency. The micromanipulation capability of the developed gripper was demonstrated by gripping three tiny objects of different sizes and shapes.