Design of asymmetric flexible micro-gripper mechanism based on flexure hinges

Symmetric micro-gripper mechanism is very easy way to destroy the micro-components or parts for nonuniform force in the processing of micro-assembly. Aiming at the requirements of micro-assembly for the microtubule (diameter of 0–200 μm) components, a new type of asymmetric flexible micro-gripper mechanism based on flexure hinges was designed and studied. The asymmetric micro-gripper mechanism was driven by piezoelectric actuator, whose output displacement was amplified and transmitted by flexure hinges, and the flexible parallel four-bar mechanism was used to ensure that the micro-clamp moves and is held parallel. The displacement amplification ratio of the asymmetric flexible micro-gripper mechanism was deduced theoretically, and the finite element analysis and the experiment were also carried out to study the displacement amplification ratio in detail. The experiment results show that the displacement amplification ratio of the asymmetric flexible micro-gripper mechanism is 4.16, compared with the finite element analysis result and the theoretical calculation result; the error between them is 1.89% and 5.67%, respectively. The experiment results also show that the step-wise resolution of the micro-gripper is 7.50 μm, and the output force of the right micro-clamp was measured at 0.28 N. The asymmetric flexible micro-gripper mechanism is able to perform the micro-assembly tasks for the microtubule parts, and it is helpful to design this type of micro-gripper mechanism.