Design of low parasitic motion microgripper based on symmetrical parallelogram mechanism

Parallelogram mechanisms are widely used in microgrippers due to their translational output. However, the parasitic displacement generated by the rotation of the parallelogram mechanism affects the gripping accuracy of the microgripper. Aiming at this problem, a symmetrical parallelogram mechanism with displacement compensation characteristics is proposed in this paper, and it is successfully applied to microgrippers. The piezoelectric actuator is placed outside the amplification mechanism (AM), which solves the parasitic displacement caused by the bending of the bridge-type AM side wall caused by the built-in method. Based on the pseudo-rigid body model (PRBM) method and the flexure beam deformation theory, the performance of the mechanism is calculated. Finite element analysis (FEA) software is used to optimize the structure size and performance analysis of the mechanism. In addition, the experimental model is processed and the experimental platform is built. The experimental results show that compared with similar microgrippers, the microgripper designed in this paper has a higher resonance frequency and lower parasitic displacement, which proves the rationality of the design.