Design and mechanical modeling of high-magnification and low-parasitic displacement microgripper with three-stage displacement amplification

The common point of multi-stage displacement amplification mechanisms (DAMs) is that the output end of the upper-stage DAM is connected to the input end of the next-stage DAM. Therefore, the input stiffness of the next-stage DAM will have an impedance effect on the output displacement of the upper-stage DAM. Based on this, the paper introduces a three-stage amplification microgripper, which is driven by a piezoelectric actuator. The three-stage DAM is composed of a compound rhombic mechanism, a bridge mechanism and two parallelogram mechanisms. Based on Cartesian second theorem and flexure beam theory, the mechanism's displacement magnification model, input force and output force relationship model, force-displacement relationship model, input stiffness model and parasitic displacement compensation model are established. The correctness of mechanical modeling is verified by simulation analysis and experiments. The results show that the mechanical model has high prediction accuracy.