Designing a novel model of 2-DOF large displacement with a stepwise piezoelectric-actuated microgripper

Expanding the gripping stroke is the key problem in the research of microgripper. Generally, the magnification of the multi-stage amplifier is larger than that of the single-stage amplifier, but the multi-stage amplifier has a certain inhibition effect on the single-stage amplifier. The effect of simply increasing the number of the amplification mechanism on increasing the magnification is lower. To solve the above problems, a two-degree-of-freedom large displacement stepwise microgripper from the perspective of multiple degrees of freedom is designed, which improves the gripping displacement and stability of the microgripper. The relationship between theoretical input variables and output variables is calculated based on pseudo-rigid-body method; the gripping performance of microgripper is analyzed by finite element analysis (FEA); The piezo-driven is used as the input drive of the microgripper, and the actual output displacement are 5.21 and 8.06% respectively compared with the theoretical and simulated output displacement, which proves the correctness of theoretical calculation and simulation analysis. Under the maximum driving voltage of 150 V, the maximum output displacement is 924 μm, which can grip micro-parts of arbitrary size and shape in the range of 0–1724 μm; the displacement amplification of microgripper is 23.1 times on one side, and the total amplification is 46.2 times. The validity of the design is verified by the successful parallel and stable grasping of micro-parts with various shapes.