Nonlinear topology optimization of parallel-grasping microgripper

This paper presents a piezo-driven microgripper which can realize parallel grasping in a large displacement range (more than 140 mu m). The proposed microgripper is derived by a two-step nonlinear topology optimization method. A conventional linear topology optimization problem with loose boundary condition is solved first, and its solution is used as the initial design domain of the following nonlinear topology optimization. The comparison of the convergence results shows that this method can find a better structure of microgripper and save computation time simultaneously. Both the finite element analysis and experiment are used to verify the performance of the proposed microgripper. The experimental results show that the parasitic movement of the jaw is only 0.299% of the grasping movement and the average inclination angle of the jaw is 0.055mrad/mu m. A pair of strain gages is integrated as a displacement sensor, and its performance is presented and verified by experiments.