Improving Velocity of Stick-Slip Piezoelectric Actuators With Optimized Flexure Hinges Based on SIMP Method

Abstract

Flexure hinges have been widely applied in driving mechanisms to achieve the high velocity of stick-slip piezoelectric actuators. However, the majority of driving mechanisms are designed with existing flexure hinge forms, and it is difficult for the actuators to realize the optimal velocity performance. Therefore, a systematic method based on the topology optimization to design flexure hinges of driving mechanisms is proposed in this paper for improving the velocity of the actuators. According to the working principle, the velocity can be increased by maximizing displacement of a driving foot along the positive direction of $x$ -axis. The optimization problem of flexure hinges is described utilizing the Solid Isotropic Material with Penalization (SIMP) method. To illustrate the proposed method in detail, a four-bar mechanism with optimized flexure hinges is designed. Among them, three optimization schemes are implemented based on positions of flexure hinge design domains, and then deformations and equivalent stresses of the four-bar mechanism are investigated by simulation to find optimal flexure hinge forms. To prove the feasibility of the proposed method, the characteristic experiments of prototype are conducted. When the driving voltage and driving frequency of prototype are 100 Vp-p and 470 Hz, the maximum velocity is 17.50 mm/s, the maximum load is 220 g. And it is interesting to find that the prototype has no backward motion. Compared with the previously reported actuators with four-bar mechanisms, the velocity of prototype is significantly improved.