A novel inchworm piezoelectric actuator with rhombic amplification mechanism

The inchworm drive type piezoelectric actuator that imitates the moving mode of inchworms in nature has the advantages of unlimited stroke, high stability, high accuracy, and excellent loading capacity. An inchworm piezoelectric actuator with rhombic amplification mechanism, which is utilized to amplify the output displacement of the PZT stack, is proposed and experimentally studied in this paper. The rhombic amplification mechanism has multiple flexible hinge features to make the moving step as large as possible and ensure the completely releasing of the clamping units from the guide rail. The configuration of the proposed actuator is presented to indicate the working principle in detail. The rhombic amplification mechanism is simplified, and its numerical analysis models is presented and analyzed. On this basis, experiments based on the fabricated prototype are carried out to investigate the characteristics. Results show that when the excitation voltage is 75 V, the maximum output displacement and displacement magnification of the rhombic amplification mechanism are 72.3 µm and 7.5 respectively. Furthermore, a maximum no-load moving speed of 1260 µm/s and a thrust force of 3.5 N are achieved. Herein, the experimental results confirm that the proposed inchworm piezoelectric actuator can achieve a compact structure and has potential in intelligent driving fields of biological manipulation robots and aerospace devices.