Achieving high speed of the stick–slip piezoelectric actuator at low frequency by using a two-stage amplification mechanism (TSAM)

The stick-slip piezoelectric actuator is a promising type for precision positioning with large stroke and high resolution; however, it is still challenging to achieve high motion speed at a relatively low driving frequency. To solve this problem, a novel two-stage amplification mechanism (TSAM) was designed, and correspondingly, a stick-slip piezoelectric actuator was developed. The structure, two-stage amplification principle, and motion processes of the designed actuator were addressed in detail, followed by analyzing the displacement amplification ratio and stress of TSAM via the elastic beam method and finite element method, respectively. Then, the actuator prototype was fabricated, and its output performances were tested under various experimental parameters. By comparative analysis with the actuator that only used the first-stage amplification hinge, the significant improvement in stepping displacement was verified when employing the TSAM. The resultant maximum motion speed was 20.05 mm/s, achieved under the locking force of 2 N, the input voltage of 100 V, and the driving frequency of 700 Hz. In addition, the developed actuator still maintained competitive motion resolution and loading capacity. The comparative analysis with some previous studies further indicated that the developed actuator with the TSAM had successfully achieved a relatively high motion speed at a relatively low driving frequency, which would be beneficial to the practical application.