A low speed piezoelectric actuator with high displacement smoothness and its multi-objective optimized method

Piezoelectric actuators are widely utilized in the precision industry field, but the existing piezoelectric actuators are difficult to achieve high displacement smoothness at low speed, which limits the practical application of the piezoelectric actuators. This work proposes a piezoelectric actuator that can achieve high displacement smoothness through a multi-leg coordinated actuation principle. A multi-objective optimized method based on adaptive mutation genetic algorithm is utilized to design the driving leg by comprehensively considering five design variables. The design goal of the maximum displacement of the driving foot and the minimum size of the driving leg are achieved. A prototype is fabricated and the characteristics are tested. The experimental results demonstrate the effectiveness of the optimized method. High displacement smoothness at low speed is also achieved. The output displacements of the proposed actuator at different driving voltages and frequencies show no regression and intermittent motion. The linearity R ² could reach 0.9978, and the low output speed of the actuator could reach 22.69 µrad s⁻¹ at voltage of 100 V_p–p and frequency of 1 Hz.