Development of a Stick-Slip Piezoelectric Screw Actuator With High Thrust Force Density

Stick-slip piezoelectric actuators are favored for simple structures, high resolution and convenient excitation systems. However, low thrust force and weak output-maintained capability are inevitable challenges facing practical applications. To address these issues, a novel stick-slip piezoelectric screw actuator featuring a fusion of longitudinal-torsional micro motion and threaded transmission is proposed. Specifically, the longitudinal-torsional motion conversion mechanism effectively reduces the planar dimension, while achieving a high thrust force and self-locking at power-off through threaded transmission. The corresponding structure description and motion principle are represented in detail. Subsequently, a dynamic model and finite element simulations are conducted to predict the output performance. Moreover, an actuator prototype with dimensions of Φ30 × 93 mm is fabricated, and experiments are performed to assess its performance. The results reveal that the developed actuator achieves a maximum thrust force of 25.3 N and a corresponding maximum thrust force density of 384.86 mN/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>. The proposed actuator combining large working stroke, high resolution, large thrust force and compact structure exhibits promising applications, such as optical posture adjustment and medical instruments.