Smooth motion in piezoelectric stick-slip actuators at low driving voltage enabled by an orthogonally coupled symmetric mechanism

Abstract

To achieve smooth motion over a wide velocity range in micro-nano manufacturing, this paper presents a novel piezoelectric stick-slip actuator (PSSA) actuated by an orthogonally coupled symmetric mechanism (OCSM). The OCSM comprises two vertically symmetric branches, each branch containing a vertically series-connected III-shaped guiding and i-shaped passive flexible mechanism, enabling efficient transmission of the piezoelectric actuator (PZT) displacement to the driving foot while enhancing end stiffness and first-order natural frequency. The impact of the stiffness of each flexible mechanism on motion smoothness is investigated through theoretical analysis. Key parameters are determined, and finite element analysis is conducted for verification. A prototype of the PSSA has been manufactured, and experimental tests are conducted. The results indicate that the developed PSSA exhibits a compact structure, smooth motion under low driving voltage, high stepping mode resolution (38.5 nm), and rapid velocity (6.21 mm/s). The influence of driving voltage, driving frequency, and the number of pulse cycles per step on motion smoothness is analyzed. A macro-micro switching positioning experiment is conducted. And the scanning mode resolution is 20 nm. Tip-based nanofabrication (TBN) experiments are conducted to create micro-nano structures on silicon wafer surfaces.