Achieving smooth motion and high-speed for piezoelectric stick-slip actuator based on the two-stage lever principle

A bipedal cooperative drive method for the stick-slip piezoelectric actuator to achieve smooth motion

Existing kinds of stepping piezoelectric actuators have difficulty in maintaining smooth stepping characteristics in motion, especially with applied loads, because they are limited by their driving principle and structural design. However, non-smooth stepping characteristics not only reduce the output performance of piezoelectric actuators but also greatly limit the applications of piezoelectric actuators. In this paper, a bipedal cooperative drive method for the stick-slip actuator is proposed to improve stepping characteristics and achieve smooth motion under different conditions. Two flexible driving feet alternately push the rotor to rotate clockwise. Experimental results show that the stepping characteristics vary with the driving voltage, and the displacement curve transitions from non-smooth to smooth to sudden jump as the driving voltage rises. Furthermore, the displacement curves can maintain good smoothness within a horizontal load range of 20-30 g. The maximum angular speed of the designed actuator is 1452 mrad/s when the driving voltage and driving frequency are 100 V and 1400 Hz, respectively. These features help broaden the practical application of actuators.

Design and Analysis of a Hybrid Displacement Amplifier Supporting a High-Performance Piezo Jet Dispenser

In this study, a compliant amplifier powered by a piezoelectric stack is designed to meet high-performance dispensing operation requirements. By studying the issue of low frequency bandwidth on the traditional bridge-type amplifier mechanism, we propose a displacement amplifier mechanism, hybrid bridge-lever-bridge (HBLB), that enhances its dynamic performance by combining the traditional bridge-type and lever mechanism. A guiding beam is added to further improve its output stiffness with a guaranteed large amplification ratio. An analytical model has been developed to describe the full elastic deformation behavior of the HBLB mechanism that considers the lateral displacement loss of the input end, followed by a verification through a finite element analysis (FEA). Results revealed that the working principle of the HBLB optimizes the structural parameters using the finite element method. Finally, a prototype of the displacement amplifier was fabricated for performance tests. Static and dynamic test results revealed that the proposed mechanism can reach a travel range of 223.2 μm, and the frequency bandwidth is 1.184 kHz, which meets the requirements of a high-performance piezo jet dispenser.