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.