Research on variable stiffness asymmetrical resonant linear piezoelectric actuator based on multi-modal drive

In this paper, a linear piezoelectric motor with variable stiffness and asymmetric resonance is proposed, which is driven by a single harmonic signal. Working in the resonant state improve the output performance of the motor. Motor control is relatively simple and can realize reverse movement under the driving of second-order single harmonic signal. At the same time, the new motor can obtain different operating speed and step distance by changing the clamping position in front and back to meet the requirements of different loads and different working conditions and has strong applicability. By experiment, the first_order optimal operating frequency of the motor prototype at three different stiffness adjustment positions is 88 Hz, 90 Hz and 92 Hz respectively. Under the excitation of 240 V_p–p first_order resonance signal, the corresponding output speed of the motor prototype is 16.116 mm s⁻¹, 20.457 mm s⁻¹ and 25.015 mm s⁻¹ respectively, and the corresponding displacement resolution is 0.18 mm, 0.22 mm and 0.27 mm respectively. When the stiffness adjustment positions is 2 mm, the maximum load of the motor prototype reaches 450 g. The second-order optimal operating frequency at the stiffness adjustment positions 1 mm is 601 Hz. Under the excitation of a 240 V_p–p second-order resonant signal, the reverse output speed of the motor prototype is 13.126 mm s⁻¹, and the corresponding displacement resolution is 0.02 mm.