Establishment and analysis of a piezoelectric actuator dynamic model with temperature-dependent damping, stiffness, and piezoelectric constant

The characteristics of the piezo-stack and the flexible mechanism are both influenced by temperature, which induces the performance change of piezoelectric actuators in low-temperature. This study investigates how temperature affects the dynamics model's stiffness, damping, driving force, and friction. An axial heat conduction model based on Fourier's heat conduction law was established, and finite element analysis was carried out to study the temperature distribution of the piezo-stack. Moreover, finite element analysis was carried out at various temperatures to investigate the impact of temperature on the flexible mechanism's deformation. Based on the aforementioned study, a dynamics model with variable stiffness and damping is proposed in this paper, and the simulation results are verified. In the experiment, the effects of temperature, voltage, and frequency on the output performance of the piezoelectric actuator were investigated separately using impedance and amplitude-frequency characteristic curves to determine the resonant frequency and damping ratio of the flexible mechanism at low temperatures. Theory and experiment show that high stiffness and low piezoelectric constants at low temperatures reduce the piezoelectric actuator's output displacement, friction reduction will enhance the driving displacement of the piezoelectric actuator, and the effect of damping on output displacement is insignificant. This study offers significant theoretical value and guidance for the use of piezoelectric actuators in lowtemperature situations.