压电叠堆致动器在大刚度负载下位移损失因素分析

Analysis of Displacement Loss Factors in Piezoelectric Ceramic Stack Actuators Under High-Stiffness Load

摘要:

通过测量大刚度负载下压电叠堆微动台的位移输出特性,表明其输出位移明显小于商用压电叠堆说明书中的预期值,且随着压电叠堆上预压力的增大,其输出位移先增大后减小。经分析发现,在大刚度负载、低预压力下,压电叠堆与负载之间的机械接触刚度与叠堆刚度在同一数量级,驱动端有效刚度的减小将导致输出位移损失;随着预压力的增大,压电叠堆内非180°畴重定向增强了压电效应,且机械接触刚度增大直至极限值。但叠堆的压电系数在压力过大时会因退极化而降低,故微动台总体上将有较大的位移损失,且在接触刚度和退极化两种因素作用下,位移在某预压力时达到极值。

Abstract:

The displacement output characteristics of a piezoelectric stack micropositioner under high-stiffness load were measured, revealing that the output displacement is notably lower than expected. This displacement ini tially increases and then decreases as preload increases. It was found that under high-stiffness load and low preload, the mechanical contact stiffness between the piezoelectric stack and the load is of the same order of magnitude as the stack stiffness. This reduces the effective stiffness of the driving end, leading to displacement loss. As preload in creases, non-180° domain reorientation within the piezoelectric stack enhances the piezoelectric effect, and mechani cal contact stiffness increases until it reaches its limit. However, at higher loads, the piezoelectric coefficient of the stack decreases rapidly owing to depolarization. Overall, the micropositioner exhibits significant displacement loss, with displacement reaching its peak at a specific preload owing to the combined influence of these two factors.