尺蠖式压电线性作动器设计及实验研究

Journal of Vibration,Measurement&Diagnosis Vol.43 Design and Experimental Study of a Novel Inchworm Piezoelectric Linear Actuator

针对空间环境下小型抓取操作机构对新型作动器的使用需求,考虑压电作动器具有耐温范围宽、无电磁干扰及断电自锁等特点,仿照昆虫尺蠖的行走方式设计一种新型压电线性作动器。首先,利用柔性铰链式位移放大机构放大压电陶瓷(Pb-Zr-Ti,简称PZT)叠堆的输出位移,以增大线性作动器的移动步长及对导轨的夹紧变形量,将多个压电陶瓷叠堆器件分为3组,分别作为尺蠖式压电线性作动器的2个夹持单元和1个推进单元的激励源,以获得较大的驱动力并进一步增大作动器的移动步长;其次,借助有限元仿真分析软件,研究压电陶瓷叠堆力电耦合行为的预测方法,并实验验证该方法的可行性;然后,简化柔性铰链式位移放大机构,提出放大倍数的数值分析方法,对位移放大机构在压电陶瓷叠堆作动方向上的刚度进行仿真分析,并验证放大倍数的数值分析方法的准确性;最后,基于设计的线性作动器开展实验研究。结果表明:位移放大机构对压电陶瓷叠堆输出位移的放大倍数为7.3,处于理论值与仿真值之间;在激励电压频率为5 Hz时,作动器的最大空载移动速度为413μm/s;作动器的最大推动力为16 N,对应的驱动速度为19μm/s。以上研究结果能为小型抓取操作机构的智能驱动提供技术支持。

Considering the piezoelectric actuators have characteristics of wide temperature resistance range,no electromagnetic interference,and self-locking when powered off,a novel inchworm piezoelectric linear actua-tor,which meets the demand of new actuators for small grasping operating mechanisms in the aerospace environ-ment,is proposed imitating the walking mode of the insect inchworm.A flexible hinge-type displacement ampli-fying mechanism is utilized to amplify the output displacement of the Pb-Zr-Ti(PZT)stack,so as to increase the movement step length of the linear actuator and the clamping deformation of the guide rail.The multiple PZT stacks are divided into three groups,which are respectively used as two clamping units and one propulsion unit of the actuator to obtain a larger driving force and further increase the movement step.Through the finite ele-ment analysis method,the prediction method of the electromechanical coupling behavior of the PZT stack is studied,and the feasibility of the method is verified by experiments.The flexible hinge displacement amplifica-tion mechanism is simplified,and the numerical analysis method of magnification is proposed.On this basis,an experimental study is carried out based on the designed linear actuator.The test results show the magnification of the output displacement of the PZT stack by the displacement amplifying mechanism is 7.3,which is between the theoretical value and the simulation one.When the excitation voltage frequency is 5 Hz,the maximum noload moving speed of the actuator is 413μm/s;the maximum driving force is 16 N,corresponding to a driving speed of 19μm/s.The above research results can provide technical support for the intelligent drive of small grasping operating mechanisms.