四自由度压电微夹钳的结构设计及尺寸参数优化

Structure Design and Size Optimization of a 4-DOF Piezoelectric Micro-Gripper

为提高微夹钳操作微对象时的灵活性,探索四自由度压电微夹钳的实现问题,将制成相应形状并分割驱动电极的两片压电陶瓷晶片进行粘结,制作出微夹钳,并将两组空间垂直交叉的横向逆压电效应作用于钳指上,使单个钳指产生夹持方向和垂直于夹持方向的微位移,从而使整个微夹钳(两个钳指)具有4个自由度.在综合考虑微夹钳输出位移、固有频率、制作工艺的情况下,采用有限元分析方法,对钳指长度、宽度、厚度进行了优化,对优化后微夹钳的输出位移和振型进行了分析.对微夹钳的输出位移进行了测试,结果表明:在60 V的最高驱动电压作用下,左、右两钳指沿夹持方向的最大位移分别为25.6μm、24.3μm,沿垂直于夹持方向的最大位移分别为32.1μm、30.9μm;两钳指的输出位移具有良好的重复性.

To improve the operation flexibility of the micro-gripper, a novel four degree of freedom （4- DOF） piezoelectric micro-gripper was developed. A couple of piezoelectric ceramic wafers with finger shape and divided driving electrodes were bonded together. Furthermore, a couple of transverse inverse piezoelectric effects, perpendicularly crossing, were applied on the fingers. Correspondingly, micro displacements of one finger both in the gripping direction and perpendicular to the gripping direction were generated. Thus, 4-DOF motions of the micro-gripper （ including two fingers） were realized. Considering the output displacement, natural frequency and production process of the micro-gripper, the length, width and thickness of the fingers were optimized, using finite element method. Then, the output displacement and vibration shapes of the optimized micro-gripper were analyzed. Finally, the static and dynamic performances of the micro-gripper were tested. Experimental results show that at the maximum driving voltage of 60 V, the maximum displacements of the left and right fingers in the gripping direction are 25.6 μm and 24.3 μm, respectively ; while the maximum displacements of the two fingers perpendicular to the gripping direction are 32. 1 μm and 30. 9 μm, respectively. And the output displacement of the two fingers enjoys good repeatability.