一种新型柔性双轴微夹钳的设计与分析

Design and analysis of a novel flexible dual-axis micro-gripper

针对传统的微夹钳在复杂的微操作中只能沿单轴进行夹持操作的不足,文中设计了一种柔性铰链的双轴微夹钳,结构简单又紧凑,该微夹钳由一个压电陶瓷驱动器驱动,实现夹持和旋转两种操作。采用非对称结构设计,实现左边完成向前旋转动作,右边完成夹持动作。通过左右两边两级放大机构结构设计不同,实现位移放大和运动传递。为实现抓取和搓动功能的解耦,对两部分的运动导向机构进行了正交设计。采用伪刚体法建立了机构的伪刚体模型,建立了机构的运动学和动力学模型,包括运动机构放大比、输入刚度和机构的固有频率。通过有限元分析方法验证了微夹钳的性能模型的准确性。仿真试验结果表明,左侧机构的放大比为8.01,右侧放大比为8.56,最大输出位移可达171.36μm。所设计的微夹钳具有良好的抓取和搓动的性能,可实现高精度的抓取和释放操作。

In this article,in view of the deficiency that the traditional micro-gripper can only be gripped along a single axis in complex micro-operation,a flexible dual-axis micro-gripper driven by a piezoelectric ceramic actuator is proposed.It is simple and compact in structure,in order to realize grasping-revolving micro-operation.The micro-gripper has an asymmetrical structure,with its left part used for revolving and its right part used for grasping.The different two-stage amplification mechanisms are adopted to achieve displacement amplification and motion transmission.In order to realize the decoupling of grasping and releasing functions,the motion-guide mechanism of the two parts is subject to orthogonal design.The pseudo-rigid-body model of the mechanism is set up with the help of the pseudo-rigid-body method,as well as the kinematic and dynamic models,including the motion mechanism's magnification ratio,input stiffness and natural frequency.The micro-gripper's performance models prove to be correct by means of the finite-element analysis.The simulation results show that the magnification ratio of the left mechanism is 8.01,the magnification ratio of the right mechanism is 8.56,and the maximal output displacement is up to171.36μm.This micro-gripper with good performance of grasping and rubbing can achieve the high-precise grasping-releasing tasks.