为使夹持器小型集成化且夹持力可控,采用体硅加工技术研制了一种基于单晶硅的、具有微力检测功能的新型四臂式MEMS微夹持器。以压阻检测技术为基础,利用MEMS侧面压阻刻蚀工艺将力传感器集成在微夹持器的夹持臂末端,实现夹持力的微力检测。采用有限元软件分析,微夹持器机构和传感器弹性体,并通过S型柔性梁结构的设计将梳齿驱动的直线运动转化为夹持臂末段的转动,然后结合四臂式的末段结构,有效地扩展夹持器的夹持范围。利用硅玻璃键合技术实现夹持臂的电隔离,通过施加80 V电压,夹持臂的单臂运动范围为25 μm,夹持器的夹持范围为30~130 μm。实验标定出传感器的最大量程在1 mN以上,分辨率为3 μN,可以实现夹持力的有效反馈。

A novel four-arm structure single crystal silicon MEMS gripper integrated with force sensors is successfully developed by using a silicon bulk machining method to realize the monolithically fabrication and the control of gripping force.Based on the technology of the piezoresistive detection,an effective technique for fabricating vertical sidewall piezoresistors in planes is used to fabricate the piezoresistor in the end of the end-effectors.The Finite Element Analysis (FEA) is used to analyze the structure of the gripper and the flexible beams of the force sensors.The comb microactuator generates a linear horizontal motion,which is converted into a rotational motion by an S-type flexible beam system to realize the gripping motion.Combined with the four-arm structure,the manipulating range is expanded.The bonding of the silicon and the glass is used to realize the electrical isolation of the gripping arms.At a voltage of 80 V,the deflection of the arm tip is 25 μm and the ranges of the operation are 30~130 μm.Testing results show that the maximum measurement range of the piezoresistive sensors is better than 1 mN and the resolution is better than 3 μN,which can be used effectively in the force feedback.