基于散斑数字图像相关的柔顺结构力传感单元设计与试验研究

Design and Experimental Study of Compliant Structural Force Cell Based on Digital Image Correlation

随着微机电系统(Micro-electro-mechanical systems,MEMS)越来越复杂,对微装配、微操作的微力测量要求越来越高。根据微夹持视觉导航与夹持力传感的要求,研究一种面向微夹持器的柔顺结构视觉力传感单元。该传感器单元与微夹持器采用结构一体化设计思想,加工简易,可在同一视场内实现视觉导航与夹持力传感。通过提出集成该视觉力传感单元的微夹持器构想,推导该视觉力传感单元的力-位移理论关系,建立基于散斑数字图像相关(Digital image correlation,DIC)方法的精密位移测量方法,构建该柔顺结构力传感单元。在此基础上,基于柔顺结构力传感单元的放大模型,建立验证力传感单元的力-位移关系的试验系统,进行传感单元的力-位移关系试验研究。研究表明,所提出的柔顺结构视觉力传感单元测量性能达到预期要求。

Micro force measurement is required as following more complicated micro-electro-mechanical systems （MEMS） in its micro-assembly and micro-manipulation. According to the requirements of integrated vision-based navigation and micro-force sensing for a micro-gripper, a kind of vision-based compliant structural force cell is presented oriented to the micro gripper. The force-sensing cell is designed in the idea of integration of a force-sensing cell with a micro-gripper, which embeds the characteristics of monolithic structure, easy machining, vision-based navigation and gripping force sensing in a same vision field. After the idea of micro-gripper integrated with the force sensing cell is presented, a vision-based force sensing cell is built up by the following works that the function of loading force with the displacement is derived, and a precision displacement measurement method based on speckle digital image correlation （DIC） is formulated. The experimental setup based on a amplified model of a compliant structural force sensing cell also is built up in order to verify the relationship between its force and displacement. The results indicate that the performance of the vision-based compliant force cell reaches the expected requirements.