Research On Dimension Measurement Algorithm Of Mechanical Structure Of MEMS Gyroscope Under Microscopic Vision

MEMS(Micro-Electro Mechanical System)gyroscopes,as angular rate sensors,are widely used in navigation systems for aerospace vehicles,smart vehicles,and smart devices such as mobile phones.Due to the existence of errors in the processing process of MEMS gyroscopes,its measurement accuracy is affected,so it cannot meet the high-precision navigation requirements of intelligent equipment such as space satellites and aircraft.Ultra-short pulse lasers are an effective way to improve the structural errors of MEMS structures.The mechanical structure of the MEMS gyroscope reaches the micro-nano scale.If the trimming process is done manually,it is difficult to precisely etch the size,which will eventually lead to poor trimming accuracy and low trimming efficiency.In view of the above problems,this dissertation introduces the image processing technology into the laser trimming process of the MEMS gyroscope mechanical structure,and accurately measures the size of the MEMS gyroscope mechanical structure at the micro-nano scale,thereby improving the trimming accuracy and efficiency of the micro-nano structure.The main research contents of this dissertation are as follows:(1)Calibration of the camera of the measurement system.In the field of microscopic vision,camera calibration algorithm is usually used to obtain camera parameters.This algorithm uses lens focal length to calculate camera parameters,which has poor robustness,resulting in inaccurate results.In response to this problem,this dissertation proposed a new camera calibration method that used the origin of the world coordinate system and the coordinate axis point to calculate the parameters,which replaced the existing method of calculating the calibration parameters of the focal length of the lens to improve the calibration accuracy of the camera 1 pixel.(2)Research on dimensional measurement of MEMS gyroscope mechanical structure.The dissertation adopts filtering,threshold segmentation,edge extraction,and line detection to measure the pixel size of the MEMS gyroscope mechanical structure.For image filtering processing,the traditional bilateral filtering algorithm was insufficient to preserve the structural edge information,and the sharpening edge algorithm of bilateral filtering was used to sharpen the structural edge.For image threshold segmentation,a threshold segmentation algorithm based on pixel variance was proposed to accurately segment images for the problem that global threshold cannot be accurately segmented.For image edge extraction,there was an error in the structure edge that may be affected by impurities.An error edge repair algorithm based on the curvature value of the edge point was proposed to ensure the accuracy of the edge.For image line detection,in view of the low detection accuracy and low efficiency of Hough line detection algorithm,a fast Hough line detection algorithm based on structural geometry was proposed to quickly detect line information.In this dissertation,the camera calibration and size measurement experiments are designed respectively,and the real size of the MEMS gyroscope mechanical structure is calculated based on the camera calibration results and the size measurement algorithm results.The experimental results are counted and analyzed,and the size measurement accuracy and error are summarized.The experimental results show that the measurement accuracy of the algorithm in this dissertation is about 1 μm,which meets the requirements of the trimming system.