On Line Vibration Measurement System Of MEMS Devices Based On Micro Photoelectric Array

MEMS(Micro-Electro-Mechanical Systems)devices have many excellent characteristics,such as small size,light weight,low energy consumption and so on.They have broad development prospects and are widely used in many fields.The research on the dynamic characteristics of MEMS devices is of great significance,especially the vibration measurement of MEMS devices.In this paper,an on-line vibration measurement system of MEMS devices based on micro photoelectric array is designed and developed to meet the application requirements of small volume and micro amplitude measurement.The main contents of this paper include:1.The research status and trend of micro vibration measurement methods at home and abroad are investigated.The principle,advantages and disadvantages of laser triangle vibration measurement method,laser Doppler vibration measurement method and capacitance vibration measurement method are analyzed.According to the volume and applicable environment of these methods,a vibration measurement method based on photoelectric array is proposed.2.In order to eliminate the influence of the tilt between the object and the photoelectric array on the output characteristics of the micro vibration measurement system,the layout of the photodiode of the micro photoelectric array is designed in the way of two-dimensional concentric circle.The influence of the inner and outer radius of the concentric circle on the linearity and sensitivity of the system is analyzed,and the optimal design scheme is given.3.In order to improve the signal-to-noise ratio of the micro vibration measurement system,analyze the noise of the light source,the output noise of the photoelectric array and the noise of the acquisition circuit,give the method of controlling the hardware noise and make quantitative estimation.4.In order to collect nine photodiode light intensity signals in real time,arm program is written to realize the algorithm of obtaining vibration amplitude by variable sampling,and the performance of signal processing system is tested.5.At last,the experimental device is designed,and the calibration experiment,repeatability experiment and dynamic experiment are carried out.The results show that the linearity of the output signal is the best when the distance between the plane mirror and the photoelectric array is in the range of 6.8 mm ～ 7.8 mm,and the micro vibration amplitude with a frequency of 20 Hz is measured with an accuracy of 2 ‰.