Three optical path signal compensation system and method in optical mems accelerometer

Abstract

The invention discloses a three-optical path signal compensation system and a method thereof in an optical MEMS accelerometer, including a three-optical path compensation path and a subsequent signal processing system; wherein the three-optical path compensation path includes an optical isolator, a miniature beam splitting prism, a plane reflector, Attenuator, photodetector; compensation signal processing system includes three analog-to-digital conversion AD conversion modules, subtractor, divider, data storage and averaging module, multiplier, the above modules are realized by a programmable digital signal processor . The invention has a relatively simple structure, can effectively reduce the influence of the power fluctuation of the light source itself and ambient light on the output signal, and can effectively reduce the cost of the optical MEMS accelerometer compared with the scheme of using a laser with high power stability. Moreover, the system and method can be effectively applied to the optical MEMS accelerometer, reduce the disturbance of its output signal, and finally improve the stability and accuracy of the acceleration measurement zero bias.

Description

technical field [0001] The invention relates to a signal compensation system and method in an accelerometer, in particular to a three-light path signal compensation system and a compensation method for suppressing signal disturbance caused by power fluctuations of the light source itself and ambient light in an optical MEMS accelerometer. Background technique [0002] The accelerometer is a sensor that measures the acceleration of an object. Its basic measurement principle is based on Newton’s second theorem. The accelerometer converts the acceleration into the displacement of the mass block in the elastic structure. The displacement has a definite relationship with the input acceleration. The magnitude of the input acceleration can be obtained by measuring the displacement. Therefore, the accelerometer usually includes a mechanical acceleration sensitive system and a displacement measurement system, and the measurement sensitivity of the acceleration and the noise of the ac...

AI Technical Summary

Problems solved by technology

The laser in the optical MEMS accelerometer has power fluctuations and frequency fluctuations. In the actual measurement process, frequency fluctuations will introduce phase errors in the interference field, thereby affecting the measured displacement and acceleration values. For this error, you can choose a stable The power fluctuation of the laser itself will directly cause the disturbance of the output signal. The power fluctuation of the common laser is on the order of 1%. Choosing a laser with high power stability will greatly increase the cost of the optical MEMS accelerometer

Since the current optical MEMS accelerometer takes the input laser light intensity as a fixed value when calculating the input acceleration value, the existence of power fluctuations in the laser light source itself will introduce calculation errors, which limit the improvement of displacement measurement accuracy and acceleration measurement accuracy.

Moreover, the ambient light and stray light in the actual measurement environment will also disturb the output signal and affect the measurement results. When the accuracy of the optical displacement measurement system reaches the nanometer level, these effects cannot be ignored

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