Research On Testing Technology Of Semiconductor Laser Self-mixing Interference Accelerometer

Accelerometers is a key inertial testing device in inertial navigation and precision guidance devices which are widely used in inertial navigation systems in areas such as automobile driving,drones,ballistic missiles,space shuttles,and warships.The performance of accelerometer will have a very important impact on the accuracy of the whole testing system.Therefore,in order to ensure the quality of the manufactured accelerometers,we need to utilize extremely stable and efficient testing methods to perform rigorous testing and analysis on accelerometer performance parameters in a fully qualified test environment.Laser self-mixing interference is an optical precision measuring technique that has gradually emerged in recent years.The laser self-mixing interferometer developed with this technology is widely used in aerospace,automotive navigation,safety production and other measurement fields due to its advantages such as simple and compact structure,high measurement accuracy,easy alignment,and non-contact measurement.This interference really plays an important role on reducing application costs and increasing production efficiency.Therefore,applying the self-mixing interference device to the accelerometer testing will greatly improve the test efficiency and reduce the testing cost.This paper presents an accelerometer testing system based on a laser self-mixing interference device.The external cavity reflection target surface of the self-mixing interference system and the accelerometer to be measured are all fixed to the vibration end of an exciter.According to different vibration frequencies,the fringe counting method or Bessel function zero value method is used to demodulate the acceleration information from the self-mixing interference signal.The results of multiple test groups for commercial accelerometers show that the sensitivity of the accelerometer tested using this system is about 24.33mV/g,which is in good agreement with the sensitivity parameter given by the accelerometer manufacturer.Based on the previous research,an improved self-mixing interference testing system was proposed.The reflection diffraction grating was integrated into the traditional self-mixing interference device.A self-mixing grating interference accelerometer testing system was designed using grating Doppler effect.Compared with the testing system of the previous chapter,the laser self-mixing grating interference reduces the influence of the frequency fluctuation from light source on the testing results meanwhile enhances anti-interference ability of the testing system and the practical value.At the same time,the test method specified by the International Standards Organization was modified adaptively.Finally,the results of multiple groups of commercial accelerometers showed that the sensitivity of the accelerometer measured by this testing system more closely approximated the sensitivity standard parameter 24.20mV/g given by the accelerometer manufacturer.The minimum sensitivity error measured by the testing system in the experiment can reach to 0.02mV/g,which shows a good testing performance and testing accuracy.Moreover,the device converts the measured minimum reference unit from the original half wavelength to a fixed grating pitch,which greatly increases the possibility of this system invested into commercial applications.So it reflects potential application prospects.