| MEMS accelerometers are often used for vibration and inertial measurement in the aerospace,petroleum exploration and other fields.In order to ensure the accuracy and effectiveness of measurement signals,it is necessary to calibrate accelerometers regularly according to national metrological verification regulations.Because the direction of gravity acceleration is not accurately measured,in the accuracy of existing accelerometer gravity field method calibration can be further improved.In this paper,we study the the gravity field method calibration based on machine vision to improve the calibration accuracy.The emphasis is the accurate orientation of the gravity field and the measurement of the angle between the sensitive axis of the accelerometer and the direction of the gravity field.The main contents of this paper include:1.According to the actual calibration requirements,the calibration scheme of gravity field method calibration of accelerometers based on machine vision is proposed on the basis of the domestic and foreign gravity field method calibration devices.2.The gravity field orientation and the rotation angle measurement optical systems of shearing interference and autocollimation are designed.The rotation angle measurement systems of shearing interference and laser autocollimation based on machine vision are built.The rotation angle measurement system is used to orient the gravity field and measure the angle between the sensitive axis of the accelerometer and the direction of the gravity field.3.The gravity field calibration system based on machine vision is set,the static calibration and the low-frequency calibration of the accelerometer sensitivity amplitude are realized by using the calibration system.The calibration results and the measurement uncertainty of the calibration system are analyzed.The gravity field calibration system of accelerometers based on machine vision designed in this paper can accurately orient the direction of the gravity field and measure the rotation angle.The accelerometer sensitivity amplitude has higher calibration accuracy in zero frequency and low frequency range which is from 0.1～2Hz. |
