Design Of Wide Range High Accuracy Inclinometer Based On MEMS Sensors

With the rapid development of China's industrial technology,the requirements for the measurement of tilt angle in aerospace,civil construction and medical equipment are also increasing.In particular,precision equipment such as radars,precision robotic arms,medical CTs,etc.,require wide range high accuracy inclination measurement.Aiming at the fact that most of the inclinometers can only achieve a large range of low accuracy or a high accuracy of a small range,a large measuring range and high accuracy inclinometer based on MEMS sensor was designed.In this paper,starting from increasing the measuring range of the system,the measuring unit is composed of three single axis MEMS accelerometer and adopts the orthogonal triaxial measurement model.Based on the same measurement accuracy,the measurement range of inclination angle is increased.The hardware design part chooses the low noise high precision acceleration sensor,the high resolution analog-to-digital conversion chip and the high operation rate control solution chip,lays the foundation for the data high accuracy collection processing.Then,the main factors affecting the measurement accuracy of the system are summarized by analyzing the structure and the measurement model of the system.Aiming at the shortcomings of traditional calibration methods,a multi-position calibration method based on the turntable is proposed,which realizes the high precision calibration of system scale factor matrix and zero voltage.Aiming at the problem that the scale factor and the zero point voltage of the accelerometer after calibration have drifted with temperature changes,a segmented temperature compensation method is proposed to reduce the influence of the change of ambient temperature on the system measurement results.Aiming at the problem of zero point voltage drift during the long-term use of the inclinometer system,an on-line self-calibration method is proposed,which greatly increases the practicality of the inclinometer system.Finally,the multi-position calibration compensation method,the segmented temperature compensation method and the on-line self-calibration method were verified experimentally using a three-axis position temperature control turntable,and the effectiveness of the three error compensation methods was proved.The experimental verification shows that the system can achieve 0°~360° tilt angle measurement over the full temperature range(-20?~60?)and the maximum error of measurement is not more than 0.01°.