Implementation And Research Of Auto-calibration Algorithm Of Mems Imu

MEMS (Micro-electromechanical Systems) inertial measurement unit has advantage of small size, wide measurement range and high reliability. At present, it has been widely used in automotive electronic, precision instrument, aviation and space technologies, etc. However, with the low accuracy, large noise, sensitive to the external environment, such as temperature and press, it must be taken the necessary measures to improve accuracy. On the one hand, the performance of the chip signal processing circuit and electromagnetic shielding characteristic can be improved from the manufacturing process to optimize the mechanical design; on the other hand, the output error can be reduced by adopting error compensation technology.Taking the MEMS IMU produced by DJI as the research object, its error analysis, modeling and automated calibration compensation are studied in detail. Firstly, this paper briefly introduces the application of IMU in strapdown inertial navigation system. And the influence of the IMU performance on strapdown inertial navigation system precision is analyzed. Secondly, from the mechanical structure and mechanical principle of IMU has carried on the analysis to accelerometers and gyroscopes measuring principle, points out the cause of the error, and gives the mathematical models of the major error. Finally, the paper expounds how to realize the automation of IMU error compensation process.This article, which has analyzed the character of IMU temperature drift,proposes the small cycles method. By this way and the design of the 45°tilting rotary table, the system can collect accelerometer and gyroscope data at the same time. For three-axis accelerometer and gyro nonorthogonality error, the error matrix method is introduced for calibration. In addition, the temperature drifts error of polynomial fitting methods used for model parameter identification. The CAN bus is employed as information exchanging channel between host computer and IMU, and self-defined protocol is used for communication. In the PC side, the labview software is used to acquisition, processing and display the data and control of the program to realize the operation of the automated calibration system.