Design Of Micro Inertial Measurement System Based On STM32 And MEMS Devices

Since MEMS technology has set up, more and more institutions from domestic and foreign theoretical always have been studying the technology in theoretical research and practical application. The measuring system with MEMS inertial devices built has the advantage of small size, light weight, low cost and working independently and so on. It has been very widely used in the field of aerospace, military and civilian. Therefore, this article designed the micro inertial measurement system based on STM32 and MEMS devices under the function of MEMS technology.Through analyzing the composition of the micro inertial measurement system, we finalize determined the design of this system. The system is composed by the three-axis gyroscope, three-axis accelerometer, three-axis magnetometer, a microcontroller STM32F103 and computer processing system. In this system the gyroscope can ensure the dynamic performance of the carrier, and the accelerometer and magnetometer can compensate for the zero drift of gyroscope. This design has not only improved the accuracy of the system, but also enhanced the robustness of the system. Attitude Algorithm is an important part of this article. First, the attitude angles are calculated by the measured values of gyroscope on the way of four elements algorithm. Then attitude angles could be calculated by the measured values of accelerometer and magnetometer combining the gravity field and the geomagnetic field. Finally, designing a Kalman filter according to the characteristics of the inertial sensors correct the error of attitude angles, and obtaining the optimal estimate of attitude angles to ensure accuracy. The hardware platform of micro inertial measurement system was designed integrating STM32F103 microcontroller and MEMS devices(micro inertial gyroscopes, accelerometers and magnetometers) under the Altium Designer development environment. The software platform was designed connecting software and hardware interfaces through software driver modules under the Keil MDK compiler environment. The three-dimensional dynamic display interface was designed combining with Open GL and MSComm serial control under VS2010 development environment.Finally, through the experiments of the micro inertial measurement system, we analyzed the static error and dynamic error of the system. It proved the effectiveness of the inertial measurement system from the perspective of the experiment.