The Attitude Test Algorithm Based On MEMS Multidimensional Inertial Sensors

Attitude is the representation of spatial location information of the moving target objectin a specific coordinate system, which is expressed by eulerian angles as well. The way toobtain posture is by data fusing the various kinds of motion information of target objectinstead of measure it directly. Therefore, the application of tracking and estimating theposture of moving target object accurately is quite wide in many fields. When theperformance and accuracy of MEMS(Micro-Electro-Mechanical Systems) device areimproved constantly along with continuous development of MEMS technology, researchersattach great importance to MEMS device in tracking system of inertial posture, especially inthe inertial sensors-based research of human postuer because of its superiorities such as smallsize, light weight and low price. In IMU(Inertial measurement unit) system, which combinedwith MEMS gyroscope and accelerometer, there are errors existing when gyroscope isdrifting as time goes by, for this reason more and more researchers are inclined tocombination system of magnetic resistance sensor and inertial sensor to post estimate.Firstly,this paper discussed the research status and introduced some basic theory forhuman body motion track based on MEMS inertial sensors, some algorithmes for humanbody motion track are described in detail and the various kinds of characteristices based onthem are analyzed and compared in the next place. Secondly, we analyzed the characteristicof MEMS inertial sensor and magnetometers, and build error model.After that, Kalman filterand Complementary filter are introduced and an algorithm which able to decrease thedistortion of attitude angle as much as possible is proposed. The proposed algorithmmentioned above is according to the distortion problem of heading angle, roll angle andpitching angle during the posture calculating which based on quaternion method. Because ofEuler angles algorithm has the characteristic of getting tilt angles(roll angle and pitchingangle) and heading angle separately, so tilt angles are interference free when the outsidemagnetic field has distorted. Overcoming the singular value problem during posturecalculating by using Euler angles is proposed and a new element of posture calculating isbrought in as well as an adaptive filtering method iming at the singular value problem. In theend, this paper proceed a posture test to the proposed algorithm of calculating posture whichaccording to Euler angles method by using posture measurement system based an optical,and compared the tested one to the posture come from the quaternions. The proposedalgorithm in this paper had overcame the singular value problem in the traditional Euler method, and approximate to quaternions without outside magnetic field distortion. Whendistortion has taken place in outside magnetic field, the proposed algorithm in this papershowed better performance which specifically in the respect that roll angle and pitching angleweren’t effected by distortion of magnetic field than the quaternion algorithm. and proposedalgorithm in this paper with body attitude test system binding to achieve a real-time trackingof the human body posture.