Research Of Attitude Measurement System Based On Quaternion Nonlinear Filter Algorithm For Quadrotor

Many nonlinear factors in the quadrotor attitude measurement system cannot be ignored.The nonlinear data fusion algorithm is one of the methods to solve the nonlinear problem,which has become a research hotspot in the field of quadrotor.This paper tightly around the multi-sensor attitude measuring data fusion and quadrotor attitude model with nonlinear two problems and focuses on the improvement of the accuracy of attitude estimation by using nonlinear data fusion algorithm.From two different perspectives of frequency domain and time domain,the nonlinear attitude filtering model of the system is established by using quaternion method.In order to solve the problems that system is susceptible to interference and the convergence speed of attitude is slow,the attitude improvement algorithm based on Quaternion Complementary Filter(QCF)and Quaternion Extended Kalman Filter(QEKF)are proposed respectively,and a low-cost inertial navigation/magnetometer attitude measurement system of quadrotor is designed for the algorithm verification.Firstly,by analyzing and summarizing attitude measurement system design method and the nonlinear data fusion technology research situation,and comparing to common attitude system measurement systems,this paper proposes inertial navigation/magnetometer attitude measurement system plan.The system consists of low cost Micro-Electro-Mechanical System(MEMS)gyroscope,accelerometer and magnetometer,which can realize the quadrotor all-attitude measurement.Secondly,the principle and method of attitude calculation for quadrotor are introduced,and the quaternion method is used to solve the attitude calculation.Then,by analyzing the error characteristics and measurement principle of the attitude sensors,the error model and attitude measurement model of sensors are established,which lays the foundation for the later study.Thirdly,according to the problems that Conventional Complementary Filter(CCF)stop-band attenuation rate is slow and has steady state error and is difficult to solve nonlinear problems,the QCF algorithm with independent control parameters is designed.In order to further improve the accuracy of attitude calculation,a nonlinear filter equation based on quaternion is established,and QEKF algorithm is designed.For the quadrotor is susceptible to motion acceleration and magnetic interference problems,the modulus discriminant method is adopted to modify the original algorithms,and the Adaptive Quaternion Complementary Filter(AQCF)and Adaptive Quaternion Extended Kalman Filter(AQEKF)algorithm are designed.For the convergence speed of attitude is slow,the QCF/QEKF combination algorithm is designed.Finally,the design and construction of the hardware platform of attitude measurement system are completed and used for experimental verification.The sensor signal is preprocessed by IIR digital filter before the filter update,and the horizontal rotation method is used to calibrate the magnetometer.The simulation and experimental results show that the proposed algorithm can effectively eliminate the interference and improve the convergence speed at the start-up time.