Design Of An Attitude Measuring System For Micro Rotorcraft

In recent years, unmanned aerial vehicles (UAVs) have been widely used in both military and civil applications. Rotorcrafts have the ability of hovering, vertical take-off and landing, easily adapting to complicated urban and rural areas. They can keep flying near to buildings and provide accurate positioning information. Nowdays the advantages of rotorcrafts, such as strong maneuverability, high concealment and low cost, make they considered as one of the research focuses on UAVs. Due to the loading of the micro rotorcrafts, the attitude measuring systems working for them should be small and light with low power consumption. With the development of MEMS inertial sensors and embedded systems, it has already met the demands of the attitude measurement.In this dissertation, an attitude measuring method based on ARM processor is proposed, which gives out attitude informations of medium and low accuracy. The system is consisted of three-axis MEMS gyroscopes, MEMS accelerometers and magnetometers, providing the information of angular velocities, accelerations, magnetic field intensities in three-axis. Through strap-down resolving, the yaw, pitch and roll angles are obtained, and supplied to the fight control systems.Firstly, the background information of this subject is discussed. Secondly, the relevant mathematical theories of strap-down attitude updating are introduced. By comparing the integrated attitude determination mothede based on extended Kalman filter (EKF) and quaternion is chosen. Thirdly, error analysis of the attitude measuring system is performed. With the output models of the MIMU and magnetometers established, systematic calibration of the inertial sensors is carried out. Fourthly, the EKF for integrated attitude determination is designed, and the simulation result is given to show the effectiveness of the proposed algorithm. Finally, overall design is finished. The inertial sensors and circuit components are chosen on the basis of the system requirements. The experiment is performed and the result is analyzed, while both of the software and hardware of the attitude measuring system are realized,.Experimental result shows that the attitude measuring system based on ARM processor is running well, and meets the requirements of the micro rotorcraft.