小型尾坐式飞行器航姿测量系统设计与验证

针对小型尾坐式飞行器航姿测量问题,设计了航姿测量系统。采用四元数法更新航姿参数再转换成欧拉角输出。由于小型尾坐式飞行器姿态变化范围大,针对传统四元数到欧拉角的转换算法在扰动下航向和姿态角易发生振荡的问题,提出了一种改进的全姿态四元数转换到欧拉角的转换算法,通过分析姿态矩阵中元素的符号,由四元数得到两组欧拉角,以姿态控制利益为牵引,选择正确的一组。针对无迹卡尔曼滤波(unscented Kalman filter, UKF)算法在外界噪声干扰下测量精度降低的问题,引入自适应算法,使量测噪声统计特性随噪声的变化而自适应的调整,提高系统的抗干扰能力。针对小型尾坐式飞行器姿态易突变的问题,设计了强跟踪滤波器,利用多个渐消因子减小历史数据在测姿中的作用,提高当前信息的比重,提高系统对突变姿态的跟踪精度。最后,通过实验验证了全姿态解算算法、自适应UKF滤波算法和强跟踪算法的可行性,实验结果表明了设计的航姿测量系统对小型尾坐式飞行器的适用性。

Design and validation of attitude and heading measurement system of small tail sitter aircraft

For the problem of measuring heading and attitude of small tail sitter aircraft, a measurement system is designed. The quaternion method is used to update heading and attitude, then the quaternion is transformed into Euler angle for output. Due to large change range of attitude, for the surge problem of attitude under disturbance from quaternion to Euler angles, an improved all attitude conversation algorithm is proposed. By analyzing the symbol of elements in attitude matrix, two groups of Euler angles are obtained from the quaternion. The right group is chosen in the interests of attitude control. For the precision decreasing of unscented Kalman filter (UKF) in the interference of outside noise, the adaptive algorithm is introduced to make the statistical feature of measurement noise adjust adaptively along with the change of noise. The anti-interference ability of the system is improved. For the problem of attitude mutation of small tail sitter aircraft, a strong tracking filter is designed. The role of historical information is reduced and the share of current information is increased by multiple fading factors. The precision of tracking rapidly changing state is improved. Finally, experiments verify the feasibility of the all attitude solution algorithm, adaptive UKF and strong tracking filter. The result shows the applicability of the designed heading and attitude measurement system in small tail sitter aircraft.