基于双GNSS天线及单陀螺的车轮转角测量系统

Wheel Turning Angle Measurement System Based on Double GNSS Antennas and Single Gyro

针对农业机械自动导航中,传统绝对角度传感器连接件多、安装复杂且容易出现故障,而陀螺测量前轮转角虽然安装容易,但陀螺零偏等仪器误差造成测量误差随时间累积的问题,提出了基于双GNSS天线和单轴MEMS陀螺组合测角系统,该系统通过双GNSS天线解算的航向角、速度等信息计算观测量,通过卡尔曼滤波器对陀螺计算的角度进行实时校正,提高了车轮转角的测量精度。实车试验结果表明,该系统具有较好的合理性和准确性,车轮转角测量结果与绝对角度传感器输出结果比较:直线试验误差在0.5°以内,曲线试验误差在1°以内,满足了农业机械自动导航的测角精度要求。

For the problem that the traditional angle sensor＇ s complex mechanical structure and prone to failure and the gyro bias cause the error accumulates over time in automatic driving system, a wheel turning angle measurement system based on double GNSS antennas and single gyro was proposed. The system＇s sensors mainly included two GNSS antennas and a MEMS gyro. The double GNSS antennas were mounted on both side of the vehicle and provided the speed, attitude angle, latitude and longitude of the vehicle. The single MEMS gyro was mounted on the wheel and the angular rate was measured. An algorithm used the above data was designed to integrate the angular rate to obtain the steering angle. In order to solve the problem that the error accumulates over time, a Kalman filter based on the vehicle dynamics model was designed to calibrate the error of integration of the gyro data. At the same time, the lever-arm compensation algorithm was used to solve the speed error caused by lever-arm. The straight line experiment was carried out to verify the effectiveness of the system and the curve line experiment was carried out to verify the effectiveness of the lever-arm compensation algorithm. Compared the steering angle of the proposed system with the Hall effect angular sensor, the average error of the straight line experiment was -0. 064° and the error variance was 0. 309° and the cure line experiment＇ s mean error was 0. 299° and the error variance was 1. 009°. The result of the experiments showed that this system could replace the traditional angle sensor and it was easy to install and overhaul.