控制力矩陀螺作为航天器姿态控制的一个重要部分, 对其输出力矩的速度及精度要求越来越高。目前, 对于高精度的框架控制性能进行标定和验证, 大都是依靠控制力矩陀螺自身角度位置传感器进行评价, 精度存在一定的误差。针对这种情况, 设计了一种独立于控制力矩陀螺的视觉测量标定方式。在力矩陀螺上安装6个测量靶标, 靶标在相机成像平面上呈现出由离散点组成的圆弧, 对标志点中心进行定位, 获得高精度像元提取精度, 进一步处理得到二维像点坐标, 拟合出圆心和半径; 根据相片上像点位置及时间信息, 计算得出控制力矩陀螺在不同时刻的角速度。采用快速傅里叶变换对角度信息进行处理, 得到频率和相应的幅值, 根据幅值计算框架绝对稳定度及相对稳定度, 最后对框架角速度控制精度和角速度稳定度进行分析。试验表明, 角速度绝对稳定度不低于0.02, 相对稳定度不低于0.7%, 且随着角度的增大稳定度逐渐提高; 角位置测量精度经过实验验证可以达到1″, 满足控制力矩陀螺高精度标定要求。

The control moment gyro is an important part of the attitude control of the spacecraft, and the speed and accuracy of its output torque are getting higher and higher. At present, for the calibration and verification of high-precision frame control performance, most of them rely on the control of the moment gyro's own angular position sensor for evaluation, and there is a certain error in accuracy. In response to this situation, a visual measurement calibration method independent of the control moment gyro is designed. Six measuring targets are mounted on the torque gyro, and the target presents an arc composed of discrete points on the imaging plane of the camera, and the center of the marking point is positioned to obtain high-precision pixel extraction precision, and further processed to obtain two-dimensional image point coordinates. The center and radius are fitted; the angular velocity of the control moment gyro at different times is calculated according to the position and time information of the image point on the photo. The fast Fourier transform is used to process the angle information, and the frequency and corresponding amplitude are obtained. The absolute stability and relative stability of the frame are calculated according to the amplitude. Finally, the frame angular velocity control accuracy and angular velocity stability are analyzed. The test shows that the absolute stability of angular velocity is not less than 0.02, the relative stability is not less than 0.7%, and the stability gradually increases with the increase of the angle; the angular position measurement accuracy can reach 1″ by experiments, which satisfies the high-precision calibration requirements of the control torque gyro.