针对以往变速控制力矩陀螺(VSCMGs)加权操纵律存在增益调度与卫星姿态机动信息脱节的不足,设计一种VSCMGs改进增益调度操纵律.不同于以往VSCMGs加权操纵律仅通过奇异度进行增益调度,改进型操纵律采用奇异度结合误差四元数进行增益调度设计,能够根据卫星姿态机动信息进行增益调度,同时该操纵律通过添加零运动,实现规划CMGs框架角和转子转速收敛在标称值附近,避免转子转速饱和.仿真结果表明改进增益调度操纵律能够实现CMGs模式和RWs模式二者之间平滑切换,有利于实现大力矩输出和精细力矩输出.
A modified singular avoidance steering law for variable-speed control moment gyros (VSCMGs) is proposed in this paper. Contrary to the traditional weighted steering law that uses singular measure in reaction wheels (RWs) mode for singularity avoidance, the modified steering law uses both the singular measure and error quaternion for gain schedule and singularity avoidance, the modified steering law decreases the CMGs mode coefficients and increases the RW mode coefficients to generate precise torque. The null motion is added to steer the gimbal angle and rotation speed approaching to the nominal value. Numerical simulations demonstrate the effectiveness of the modified gain scheduled steering law.