使用变速控制力矩陀螺的航天器鲁棒自适应姿态跟踪控制

 研究以变速控制力矩陀螺群（VSCMGs）为执行机构的航天器姿态跟踪问题。采用四元数描述姿态, 在姿态误差的描述中引入了现时姿态与期望姿态之间的方向余弦矩阵。考虑执行机构模型参数不确定和有外干扰的情况, 姿态误差动力学方程为多输入多输出(MIMO)的非线性系统。基于Lyapunov理论设计了鲁棒自适应控制器, 运用光滑投影算法避免了估计参数陷入奇异。仿真结果表明, 设计的鲁棒自适应控制律明显地缩小了姿态跟踪误差, 很好地解决了外部环境干扰和执行机构由于安装误差或机械磨损造成的轴承方向未对准的问题。

Spacecraft Adaptive Robust Attitude Tracking Control with Variable Speed Control Moment Gyroscopes

This paper deals with the attitude tracking of spacecraft with single-gimbal variable-speed control moment gyroscopes(VSCMGs) as actuator. The quaternion is used to describe the attitude, and the attitude error includes rotation matrix from desired attitude to current one. Considering actuator model parameter uncertainties and external disturbances, the spacecraft equations of motion are fully nonlinear and can be represented as a multiple-inputmultiple-output(MIMO) system. The adaptive robust controller is derived based on Lyapunov theorem, and a smooth projection algorithm is then applied to keep the parameter estimates from singularity. Simulation results show that the proposed law attenuates the attitude error obviously, and successfully deals with the external disturbances and unknown misalignment of the axis directions of the actuators due to installation error or wearing out of the mechanical parts.