Constrained Attitude Control of Uncertain Spacecraft With Appointed-Time Control Performance
研究了航天器在特殊正交群上的指定时间姿态跟踪控制，提出一种投影函数将敏感仪器视轴映射到欧氏空间，通过向量化误差函数和自适应控制方案，在参数不确定和外部干扰下同时满足姿态约束和指定时间性能。
This article studies the appointed-time attitude tracking control of the spacecraft on the special orthogonal group, with the attitude forbidden zone, the parameter uncertainties, and the external disturbances. A novel projection function is proposed, such that the normalized boresight vector of the sensitive instrument is mapped to a reduced dimensional vector in the Euclidean space. If the reduced dimensional vector is uniformly bounded, the constraint on the attitude forbidden zone will be satisfied at all the time. By virtue of the designed reduced dimensional vector and the associated auxiliary vectors, a set of vector-based error functions, the appointed-time performance constraints, and the according switching law is carefully constructed. The proposed vector-based adaptive control scheme ensures that the spacecraft attitude can satisfy the attitude constraint and appointed-time control performance simultaneously, in the presence of parameter uncertainties and external disturbances. Simulation results show the effectiveness of the designed control scheme.