控制受限航天器时变滑模姿态控制

Variable structure attitude control with time-varying sliding surface for flexible spacecraft under control input constraint

在推力器执行机构输出力矩受限的条件下,针对带有输入饱和特性的挠性航天器的姿态机动问题,提出了一种将线性滑模面和时变滑模面相结合的变结构控制器设计方法,给出其切换机制以实现挠性航天器快速姿态机动给出了变结构输出反馈控制器设计的方法;最后,将本文提出的方法应用于三轴稳定挠性航天器的姿态机动控制,仿真结果表明:在推力器的控制受限条件下,完成姿态机动的同时,有效地抑制挠性附件的振动.

spacecraft A control system design method is presented for the three-axis-rotational attitude stabilization of a with flexible appendages. The design of attitude controller is based on the variable structure control （VSC） theory leading to a discontinuous control law. To accomplish asymptotic attitude maneuvering and be insensitive to the interaction of elastic modes in the presence of unknown disturbances/uncertainties and input saturation as well, a switching mechanism was employed to design the sliding surface, such that outside the sliding region, the VSC law with a time-varying sliding surface was implemented, and inside the region, the VSC law with a linear sliding surface was activated. Furthermore, a hyperbolic tangent function in conjunction with a sharpness function permitted to vary with time according to a set of user-defined parameters was implemented to offset the disadvantages of existing saturation-respecting controller and chattering. Numerical simulations were performed to show that the rotational maneuver and vibration suppression can be accomplished in spite of the presence of disturbance torque, parameter uncertainty and control saturation nonlinearity.