Nonlinear h-inf via modified rodrigues parameters for attitude control in the reuse of retired spacecraft antenna

The attitude control problem for flexible spacecraft has attracted much more significant attention and research. The problem is readily formulated by the classical parameters like Euler parameters or quaternion for the spacecraft's attitude description. This paper combines the Modified Rodrigues Parameters (MRPs) with their shadow set, displacement theory and assumed mode method to obtain a singularity-free parameterization. On this basis, the dynamic modeling for large scale space antenna is shown. The retired spacecraft antenna's nonlinear dynamic equation with multi-Satlet is derived by using the MRPs. After that, this paper proposes a suboptimal H-inf nonlinear feedback law consisting of a linear combination of the spacecraft angular velocity, the generic MRPs and the vibration mode which can locally solve the nonlinear H-inf state feedback problem. Furthermore, the numerical simulation is given at last to demonstrate that the retired spacecraft antenna's attitude control law is valid in the reuse mission when the nonlinear controller is used in the antenna's control system.