Adaptive Backstepping Control Design for Uncertain Rigid Spacecraft With Both Input and Output Constraints

In this paper, a barrier Lyapunov function (BLF)-based backstepping control design is proposed for uncertain rigid spacecraft with both input and output constraints. A modified BLF (MBLF) is constructed to extend the application scope of the traditional logarithmic BLF. Through using the MBLFs in each step of the backstepping design, an adaptive constrained control scheme is presented to guarantee the tracking performance and the constraint requirement of spacecraft systems, and the differentiation of the virtual control is avoided with the employment of the tracking differentiator. The uncertainty bounds are estimated by designing adaptive update laws, such that no prior knowledge is required on the bound of the lumped uncertainty including input saturation and faults. Numerical simulations demonstrate the effectiveness of the proposed scheme.