Additive State Decomposition with Control Allocation Priority for a Class of Input-Constrained Nonlinear Systems

This paper presents a control strategy based on additive state decomposition (ASD) to enhance the robustness and stability of input-constrained nonlinear systems in the presence of uncertainties, including disturbances and failures. The proposed method decomposes the system into an LTI primary and a nonlinear secondary subsystem. Separate controllers are designed for the primary system, responsible for tracking, and the secondary system, which focuses on stabilization. A priority allocation algorithm is introduced to prioritize stabilization over tracking, ensuring system stability under constraints such as saturation and system failure. Simulation results demonstrate that the proposed ASD-based priority allocation control approach maintains system stability despite failures. The simulations further validate that the proposed method outperforms the traditional ASD-based control method regarding robustness and stability.