Disturbance Observer-Based Model Predictive Control for Multi-Frequency Interference Suppression in Space Laser Communication Systems

High-precision beam pointing control is essential for achieving reliable data transmission in space laser communication systems, requiring effective suppression of multi-frequency disturbance-induced tracking residuals. To address this issue, a synergistic model predictive control and disturbance observer (DOB-MPC) architecture is developed. The proposed hierarchical control framework is constructed based on gimbal servo dynamics and implemented through the following steps. A frequency-decoupled disturbance observer (DOB) is employed to estimate multi-frequency disturbances using spectral separation principles, while a model predictive controller (MPC) enhances steady-state accuracy by compensating for time-delay effects through trajectory optimization. Crucially, the disturbance estimates are incorporated into the MPC’s prediction horizon via receding-horizon optimization, establishing a cooperative control mechanism. Simulation results demonstrate improvements of greater than 25% in dynamic response and over 80% in residual error reduction compared to conventional methods. Experimental results further validate the efficacy of the proposed architecture for space laser tracking systems.