Disturbance modeling and parameters identification of reaction wheel assembly on spacecraft

An improved disturbance model was proposed to predict the effects of reaction wheel assembly (RWA) micro-disturbance on the spacecraft. Because the disturbance amplification by excitation of the structure modes was the most dominating effect on spacecraft attitude accuracy by RWA, the improved model expressed the effect of the structure's nature frequency to disturbance by introducing amplification coefficients. As the nonlinear characteristic of improved model, simulated annealing genetic algorithm was used to identify the parameters of improved model. A rigid six-axis test bed was designed, and the disturbance of RWA was measured. The improved model as well as the results of parameters identification was validated by experimental data. The experimental results show that the improved model captures the disturbance characteristic precisely, and simulated annealing genetic algorithm can improve the identification accuracy.