Abstract: The signals by the attitude sensors with concentrated placement will be significantly affected by the flexible vibration when the size of space structure is large. To reduce the influence of structural vibration on the measured attitude signal, the distributed placement of attitude sensors in a space solar power station is studied, and a novel recursive method called variable forgetting factor coupled least squares is proposed to identify the inertia tensor parameters of the structure. The proposed method determines the time-varying forgetting factor in the recursive procedure by computing the system mean square deviation, and thus the inertia tensor parameters of the system are identified based on the distributed measurement results of attitude signals. The numerical simulation results indicate that for such a large flexible space structure, the distributed placement of attitude sensor can reduce the influence of vibration on the measurement accuracy of attitude signal to a certain extent, thereby increasing the identification accuracy of inertia tensor parameters. In addition, the analysis results also demonstrate that the proposed method can be used to effectively identify the inertia tensor parameters of the large flexible space structure and has high noise-immunity ability and low computational complexity. The absolute and relative values of the average relative error is decreased by approximately 25.4% and 68.9% maximum respectively on using the proposed recursive algorithm compared to that obtained using the conventional recursive least squares method when the measurement signal-to-noise-ratio is 15 dB.

Key words: inertial parameter identification, space solar power station, optimal sensor placement, large flexible structure, variable forgetting factor