Coupling dynamics of super large space structures in the presence of environmental disturbances

Considering the effects of the gravity gradient, the solar radiation pressure (SRP) and the thermal radiation, the coupling dynamical model is established for a super large flexible beam structure, which moves in the orbital plane around the earth. The effects of environmental disturbances on the orbital motion, the attitude motion and the structural vibration are analyzed simultaneously. Influences of the initial attitude angle, the structure size and other system parameters have been investigated for the coupling dynamics. The results show that the envelop shapes of the vibration responses are dependent on the attitude motion, and the perturbation of orbital motion increases with the growth of the initial attitude angle. When the structural fundamental frequency is close to the attitude frequency with the increase of the structure size, the average orbit altitude would decrease slightly. The main frequency component of the attitude motion decreases and the frequency component related to the structural vibration encounters and grows up. The resonance then leads to system instability. Moreover, the magnitude of the attitude motion can also be influenced by the slightly intense structural vibration, which might be excited by the momentum exchange devices of the attitude control system. In addition, in the presence of the SRP, the orbital radius is perturbed obviously and the eccentricity of orbital motion is generally changed. The effects of the thermal radiation and the gravity gradient are in the same order of magnitude on the structural vibration in the low orbit while the former one turns to be dominant in geostationary orbit.