Three-axis Stabilized Flexible Satellite PD And Sliding Mode Variable Structure Attitude Control Methods

Nowadays, as the cost of launching and carrying capacity constraints, more and more advanced light material is used to make the mechanical structure of satellite.The property of this material is flexible and low damping. So, it's easy to be oscillatory when there is the external interference.And the vibration will influence the stability of the satellite system and the normal work of the payload. The paper took the three axis stabilized flexible satellite as the controlled object, having designed the satisfied control algorithm for attitude maneuver and stable request of flexible satellite.First of all, based on the attitude and attitude dynamics, the mathematical model of three axis stabilized flexible satellite was established.In the light of the control demand about attitude maneuver and stable of flexible satellite,two types of attitude controller law were designed.(1) PD feedback attitude control law of the flexible satellite. According to the problem of initial control torque amplitude is too large, the improved scheme of adaptive PD feedback was put forward. In allusion to the buffeting phenomenon which is caused by the motivated flexible panels modal, its improved algorithm, adaptive PD feedback which has considered the structural parameters of rigid-flexible coupling, was proposed.(2) Sliding mode variable structure attitude control law, which is strong robustness and anti-jamming.According to the problem of chattering which is brought by the symbols function in switch control, the improved scheme of fuzzy sliding mode variable structure was put forward. In allusion to the buffeting phenomenon which is caused by the motivated flexible panels modal, its improved algorithm, sliding model variable structure control which is based upon output feedback compensation, was proposed.Finally, According to the proposed control laws, numerical simulations were carried out.The results indicated that the improved control algorithms are suited to the flexible satellite with rigid-flexible coupling and have good robustness for its uncertainty.