Flexible Spacecraft Model and Robust Control Techniques for Attitude Maneuvers

In this work, a mathematical model for the attitude dynamics of a modular satellite is developed, to evaluate the contribution of each single body to the overall dynamic equations of the system. The main advantage of this method is the possibility of redefining the configuration of the satellite with minimal computational work. Furthermore, the flexibility of one of the modules is accomplished in the dynamics model. Due to the coupling effect between the flexible and rigid structures, the vibration of the flexible parts of the spacecraft can cause a deterioration of its performance. On the other hand, a fast attitude maneuver can introduce high levels of vibrations to the flexible parts, which must be taken into account when the control strategy is implemented. Since the dynamics of the modular and flexible system includes parametric uncertainties and vibrational phenomena, a robust controller is proposed for the precise attitude maneuver of the spacecraft. The main objective is to analyze the effectiveness of the proposed control methodology to manipulate the configuration of the spacecraft, to maintain the desired orientation of each module and to suppress the structural vibrations. Numerical simulations are performed for different configurations of the multibody spacecraft, to show the robustness of the proposed control methods against the variations of system parameters.