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In this paper, a hybrid adaptive sliding mode/Lyapunov controller is designed for both the rotational maneuver and the vibration control of smart flexible appendages of a satellite moving in a circular orbit. The satellite is considered as a rigid hub and two flexible appendages with attached piezoelectric layers as sensors and actuators. Each appendage is considered as a nonlinear beam undergoing large deflection. These governing equations of motion are obtained using a Lagrange–Rayleigh–Ritz technique and assumed mode method. The dynamic equations of motion are nonlinear and coupled due to the large angle trajectory and appendages large deflection. A through look at the resulting equations shows that the flexible satellite dynamics including the vibrations of the appendages and their rigid maneuver occur in two different time scales. Using the singular perturbation theory, the dynamics of the flexible satellite are divided into two slow and fast subsystems, the former associated with rigid-body maneuver, while the latter is a result of the vibrations of the appendages. Use of this hybrid controller allows us to cope with parameters uncertainty and disturbances of the system. The stability of the hybrid controller is studied by using the Lyapunov approach. Finally, the whole system is modeled and the simulation results show the efficient performance of the proposed hybrid controller.

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In this paper, a nonlinear active control scheme is applied to suppress the flutter vibration of a wing/store. The system is considered as a two dimensional airfoil with attached store. The nonlinear aero-servo-elastic model of the system is obtained based on the Lagrange's formulation. The proposed active pylon involves the piezoelectric wafer strut as the actuator. The aero loads are modeled using Theodorsen function. A gust disturbance model is also added to the system governing equations of motion. An adaptive-robust control scheme is used to suppress the flutter vibration of the wing/ store system. The proposed adaptive-robust controller is a composition of the adaptive and robust controllers and so can be considered as a useful controller in presence of unknown parameter uncertainty and disturbances. Finally, the system is simulated and the controller is applied to the system to control the flutter vibrations. The results illustrate the high performance and effectiveness of the controller.

In this paper, the three axes maneuver control and vibration suppression of a smart flexible satellite moving in a circular orbit are studied. First, by using Lagrange-RayleighRitz technique and assumed mode method, the governing equations of a flexible satellite with PZT (lead zirconate titanate) piezoelectric patches are obtained. The flexibility of the appendages and the assumption of a large angle trajectory cause the governing equations to be nonlinear and coupled. The piezoelectric layers, attached to both sides of the appendages, are considered as sensors and actuators. A thorough look at the resulting equations reveals that the flexible satellite dynamics that include the appendage vibrations and rigid maneuver occur in two different time scales. By using the singular perturbation theory, the system dynamics is divided into two fast and slow subsystems. The slow and fast subsystems are associated with rigid motion dynamics and flexible appendages dynamics, respectively. A hybrid controller, which is proposed for use, consists of a variable structure controller (VSC) for maneuvering control of the slow subsystem, and a Lyapunov based controller for vibration suppression of the fast subsystem. The stability of the controllers is studied using the Lyapunov stability theory. Finally, the system behavior is simulated and the simulation results show the efficient performance of the proposed hybrid controller.