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Abstract

Attitude control of a flexible spacecraft model by on-off thrusters is addressed in this study. A switching function which constists of attitude error as well as internal boundary reactions between adjacent sub-structures is incorporated into the control law producing control command. PWM(Pulse Width Modulation) is employed in order to minimize frequent firings due to the direct nature of the switching function. The performance of the switching fucntion has been further directed to improvement by inserting a low pass filter. The low pass filter is used to smooth the original switching function, which eventually leads to a smooth response of the actuator. Simulation results are provided to validate the proposed control scheme.