High-precision attitude control and active vibration suppression of flexible satellite

A hybrid control scheme is proposed which combines the intelligent sliding mode control and vibration control. Considering the movement of flexible and rotating parts imposes large disturbances on the satellite, and affects the pointing accuracy and stability of attitude, a sliding mode controller is used to eliminate attitude error and ensure system stability. Self-recurrent wavelet neural network (SRWNN) is used to estimate sliding mode switching gain on-line, which can effectively weaken chattering caused by discontinuous sliding mode control. For actively damping the excited elastic vibrations, the strain-rate feedback control is also employed by using piezoelectric materials as additional sensors and actuators. Finally, simulation results indicate that the proposed hybrid controller provide a small steady error, a fast dynamic response, and an obvious rejection of flexible vibrations.