Spacecraft Attitude Tracking Control Based On Prescribed Performance

With the advancement of satellite technology and the expansion of its service range,rapid and high-precision data acquisition capabilities have become the requirements of the next-generation satellite.To address these needs,this paper studies the spacecraft attitude maneuver and tracking issues that consider flexibility.The main contents are as follows:Aiming at the issue of rapid attitude maneuver of flexible spacecraft,a trajectory planning strategy that can achieve both time-optimal maneuver of spacecraft and vibration suppression of flexible appendage during the maneuvering process is proposed.The smoothing of the trajectory is achieved by constraining the amplitude of the control torque derivative(CTD)in the trajectory planning.Through the weighted combination of the time index and the smoothness index,a time-optimal trajectory in a certain smooth sense can be obtained.In addition,desired trajectories with different smoothness and maneuvering time can be obtained by adjusting the index weights.For the attitude tracking problem of flexible spacecraft,a control law that can prescribe the error quaternion response process of attitude tracking is given firstly.In the tracking control law,a kind of neural network is introduced to approximate the nonlinearity and external disturbance of the attitude motion model.The adjustment of neural network parameter is completed by the online adaptive law.Secondly,based on the error-driven control theory,a model-free tracking control law that can prescribe the attitude tracking error quaternion and error angular velocity response process is proposed.It is pointed out that there are two kinds of effective and special forms of the control law with different parameter selection.By deducing the Lagrange model of the attitude tracking motion of flexible spacecraft,the stability of the tracking controller is proved.By balancing the sensitivities about the error quaternion and the error angular velocity of the control law,the control frequency in the practical application of the controller is greatly reduced.Finally,the attitude tracking control law for no angular velocity measurement is given by using the tracking differentiator.By introducing a dead-zone-based saturation model,the problem of stability analysis about control input saturation is solved theoretically.At the same time,the designing method of the prescribed performance parameters is given for being referred to by practical application.