Research On Control Algorithms Of High Precision Pointing And Tracking System For Optical Intersatellite Communications

In this thesis, focusing on high precision pointing and tracking system in optical intersatellite communication, vibration suppression and performance improving used advanced control algorithms are researched, and then the simulation results are given. The topics are as follows:First, the sources and kinds of vibration in optical intersatellite communication are discussed, and base on actual vibration spectrum measured on the communication satellites, some rules are summarized. As an example using sine wave, the effect of vibration amplitude and frequency and time on bit error rate is researched. Finally, the technique of vibration suppression is discussed. The passive isolation that is simple is adopted for high frequency part and the effort of high frequency suppression is obvious. The bandwidth adaptive that doesn't need new plants is adopted for low frequency part and simulation results indicate that the scheme is valid for the suppression of bit error rate increasing produced by satellite platform vibration.Secondly, the performance of the acousto-optic steering system is deteriorated as a result of the coupling because of nonlinear of quadrant detector and the pointing error introduced by satellite platform vibration. For this problem, this paper introduces the model reference adaptive control system, and presents the perfect model. The model reference adaptive controller is designed to force the output of the acousto-optic steering system following the output of the perfect model to improve the system performance. Then the hyperstability theory is used to make sure the adaptive parameters and analyze the stability of the system. Finally, the simulation is performed to examine the capacity of the system performance improvement and platform vibration suppression.Finally, the paper presents the Lyapunov-based decentralized control system because the piezo-electric steering system is complex dynamics and can't know status of controlled plant. The decentralized adaptive controller is designed and the adaptive parameters are decided by the Lyapunov function in order to assure the system is stable. Finally, the simulation is performed to examine the capacity of the system performance improvement and platform vibration suppression.