| In recent years,with the rapid development of professional technology in the aerospace field,space missions such as remote sensing information acquisition and on-orbit service non-cooperative target approach have put forward higher requirements for satellites'continuous gaze to the earth,large angle sidelobes,single line array 3D imaging,observable strip expansion functions,etc.Therefore,hyper agility and stability play crucial roles for satellites,i.e.,satellites are required to have higher attitude maneuver capability and maintain high stability at the end of attitude maneuver.In order to meet the above-mentioned requirements,the hyper-agile satellite actuator,control law,and attitude control algorithm are investigated in this dissertation.Single-frame control moment gyroscope(SGCMG)has large output torque and good dynamic performance,so it is widely used in agile satellites,but the SGCMGs configured in mainstream spacecraft are generally large in volume and small number of monomers,resulting in the output torque cannot meet the requirements of hyper-agile satellite missions,so it is urgent to design distributed SGCMGs to solve the above problems.Meanwhile,since the hyper-agile satellite actuator is easily to fall into the singularity during maneuvering,a fast escape singular steering law needs to be designed to solve it.On this basis,a hyper-agile satellite attitude control algorithm needs to be designed to further realize the hyper-agility and stability.This research contents are as follows:Firstly,SGCMG high-precision steady speed control method is designed based on the genetic algorithm(GA)proposed quasi-dual loop-phase-locked loop(PLL)dual-mode control strategy,and by setting the steady speed control limit switch for dual-mode switching,the fast convergence and fine steady control of SGCMG rotor speed is realized.On this basis,the feedforward compensation method of constant speed control is adopted.At the same time,the experimental data are fitted and deduced.The relationship between the angular velocity of the frame and the unknown disturbance moment is discussed and taken as the basis of the analysis of the formula.The interference feed-forward compensation module for uncertain interference compensation further realizes high-precision constant speed control.Then,the angular momentum envelope characteristics and singular angular momentum envelope characteristics of different distributed SGCMGs reconfigurable configurations are analyzed,which are used as the basis for selecting the hyper-agile satellite actuator.Based on the comprehensive allocation method,a distributed SGCMG allocation selection evaluation method was proposed.The subjective hierarchy method and entropy weight matrix were reconstructed by the least square method.The factors such as angular momentum envelope,singularity,reconfigurable,quality,cost,system energy consumption and torque output accuracy were considered respectively.The distributed reconfigurable octagonal pyramid-pyramid configuration was analyzed and verified to be the best option for the ultra-agile satellite actuator by applying a solution evaluation scheme based on positive and negative ideal point distances.Furthermore,an efficacy function-based singular robust steering law with zero motion is designed based on the singular robust steering law,and the singular metric term with zero motion is constructed by the efficacy function,and then the zero motion solution is optimized to achieve the goal of distributed SGCMGs with both fast escape from singularity and high utilization of angular momentum.To solve the problem of local minima in the frame angular velocity due to the influence of internal singularities,a dilation factor is introduced to adjust the ratio between the scaling factor and the efficacy function,and then the scaling factor is updated to improve the singularity term with zero motion to avoid local minima.At the same time,the optimal initial frame angle is introduced into the steering law,and the initial frame angle is changed by presetting the distributed SGCMGs initial frame angle instead of adding zero motion,which optimizes the maneuver path and improves the operational efficiency.Meanwhile,RBF network friction compensated sliding mode control algorithm is designed for the problems of rigid-flexible coupling effects,external disturbances and actuator friction nonlinearities in flexible satellite attitude control system,Lyapunov theory and La Salle invariant set theory are used to derive and prove the stability of the system.Combined with the super agile satellite actuator and the control law,the attitude control strategy of the super agile satellite is designed,and the configuration of distributed SGCMGs is switched by setting the time window switching switch.The octagonal SGCMGs are used as the actuators to output large torque at the beginning of the maneuver,and the pyramidal SGCMGs are used as the actuators to output fine torque at the end of the maneuver,which can meet the requirements of stability while meeting the ultra-fast maneuver of the satellite.Finally,considering the precision and complexity of the hyper-agile satellite attitude control system and the large number of components,this dissertation designs a fault detection method for the hyper-agile satellite attitude control system based on the supervised local linear embedding(SLLE)method for the safety problems that may occur in the on-orbit maneuvering mission,The multidimensional hyper-agile satellite attitude control system telemetry data is used for dimensionality reduction feature extraction,and the statistical quantities SPE and T~2 are combined to design a fault detection scheme,which integrates the false alarm rate and the missed alarm rate to define the fault detection accuracy.The fault detection method solves the problem that the local linear embedding(LLE)algorithm is difficult to update the database in real time,and ensures the accuracy of dimensionality reduction feature extraction,thus improving the fault detection accuracy. |
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