| Zero propellant maneuver(ZPM)is an advanced concept of attitude maneuver control,which has been applied to International Space Station.The ZPM technology has practical significance for reducing fuel consumption,prolonging on-orbit time and enhancing the safety of space station.With the background of preliminary tasks of the China's Space Station project,this dissertation mainly focuses on the mechanism analysis of ZPM,the control algorithm design,the steering algorithm design,the path planning of attitude maneuver,and demonstration scheme design.The main achievements obtained in this dissertation are summarized as follows.The mechanism of zero propellant maneuver is analyzed.1)The singular state equations are deduced,and the definite and indefinite singular surface distribution characters of typical single gimbal control gyroscopes(SGCMG)are analyzed.2)Using optimization method,the maximum values of SGCMG momentum are calculated,and the envelope characters of typical SGCMG are analyzed.3)The angular momentum conservation relationship of space station and gimbal control gyroscopes(CMG)is established.The conditions of ZPM path existence are deduced,which don't need complex calculation.The proposed existence conditions can provide a convenient and effective method to determinate whether the ZPM path exists,which can provide significant theoretical argument for ZPM technology to apply to China's Space Station in future.Using the artificial potential function method,a saturation avoidance algorithm for control momentum gyroscopes is proposed.1)In order to design the control laws to avoid CMG saturation during attitude maneuvers,novel potential functions for spacecraft are proposed based on the artificial potential function,in which the distance between the present attitude and the aiming attitude is used as an attractive potential function and the saturation state of CMGs is employed as a repulsive potential function.2)Based on the proposed artificial potential function,saturation avoidance control laws for stable and unstable terminal attitudes during maneuvers based on the potential function are then deduced.3)Numerical simulation results show that the proposed control laws can avoid CMG saturation during attitude maneuvers for both the stable and unstable terminal attitude.This proposed method can offer an effective way to solve the saturation problem of CMG during spacecraft maneuvers.Based on the definite-indefinite singular function,a new steering law for control momentum gyroscopes is proposed.1)A definite-indefinite singular function of SGCMG is constructed,which is able to distinguish the definite and indefinite singular state of SGCMG effectively,and can anticipate the singular state.2)Based on the definite-indefinite singular function,a self-adaption steering law is proposed.The new steering law has both advantages of null-motion and robust steering laws,which can escape the singular state for SGCMG,and no error exists during the motion.3)Considering unpredictability of the SGCMG fault,an fault-response steering law is designed.Using this steering law,the fault state of SGCMG can be detected and the parameters of the steering law can be self-tuned.The attitude maneuver path planning considering control momentum gyroscopes singularity and saturation is studied.1)Performance indexes for the attitude maneuver path planning are constructed,which contain singularity and saturation performance indexes.2)The path planning model is established,and a hybrid approach that combines the pseudospectral method and direct shooting method is proposed.The hybrid approach provides a quick and efficient tool for the large angle maneuver of space station while considering SGCMGs' saturation and singularity.By using the planning model and hybrid approach,an attitude path that prevents SGCMG from saturation and singularity can be obtained.3)The multi-objective optimization model of zero-propellant maneuver is established.A solving strategy approach using physical programming is proposed.It is found that the proposed optimization model and the physical programming are effective to solve the optimal multi-objective zero propellant maneuver problem.By identifying multiple solutions,the method can produce a variety of missions to meet different requirement.According to the similarity principles,a ground-based validation scheme of attitude maneuver is designed.1)Based on the similarity principles,the scaling factor design method of space station attitude maneuver ground-based validation is proposed,and the similarity criteria are deduced.2)The ground-based validation similarity system is designed.According to the similarity criteria,the similarity design of subsystems are accomplished,and the parameters of space-borne algorithm are determined.3)The correctness of the similarity system are validated by simulation.The data of similarity system are all proportional to that of prototype system.The similarity system can reduce the time consumption of ground-based validation,which provides an effective approach to validate ZPM technology on ground.Based on the engineering requirement of China's space station program,this dissertation focuses on attitude maneuver control strategy and path planning using SGCMG,which can be of practical relevance and technical help for on-orbit flight and space operation of China's future space station.Thus,the achievements obtained have important engineering application values.This dissertation summarizes the essence of attitude problem from the space station operational engineering practice,furthermore,the proposed control strategy,constructed path planning method and designed validation scheme also have some theoretical significance. |
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