Font Size: a A A

Research On Differential Game Control Of Cell Satellite Group Under Control Redundancy

Posted on:2021-03-08Degree:MasterType:Thesis
Country:ChinaCandidate:N XiaoFull Text:PDF
GTID:2392330611999087Subject:Aerospace engineering
Abstract/Summary:PDF Full Text Request
With the increasing volume and complexity of space system,it becomes an important part of future space mission to transport spacecraft to space in the form of unassembled modules.In this paper,several cell satellites fixed on the substructure are studied,which can adjust the attitude of the substructure and complete the service tasks such as on orbit assembly.The spacecraft combined with cell satellite is a kind of multi redundant actuator,which has many degrees of freedom and high reliability.In order to coordinate the control of each cell satellite,to achieve the required attitude of the task,and to have a good fault tolerance,this paper transforms the problem into a differential game problem,looks at the cell satellite as multiple participants,and obtains the control strategy of each cell satellite.And on this basis.The main contents are as follows:Firstly,based on the linearized attitude dynamics system of the combined spacecraft,the open-loop finite time Nash strategy is designed.The problem of control coordination and allocation among spacecraft cell satellites is transformed into a differential game problem with multiple participants.Then,by setting the independent optimization performance index of each module,the optimal decision-making control method of each cell satellite is studied,and the open-loop control strategy of each module is obtained.Then,the attitude tracking error system model of cell satellite is transformed into SDC model.Based on this model,the related differential game performance requirements are designed,the Nash strategy of differential game in closed-loop feedback of cell satellite system is obtained,and the Nash equilibrium strategy of microsatellite is approached by decoupling Riccati algebraic equation.In addition,in order to reduce the problems of large number of communication between cell satellites,heavy calculation burden and short power supply life in the closed-loop system,the event driven control method is introduced,and the event triggering threshold is designed by using the state error to reduce the communication and calculation of the network system.Finally,when the angular velocity information is unavailable,a neural network observer is designed to estimate the internal state of the system from the measurable feedback.According to the design principle of differential game strategy,the control strategy of non-zero sum differential game of each cell satellite in this situation is obtained.Then,based on the observed state,the adaptive dynamic programming(ADP)controlmethod is used to estimate the performance index of the system,and the evaluation neural network algorithm is designed to learn the control strategy online.After that,the aperiodic event triggering control mode is adopted to update the controller according to the designed triggering conditions,so as to save communication and calculation.The validity and correctness of the above control methods are verified by the corresponding numerical simulation.
Keywords/Search Tags:Cell satellite, differential game, neural network, event trigger control, neural network observer
PDF Full Text Request
Related items