The Modular Design Approach Of Thesatellite Attitude Control System

In order to meet the fast response task, the satellite is needed to be integrated to support the rapidly changing mission in the shortest period of time, and the satellite must have the capabilities of rapidly design and integration. The modular design, the principle of which is standardization is a method which can shorten the development and manufacturing cycles, thus realizing module design of satellite is necessary. The attitude control system is the subsystem which finishes the mission of maintaining or changing its spatial direction when the satellite is on orbit, so as a very important part in the satellite platform, to realize the modular design of it is also necessary. With the background of rapid response of satellite control system, the modular design of satellite attitude control system is studied.Modular division is the basis of modular design which directly affects the design result. This paper presents a method of modular division of satellite attitude control system based on fuzzy tree. The method is based on the analysis of correlation between the parts of the system, and the principle of the method is to keep the maximum of the correlation in the module and the minimum between the modules. A satellite as an example, is established the relation matrix between parts, and based on the module partition the optimization objective function is established. Then obtain the optimal module partition results of satellite attitude control system by selecting the truncation threshold.Module configuration is the process of getting the configuration that can best meet the specific needs. In this paper, based on the mathematical model of the configuration problems, put forward a kind of method to saving the problem of the satellite attitude control system module configuration based on the simulated annealing algorithms, and put forward a method to update the database for the module configuration. Based on the modular division, this paper have foundated module case library, performance index database and user needs, and have established the relation matrix between the module case base and performance index database and the relation matrix between the performance index database and user requirement database. On the basis of module configuration conditions, have built objective function and the constraint for the configuration problems and given the process of solving the model based on the simulated annealing algorithm. The results of simulation show that the use of simulated annealing algorithm to module configuration is feasible.Product description is based on the analysis of product structure tree, and describes the variant product in family. It is the basis for the modular design of product in cycle of life. Axiomatic theory departs from mapping the functional requirements and design parameters, it connects the description and the users’ demand, and therefore it can aid design directly. Based on the core knowledge representation in the satellite attitude control system design process, this paper presents a method to describe the product family of the attitude control system of satellite by the axiomatic theory. Then describe the control system in cycle of life comprehensively by this method. And on the basis of establishing the general database structure of product family description, propose a method for designing the attitude control system of satellite based on the product description.Module parameter design determines the correlation between the module instance and the performance inde.So it is an important part of module configuration and the attitude accuracy estimation is the core problem of attitude measurement module’s parameter design. This paper analyzes the attitude measurement module’s attitude determination accuracy, gives some sensors’ attitude determination accuracy and the algorithm of attitude determination accuracy for one or a plurality of sensors by sensor parameters. On the basis of establishing the control system model, propose a method for attitude control accuracy estimation based on linear covariance theory, the method linearizes the model and obtains the accuracy of attitude control and the effect of the parameters of each module on control accuracy by the transfer of variance. With the background of the attitude determination system using only solar sensor and gyro, have simulated and compared with the traditional Monte Carlo analysis. The results show that the linear covariance is a kind of effective attitude control accuracy estimation methods, and it can also analyze the contribution of the attitude control parameters on the total accuracy, at the same time has great advantage in the time of estimation compared with the traditional method.The controller module is the core part of the attitude control system. the controller module’s parameters design’s main contents is the calibration of controller parameters. In this paper, With an example of a satellite attitude PID controller, the controller design problem is transformed into a kind of product design problems and put forward a kind of controller parameter tuning method based on the axiomatic design method. The function requirement of the attitude controller needs to decompose and decouple. The definition of the information and parameters optimization selection method under this definition is given, and based on the information axiom of the controller parameters have optimized. With the background of PID controller of a satellite, have applicated the method and simulated. The results show that the proposed method is an effective means for controller parameters design.