Methodological Foudations of Aviation Complex External Design
Аuthors*, **, ***
State Institute of Aviation Systems, 7, Victorenko str., Moscow, 125319, Russia
AbstractThe paper focuses on pre-design of Complex Aviation Systems (CAS) as the initial stage in the process of creation (modernization, modification) of aircraft with different missions. This is the stage whenfunctional-and-technicalidea (requirements and possibility of creation)and concept of the CAS within the country's aviation areshaped and proved. This is also whenthe rational main performance and parametersas well as the type of the created CASaredetermined.Pre-design stage defines themodes of CAS rational operationand ways of itsinteraction with other systems and complexes, which are involved in the process of CAS creation and operation duringmission fulfillment.
The topic of the paper are the main methodological approaches and methods of solving the key pre-design problems: the problem of CAS synthesis (CAS fleet structure), which consists in determining the rational values of main CASperformanceand parameters (i.e. the performance and parameters that have the greatest influence on CAS mission effectiveness and cost)according to the adopted objective function; and the fleet-type problem, which consists indetermination of qualitative and quantitative composition of the CAS fleet structure under the requirement that this fleet should be able to successfully carry out the whole set of the missions allocated for aviation with the considered purpose.
The paper seeks to improve theeffectiveness and justifiability of the decisions madeduring pre-design via the use of scientifically proven methodology ofthe solution of main design problems.
The paper proposes to simultaneously solvethe problem of rational CAS fleet structure optimization in terms of quantity and type nomenclature together with the problem of optimization of the main performance andparameters of each type ofCASwithin this fleet as a two-level iterative optimization procedure. The first level of this procedure provides fora consecutive solution of two optimization problems: the problem of CAS synthesis for the given set of missions, which are assigned to the fleet and should be carried out by it; and the fleet-type optimization problem, which determines the fleet structureand the distribution of missions among the different CAS types.
The second level (cycle) of the iteration procedure is determined by the correction of the given multitude of missions according to the optimization results obtained at the first level.
The problem of CAS synthesis that is solved at the first level of the iterative cycle is a classical calculus of variations large-scale problem. A decomposition method is used to reduce the length of the control vector. At that structural CAS decomposition is coupled together with the operational decomposition, which aims at selecting main performance and parameters of the CAS subsystems at the lowest possible levels of the operation hierarchy that are described by simpler operation models.
The created hierarchical system of operation models is used during the process of pre-design for the evaluation of the CAS mission effectiveness. At that the method of reversed invariant standard etalon creation is used forproviding solvability of the problems of selection of optimum ways of the CAS operation, which are especially complex at the upper levels of the operation hierarchy. Thismethod allows making unequivocal reverse transition from the reference (etalon) phase coordinates of the operation process to natural ones.
The work resulted in the development of methodological approaches and methodsfor the solution of problems of synthesis and fleet-type structure optimization of CAS, which are intended for carrying out given missions during a conflict under the conditions of uncertainty. At that the missions themselves and the conditions, under which they must be carried out,can change during the considered planning period of time.
The paper describes the above mentioned methodological approaches and methods for the solution of the problems of CAS synthesis and fleet-type structure optimization. These methods allow substantiating the rational values of the main performance and parameters of advanced types of CAS. This justification essentiallymakes up the initial information, which is necessary tostart the design and development of these CAS. This initial information should be adduced in the request for proposal forCASconcept projects. Besides,thecreated methods allow developingversions of rational CAS fleet structurefor various values of the initial dataduringa short period of time.Such development can be carried out for the cases when the accurate forecast of the initial datafor the planned period of timegives only an interval estimate orisessentially impossible to make. The development of such versions of rational fleetsgives the necessary baseline for advanced planning of the creation and production of CAS.
Keywords:external designing, synthesis, shape, type and park of aviation complexes, operation modeling, decomposition
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