and Computational Methods

doi: 10.18698/2309-3684-2021-3-6273

A model of genetic algorithm with binary coding with independent Schaeffer selection is constructed, which allows one to search for a global optimum by several criteria without their scalarization. The calculations take into account the range of all possible motions of actuators under uncertain external influences in some predetermined range. An algorithm has been developed that allows storing intermediate results to eliminate the problem of a large number of repeated calculations in the course of the evolutionary algorithm, which reduced the computation time. The effectiveness of the optimization algorithm is demonstrated on the example of solving a model problem.

Бушуев А.Ю., Резников А.О. Применение генетического алгоритма в задаче моделирования и оптимизации пневмогидравлической системы синхронизации исполнительных органов. Математическое моделирование и численные методы, 2021, № 3, с. 62–73.

doi: 10.18698/2309-3684-2024-3-100119

In various technical systems hydraulic devices are widely used to ensure the synchronous movement of executive bodies — unregulated chokes, flow dividers, regulators and/or flow stabilizers. The latter are characterized by the fact that their functioning occurs in the range of pressure drops of liquid amounting to several hundred atmospheres. The issues related to the numerical simulation of non-stationary physical processes in the flow stabilizer the design of which is protected by a patent of the Russian Federation for the invention are considered. The results of computer modeling based on a theoretical model with concentrated parameters, the use of the finite-difference implicit Geer method for solving a system of rigid differential equations are presented. The problem of optimal improvement of the design of such flow stabilizer in accordance with the selected criterion is formulated and solved. This optimization criterion is to ensure the condition of the minimum possible positive statism of the flow-drop (static) characteristic in conditions of wide change in the pressure drop on the device and the effect of the axial component of the hydrodynamic force. The problem of optimal design improvement was solved using one of the widely used evolutionary optimization algorithms — genetic algorithm with real coding. The results of computational experiments in modeling physical processes of the analysis problem correspond to the available experimental data that were previously obtained by the authors of the work. It is shown that improvement of the existing design of the flow stabilizer is possible — the angle of inclination of the flow-drop characteristic to the horizontal axis has decreased almost twofold. At the same time, it was possible to obtain higher accuracy of maintaining volumetric flow rate of the liquid. This accuracy is on the order of ±7,5 % of the nominal (tuning) value of the flow stabilizer. For comparison, the accuracy of maintaining the volume flow rate of the liquid before performing the optimization procedure was about ±10 %.

Иванов М.Ю., Бушуев А.Ю., Щербаков Н.С., Реш Г.Ф. Компьютерное моделирование динамических процессов в гидравлическом стабилизаторе расхода и его оптимизация на основе эволюционного алгоритма. Математическое моделирование и численные методы, 2024, № 3, с. 100-119.

doi: 10.18698/2309-3684-2022-2-313

A mathematical model of functioning of synchronization systems of actuators based on a throttle flow divider was developed to solve design problem. The solution of the optimization problem of a mismatch time of movement of actuators operating under conditions of external alternating-sign force effects is given, performed using the genetic algorithm and refined using the Nelder-Mead algorithm

Бушуев А.Ю., Данилов Н.А. Математическое моделирование гидравлической системы синхронизации исполнительных органов на основе дроссельного делителя потока. Математическое моделирование и численные методы, 2022, № 2, с. 3–15

doi: 10.18698/2309-3684-2014-2-101114

We have built a mathematical model for deployment of multibody solar array with a cable system of deployment. On the basis of analysis of the kinematic scheme of deployment system we have chosen the dimensions of the radii of the rollers and gear ratio of the two types of gear mechanisms which provide the preset sequence of fixation of sections. We used Lagrange equation of the second kind for studying deployment of the solar battery array. A distinctive feature of this approach is application of iterative method for taking into account deformation of the cables of synchronizing system. The mathematical model can be used to choose optimal design factors and deployment system performance requirements. It is also valuable for dealing with worst-case situations and verifying the reliability of deployment procedure.

Bushuev A., Farafanov B. Mathematical modelling of deployment of large-area solar array. Маthematical Modeling and Coтputational Methods, 2014, №2 (2), pp. 101-114

doi: 10.18698/2309-3684-2019-4-314

The optimization problem is formulated, which consists in ensuring the maximum time of maintaining the pressure in the filled container in the range from the maximum reached to 70 ATM. A mathematical model of a system consisting of a solid-fuel gas generator and a constant-volume filling tank is constructed. The optimization problem was solved by the Hook-Jeeves method and a genetic algorithm with real coding. The results were compared. A software package has been developed with the help of which a system of ordinary differential equations describing the state of the object under consideration is solved.

Бушуев А.Ю., Ряузов С.С. Оптимизация конструкции твердотопливного модельного газогенератора. Математическое моделирование и численные методы, 2019, № 4, с. 3–14.

doi: 10.18698/2309-3684-2020-1-103117

A software environment was developed for computer-aided design of optimal throttle hydraulic synchronization systems of actuators of various functional purposes operating under conditions of external alternating-sign force effects. The criterion of an optimization procedure was the minimization of a mismatch time of relative movement of actuators during operation. A compute core of an object-oriented code was constructed on the basis of a dynamic mathematical model of a synchronization system consisting of four power cylinders. A model problem was solved with the help of the created software environment. This model problem demonstrated the efficiency of the proposed multidimensional optimization process. The methodology was based on the use of the well-known heuristic method (binary coded genetic algorithm) and the subsequent improvement (in the sense of a given objective functional) of the obtained solution by a method on the basis of the Hooke-Jeeves algorithm. Recommendations on the practical application of the software and mathematical support for achieving the best convergence to the extreme value of a vector of controlled parameters were formulated.

Бушуев А.Ю., Иванов М.Ю., Коротаев Д.В., Реш Г.Ф. Программная среда dgsSynchCAD для моделирования и автоматизированной эвристической оптимизации дроссельных гидросистем синхронизации. Математическое моделирование и численные методы. 2020. № 1. с 103–117.

doi: 10.18698/2309-3684-2018-3-2237

When dealing with many applications there is a problem of finding the global extremum. Of particular relevance are the optimization methods that allow solving problems effectively when the objective function depends on a complex mathematical model that requires large computing resources for its solution. In this paper, a comparison is made between the Ψ-transformation optimization method and the canonical particle swarm optimization method. The flaws of some known algorithms of the Ψ-transformation optimization method are revealed and a modification based on the replacement of a random law with uniform distribution for generating statistical realizations on the second and subsequent iterations of the standard algorithm by the normal distribution law with parameters determined by the results of the previous iteration is proposed. On the basis of the extensive computational experiment, the advantage of the modified algorithm of the Ψ-transformation optimization method is shown in comparison with algorithm of the canonical particle swarm method.

Бушуев А.Ю., Маремшаова А.А. Сравнение модифицированного метода Ψ-преобразования и канонического метода роя частиц. Математическое моделирование и численные методы, 2018, № 3, с. 22–37.