Видання НТУ "ХПІ"

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On the stability of the stabilized motion of a carrier rocket with a liquid-propellant jet engine and an onboard digital computer in the stabilization loop
(Національний технічний університет "Харківський політехнічний інститут", 2022) Aleksandrov, Eugene; Aleksandrova, Tetiana; Kostianyk, Iryna; Morgun, Yaroslav
The problem of choosing the values of the variable parameters of the digital stabilizer of the cosmic stage of a carrier rocket with a liquid-propellant jet engine and an onboard digital computer in the stabilization loop, which ensures stable movement of the stage along the entire active section of the flight trajectory, is considered. The effect of the stabilizer quantization period on the stability region of a closed-loop stabilization system is considered. It is recommended to choose the intersection of stability regions corresponding to uniformly distributed moments of time along the active section of the stage flight trajectory as acceptable values for the variable parameters of the stabilizer of a non-stationary stabilization object.
Parametric synthesis of an electro-hydraulic executive device of a digital system of automatic control of a moving object
(Національний технічний університет "Харківський політехнічний інститут", 2022) Aleksandrov, Eugene; Aleksandrova, Tetiana; Kostianyk, Iryna; Morgun, Yaroslav
Most modern moving objects, including military moving objects, are equipped with guidance and stabilization systems with electro-hydraulic executive devices. Intercontinental ballistic missiles, space vehicles, aircraft, the main armament of tanks and ships have high-precision digital guidance and stabilization systems with electro-hydraulic actuators with potentiometric feedback, capable of ensuring high accuracy of stabilization of a moving object in a given direction. The work is devoted to the development of a methodology for selecting the value of the feedback channel amplification coefficient, which provides the maximum margin of stability and the maximum speed of the closed digital system of guidance and stabilization of a moving object. The proposed technique is based on the application of a discrete-continuous mathematical model of a closed digital system of guidance and stabilization of a moving object, which contains ordinary differential equations for describing the disturbed motion of the continuous part of the stabilized object, as well as difference equations for describing a discrete stabilizer. To construct the characteristic equation of a closed discrete system, the mathematical model is reduced to a system of difference equations using matrix series. At the same time, the number of considered members of the matrix series depends on the value of the quantization period of the digital stabilizer, therefore, in addition to determining the amplification coefficient of the feedback channel of the executive device, the proposed technique also includes the determination of the value of the quantization period of the digital stabilizer.
Parametric synthesis of the digital regulator of the diesel generator set for industrial purpose
(Національний технічний університет "Харківський політехнічний інститут", 2024) Aleksandrov, Yevgen; Aleksandrova, Tetiana; Kostianyk, Iryna; Lyshevski, Sergey
The object of research is the dynamic processes of high-quality electric power generation by a diesel generator set (DGS) with a digital fuel supply regulator. The subject of research is the methodology of choosing varied parameters of the digital fuel supply regulator, which ensure high stability of the frequency of the generated voltage in conditions of a wide range of changes in the external load on the part of electric energy consumers. The results obtained. A mathematical model of the disturbed motion of the diesel generator set was developed and varied parameters of the digital fuel supply regulator were determined. With the application of the combined algorithmic optimization method, which is a combination of the Sobol grid method and the Nelder-Mead method, in the plane of the varied parameters of the regulator, the values of these parameters were found, which deliver a minimum to the integral quadratic functional, which is a quantitative indicator of the degree of non-uniformity of the digital fuel supply regulator of the DGS. Conclusions. The use of a digital electronic fuel supply regulator instead of a hydromechanical regulator in a diesel of DGS significantly improves the quality of generated electricity relative to the stability of the three-phase voltage frequency at the output of the diesel generator set.
Parametric synthesis of the invariant system of car course stability
(Національний технічний університет "Харківський політехнічний інститут", 2023) Aleksandrov, Yevgen; Aleksandrova, Tetiana; Kostianyk, Iryna; Morgun, Yaroslav
The problem of constructing the invariant stabilizer of the ESP (Electronic Stability Program) car course stability system is considered by implementing two control principles by the electronic brake force distribution unit EBD (Electronic Brakeforce Distribution) – the principle of control by deviation and the principle of control by external disturbance. The values of the variable parameters of the stabilization algorithm are selected from the conditions for minimizing both the static and dynamic errors of the system. Two brake fluid pressure sensors are introduced into the EBD structural-functional scheme in the brake lines of the right and left sides of the car. It is proven that the pressure difference of the brake fluid, which is measured by pressure sensors, is proportional to the external disturbance acting on the car body from the side of the road surface. Therefore, in order to give the ESP system the property of invariance to external disturbances, the control signal generated by the EBD electronic unit contains current information not only about the parameters of the disturbed movement of the car, namely, about the angle of deviation of the longitudinal axis of the car relative to the given direction of movement, about the angular velocity of rotation of the body relative to its vertical axis and about lateral displacement of the center of mass of the body, but also the current information about the external disturbance acting on the car body. Recommendations for choosing the values of variable parameters of the ESP system stabilizer are given, which ensure the minimization of both static and dynamic errors of the closed system in the emergency braking mode.
Selection of the set of allowable values of the variable parameters of the stabilizer of a complex dynamic object
(Національний технічний університет "Харківський політехнічний інститут", 2023) Aleksandrov, Yevgen; Aleksandrova, Tetiana; Kostianyk, Iryna; Morgun, Yaroslav
Topicality. One of the most important tasks in the application of computational methods for the parametric synthesis of controllers of complex dynamic objects is the task of determining the set of permissible values of the variable parameters of the controller, where the target function is calculated based on the solutions of the mathematical model of the disturbed motion of the dynamic object with its subsequent minimization. The purpose of the work is to construct the set of permissible values of variable parameters of the stabilizer of a complex dynamic object when applying the algorithmic combined method of parametric synthesis of stabilizers of complex dynamic objects, the essence of which is the direct calculation of the integral quadratic functional on the solutions of a closed dynamic system with subsequent finding of its global minimum through a sequential combination of two algorithms – the Sobol grid algorithm and the Nelder-Mead algorithm. Results. With the help of the Sobol grid construction algorithm, the starting point of the computational process is brought to the node of the Sobol grid, which is located in the small vicinity of the point of the global minimum. At the second stage of optimization, the found Sobol grid node is selected as the starting point for applying the Nelder-Mead method, which is implemented by the Optimization Toolbox software product of the MATLAB package or the Minimize software product of the MATHCAD package and leads the computational process to the point of the global minimum. Conclusion. The paper proves a theorem according to which the stability region of a closed system of the first approximation can be taken as such a set, and also gives an example of a solution to the problem of parametric synthesis of the stabilizer of the car's course stability system during its emergency braking.
Simulation of random external disturbance acting on the car body in the urgent braking mode
(Національний технічний університет "Харківський політехнічний інститут", 2023) Aleksandrov, Eugene; Aleksandrova, Tetiana; Kostianyk, Iryna; Morgun, Yaroslav
Topicality. When creating ESP (Electronic Stability Program) car stability systems, the main task is to determine the values of the varied parameters of the EBD (Electronic Brake Distribution) electronic block, which ensure the required accuracy of stabilization of the car body in urgent braking mode relative to the given direction of movement. The purpose of the article. To solve the problem of parametric synthesis of the EBD block, it is necessary to create a simulation model of external disturbances acting on the car body from the side of the road surface. Well-known simulation models are created for car movement modes on a random surface with a constant speed. At the same time, random externaldisturbances are stationary in nature. The urgent braking mode is characterized by an intense decrease in the current speed of the car. Results. The paper proposes a method of constructing a random function of an external disturbance acting on the car body in urgent braking mode. It is proved that this perturbation is non-stationary in nature; the forming dynamic link, the input of which is supplied with single "white noise", and the output of which is an external disturbance, is an oscillating dynamic link, the gain and time constants of which depend on the current value of the car's speed during urgent braking.