The construction and useful practice of gas-turbine engine diagnosis systems depend largely on the availability of the engine mathematical models and its certain components in their structure. Utilization of multi-stage axial flow compressor performance with account for erosive wear of its parts during the operation fundamentally raises possibilities of such systems as erosive wear of flow channel, blade rings of impellers and vane rings of multi-stage compressor is a common cause of preschedule gas-turbine engine detaching from an aircraft. As evidenced by various contributions presented in the article, special emphasis on abrasive wear impact assessment on axial flow compressor performance is placed upon rotor-wing turbo-shaft engine due to their particular operating conditions. One of the main tasks in the process of mathematic simulation of an axial flow compressor blade ring is consideration of its wear type that again has a nonlinear distribution along the level of the blade. In addition, wear rate at entry and exit blade edges often have different principles. Detecting of these principles and their consideration when constructing the compressor mathematical model is a crucial task in diagnostic assessment and integrity monitoring of rotor-wing turbo-shaft engine in operation. The article represents a concept to an estimate nonlinear erosive wear effect of axial flow compressor blades on its performance based on the three-dimensional flow approach in the gas-air flow duct of compressor with a formulation of the blade rings. This approach renders possible to take into account the nonlinearity of the compressor blades wear during their operation. Through the example of the inlet compressor stage of a rotor-wing aircraft gas-turbine engine, the engine pump properties predictions with different kind of rotor blade wear have been presented.

Управление техническими объектами 23 2, 2019 СИСТЕМНЫЙ АНАЛИЗ И ПРИКЛАДНАЯ ИНФОРМАТИКА УДК 629.735-519 В. А. МАЛКИН 1 , И. В. РОЖКОВ 2 , А. А. САНЬКО 2 ВЛИЯНИЕ ВЕТРОВЫХ ВОЗМУЩЕНИЙ И НЕЛИНЕЙНОСТЕЙ СЕРВОПРИВОДА НА КОНТУР СТАБИЛИЗАЦИИ ВЫСОТЫ ПОЛЕТА БЕСПИЛОТНОГО ЛЕТАТЕЛЬНОГО АППАРАТА 1 Учреждение образования «Военная академия Республики Беларусь» 2 Учреждение образования «Белорусская государственная академия авиации» В статье рассматривается математическая модель ветра с учетом его стохастической составляющей и ветра устойчивого направления, представлены результаты сравнительного анализа влияния параметров ветра на суммарный вектор скорости ветра, действующего на беспилотный летательный аппарат (БЛА). Рассмотрены основные нелинейности элементов сервопривода автопилота и их влияние на выходной сигнал. Рассмотрена реакция контура стабилизации высоты полета БЛА на ветер с учетом нелинейностей элементов сервопривода. Доказана необходимость учета ветра при синтезе систем автоматического управления (САУ) и контуров угловой стабилизации БЛА на этапах, где скорости полета БЛА меньше 30 м/c. Ключевые слова: ветер; беспилотный летательный аппарат; математическая модель ветра; математическая модель сервопривода, нелинейности сервопривода.

The problem of controlling a typical nonlinear servo motor of an unmanned aercraft with non-stationary parameters using a robust PID controller is considered. The procedure for calculating the parameters of a robust PID controller based on the localization method (further - LM PID controller) for continuous and discrete control systems is studied. The influence of disturbing factors (internal and external) acting on the servo motor is considered. It is established that the main perturbations acting on the servo drive include internal perturbations, which are changes in the time constant and its gain from the temperature of the environment and the quality of the supply voltage. The simulation in the class of linear and nonlinear continuous systems showed that a servo drive with a ML PID controller has the property of robustness in the working range of changes in both the input signal and the parameters of the servo drive and controller. Simulation results showing the research are presented. When describing a servo motor with an LM PID controller in the class of linear discrete systems, its robustness is limited by a narrow range of variation of both its parameters and the quantization period of the input signal. As the degree of uncertainty in the parameters of the servo motor increases (approaching the working range of their change), the discrete system loses stability. For the synthesis of robust control circuits of an unmanned aercraft with given characteristics, mathematical dependences of the settling time and static error of a typical servo motor with LM PID controller from the quantization period of the input signal and the degree of uncertainty in its parameters are presented.

The article proposes the approaches to updating a strapdown inertial navigation system (SINS) based on data of the airborne electro-optical system (EOS) of an unmanned aerial vehicle (UAV). It is specified that the EOS is presented as a navigation data sensor. The rationale for the feasibility of such an approach is formed, especially in the terms of signal lack or suppression of satellite radio-navigation systems. It is proposed to ensure the accuracy of self-contained navigation by assigning an UAV route, including waypoints with terrestrial references (TRs). Notably, TR-associated image information is preliminarily downloaded into the flight management computer (FMC). The automated TR identification system with denoted coordinates at next waypoints, using airborne data, in fact, allows for alternative global positioning. The reliable operation of such an integrated navigation system over sufficiently extended legs of flight path, first, depends on the accuracy of its constituent elements. Taking into consideration the fact that conventional sensors of navigation information, such as a SINS and an altimeter, are quite well studied in numerous contributions. The article focuses on the UAV airborne electro-optical system and, specifically, on its application features as a navigation sensor. The factors influencing the accuracy of the UAV positioning data determination at waypoints according to the data of the airborne EOS are considered. The developed mathematical model of errors for the UAV inertial optical navigation complex (IONC) is presented. The analysis of the impact of airborne altimeter inaccuracies, earth’s surface features and the shift of the onboard digital camera optical axis, caused by random evolutions of the carrier body in turbulent atmosphere on the positioning accuracy, was conducted. The results of calculating lapses in determining the UAV positioning data, equipped with IONC, are given.

The principle of organization of strap-down inertial navigation systems is based on numerical integration of angular velocities and accelerations. The purpose of numerical integration algorithms is to approximate the behavior of a dynamic system (unmanned aerial vehicle – UAV) with continuous time using a digital computer. The efficiency of numerical integration is determined by the accuracy and stability of the computational process. The integration algorithm may have a small integration error, but at the same time be inefficient due to the instability of the numerical method when the step or conditions of integration change. The standard way to test integration algorithms for stability is to test them under control operating conditions (when performing a typical UAV flight along the route and canonical movement). The article presents the results of simulation modeling of traditional numerical integration algorithms in the conditions of rectilinear and conical UAV motion, when calculating the values of angular velocities by various methods. The analysis of the obtained research results is carried out, which allows us to choose an algorithm that has an advantage with respect to accuracy and computational simplicity, depending on the flight conditions. For a UAV that has no or minimal undampened angular harmonic oscillations of its body, when performing a typical flight along the route, the best, in terms of accuracy and volume of calculations, is a second-order accuracy algorithm implementing the average speed method. Its average error in calculating angles ranges from 3.6 to 43%, which is approximately equal to the errors values when using the considered algorithms (an algorithm implementing a second approximation to the average speed method, a one-step algorithm of the thirdorder of accuracy), with a three-fold smaller amount of mathematical calculations.