Search Results

1 - 10 of 17 items

  • Author: Andrzej Żyluk x
Clear All Modify Search

New Technologies for Air Traffic Security

Security of increasing intensity of air traffic requires significant technological support. In Europe, the dynamics of this phenomenon will be additionally stimulated by implementation of unmanned aerial vehicles (UAVs) into the air traffic. For effective operation of aircraft fleet it is necessary to employ new on-board diagnostic devices and flight recorders in order to evaluate technical condition of aircraft's instrumentation. Reducing the pilots' workload requires the development of new integrated digital avionics. On the other hand, in order to make the air traffic more secure, it is necessary to develop "sense and avoid" systems not only for UAVs, but for piloted aircraft, as well. On-ground support requires the effective airport/airfield protection and keeping airfield pavements well-maintained and safe.

Abstract

One of the most important parameters specifying the usability of the miniaturised electrohydraulic servomechanism includes a static friction degree in its slide pairs, i.e. resistance of the slider’s movement from rest after some time of its staying at rest under pressure. Therefore, at the stage of designing and construction of the electrohydraulic servomechanism, it is important to determine the greatest static friction degree, which may arise in the slider hydraulic pair of this device during its operation. The objective of this article is to present a method for estimating the maximum static friction values in the slide pair based on the extreme value theory. The operation and loading conditions of the slide pair of the electrohydraulic servomechanism for the unmanned aircraft control system were described. The procedure for estimating the maximum static friction degree in the slide pair with the use of the extreme and probabilistic grid was presented. The extreme and probabilistic grid structure was based on the Gumbel probability graph. The graphic presentation of results of the static friction experimental studies in the slide pair on the extreme and probabilistic grid was discussed. By using the graphics method, the empirical dependence of the static friction force in the slide pair on the working fluid pressure in the hydraulic drive (loading conditions) was determined. A practical example of estimating the maximum values of the static friction force that may occur in the slider hydraulic pair of the miniaturized electrohydraulic servomechanism is shown.

Abstract

Usage of mobile technology will help the flying personnel to coordinate and implement assigned tasks. Due to usage of smartphone, equipped with appropriate application, user will have the ability to track all task and recommendations with are automatically generated by the system. This type of solution will eliminate prophylaxis and training failings and positively affect the ability to flight of aviation personnel. Furthermore presented tool is also a mobile source of knowledge, data base containing: bulletins, information about aviation events, etc. The paper is a characteristic of the mobile application designated to supervise preventive and training duties of flying personnel, it presents operation algorithm, mathematical model and describes the purpose of the application.

Abstract

This article is concerned with the issue related to studying the dynamic properties of the aerial target imitator. Applying the modelling principles, the structure and technical data of aerial target imitator were described and utilising the PRODAS software a physical model of the aerial imitator was developed based on the conducted simulation studies. Mass, aerodynamic and basic parameters of flight path were determined. Then, experimental studies of basic dynamic characteristics were discussed. The comparison of results obtained from experimental and theoretical studies proves the correctness of the developed model.

Abstract

It is known, that small disturbances generated by the micro actuators can alter large-scale vortex structures, and consequently, generate appreciable aerodynamic moments along all three axes for flight control. In the current study, we explored the possibility of independently controlling these moments. We perform analytical simulations showing optimal position of LEX generators, and water tunnel measurements showing effectiveness of MEX generators as MAV control devices. We applied array of actuators located on either the forward or the rear half section of the leading edge. Both one- and two-sided control configurations have also been investigated. Experimental results showed that asymmetric vortex pairs were formed, which leads to the generation of significant torques in all three axes. The article presents typical vortical flow over a delta wing, water tunnel at Wroclaw University of Technology, experimental setup and procedures, static test results on water tunnel testing including normal forces, pitching and yawing moments, maximum values of rolling, pitching, and yawing moment coefficients, effectiveness of pitching and yawing control.

Abstract

The article is close connected with building flying object, that fly like an insect (entomopter). Present work concerns on concept of aerodynamic model using artificial neural networks. Model is used in simulations of flight of entomopter. Aerodynamic model based on experimental data. Necessary data are taken from experiment performed in water tunnel on entomopter model. For this case dynamic test are required. Measurements are ducted during sinusoidal motion of whole model. Modelled object is dipterous. Each wing can perform various spherical motions (wing is rotated around point). The motion of the wing in this case was two-dimensional; it was rotated around two axis. As a model, specially trained neural network is used. For training are used data from measurement. Presented in this article approach is based on artificial neural networks. In this article, innovative concept of model, describing unsteady aerodynamics of entomopter was proposed. It was shown that it could be easily implemented as mathematical model. Unsteady effects related to many state variables can be easily captured. Model can be easily adopted to predict different states of flight by networks training on appropriate data. Test has to reproduce real conditions as close, as it is possible. In reality, it is challenging to design test that will reproduce similar motion.

Abstract

In aeronautics, the question of maintaining the highest possible level of flight safety is the most crucial issue. This is the reason why the scientists, engineers, and aerospace/aviation engineering staff keep searching for ever newer and more reliable methods of increasing the safety level. Therefore, new methods - primarily nondestructive ones - to diagnose aircraft turbine engines are looked for. These methods are expected to prove useful for the real-time monitoring of actual health of the engine and its assemblies. The paper has been intended to outline the most recent methods of diagnosing aircraft turbine engines, including the computed tomography methods as applied to assess health/maintenance status of turbine blades, for the phase mapping of increments in the engine’s rotational speed, to diagnose health/maintenance status of the compressor’s 1st stage rotor blades in pure jets. Other methods discussed are, e.g. vibroacoustic and tribological ones

Abstract

The article presents the selected methods of identifying static and dynamic properties of the measuring paths to the extent necessary for the proper integration of on-board systems with the helmet-mounted flight parameter display system. It presents the methods of identifying static and dynamic properties of the WR-10MK on board variometer as one of more difficult identification elements. Its identification was carried out on the basis of the basic dependencies of the International Standard Atmosphere and the instruments construction’s parameters. It built a mathematical model describing the physical phenomena associated with vertical speed measurement. This model differs from the models found in the literature in terms of detail and description accuracy. On this basis, in the Simulink environment, it built a simulation model corresponding to its mathematical model. The non-linear model was the starting point for the construction of the linearized model based on the operator transmittance. The developed models were evaluated for errors of vertical speed’s dynamic indications. This allowed assessing the usefulness of the individual models for further works on ensuring the correlation of indications of the on-board variometer and the SWPL-1 helmet-mounted flight parameter display system. The presented simulation models include design details, as well as the characteristics of technological errors and disturbances of a stochastic nature. Another approach to the issue of identification is to use the characteristics provided by the manufacturer in the form of approximate characteristics of a module.

Abstract

The article presents the results of numerical simulations of the bomb-fluger system drop. This system consists of two rigid bodies – a bomb and a fluger, which are connected by a biaxial joint. For the analysis, an author's program was used to simulate the bomb-fluger system drop. Influence of the characteristic points of the system on its stability and dynamics was investigated. Particularly, locations of a bomb mass centre, a fluger mounting point, a fluger aerodynamic focus were tested. The article presents a model of the examined bomb in the wind tunnel, characteristic points of a bomb-fluger system, waveforms of values rate of change angles and the values of angles for different distances, waveforms of values of the angle of nutation and the pitch angle of the fluger relative to the bomb, diagrams of examined points of the location of the centre of the mass and pressure of the fluger, waveforms of values rate of change angles and the values of these angles for different locations of the centre of the mass of the fluger, waveforms of values of the angle of nutation and the pitch angle of the fluger relative to the bomb for different locations.

Abstract

The article presents the results of numerical simulation of a laser-guided bomb, which is dropped in calm weather conditions. The prototype of such a bomb was developed at the Air Force Institute of Technology. It was a result of the modification process of the classical training bomb. The modification consisted of building on the bomb's board a detection system to track targets that are designated by laser and a control system to adjust bomb’s glide path to precisely strike the target. In the simulation research, geometric and mass characteristics of the classical training bomb were used. Aerodynamic characteristics of the bomb have been determined using commercial software PRODAS. Using the mathematical model of the bomb spatial motion and model of the laser detection system series of simulations were performed. The main goal was to determine the effectiveness of the adopted construction solution. Therefore, simulations were performed for various initial positions of the bomb and fixed position of the target. It allowed finding the set of control laws coefficients giving the most accuracy of the bomb. The influence of structural modifications of the detection system on the possibility of effective detection and location of the target was also investigated. In the article, exemplary results of numerical calculations performed with the author's software are also shown.