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  • Author: Michał Jóźko x
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Abstract

The test stand for investigations of flow characteristics of pneumatic distributor has been presented in this paper. This test stand has been composed as requirements include in standard PN-92/M-73763. The results of experimental and simulation investigations for standard five ways and two position pneumatic distributor have been presented. In simulations have been used CFD of SolidWorks Flow Simulation application. Flow characteristic of pneumatic distributor is necessary for design process of special pneumatic circuits of UAV launchers. CFD methods allow specify flow characteristics. Simulation research allow effective pneumatic components modification, whose used of special pneumatic circuits of UAV launchers. Results of experimental and simulation investigations were analyzed and compared.

Abstract

The subject of the article is the environmental research of the Pneumatic Para-chute Rescue System (PPRS) for an unmanned aerial vehicle, in which the parachute will be initiated from the reservoir by means of compressed carbon dioxide (CO2) stored in a special chamber. The research team has developed a program for researching the natural environment to simulate the conditions that may occur during the operation of an unmanned aerial vehicle and thus the Pneumatic Parachute Rescue System. UAV emergency scenarios were developed in which the developed rescue system should operate.

Abstract

The development of unmanned aerial systems (UAS) encountered the problem of controlling the process of technical operation. The literature that is available to the authors lacks credible information concerning the principles of specifying the strategy and control of the process of UAS operation. Hence, it is necessary to recognise and interpret the basic UAS operation features. The purpose of the publication is to present the properties of the UAS as an object of operation and the mutual relation of the technical operation process with the UAS’ technical condition alteration process. We present the results of analyses in terms of functionality and the UAS’ utility potential. The publication pays special attention to the properties of the UAS as an object of operation. The paper includes the analysis of the UAS operation principles and the specification of the advantage and disadvantage of those principles, i.e. using a non-repairable UAS until damaged, using a repairable UAS until damaged, periodical technical servicing, continuous diagnostic operation. The proposals for the control models in the UAS operation system have also been included.

Abstract

This publication addresses the proposed structural solution for a system, of which the conceptual essence involves a rescue parachute being ejected from an accumulator using compressed carbon dioxide. The suggested rescue system is intended for unmanned multicopter aircraft. The article presents a developed digital solid model and the results of its simulation tests. The paper also contains results of basic calculations of the pneumatic supply system energy balance and the power balance of the electric control system. It also presents the results of first in-flight tests with a simulated emergency situation and the use of a technology demonstrator in operating conditions. Simulational and experimental methods were chosen to solve the research problem.

Abstract

The correct operation of the hydraulic pump and achieving the assumed durability depends on the purity of the used working fluid. The research paper discusses a method for evaluating the contamination sensitivity of a hydraulic plunger pump. The theoretical grounds for evaluating the contamination sensitivity of hydraulic plunger pumps of a hydraulic drive based on the contamination sensitivity factor were presented. An example of evaluating contamination sensitivity of an NP-34M hydraulic plunger pump was discussed.

Abstract

One of the approaches to ensure friction stability in hydraulic precise pairs can be coating their components with low-friction materials with the friction coating method using a metal, e.g. brass. The article presents the method of applying brass on the steel surface of a hydraulic pair using friction. It discusses the technology of brass plating of hydraulic precise pairs and the results of laboratory tests involving friction-brasses hydraulic precise pairs. The factors impacting the quality of brass-coating process of hydraulic precise pairs and the requirements set for hydraulic precise pairs subject to friction-brassing were also discussed.

Abstract

The paper outlines workflows associated with troubleshooting of avionic hydraulic systems with detailed description of the troubleshooting algorithm and classification of diagnostic signals provided by avionic hydraulic systems and their subassemblies. Attention is paid to measurement sequences for diagnostic signals from hydraulic systems, circuits and units. Detailed description is dedicated to an innovative design of a troubleshooting device intended for direct measurements of internal leaks from avionic hydraulic units. Advantages of the proposed measurement method are summarized with benefits from use of the presented device and compared against the methods that are currently in use. Subsequent phases of the troubleshooting process are described with examples of measurement results that have been acquired from subassemblies of hydraulic systems of SU-22 aircrafts currently in service at Polish Air Forces with consideration given to cases when the permissible threshold of diagnostic signals were exceeded. Finally, all results from investigations are subjected to thorough analysis.

Abstract

The subject of this publication is a mathematical model of a pneumatic supply system for an emergency parachute system. This system is intended for a vertical take-off and landing UAV. An overview of emergency parachute landing system designs is presented in the introduction. Based on a schematic diagram and a 3D computer model, the construction and operation principles of an emergency parachute system, currently being developed at AFIT, was presented. A mathematical model, which enables the determination of the energy of gas (compressed CO2) stored in the accumulator tank was described. The conducted tests, which involved weighing the accumulator after filling with liquefied CO2 from a special cartridge and equivalent mass ejections were discussed. These tests involved recording the track of the equivalent mass movement and time necessary to determine velocity. The results of calculations regarding the equivalent mass energy imitating an emergency parachute, CO2 volume and mass in the accumulator in liquefied and gaseous state were presented. Based on the conducted calculations and the obtained characteristics, the developed mathematical model was assessed, and the final conclusions formulated.