Advanced Materials Research Vol. 1016

Abstract: In order to avoid vacuum discharge, it is necessary for the satellite to have real-time monitoring by the vacuum degree of the electrical components that are sensitive to vacuum degree in the process of the thermal vacuum test. This paper introduces two methods of measuring vacuum degree inside the satellite, makes an analysis of failure mechanism of ionization gauge method, and offers suggestions for improvement.

Abstract: The structure of the robust stabilization system of cable tension for the test bench of weightlessness simulation was developed. The algorithm of a parametric synthesis of the robust PI–controller based on the coefficient method and the criterion of maximum degree of stability was suggested. The operability of the synthesized robust system was confirmed by the results of digital simulation.

Abstract: This work presents a comparative study of aerodynamic and performance characteristics of relevant examples of low speed aircraft that have been built and flown between 1890 and 1990. As speed is related to aircraft mass and wing loading and power, the aircraft analyzed present low weight, low wing loading and low power. To generate this study a set of tools have been developed, which are specifically aimed to slow and light aircraft. One additional goal of the study is to obtain a consistent reference data basis - by using the developed tools to analyze existing aircraft - prior to use these tools in new designs with the features of low speed, low wing loading and low power.

Abstract: This work concerns a construction of surrogate models for a specific aerodynamic data base. This data base is generally available from wind tunnel testing or from CFD aerodynamic simulations and contains aerodynamic coefficients for different flight conditions and configurations (such as Mach number, angle-of-attack, vehicle configuration angle) encountered over different space vehicles mission. The main peculiarity of aerodynamic data base is a specific design of experiment which is a union of grids of low and high fidelity data with considerably different sizes. Universal algorithms can’t approximate accurately such significantly non-uniform data. In this work a fast and accurate algorithm was developed which takes into account different fidelity of the data and special design of experiments.

Abstract: Generally faults in complex technical systems (such as aircrafts) can be considered as rare events. In this paper we apply classification techniques to problem of rare events anticipation and demon-strate the approach to predictive maintenance of aircrafts through the real-world test cases from aircraft operations based on the data granted by AIRBUS.

Abstract: The purpose of this project is to study and practice the techniques discussed in multidisciplinary courses aeronautical structure and load calculations to estimate the mass of an aircraft wing. The model studied is the Airbus A320. We first describe the characteristics of the wing of the aircraft. We will then study the aerodynamic forces, their distribution in the wings and aerodynamic load cases. In the next section, we will calculate the stresses induced by the bending of the wing and deduce the thickness of coatings that resist buckling. We also do a sensitivity analysis on the pitch of the ribs and stiffeners. Then, we will model the wing in SolidWorks and we will issue the card with Nastran constraints. Finally, we will provide our comments on the orders of magnitude obtained and the assumptions made the means to implement must be substantial to obtain an accurate result. The challenge of this project is to model the wing sufficiently wise to obtain an order of magnitude closer to reality. We consider an error of 15-20 % compared to the actual weight of the wing is suitable as part of a project like this [1].

Abstract: Based on the study of the duct leak detection system of commercial aircraft in existence, the insulation structure of high temperature pneumatic duct system of the aircraft is improved with multilayer insulation method and its engineering calculation method is derived. Also, the insulation experiment platform of the high temperature pneumatic duct system is built to verify the applicability and feasibility of the engineering calculation method. The research result shows that the results from the engineering calculation method is not fit the experimental data perfectly, the margin of error is 17 percentage. The main reason is that the diversion tunnels has a little effect on the temperature distribution and in these cases parameter modification method should be adopted in the engineering calculation method. These works would be helpful for the design and optimization of the high temperature pneumatic duct system.

Abstract: Airborne sensors become a primary system in any combat program and the effectiveness depends on the coverage spectrum of the sensors and also the ability of flying machine. However evaluating the mission functionalities using sensors in flight involves tasks namely, Man Machine interface evaluation, Sensor function capability evaluation, System interface evaluation, Performance evaluation, pilot work load etc needs to carried out and the issues observed during the flight test needs to be cleared before accepting the system. It is one of the challenging task for any combat aircraft development program and proving require time, effort and also may lead to time and cost overrun. To minimize the effort one of the method adopted in recent flight development programs are using high fidelity sensor model to evaluate the mission function in the simulator which will reduce the actual test required in flight. Flight simulators during development of combat aircraft program have increased drastically in recent times with new technologies, possible to bring realism in a close room environment. However the success of any simulators depends on the fidelity of each subsystem integrated with in the simulator. Simulator contains simulation model which represents system in the aircraft world and the system which represents the outside world in a simulated manner. Mathematical based Avionics and weapon system Sensor simulation models is one of the major sub systems in any combat simulator and its level of usage depends on its fidelity. This paper proposes a unique and new methodology for evaluating the fidelity of simulated sensors used in the combat simulators. System identification technique allows generating mathematical model for dynamic systems having multiple input and output parameters. The developed model using System Identification Technique is a referent model through which the sensor model fidelity is evaluated.

Abstract: In recent years Unmanned Aerial Vehicles (UAV) has become a significant segment of the aviation industry. They can be chosen to be designed as fixed wing or Rotary wing type. Fixed-wing aircraft has the performance of fast forward movement, long range and superior endurance due to its gliding capabilities with no power. Unlike the fixed wing models, rotary wing mini-copters are able to fly in all directions, hover in a fixed position with minimal space for takeoff and landing. This makes them the perfect instrument for detailed inspection work or surveying. Implementing a hybrid UAV has the advantages of both fixed-wing and rotary wing UAV. This paper aims to brief on the design, development and testing of a hybrid tilt body UAV with four rotors. The hybrid vehicle comprises two units, an aerial unit and a ground unit. The aerial unit consists of an unmanned aircraft system. The ground unit consists of means to view and post-data processing of video/image sent by the UAV if it is used for aerial surveillance and control, navigate and guide the aircraft. To proceed, a novel hybrid UAV with capability of Vertical Take Off and Landing (VTOL) and horizontal flight is developed and its response during the transition from VTOL to horizontal flight is analyzed.

Abstract: Instability phenomena such as bus voltage fluctuations are occurred in serial MPPT(Maximum Power Point Tracking) electrical power system. To study the system stability, the system equivalent circuit models were built based on a serial MPPT unregulated bus electrical power system topology for space application. The small-signal equivalent analysis method and solving eigenvalues of state space equations method were adopted to perform stability analysis in two-domain control modes separately, from which the key conclusions were obtained.