19 research outputs found
THEORY OF ANOMALIES AND ITS APPLICATION TO AIRCRAFT CONTROL
The anomalies are deviations in the system parameters or service characteristics initiating
the changes in the technical and operational characteristics and finally generate decreasing
of the prescribed or designed working quality of system.
The general lecture deals with the basic elements of the theory of system anomalies.
describes the mean problems of theory and shows the recommended models for valuation
of anomalies effects on system characteristics. The system anomalies play an important
role in accuracy and dynamics of control systems. In many cases they can be modelled
as the additive errors in the output characteristics (motion variables) measured and used
as feedback signals. Some specific problems of application of system anomalies theory to
the aircraft control systems are discussed in the second part of the paper
Simulation Model Based Response Management Related to Railway (Earthquake) Disaster
Railway system as part of the general transportation system is a strategic element that supports the economy and the society. Its role is continuously rising with rapid industrialization, urbanization, and changes in the society expectations regarding sustainable systems. New and emerging technologies call and permit the augmentation of the railway systems’ disaster management. This paper deals with the development of an improved response management concept related to railways’ damage, caused by earthquakes. The paper synthetizes the latest technologies, engineering, and management methods in one improved response management system. After the concept inspiration, the paper describes the applicable novel models and introduces an improved response management being developed for railway systems, damaged by earthquakes. The concept is verified in simulation. The novelty includes a new approach in the identification of the critical infrastructure, the risk assessment, the prediction of aftershocks and the recursive application of the adaptive Markov process to the simulation supporting the response management concept
Total impact evaluation of transportation systems
Impact assessment, in general, includes the environmental safety and security considerations, and cost/cost-benefit analysis of the used sources. As usual, the impact is evaluated at two levels: (1) impact during operation (usage) related to a chosen operational unit (e.g., running distance [km], operational time [h] or calendar time [h]), (2) the life-cycle (project life-cycle) impact. The environmental impact is characterized by the chemical and noise emissions. Safety and security are estimated by risks. Costs are calculated based on the required financial support and caused losses. All these calculations are related to the individual vehicles or vehicles with average behaviours. The investigation of sustainability impact requires a wider evaluation and approach, for example, by also including production and recycling beside the operational aspects. This paper generalizes the impact analysis. At first, it considers all types of impacts including the direct (e.g., accidents) and indirect long-term effects (e.g., health problems caused by emissions). All the impacts are expressed as costs. The defined Sustainable Transportation Performance Index (STPI) is the Total Life-Cycle Cost (TLCC) related to the unit of transport work. As such, it combines the life-cycle emissions evaluation and transport costing methods. It contains the total operational and total impact costs. The proposed approach introduces three new specific features in the impact analysis: (1) the impact is evaluated on the transportation system level, (2) the impact is estimated as the total value (including all the related sub-systems and elements, like vehicles, transport infrastructure, transport flow control, etc.), (3) proposes a unique index to describe the total impact. The paper describes the general equations and the developed methodology for the estimation of the total impact and analyses its applicability. The preliminary results demonstrate the applicability of the defined index and its evaluation methodology. It also shows the limitations of traditional cost models. Further test results and wider application of the methodology will be provided in a series of follow up papers by the research team
Tunnel/Predictor Display for Trajectory Control in Hypersonic Flight
A tunnel/predictor display which presents guidance information in a 3-dimensional format is considered for improving trajectory control in hypersonic flight. The displayed 3-dimensional information comprises a tunnel image and a predictor for indicating the aircraft position at a specified time ahead. The 3-dimensional guidance information is introduced to support the pilot in controlling the flight path. It is considered that piloting problems can be avoided which exist with conventional trajectory control techniques due to path-attitude decoupling. A predictor control law is constructed which yields controlled element properties (predictor-aircraft system) requiring minimum pilot compensation. This predictor control law forms the basis of the trajectory control improvement goal. Results from hypersonic flight simulation tests at the NASA Dryden Flight Research Center are presented for experimental verification. This paper is an outcome of a joint research effort of the NASA Dryden Flight Research Center, and the Institute of Flight Mechanics and Flight Control of the Technische Universität München and the Department of Aeronautics, Naval Architecture and Railway Vehicles (former Department of Aircraft and Ships at the Budapest University of Technology and Economics
Compressible viscous flow solver
Nowadays, in spite of disadvantages of turbulence closure models for RANS
(Reynolds Averaged Navier-Stokes equations), they are at present the only
tools available for the computation of complex turbulent flows of practical
relevance. Their popularity comes from high efficiency in terms of accuracy
and computational cost, which makes them widely used in commercial codes and
related multidisciplinary applications. Hence, for modelling compressible
flow, as a framework of complex inverse design optimisation tool,
Navier-Stokes solver is implemented by using k-ω turbulence model in
C++ environment. The governing equations in conservative form are deduced by
using Favre averaging to filter local fluctuations. The code is based on
structured, density based cell centred finite volume method. The convective
terms are discretized by Roe approximated Riemann method. Central
discretization is applied for diffusive terms. MUSCL approach is implemented
for higher order spatial reconstruction with Mulder limiter for monotonicity
preserving. Wilcox k-ω two equations turbulence model is implemented
for turbulence modelling. The explicit system of the equations is solved by
the 4th order Runge-Kutta method. The numerical boundary conditions are
based on the method of characteristics. The interest is mostly in high speed
aeronautical applications with the possibility of extension for surface
optimisation. Hence, the applied validational test cases are in transonic
and supersonic flow regime: circular bump in the transonic channel and
compression corner
The role of inland waterway navigation in a sustainable transport system
Sustainable development has become a guiding principle of human activities nowadays. Sustainable transport can take a great part in future development. Today this is not the case, and road transport contributes to this above all. For sustainable transport development the necessity of modal shift is inevitable and the inland waterway navigation should get the higher share of the total transport where there is an alternative. This presentation shows the reasons why the inland waterway navigation can increase the level of sustainability.
First Published Online: 27 Oct 201