International Conference on Simulation (1998)
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- Location: York, UK
- Conference date: 30 Sept.-2 Oct. 1998
- ISBN: 0 85296 709 8
- Conference number: CP457
- The following topics are dealt with: computer simulation; air transport; biomedical engineering; aerospace; surface transport; space systems; automotive systems; management systems; control systems; manufacturing systems; physical phenomena; industrial plants; motor drives; power distribution; and electronics and communication systems
1 - 20 of 68 items found
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The mother of invention
- Author(s): P. Denne
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The article looks at innovation and how it can arise from the use of simulation. As an interesting twist on this theme, the author describes why a new linear actuator had to be invented to solve an urgent requirement of the entertainment simulator business. He also describes some of the ways the actuator may be used in other industries.
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Simulation of space vehicle control under uncertainty of information
- Author(s): S.I. Kumkov
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Simulation of a space vehicle (SV) approach to a dangerous space object (DSO) is considered. SV on-board control system uses algorithms based on methods of differential game theory and informational sets (IS) ideology. Computational algorithms for building the informational sets were elaborated. SV control law close to the optimal one and methods for yielding the worst measurement disturbances were constructed.
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Avionic system modelling
- Author(s): R.J. Bluff
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Through the need to reduce the risk of adopting future avionic architectures and standards, a better understanding of the operation of evolving system instances and standards early in the design cycle are required. A flexible means of achieving this aim is to conduct an analysis through the development of an avionic system model based on behavioural and performance simulation. The paper defines a modelling framework for the construction of an Avionic System Model that would provide a means of assessing the hardware and software components and their interaction in a system. The Shlaer-Mellor Object Oriented Analysis (OOA) method (S. Shlaer and J. Mellor, 1992) has been used to define the model. To form an avionic system model, three modelling domains have been defined: behavioural, performance and visualisation. Behavioural models constitute primarily the software components of the system, the performance models analyse the hardware concepts, and visualisation models provide a means of understanding the system's operation. The modelling domains can be applied separately or they can be linked together to form a system model. A developed performance model of the Aeronautical Radio, INC (ARINC) 651 Integrated Modular Architecture (IMA) is described. It is discussed how architecture bottlenecks and system capacity can be derived. An APplication/EXecutive (APEX) is also described. The behavioural analysis of this interface is illustrated and system visualisation concepts are discussed. How the various modelling components can be combined to form an avionic system model is also described.
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A simulation tool for the reliability analysis of communication satellite payloads
- Author(s): M. Ruggieri and E. Cerone
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A simulation package has been developed aiming at a quick and design oriented evaluation of the reliability performance in satellite communications payloads. The software package, named RESIST (REliability Simulator of Satellite payload Transmitters), is able to relate the reliability performance of the on-board transmitter to the system requirements and the antenna complexity. Furthermore, it can be exploited in the design of the on-board transmitters, moving from reliability specifications and constraints.
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The use of simulation techniques in the design and manufacture of satellites
- Author(s): T. Kennedy ; D. Self ; A. Self ; M. Safa
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In 1996 the Russian association (Russia's equivalent of NASA) launched their most ambitious spacecraft to date to the planet Mars. The spacecraft (Mars96) was intended to be the first of a series of cornerstone missions aimed at further planetary exploration. Mars96 comprised three individual research systems: an orbiter, two soft landers and a pair of penetrator probes. Together, these research systems were to investigate Mars, with particular emphasis on the planet's atmosphere, surface structure, interior and planetary interaction with the solar wind. Mullard Space Science Laboratory (MSSL), as primary investigator, played a key role in the development of the FONEMA instrument, one of a suite of plasma instruments to be flown on the Mars96 orbiter module. The instrument was intended to investigate the plasma population of near Mars space, with particular emphasis on the mechanics of atmospheric erosion. The development of one of the FONEMA instrument's core electronic sub-systems is part of MSSL's contribution to the Mars96 mission, and forms the subject of an MSc by learning contract at Kingston University. The article covers the research, design and development phases of the flight model Sensor Interface Unit (SIU).
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Modelling and simulation of hydraulic components for vehicle applications - a precursor to control system design
- Author(s): S.C. George ; K.J. Burnham ; J.L. Mahtani
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The paper highlights the role of simulation as prerequisite for control system design when dealing with the hydraulic components within a vehicle application. Mathematical models based on first principles and data based models are evaluated against known system performance. The need to distinguish between models for simulation and models for control is emphasised.
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Comparison of suspension rig measurements with computer simulation
- Author(s): B. Ozdalyan ; M.V. Blundell ; B. Phillips
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A McPherson strut front suspension system has formed the basis of a study comparing actual rig measurements with a computer simulation. The study is based on a Peugeot 605 suspension located at Coventry University. The software used, ADAMS (Automatic Dynamic Analysis of Mechanical Systems) (R. Ryan, 1993) is well established within the automotive industry. The paper describes the experimental methods used to measure camber angle change, caster angle change, steer change, track change, and wheel rate. These measurements were taken when the rig was jacked up and down from a static condition. The methods used to model and obtain the same results in ADAMS are also discussed. The results obtained from both methods are compared. The paper concludes by discussing future applications of the ADAMS model for more sophisticated analyses, including the simulation of anti-lock braking systems.
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Anti-lock braking system simulation and modelling in ADAMS
- Author(s): B. Ozdalyan and M.V. Blundell
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The paper presents the application of the ADAMS (Automatic Dynamic Analysis of Mechanical Systems) computer programs to model and simulate the performance of an anti-lock braking system (ABS). A study has been conducted based on a single wheel model and dynamic simulations have been carried out which combine a braking algorithm representing the ABS. The braking models described here embody (FIALA) tyre model based on tyre tests carried out within the School of Engineering at Coventry University. These tests were conducted to explore the relationship between tyre braking force and wheel slip. Whilst braking torque is applied to the wheel, slip increases until the wheel is locked and slipping occurs. The simulation results represented here demonstrate how a simple ABS algorithm can be transformed into a vehicle braking model to prevent wheel locking, when severe braking occurs. One of the main objectives of the paper is to investigate the complicated interaction between the tyre and the ABS system, so designers can use this model to decide which tyres are more suitable with an ABS system. This is demonstrated by comparing the ABS algorithm with models using data for two different tyres and also investigating the influence of changing road conditions from dry to wet to ice. The paper concludes with a discussion of the practical difficulties involved in developing realistic algorithms to represent ABS in computer simulation.
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A mathematical transient model for the dynamics of a single cylinder Diesel engine
- Author(s): Y.H. Zweiri ; J.F. Whidborne ; L.D. Seneviratne
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This model has been developed for predictions of instantaneous engine speed and torque. The transient of the model represents the diesel engine as a nonlinear dynamic system. The instantaneous crankshaft speed is determined from the solution of the engine-external load dynamics equation, where the engine torque is tracked on a crank-angle basis. The model consists of careful modelling and analysis of all the major forces internal to the engine. It is developed with the aim of investigating different strategies for transient fuel control. Validation of the transient model during rapid engine acceleration shows that both the cyclic fluctuations in the instantaneous crankshaft speed line and the overall engine response are in excellent agreement with experimental measurement.
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Simulation of activated sludge process control strategies
- Author(s): M.K. Rangla ; K.J. Burnham ; L. Coyle ; R.I. Stephens
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Dynamic modelling and simulation is increasingly being employed as an aid in the design and operation of wastewater treatment plants (WWTPs). A simulation model is used to investigate control of an activated sludge process (ASP). It is shown how the recycle and wastage flow rate variables can be employed to continually maintain plant operation in the presence of wastewater load disturbances and plant changes. Considerations are also given as to how plant operation could be optimised in order to increase treatment capacity and reduce operating costs.
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Decompositional modelling and simulation of power system electromagnetic transients
- Author(s): I.M. Dudurych
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Electromagnetic transients are usually caused by switching operations, faults and lightning surges in power systems. These co-ordinates (instantaneous values of currents and voltages) are very important for power system planning, particularly for the protection scheme design, insulation, co-ordination etc. Generally power system electromagnetic transients are described by a set of differential, algebraic and Boolean equations, which relate instantaneous values of currents and voltages between each other. These sets of equations are usually referred to as mathematical models of power system electromagnetic transients. Mathematical models of modern power system electromagnetic transients are characterised by high dimension; and include nonlinearities, originated by the effect of electromagnetic apparatus (e.g. transformers, reactors etc.), magnetic core saturation and by nonlinear resistivity of surge arresters and overvoltage limiters. Moreover, switching elements such as relays, thyristors valves etc. should also be presented adequately. Because of the above reasons, mathematical models of power system electromagnetic transients are rigid, that is these eigenvalues, or time constants are wide spread. Therefore an integration step usually has to be chosen much smaller then the interval of interest since it is determined by the least time constant. Thus, the computation of power system electromagnetic transients is a very extensive problem which can nevertheless be efficiently solved by using decomposition methods.
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Application of minimax evaluation procedures for expansion of metrological standard on noised measurements processing
- Author(s): S.I. Kumkov
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The paper deals with an application of minimax evaluation procedures for expansion of metrological standards in the case of information uncertainty about errors in measurements. It is concluded that the discussed approach for evaluation of noised experimental data does not contradict the procedures of existing standards, but can complement them when the measurement error's statistical characteristics are unknown. The approach gives additional and practical information: a full representation of the set of admissible parameters for the describing function; a full description of admissible values of the process to be evaluated (the tube). Elaborated algorithms have rather simple numerical realisation.
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Simulation of hybrid systems based on interpreted Petri nets
- Author(s): G. Frey
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A modelling approach for hybrid systems using interpreted Petri nets is described. An implementation of the proposed method for software tools is presented. With the help of the hybrid two tank benchmark problem, the implementation is shows to be accurate. A comparison with other tools shows good results.
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The development of a total system aircraft landing control scheme
- Author(s): C. Papadopoulos ; A. Self ; G. Kapadoukas
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Current aircraft braking systems are independent single loop controlled anti-skid systems. No account is taken of the whole system behaviour or the potential use of the combined aerodynamic and mechanical braking systems. Modern multivariable techniques are used in the development of a control law designed for the purpose of improving landing and braking performance as a total aircraft approach. The problem is to design a braking system that takes into account the all-axis aerodynamic and mechanical behaviour of an aircraft at the point of touchdown and optimises landing performance. The system applies the appropriate aerodynamic and brake control action to cause the aircraft to come to rest in an optimal and controlled manner taking into account weather and runway conditions. The two factors, which are minimised, are runway centre-line offset and landing runway length. The new control scheme uses main wheel braking from the moment the main gear contacts the runway surface and the wheel velocities match that of the ground. The controller also uses the ailerons and main wheel brakes to aid in braking and the ailerons, rudder, nose wheel steering and differential braking to maintain directional stability and evenness of tyre/runway pressure. The paper briefly describes the linear aircraft model used to design the control law, the nonlinear aircraft model used to test the control law and the control rationale.
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Control systems for power electronics
- Author(s): M.N. Cirstea and M.C. McCormick
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The paper presents the design, simulation and implementation of modern control systems for power electronics used in variable speed drives. The control strategies are implemented on the basis of Application Specific Integrated Circuits (ASICs) which provide considerable advantages over present solutions. Electronic design automation (EDA) techniques were used. The experimental results showing the expected close similarity with the simulation waveforms, have proven the high performance of the systems and the accuracy of the simulation tools used for development.
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Intelligent decision-making for reactive scheduling in FMS
- Author(s): J.F. O'Kane ; D.K. Harrison ; T.S. Baines
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The paper describes research into the development of an intelligent simulation environment. The environment was used to analyse reactive scheduling scenarios in a specific FMS configuration. Using data from a real FMS, simulation models were created to study the reactive scheduling problem and this work led to the concept of capturing instantaneous FMS status data as `Snapshot' data for analysis. Various intelligent systems were developed and tested to assess their decision making capabilities. The concepts of `history logging' and expert system `learning' is proposed and these ideas are implemented into the environment to provide decision making and control across a FMS schedule lifetime. This research proposes an approach for the analysis of reactive scheduling in an FMS. The approach and system that was subsequently developed was based on the principle of automated intelligent decision making via knowledge elicitation from FMS status data, together with knowledge base augmentation to facilitate a learning ability based on past experiences.
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Optimisation of a blood separation process based on simulation
- Author(s): A. Diehl and G. Frey
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A mathematical model for the simulation of a blood separation process is presented. The simulation algorithm calculates the time-dependent three dimensional distribution of red blood cells in the sedimentation centrifuge from the geometry of the centrifuge and the dynamic process parameters such as the rotation velocity of the centrifuge or the volume flow of supplied patient blood. The resulting process model is the basis for a stepwise optimisation and automation of the complex centrifugal blood sedimentation process. The presented results were achieved in a research and development cooperation between the Institute for Process Automation and one of the leading producers of autologous blood salvage systems (FRESENIUS AG).
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MATLAB-SIMULINK® library for AC drives simulation
- Author(s): S. Ivanov ; A. Campeanu ; A. Bitoleanu ; M. Popescu
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The development of the control structures for AC motors (vector control, fuzzy control, etc.) is easier if good models are available, in order to verify the different ideas. There are necessary accurate models for the AC motors (induction and synchronous), for the different types of inverters and for the blocks often used in the control loops. By using the MATLAB-SIMULINK(R) facilities, a library containing models for the mentioned subsystems was developed. It consists of three divisions, each of them corresponding to one of the described sub-systems: power sources, motors, control. An important aspect is that the control blocks were also used for real time control of the drives, by using the friendly interface supplied by dSPACE GmbH with its DSP control board DS1102. The paper describes the structures and the facilities of the built blocks, as well as examples of models of the complete systems. The simulation results are compared with the experimental ones. The correctness of the developed models is fully confirmed, thus a strong tool for the study of the AC drives is made available.
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On optimizing the routing algorithms of a GSM infrastructure network for supporting time critical applications
- Author(s): A. Kalis and T. Antonakopoulos
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GSM (Groupe Speciale Mobile) is a digital cellular mobile radio system that services millions of customers and covers almost all European countries (R. Steele, 1995; N.J. Muller, 1995). It has a hierarchical structure, which consists of a number of base station controllers (BSCs) at the lower level, which are connected to a number of mobile switching centers (MSCs). MSCs are responsible for routing a call from the BSC that made the request, to the BSC that will receive the call. The routing of a call is done either through the Public Switched Digital Network (PSDN) or through the MSCs themselves. BSCs and MSCs form a mesh network, called GSM Infrastructure Network (GIN), that is based on medium and/or high speed point-to-point links. During the design phase of the inter-networking devices of such a GIN, the selection of the proper routing algorithm becomes the main issue. The article presents the model of such a GIN network, a model of its traffic sources, the network topology and the functionality of its nodes. Simulation studies are presented for determining how various routing algorithms affect network performance. Based on these results, the best routing algorithm for such an application is specified.
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Simulation of switched-mode power electronic circuits
- Author(s): B. Baha
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A circuit simulation package (PSPICE) and an equation solving package (SIMULINK) are used to simulate switched mode power electronic circuits. The performance of both packages are evaluated. It has been found that SIMULINK is much faster than PSPICE when simulating power electronic circuits. Furthermore, mixed mode simulation is employed to simulate power electronic circuit that contain both analogue and digital components employing mixed mode simulation.
