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Sat, 16 Mar 2019 09:55:38 +0100Sat, 16 Mar 2019 09:55:38 +0100Simulation methods of rigid holonomic multibody systems with bond graphs
https://pub.h-brs.de/frontdoor/index/index/docId/4413
Bond graph software can simulate bond graph models without the user needing to manually derive equations. This offers the power to model larger and more complex systems than in the past. Multibond graphs (those with vector bonds) offer a compact model which further eases handling multibody systems. Although multibond graphs can be simulated successfully, the use of vector bonds can present difficulties. In addition, most qualitative, bond graph–based exploitation relies on the use of scalar bonds. This article discusses the main methods for simulating bond graphs of multibody systems, using a graphical software platform. The transformation between models with vector and scalar bonds is presented. The methods are then compared with respect to both time and accuracy, through simulation of two benchmark models. This article is a tutorial on the existing methods for simulating three-dimensional rigid and holonomic multibody systems using bond graphs and discusses the difficulties encountered. It then proposes and adapts methods for simulating this type of system directly from its bond graph within a software package. The value of this study is in giving practical guidance to modellers, so that they can implement the adapted method in software.Benjamin Boudon; Thu Thuy Dang; Rebecca Margetts; Wolfgang Borutzky; François Malburetarticlehttps://pub.h-brs.de/frontdoor/index/index/docId/4413Sat, 16 Mar 2019 09:55:38 +0100Determination of a Function for a Degradation Process by Means of Two Diagnostic Bond Graphs
https://pub.h-brs.de/frontdoor/index/index/docId/3860
This paper proposes a novel approach to a bond graph model-based failure prognosis for systems represented by a mode switching linear time-invariant model. A function for a degradation process is numerically determined by using a first stage and a second stage diagnostic bond graph model (DBG). Evaluation of the Analytical Redundancy Relations (ARRs) from the first stage DBG provides residuals that enable to detect the onset of incipient faults. The second stage DBG model accounts for parametric degradation by means of an unknown function. ARRs derived from the second stage DBG make use of the residuals of the first stage ARRs and constitute an implicit relation for the unknown degradation function. The computation takes place online concurrently to the monitoring of a real system and the measurement of its output signals. Once the time evolution of a degradation process has been computed up to some time instant, the time evolution of an ARR residual using it can be projected into the future in order to estimate the Remaining Useful Life (RUL) of a system. With progress of time the computation of a degradation process can be repeated and estimations of a RUL can be improved.Wolfgang Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/3860Fri, 10 Aug 2018 02:00:35 +0200A new approach to the derivation of a single set of implicit state space equations from a fixed causality bond graph of a hybrid model
https://pub.h-brs.de/frontdoor/index/index/docId/3612
This paper proposes a novel approach to the generation of state equations from a bond graph (BG) of a mode switching linear time invariant model. Fast state transitions are modelled by ideal or non-ideal switches. Fixed causalities are assigned following the Standard Causality Assignment Procedure such that the number of storage elements in integral causality is maximised. A system of differential and algebraic equations (DAEs) is derived from the BG that holds for all system modes. It is distinguished between storage elements with mode independent causality and those that change causality due to switch state changes.W. Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/3612Sat, 21 Apr 2018 02:00:08 +0200Fault accommodation by inverse simulation through solving a differential algebraic system obtained from a bond graph
https://pub.h-brs.de/frontdoor/index/index/docId/3610
When an abrupt parametric fault occurs in a system, active fault tolerant control (FTC) aims at reconstructing the system input after the fault has been isolated and estimated so that the fault is compensated and the system output follows a desired trajectory despite the fault.W. Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/3610Sat, 21 Apr 2018 02:00:06 +0200Analytical Redundancy Relations from Bond Graphs of Hybrid System Models
https://pub.h-brs.de/frontdoor/index/index/docId/3608
—This paper picks up on one of the ways reported in the literature to represent hybrid models of engineering systems by bond graphs with static causalities. The representation of a switching device by means of a modulated transformer (MTF) controlled by a Boolean variable in conjunction with a resistor has been used so far to build a model for simulation. In this paper, it is shown that it can also constitute an approach to bond graph based quantitative fault detection and isolation in hybrid system models. Advantages are that Analytical Redundancy Relations (ARRs) do not need to be derived again after a switch state has changed. ARRs obtained from the bond graph are valid for all system modes. Furthermore, no adaption of the standard sequential causality assignment procedure (SCAP) with respect to fault detection and isolation (FDI) is needed.W. Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/3608Sat, 21 Apr 2018 02:00:04 +0200Bond Graph Methodology
https://pub.h-brs.de/frontdoor/index/index/docId/3605
Nowadays, engineering systems are becoming increasingly complex and, for design purposes, must be considered as multidisciplinary systems made up of components from different engineering disciplines. With regard to the systematic development and the analysis of models, interdisciplinary methodologies supported by software become more and more important. Bond graphs are a graphical description formalism particularly suited for multidisciplinary systems and used by modellers across the world.
Bond Graph Methodology gives a comprehensive, in-depth representation of the state of the art, including recent results gathered from research articles, dissertations and contributions by the author on a number of topics. The structured and rigorous presentation systematically covers model development, analysis of models, numerical computation of models and modern software that can be used for a bond graph approach. The book also includes a range of case studies illustrating various applications of the methodology and provides a glossary.
Bond Graph Methodology addresses fundamentals, as well as advanced topics, e.g., models of variable structure, bond graphs for sensitivity analysis and generation of equations for the study of robustness. The compilation and presentation of the material has been inspired by the author's extensive experience in research and teaching.
A useful text for advanced courses in modelling, simulation and control, Bond Graph Methodology can also be used for self-study. It has been designed to serve readers interested in the subject of bond graph modelling and those with expertise in related areas, as well as members of the worldwide community of bond graph modellers.Wolfgang Borutzkybookhttps://pub.h-brs.de/frontdoor/index/index/docId/3605Tue, 10 Apr 2018 02:00:02 +0200Fault indicators and unique mode-dependent state equations from a fixed-causality diagnostic bond graph of linear models with ideal switches
https://pub.h-brs.de/frontdoor/index/index/docId/3547
Analytical redundancy relations are fundamental in model-based fault detection and isolation. Their numerical evaluation yields a residual that may serve as a fault indicator. Considering switching linear time-invariant system models that use ideal switches, it is shown that analytical redundancy relations can be systematically deduced from a diagnostic bond graph with fixed causalities that hold for all modes of operation. Moreover, as to a faultless system, the presented bond graph–based approach enables to deduce a unique implicit state equation with coefficients that are functions of the discrete switch states. Devices or phenomena with fast state transitions, for example, electronic diodes and transistors, clutches, or hard mechanical stops are often represented by ideal switches which give rise to variable causalities. However, in the presented approach, fixed causalities are assigned only once to a diagnostic bond graph. That is, causal strokes at switch ports in the diagnostic bond graph reflect only the switch-state configuration in a specific system mode. The actual discrete switch states are implicitly taken into account by the discrete values of the switch moduli. The presented approach starts from a diagnostic bond graph with fixed causalities and from a partitioning of the bond graph junction structure and systematically deduces a set of equations that determines the wanted residuals. Elimination steps result in analytical redundancy relations in which the states of the storage elements and the outputs of the ideal switches are unknowns. For the later two unknowns, the approach produces an implicit differential algebraic equations system. For illustration of the general matrix-based approach, an electromechanical system and two small electronic circuits are considered. Their equations are directly derived from a diagnostic bond graph by following causal paths and are reformulated so that they conform with the matrix equations obtained by the formal approach based on a partitioning of the bond graph junction structure. For one of the three mode-switching examples, a fault scenario has been simulated.Wolfgang Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/3547Thu, 22 Feb 2018 02:00:11 +0100Generation of mode-dependent ARRs from a bond graph of a mode switching LTI model
https://pub.h-brs.de/frontdoor/index/index/docId/3406
In model-based fault detection and isolation (FDI), Analytical Redundancy Relations (ARRs) play a key role. Residuals as the result of their numerical evaluation serve as fault indicators. This paper proposes a novel approach to the generation of ARRs from a diagnostic bond graph (DBG) of a mode switching linear time invariant (LTI) model with ideal switches that hold for all modes of operation. Devices or phenomena with fast state transitions such as electronic diodes and transistors, clutches, or hard mechanical stops are modelled by ideal switches giving rise to variable causalities. Nevertheless, fixed causalities are assigned only once such that a DBG with storage elements in derivative causality and sensors in inverted causality is obtained. That is, the BG reflects the configuration for a specific system mode. From such a DBG with fixed causalities, a unique system of ARRs is derived from the DBG that holds for all system modes. The ARRs are implicitly given. In order to evaluate them, first, a set of algebraic or Differential Algebraic Equations (DAEs) must be solved. A formal matrix based approach that starts from the partitioning of a BG into fields is used for the general case. For illustration, two small system examples are considered. Their equations and the ARRs are directly derived from the DBG by following causal paths.W. Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/3406Fri, 17 Nov 2017 02:00:11 +0100Bond Graphs for Modelling, Control and Fault Diagnosis of Engineering Systems
https://pub.h-brs.de/frontdoor/index/index/docId/2822
This book presents theory and latest application work in Bond Graph methodology with a focus on:
Hybrid dynamical system models, Model-based fault diagnosis, model-based fault tolerant control, fault prognosis and also addresses Open thermodynamic systems with compressible fluid flow, and Distributed parameter models of mechanical subsystems.
In addition, the book covers various applications of current interest ranging from motorised wheelchairs, in-vivo surgery robots, walking machines to wind-turbines.The up-to-date presentation has been made possible by experts who are active members of the worldwide bond graph modelling community.
This book is the completely revised 2nd edition of the 2011 Springer compilation text titled Bond Graph Modelling of Engineering Systems – Theory, Applications and Software Support. It extends the presentation of theory and applications of graph methodology by new developments and latest research results.
Like the first edition, this book addresses readers in academia as well as practitioners in industry and invites experts in related fields to consider the potential and the state-of-the-art of bond graph modelling.bookhttps://pub.h-brs.de/frontdoor/index/index/docId/2822Fri, 06 Jan 2017 15:49:29 +0100Integrating Bond Graph-Based Fault Diagnosis and Fault Accommodation Through Inverse Simulation
https://pub.h-brs.de/frontdoor/index/index/docId/2820
This chapter addresses active fault tolerant control (FTC) of engineering systems represented by a mode switching linear time-invariant model. The presented approach integrates bond graph-based fault diagnosis and inverse simulation through solving a differential algebraic (DAE) system in order to reconstruct a system input after a severe fault has occurred.In this chapter, bond graph (BG) representations of hybrid models use switches. The standard causality assignment procedure (SCAP) is used to assign fixed causalities disregarding switch modes. Equations deduced from a BG are formulated in the declarative modelling language Modelica®; as a hybrid DAE system. Causality changes at switch ports are taken into account by the Modelica implementation of switches.As to fault detection, it is known that residuals of analytical redundancy relations (ARRs) deduced offline from a diagnostic bond graph (DBG) can serve as fault indicators. It is shown that they can also be used for estimating the magnitude of parametric faults in some simple cases.Moreover, ARR residuals can also be used in the reconstruction of a system input that compensates a severe fault. To that end, the forward model of the healthy system with nominal parameters derived from a BG is considered a DAE system of the inverse model. The output of the forward model of the healthy system in response to the initial known system input serving as the desired system output of the faulty system and the ARR residuals are inputs into the inverse model. Based on these inputs the DAE system then determines the input into the faulty system required for fault accommodation. As ARR residuals are used, fault isolation and estimation are not needed for input reconstruction. Alternatively, if isolation and estimation of the faulty parameter have been performed it can replace the nominal parameter in the inverse model and ARRs as inputs can be omitted.Computation of the forward model of the healthy system, the inverse model and the evaluation of the ARRs can be performed in parallel. Advantages of the presented approach based on ARRs and inverse simulation are that neither ARRs nor the reconstructed input are needed in closed analytical form. If constitutive equations of some elements do not permit an elimination of unknown variables, a DAE system deduced from a DBG has to be solved numerically in order to determine the ARR residuals used in the process of input reconstruction. The latter one also means to solve a DAE system numerically.W. Borutzkybookparthttps://pub.h-brs.de/frontdoor/index/index/docId/2820Fri, 06 Jan 2017 15:49:28 +0100Incremental Bond Graphs
https://pub.h-brs.de/frontdoor/index/index/docId/2814
Incremental true bond graphs are used for a matrix-based determination of first-order parameter sensitivities of transfer functions, of residuals of analytical redundancy relations, and of the transfer matrix of the inverse model of a linear multiple-input–multiple-output system given that the latter exists. Existing software can be used for this approach for the derivation of equations from a bond graph and from its associated incremental bond graph and for building the necessary matrices in symbolic form. Parameter sensitivities of transfer functions are obtained by multiplication of matrix entries. Symbolic differentiation of transfer functions is not needed. The approach is illustrated by means of hand derivation of results for small well-known examples.Wolfgang Borutzkybookparthttps://pub.h-brs.de/frontdoor/index/index/docId/2814Fri, 06 Jan 2017 15:49:18 +0100Bond Graph Modelling of Engineering Systems
https://pub.h-brs.de/frontdoor/index/index/docId/2813
Bond Graph Modelling of Engineering Systems: Theory, Applications and Software Support addresses readers to consider the potential and the state-of-the-art of bond graph modeling of engineering systems with respect to theory, applications and software support. Bond graph modelling is a physical modelling methodology based on first principles that is particularly suited for modelling multidisciplinary or mechatronic systems. This book covers theoretical issues and methodology topics that have been subject of ongoing research during past years, presents new promising applications such as the bond graph modeling of fuel cells and illustrates how bond graph modeling and simulation of mechatronic systems can be supported by software. This up-to-date comprehensive presentation of various topics has been made possible by the cooperation of a group of authors who are experts in various fields and share the “bond graph way of thinking.”bookhttps://pub.h-brs.de/frontdoor/index/index/docId/2813Fri, 06 Jan 2017 15:49:17 +0100Bond Graph Modelling and Simulation of Mechatronic Systems: An Introduction into the Methodology
https://pub.h-brs.de/frontdoor/index/index/docId/2757
This paper introduces into a graphical, computer aided modelling methodology that is particularly suited for the concurrent design of mechatronic systems, viz. of engineering systems with mechanical, electrical, hydraulic or pneumatic components including interactions of physical effects from various energy domains. Beyond the introduction, bond graph modelling of multibody systems, as an example of an advanced topic, is briefly addressed in order to demonstrate the potential of this powerful approach to modelling mechatronic systems. It is outlined how models of multibody systems including flexible bodies can be build in a systematic manner.Wolfgang Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/2757Tue, 15 Nov 2016 11:27:10 +0100Bond-Graph-based Fault Diagnosis in Switched Power Electronic Systems
https://pub.h-brs.de/frontdoor/index/index/docId/2736
Switched power electronic subsystems are widely used in various applications. A fault in one of their components may have a significant effect on the system’s load or may even cause a damage. Therefore, it is important to detect and isolate faults and to report true faults to a supervisory system in order to avoid malfunction of or damage to a load. If, in a model-based approach to fault detection and isolation of hybrid systems, switching devices are considered as ideal switches then some equations must be reformulated whenever some devices have switched. In this paper, a fixed causality bond graph representation of hybrid system models is used, i.e., computational causalities assigned according to the Standard Causality Assignment Procedure (SCAP) are independent of system modes of operation. The latter are taken into account by transformer moduli mi(t) ∈ {0, 1} ∀t ≥ 0 in a unique set of equations of motion. In a case study, this approach is used for fault diagnosis in a three-phase full-wave rectifier. Residuals of Analytical Redundancy Relations (ARRs) holding for all modes of operations and serving as fault indicators are computed in an offline simulation as part of a DAE system by using a bond graph model of the faulty system instead of the real one and by coupling it to a bond graph of the healthy system by means of residual sinks.Wolfgang Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/2736Mon, 24 Oct 2016 16:12:18 +0200Fault Indicators and Adaptive Thresholds from Hybrid System Models
https://pub.h-brs.de/frontdoor/index/index/docId/2735
Initially, incremental bond graphs were introduced to support frequency domain sensitivity analysis of linearised time-invariant models. Subsequent publications have shown that they can be used for other purposes as well such as the determination of parameter sensitivities of analytical redundancy relations (ARRs) in symbolic form.W. Borutzkyarticlehttps://pub.h-brs.de/frontdoor/index/index/docId/2735Mon, 24 Oct 2016 16:12:17 +0200Bond graph model-based fault accommodation in power electronic systems
https://pub.h-brs.de/frontdoor/index/index/docId/1741
The paper presents a bond graph model-based approach to active fault tolerant control (FTC) that makes use of residuals of analytical redundancy relations (ARRs). The latter ones are computed in order to decide whether a fault has occurred. Given a single fault hypothesis can be adopted, an advantage is that the time for isolating a fault among potential fault candidates that contribute to an ARR by means of parameter estimation may be saved and as long as ARR residuals are within their thresholds no input reconstruction at all is needed. It is shown that ARR residuals can be used for estimation of faults that can be isolated. ARR based input reconstruction is demonstrated by application to a buck-converter driven DC motor as a simple example of a switched power electronic system for which an averaged bond graph model is used. Scilab simulation runs confirm analytical results. If a required input cannot be determined analytically, it can be obtained by numerically solving a differential-algebraic equations (DAE) system.W. Borutzkyconferenceobjecthttps://pub.h-brs.de/frontdoor/index/index/docId/1741Wed, 09 Sep 2015 17:22:01 +0200Bond Graph Model-based Fault Diagnosis of Hybrid Systems
https://pub.h-brs.de/frontdoor/index/index/docId/1363
This book presents bond graph model-based fault detection with a focus on hybrid system models. The book addresses model design, simulation, control and model-based fault diagnosis of multidisciplinary engineering systems. The text beings with a brief survey of the state-of-the-art, then focuses on hybrid systems. The author then uses different bond graph approaches throughout the text and provides case studies.Wolfgang Borutzkybookhttps://pub.h-brs.de/frontdoor/index/index/docId/1363Thu, 02 Apr 2015 14:43:29 +0200Bond graph model-based system mode identification and mode-dependent fault thresholds for hybrid systems
https://pub.h-brs.de/frontdoor/index/index/docId/1016
Hybrid system models exploit the modelling abstraction that fast state transitions take place instantaneously so that they encompass discrete events and the continuous time behaviour for the while of a system mode. If a system is in a certain mode, e.g. two rigid bodies stick together, then residuals of analytical redundancy relations (ARRs) within certain small bounds indicate that the system is healthy. An unobserved mode change, however, invalidates the current model for the dynamic behaviour. As a result, ARR residuals may exceed current thresholds indicating faults in system components that have not happened. The paper shows that ARR residuals derived from a bond graph cannot only serve as fault indicators but may also be used for bond graph model-based system mode identification. ARR residuals are numerically computed in an off-line simulation by coupling a bond graph of the faulty system to a non-faulty system bond graph through residual sinks. In real-time simulation, the faulty system model is to be replaced by measurements from the real system. As parameter values are uncertain, it is important to determine adaptive ARR thresholds that, given uncertain parameters, allow to decide whether the dynamic behaviour in a current system mode is the one of the healthy system so that false alarms or overlooking of true faults can be avoided. The paper shows how incremental bond graphs can be used to determine adaptive mode-dependent ARR thresholds for switched linear time-invariant systems with uncertain parameters in order to support robust fault detection. Bond graph-based hybrid system mode identification as well as the determination of adaptive fault thresholds is illustrated by application to a power electronic system easy to survey. Some simulation results have been analytically validated.Wolfgang Borutzkyarticlehttps://pub.h-brs.de/frontdoor/index/index/docId/1016Thu, 02 Apr 2015 14:19:12 +0200Bond graph modelling and simulation of fault scenarios in switched power electronic systems
https://pub.h-brs.de/frontdoor/index/index/docId/895
A bond graph representation of switching devices known for a long time has been a modulated transformer with a modulus b(t)∈{0,1}∀t≥0 in conjunction with a resistor R:Ron accounting for the ON-resistance of a switch considered non-ideal. Besides other representations, this simple model has been used in bond graphs for simulation of the dynamic behaviour of hybrid systems. A previous article of the author has proposed to use the transformer–resistor pair in bond graphs for fault diagnosis in hybrid systems. Advantages are a unique bond graph for all system modes, the application of the unmodified standard Sequential Causality Assignment Procedure, fixed computational causalities and the derivation of analytical redundancy relations incorporating ‘Boolean’ transformer moduli so that they hold for all system modes. Switches temporarily connect and disconnect model parts. As a result, some independent storage elements may temporarily become dependent, so that the number of state variables is not time-invariant. This article addresses this problem in the context of modelling and simulation of fault scenarios in hybrid systems. In order to keep time-invariant preferred integral causality at storage ports, residual sinks previously introduced by the author are used. When two storage elements become dependent at a switching time instance ts, a residual sink is activated. It enforces that the outputs of two dependent storage elements become immediately equal by imposing the conjugate3 power variable of appropriate value on their inputs. The approach is illustrated by the bond graph modelling and simulation of some fault scenarios in a standard three-phase switched power inverter supplying power into an RL-load in a delta configuration. A well-developed approach to model-based fault detection and isolation is to evaluate the residual of analytical redundancy relations. In this article, analytical redundancy relation residuals have been computed numerically by coupling a bond graph of the faulty system to one of the non-faulty systems by means of residual sinks. The presented approach is not confined to power electronic systems but can be used for hybrid systems in other domains as well. In further work, the RL-load may be replaced by a bond graph model of an alternating current motor in order to study the effect of switch failures in the power inverter on to the dynamic behaviour of the motor.Wolfgang Borutzkyarticlehttps://pub.h-brs.de/frontdoor/index/index/docId/895Thu, 02 Apr 2015 14:18:07 +0200Bond-graph-based fault detection and isolation for hybrid system models
https://pub.h-brs.de/frontdoor/index/index/docId/896
For the case when the abstraction of instantaneous state transitions is adopted, this paper proposes to start fault detection and isolation in an engineering system from a single time-invariant causality bond graph representation of a hybrid model. To that end, the paper picks up on a long-known proposal to model switching devices by a transformer modulated by a Boolean variable and a resistor in fixed conductance causality accounting for its ON resistance. Bond graph representations of hybrid system models developed in this way have been used so far mainly for the purpose of simulation. The paper shows that they can well constitute an approach to the bond-graph-based quantitative fault detection and isolation of hybrid models. Advantages are that the standard sequential causality assignment procedure can be a used without modification. A single set of analytical redundancy relations valid for all physically feasible system modes can be (automatically) derived from the bond graph. Stiff model equations due to small values of the ON resistance in the switch model may be avoided by symbolic reformulation of equations and letting the ON resistance of some switches tend to zero, turning them into ideal switches.
First, for two examples considered in the literature, it is shown that the approach proposed in this paper can produce the same analytical redundancy relations as were obtained from a hybrid bond graph with controlled junctions and the use of a sequential causality assignment procedure especially for fault detection and isolation purpose. Moreover, the usefulness of the proposed approach is illustrated in two case studies by its application to standard switching circuits extensively used in power electronic systems and by simulation of some fault scenarios. The approach, however, is not confined to the fault detection and isolation of such systems. Analytically validated simulation results obtained by means of the program Scilab give confidence in the approach.Wolfgang Borutzkyarticlehttps://pub.h-brs.de/frontdoor/index/index/docId/896Thu, 02 Apr 2015 14:18:07 +0200Comparison of different formulations of 2D beam elements based on Bond Graph technique
https://pub.h-brs.de/frontdoor/index/index/docId/611
Bond Graphs are well suited for modelling multibody systems. In this paper modelling of planar flexible beams undergoing large overall motions are studied based on finite element (FE) technique. Two well-known approaches are used - the co-rotational (CR) and absolute nodal coordinate (ANC) formulation. Two ANC formulations are analyzed - one in which elastic forces is described using classical beam theory in a local coordinate frame, and another based on a global continuum mechanics approach. Starting from these classical formulations velocity formulations are developed and used to develop Bond Graph FE components. The effect of gravity has been considered as well. These components can be put in libraries and used for systematic Bond Graph flexible body model development. It is shown that Bond Graph technique is capable of dealing with different flexible body formulations and can be used as a general approach in parallel to other modelling approaches. Models are developed and simulations are performed using the object oriented environment of BondSim. Owing to the object oriented approach, transformation from one to the other model is relatively simply. The results are illustrated by suitable examples and they confirm accuracy of the developed models. It was shown that the CR approach offers much better performance than the both ANC formulations.Majda Cohodar; Wolfgang Borutzky; Vjekoslav Damicarticlehttps://pub.h-brs.de/frontdoor/index/index/docId/611Thu, 02 Apr 2015 13:57:15 +0200Bond graph model-based fault detection using residual sinks
https://pub.h-brs.de/frontdoor/index/index/docId/609
In this paper, residual sinks are used in bond graph model-based quantitative fault detection for the coupling of a model of a faultless process engineering system to a bond graph model of the faulty system. By this way, integral causality can be used as the preferred computational causality in both models. There is no need for numerical differentiation. Furthermore, unknown variables do not need to be eliminated from power continuity equations in order to obtain analytical redundancy relations (ARRs) in symbolic form. Residuals indicating faults are computed numerically as components of a descriptor vector of a differential algebraic equation system derived from the coupled bond graphs. The presented bond graph approach especially aims at models with non-linearities that make it cumbersome or even impossible to derive ARRs from model equations by elimination of unknown variables. For illustration, the approach is applied to a non-controlled as well as to a controlled hydraulic two-tank system. Finally, it is shown that not only the numerical computation of residuals but also the simultaneous numerical computation of their sensitivities with respect to a parameter can be supported by bond graph modelling.Wolfgang Borutzkyarticlehttps://pub.h-brs.de/frontdoor/index/index/docId/609Thu, 02 Apr 2015 13:57:14 +0200Bond graph modelling and simulation of multidisciplinary systems - An introduction
https://pub.h-brs.de/frontdoor/index/index/docId/610
This paper introduces a graphical, computer aided modelling methodology that is particularly suited for the concurrent design of multidisciplinary systems, viz. of engineering systems with mechanical, electrical, hydraulic or pneumatic components, including interactions of physical effects from various energy domains. Following the introduction, bond graph modelling of multibody systems, as an example of an advanced topic, is briefly addressed in order to demonstrate the potential of this powerful approach to modelling multidisciplinary systems. It is shown how models of multibody systems including flexible bodies can be built in a systematic manner.Wolfgang Borutzkyarticlehttps://pub.h-brs.de/frontdoor/index/index/docId/610Thu, 02 Apr 2015 13:57:14 +0200Modelling methodologies and simulation. Key technologies in academia and industry. 20th European Conference on Modelling and Simulation ECMS 2006, May 28th - 31st, 2006, Bonn, Sankt Augustin, Germany
https://pub.h-brs.de/frontdoor/index/index/docId/375
The 2006 European Conference on Modelling and Simulation (ECMS 2006) is a particularly significant event. Organised by the European Council on Modelling and Simulation (ECMS) and co-sponsored by the Society for Modelling and Simulation International (SCSI), it is the 20th conference in its well established series. Bonn-Rhein-Sieg University of Applied Sciences is pleased to host this conference one year after the 10th anniversary of the University’s foundation.conferencehttps://pub.h-brs.de/frontdoor/index/index/docId/375Thu, 02 Apr 2015 13:51:34 +0200Bond graph modelling
https://pub.h-brs.de/frontdoor/index/index/docId/374
Wolfgang Borutzky; Peter Gawthroparticlehttps://pub.h-brs.de/frontdoor/index/index/docId/374Thu, 02 Apr 2015 13:51:34 +0200