Bond Graph

The application of model-based diagnosis schemes to real systems introduces many significant challenges, such as building accurate system models for heterogeneous systems with complex behaviors, dealing with noisy measurements and disturbances, and producing valuable results in a timely manner with limited information and computational resources. The Advanced Diagnostics and Prognostics Testbed (ADAPT), which was deployed at the NASA Ames Research Center, is a representative spacecraft electrical ...

... integrated into the supervision system. Despite technical progress in the field of computer science, supervisory tools for human operators have not evolved since the first digital control system were developed. One can essentially find ...

This paper deal with methods to get equations from a Bond Graph (BG) Model. Mixed Techniques to get equations from both Linear Graph (LG) and BG Models are employed. A criterion that allows to identify the tree and the co-tree in a BG model is reviewed. Also, the advantages of causal paths inherent to BG are exploited. The equivalence between a LG model and its respective BG model is also used. A procedure to get equations from a given BG model is proposed. To show the functionality of the proposed methods, examples with diodes are solved.

We present in this paper the coupling of both thermal and hydraulic energy required in the boiler, the analytical and graphical modelling present a natural circulation boiler which occurs in a homogeneous two-phase mixture between water and steam. The overall system consists of a circuit of water, a saver and a higher ball. The bond graph tool allowed us to transform the analytical model to the graphical model. Specific bond-graph simulation software SYMBOLS helped us to validate and submit the results given by the technical specifications.

Functional modelling is an analytical approach to design problems that is widely taught in certain academic communities but not often used by practitioners. This approach can be applied in multiple ways to formalize the understanding of the systems, to support the synthesis of the design in the development of a new product or to support the analysis and improvement of existing systems incrementally. The type of usage depends on the objectives that are targeted. The objectives can be categorized into two key groups: discovering a totally new solution, or improving an existing one. This article proposes to use the functional modelling approach to achieve three goals; to support the representation of physics-based reasoning, to use this physics-based reasoning to assess design options, and finally to support innovative ideation. The exemplification of the function-based approach is presented via a case study of a glue gun proposed for this special issue. A reverse engineering approach is applied, and the authors seek an incremental improvement of the solution. Since the physics-based reasoning model presented in this article is heavily dependent on the quality of the functional model, the authors propose a general approach to limit the interpretability of the functional representations by mapping the functional vocabulary with elementary structural blocks derived from bond graph theory. The physics-based reasoning approach is supported by a mathematical framework which is summarized in the article. The physics-based reasoning model is used for discovering the limitations of solutions in the form of internal contradictions and guiding the design ideation effort.

A bond graph model of entire cardiovascular system is developed in this paper. Although relying on the concepts of previously developed lumped-parameter models, this new model benefits from some advantages of general system theory which allows the modeler to include as many details as necessary. Specifically, inclusion of pace making mechanism has become much easier. The pace making mechanism is not, however, included in this stage of model development. Modular sources of effor are, instead, predicted in the model to genrate synthetic signals close to what occurs in reality. The model is simulated and results of simulation are compared with widely available data of normal cardiovascular system's pressure-flow performance. It has been shown that they are of a good agreement and the model could successfully simuulate performance of the human cardiovascular system.

Nowadays the use of complex models has increased the requirements of the simulation tools and techniques for working and analyzing with different domains at the same time. This work focuses on the study of the Scanner servocontrols of a fighter aircraft. The model has the feature of integrating various physical domains into the same system (electrical, mechanical and system control environments) with different dimensions in each domain. The technique used is the Bond Graph (BG), which is typically used in fields where different physical domains coexist, just as in the case we are dealing with, where such domains are fundamental. At the beginning of the study, the different coordinate references are introduced and the physical subsystems are also described. After this the different subsystems are presented in the form of BG submodels one by one and the global Multibond Graph (MBG) model is displayed. Lastly, an example of simulation is shown and some important conclusions are reached.

This paper studies constitutive relations of physical processes with time-scale abstractions by giving a process algebraic foundation for hybrid bond graph models. For a number of standard physical elements, it is shown how discontinuous constitutive relations that describe the behavior of hybrid bond graph mod- els can be derived from existing continuous constitu- tive relations. These discontinuous and continuous descriptions are then combined using the hybrid pro- cess algebra HyPA, which may be used to reason sym- bolically about both the continuous behavior, and the mode switching that results from the time-scale ab- straction.

The hybrid bond graph (HBG) paradigm is a uniform, multi-domain physics-based modeling language. It incorpo-rates controlled and autonomous mode changes as idealized switching functions that enable the reconfiguration of energy flow paths to model hybrid physical systems. Building ac-curate and computationally efficient simulation mechanisms from HBG models is a challenging task, especially when there is no a priori knowledge of the subset of system modes that will be active during the simulation. In this work, we present an approach that exploits the inherent causal structure in HBG models to derive efficient hybrid simulation models as recon-figurable block diagram structures. We present a MATLAB Simulink implementation of our approach and demonstrate its effectiveness using an electrical circuit example.

Abstract. The proliferation of safety-critical embedded systems has created great demands for online fault diagnosis and fault-adaptive control techniques. A number of methodologies have been proposed, but the implementation of on-line schemes that integrate the fault detection, isolation, identification, and fault accommodation or reconfiguration tasks remains challenging. We present a tool chain using a Model Integrated Computing (MIC) approach to develop Fault adaptive control systems. The domain specific features support physical ...

This paper presents an efficient simulation scheme for hybrid systems modeled as hybrid bond graphs (HBGs). Considerable computational savings are achieved when mode changes occur during simulation by identifying persistent causal assignments to bonds, and, consequently, fixed causal structures at HBG junctions when the simulation model is derived. Persistent causal assignments also reduce the possible computational structures across all mode changes, and this leads to an overall reduction in the ...

Fault diagnosis is crucial for ensuring the safe operation of complex engineering systems. Although discrete-event diagnosis methods are used extensively, they do not easily apply to parametric fault isolation in systems with complex continuous dynamics. This paper presents a novel discrete-event system diagnosis approach for abrupt parametric faults in continuous systems that is based on a qualitative abstraction of measurement deviations from the nominal behavior. Our approach systematically generates a diagnosis model from bond graphs that is used to analyze system diagnosability and derive the discrete-event diagnoser. The proposed approach is applied to an electrical power system diagnostic testbed.

A design tool, currently under development at Lancaster University, is described. This is a software package aimed at the conceptual stage of mechatronic product design and builds on Michael French's earlier work on systematic design. The software runs successfully in prototype form with a limited set of components, the output being in the form of a bond-graph-like connectivity diagram, component

Modeling and analyzing dynamic system behavior is the key to successful diagnosis of complex continuous engineering systems. The bond graph modeling language provides a systematic framework for compositional modeling of dynamic physical systems from physical principles. A description of the important properties of this modeling paradigm as they pertain to diagnosis is presented. This modeling technique facilitates the explication of causal interactions and temporal relations between parameters by drawing upon ...

The osmotic responses of isolated human islets were evaluated using a perfusion cryomicroscope device. Individual islet volumes were measured following equilibration with a series of solutions of graded solute concentration. The osmotically inactive volume for human islets was determined to be 25% from a Boyle-van't Hoff plot of these data. A network thermodynamic model was developed via the bond graph method to describe the transport of water and cryoprotective agent in pancreatic islets. The model was curve fit to transient volumetric data for the response of islets to a stepwise exposure to 1 Me2SO at temperatures of 24.0, 3.0, or -3.5 degrees C. Standard membrane transport parameters (Lp, omega, sigma) and interstitial diffusion transport properties (kappa w, kappa p) were calculated from the fitting procedure. The temperature coefficients for membrane transport properties were expressed in terms of activation energies for water (ELp) and Me2SO (E omega). Osmotic challenge experiments conducted with fresh and cryopreserved human islets indicate that frozen/thawed islets exhibit a a slight increase in transport properties.

Port-based modeling of dynamic systems is the topic of the first chapter of the book that will be one of the main results of the European project ‘Geometric Network Modeling and Control of Complex Physical Systems’ (GEOPLEX, IST-2001-34166, Key Action, Action line KAIV: Essential Technologies and Infrastructures, Action Line IV.4.2.1). In this chapter the reader is introduced to the concepts needed for port-based modeling, design and reasoning in order to prepare and motivate for the geometrical formulations of the port-based approach in the remainder of the book. After some general remarks about the modeling process, this is done from a historic perspective, which immediately relates the port concept to its original notation, the bond graph. Bond graph notation is discussed as well as the concept of causality, which allows one to combine physical and computational structure into one notation and provides important feedback on modeling decisions in the tradeoff between conceptual and computational complexity. Several simple examples of its use are presented and the details of many bond graph related transformations and analysis techniques are discussed in a series of appendices: conversion of an IPM into a bond graph, conversion of causal bond graphs into block diagrams, generation of a set of mixed algebraic and differential equations, direct linear analysis, impedance analysis using bond graphs, nonlinear mechanical systems (mechanisms), homogeneous functions and Euler’s theorem, homogeneous energy functions, Legendre transformations, co-energy functions, relations for co-energy functions, Legendre transforms in simple thermodynamics, Legendre transforms and causality, Maxwell reciprocity of constitutive relations. As it is impossible to fit all this material in this short contribution, two examples of the content are given that are more or less self-supporting/independent, viz. the Glossary, which provides a kind of bird’s eye view of the material, and the first Appendix that discusses basic model transformations. However, first the most important basis for the work on port-Hamiltonian systems, viz. the generalization of the bond graph representation into generalized bond graphs, is discussed shortly first.

Page 1. Bond Graph Modeling of Inter-Actuator Interactions in a Multi-Cylinder Hydraulic System Mutuku Muvengei and John Kihiu, Abstract—In this paper, a bond graph dynamic model for a valve-controlled hydraulic cylinder has been developed. ...

This paper presents an approach for using two-port circuit synthesis methods as a basis for designing actuator subsystems. The development of this methodology is generally motivated by problems in retrofit design, where technology reinsertion is required to replace legacy systems, or for early stage design in new mechatronic systems. The particular problem of electric ship control surface actuation is used as an example application. A procedure that integrates two-port network synthesis methods with a model-basis conveyed using bond graphs is presented and applied to the problem of synthesizing a candidate actuation system for a submarine control surface. Studying the control surface actuator problem shows that a synthesis method is capable of providing insight into balancing passive compensation with actuation (active elements). The ability to partition active and passive system elements suggests promise in developing a means for integrating passive energy storage with actuation subsystems.