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This article highlights the dynamic analysis of a proportional valve controlled hydrostatic drive. Such drives are used widely in construction and mining applications. In the drive considered for the analysis, the speed of a bent-axis hydro-motor is controlled by varying flow supplied through a proportional direction controlled valve. A non-linear mathematical model using bond graph simulation technique is developed, where detailed model of the drive system including its loading arrangement is incorporated. From the test results of the pressure-flow characteristics of the valves, its port resistances are identified. Using them and taking into account various losses of the hydro-motor, the drive model is validated through experiments. The verified model is used to study the effects of the perturbations of some critical parameters on the transient responses of the hydrostatic drive through simulation. The proposed model may be useful for initial design of such drive and the development of control systems where these drives are used as actuators. [ABSTRACT FROM AUTHOR]

The study presents power flow modelling for dynamic systems featuring chain structures. For this purpose, the Bond Graph method is particularly suitable. This tool describes engineering systems in different fields via domain-independent graphical representation using general dynamic modelling for any physical system. Even repetitive constructions called chains can be modelled. This paper aims for power flow based dynamical models of serial type chain structures. Further graphical systematization identifies four basic scalar segments which again correlate with four general vectorial total model structures. Examples and general algorithms, to obtain the scalar segment model and the vectorial overall model, support the proposed modeling. The main vectorial modelling element is identified as a relative coordinate transformation. The approach includes usage for open and closed chains plus rings of ring structures. It aims at universal usage independent of serial chain structure type, application domain or software tool. Moreover, it can be used beneficially in various non-physical fields. [ABSTRACT FROM AUTHOR]

This paper deals with the fault detection, isolation (FDI) and reconfiguration of the locomotion of a bipedal-legged robot. Initially, the planar model of the legged robot in the vertical plane is developed using a bond graph (BG) approach. Then, the planar BG model of the legged robot is extended to the three-dimensional legged robot. Two individual motors are used to actuate the prismatic leg of the robot for locomotion. The BG simulation provides results for straight walking based on an oscillating cylinder mechanism and the turning motion of the legged robot are discussed. The prototype model of the legged robot is also developed and experimentation is done for straight and inclined plane applications. Finally, an FDI technique for the three-dimensional model of a legged robot is developed for the generation of fault indicators (i.e., analytical redundancy relations; ARRs) in the presence of system failure. The ARRs are derived from the BG model of the legged robot during the occurrences of the fault. The experimental results are validated with the simulation results for FDI and reconfiguration when the robot manoeuvres in a U-shaped path. The real-time fault diagnosis and reconfiguration for locomotion of the legged robot is possible with this FDI approach. [ABSTRACT FROM AUTHOR]

Main advantage of redundant space manipulator is that it can be configured differently by actuating various joints. Space manipulators are designed to be deployed in harsh surroundings, which in turn would increase the possibility of manipulator failure. Thus, the enhancement of the capabilities of the robots and the failures thereafter are a major concern. This article presents three aspects of hyper-redundant space robot. First, the control strategies based on minimum power criterion with all healthy joints are proposed. Second, hyper-redundancy is put upon to reconfigure the space robot with the failure of locked joints. Third, the optimization of workplace trajectory of the manipulator is obtained by genetic algorithm and a minimum power criterion has been adopted in all three cases. The bond-graph technique is employed for robot modeling with the use of SYMBOLS Shakti software, which generates system equations in C++ code. This code is subsequently converted into a MATLAB program. The result obtained through simulation shows that 37% of the total power consumption was reduced by the actuators through an optimization approach. [ABSTRACT FROM AUTHOR]

In this work, a bi-directional automatic movement unit for planar welding is indigenously developed in order to obtain weld with uniform bead width along a desired path. System modeling of the fabricated setup was carried out using bond graph to predict different system behaviors as well as predict the weld bead geometric path. The effectiveness of the automatic planar movement setup was validated depositing weld bead at different speeds on low carbon steel workpiece. Weld beads were deposited at equal and unequal speeds of each axis with independent movement as well as simultaneous movement of the axes. The bead width variations, geometric path are measured and validated along with the microstructural observations of the weld bead cross-sections. The setup was found to deposit weld beads successfully following the intended weld path and perform planar welding closely resembling with the predicted weld path. [ABSTRACT FROM AUTHOR]

Following the technological advances in recent decades, advanced electronic systems linked to the gas turbine industry are increasingly considered by the designers of this field. For this purpose, new airborne systems in conjunction with jet engines are developed, which are incorporated in many challenging design problems such as control law and configuration design. Thus, a comprehensive modeling structure is needed that can bolster the integrity of the system development such as the bond graph approach, which is known as an efficient method for modeling complicated mechatronic systems. In this paper, modeling and simulation of a jet engine dynamic performance and aircraft motion are achieved based on the bond graph approach. At first, the electric starter bond graph model is constructed and physical relationships governing each engine component are obtained. In the aftermath, the modulated energy fields are developed for the jet engine components. Subsequently, the bond graph model of the engine is numerically simulated and experimentally tested and verified for a small jet engine. Finally, bond graph modeling and simulation of integrated engine and aircraft system is presented. The test results indicate the acceptable accuracy of the modeling approach which can be applied for innovative diagnosis and control systems design. [ABSTRACT FROM AUTHOR]

Highlights • A modularization method for planetary gear trains system modeling is proposed to standardize the transmission gearbox modeling procedure. • Transmission gearbox system is decomposed into three kinds of subsystem with bond graph causality definition: PGT (planetary gear trains), clutch and inertial rotator. • Two kinds of planetary gear trains dynamic subsystem is proposed: elastic contact gear model and elastic planet model. • A component tables listing procedure is introduced and demonstrated to convert the gearbox transmission schematic into subsystem connection diagram. Abstract Dynamic system modeling is prerequisite in research of automatic transmissions (AT) controls and failure diagnostic. New generation of AT includes a large number of Planetary Gear Trains which leads to increasing difficulty for dynamic system modeling. A Modularization method for Planetary Gear Trains System Modeling is proposed to standardize the modeling procedure. Transmission gearbox system is decomposed into three kinds of subsystem with Bond graph Causality Definition: PGT (Planetary Gear Trains), Clutch and Inertial Rotator. A component tables listing procedure is introduced to convert the gearbox transmission schematic into subsystem connection diagram. Subsystems can be assembled by this diagram and the gearbox dynamic model can be achieved. This research presents a standard modeling process which can be used to model complicate vehicle planetary gearbox, and can be used on study about automatic transmission control and failure diagnostic. [ABSTRACT FROM AUTHOR]

Based on non-linear systems described by multibond graphs, a procedure designed to present symbolic linearization of these multibond graphs, is presented in this paper. Firstly, a junction structure of a multibond graph with multiport gyrators that represent Eulerian junction structures is proposed. In addition, non-linear multiport resistors are considered. By knowing the non-linear causal paths and loops of the non-linear multibond graph, the linearization is obtained by two steps: (1) The original multibond graph on the nominal operating point is evaluated; (2) New and additional paths based on the non-linear causal paths and loops are included. The state space representation of the linearized multibond graph using the corresponding junction structure is presented. An advantage of this methodology is its ability to allow the user to define a nominal operating point in which the linearization will be carried out. In order to apply the proposed methodology, two physical systems are modelled and linearized by multibond graphs: a synchronous generator and a two degrees of freedom PUMA. Simulation results of these non-linear and linearized systems are shown. [ABSTRACT FROM AUTHOR]

Abstract A rotor dynamic system requires high power/torque to accelerate through its resonance conditions or critical speeds to operate at a super-critical speed. Most practical drive sources are non-ideal in nature, i.e. they can only provide a limited amount of power to the rotor system. Thus, if there is insufficient power to overcome a resonance then the rotor speed may get arrested at that resonance or take a long time to escape from the resonance; and thereby damage the system. For the present analysis, a Direct Current (DC) motor is considered as the non-ideal prime mover for a rigid rotor shaft with unbalanced disk which is supported by flexible anisotropic supports/bearings. Due to the anisotropy in the supports, both forward and backward whirl motions of the rotor get excited. This causes a multi-Sommerfeld effect where two non-linear jump phenomena are manifested at the first forward and backward critical speeds during rotor coast up and coast down. When the two critical speeds are close to each other, a complex speed capture and jump phenomena occurs. Accordingly, the transitions through both resonance conditions are examined. At first, the analytical solutions are obtained under steady state assumption and then transient simulations are performed with the help of a bond graph (BG) model. Highlights • Sommerfeld effect at forward and backward critical speeds in a rotor is studied. • Steady-state analysis is performed with input-output averaged energy balance. • Interference of two Sommerfeld effects at close critical speeds is observed. • Simulations are performed to find critical power input to escape double resonance. [ABSTRACT FROM AUTHOR]

High power density, wide speed range and overall good efficiency are the primary demands of a modern hydrostatic transmission used in heavy earth moving machineries (HEMM). Conventional hydrostatic drive consisting of a displacement controlled pump and motor is sometimes inadequate to meet such requirements. Therefore, there is a need for examining alternative concepts of drives for HEMM. This article studies one of such alternatives where the motors are connected in parallel. In another solution, one motor is permanently connected to the load and the other one is connected to the load through gear unit. The latter is used during high-torque, low-speed demand of the vehicle. The challenge with the concept is the reconnection procedure, where the disconnected motor is accelerated, synchronized to the main motor output speed and finally locked to the output shaft, all in fraction of a second. Two different principles for the reconnection are proposed: to control the connection using a disc-type clutch, or to control it from the fluid power system. The performances of the two systems are compared through bond graph model simulation with respect to pressure, speed and efficiency for the varying load demand usually catered by a HEMM. [ABSTRACT FROM AUTHOR]

Generally, industrial manipulators have parallel architecture but these are not generally used because of small workspace as compared to serial manipulators. The drawbacks of serial manipulators are their low accuracy and less load carrying capacity. Therefore, hybrid manipulators are considered to be useful because they are combination of serial and parallel manipulators. In this paper, a three-dimensional hybrid manipulator with two parallel manipulators serially connected to each other is proposed. The forward and inverse dynamics of the system is modelled with the help of bond graph. Thumb and index finger of a human right hand are considered as hybrid manipulators in this paper. The objective of present work is to track the trajectory by thumb in three-dimensional space while drawing an arc on a white board with the help of a marker pen. At the end, the simulation results and conclusions are given to prove that the response follows the command with negligible error. Hence, this type of hybrid manipulator is suitable to be used in multi-fingered robotic grippers, pick and place operations, moving things etc. [ABSTRACT FROM AUTHOR]

This work describes design and implementation of a navigation and obstacle avoidance controller using fuzzy logic for four-wheel mobile robot. The main contribution of this paper can be summarized in the fact that single fuzzy logic controller can be used for navigation as well as obstacle avoidance (static, dynamic and both) for dynamic model of four-wheel mobile robot. The bond graph is used to develop the dynamic model of mobile robot and then it is converted into SIMULINK block by using 'S-function' directly from SYMBOLS Shakti bond graph software library. The four-wheel mobile robot used in this work is equipped with DC motors, three ultrasonic sensors to measure the distance from the obstacles and optical encoders to provide the current position and speed. The three input membership functions (distance from target, angle and distance from obstacles) and two output membership functions (left wheel voltage and right wheel voltage) are considered in fuzzy logic controller. One hundred and sixty-two sets of rules are considered for motion control of the mobile robot. The different case studies are considered and are simulated using MATLAB-SIMULINK software platform to evaluate the performance of the controller. Simulation results show the performances of the navigation and obstacle avoidance fuzzy controller in terms of minimum travelled path for various cases. [ABSTRACT FROM AUTHOR]

Nowadays, rail transport is a very important part of the transportation network for any countries. The demand for high operational speed makes hunting a very common instability problem in railway vehicles. Hunting leads to discomfort and causes physical damage to carriage components, such as wheels, rails, etc. The causes of instability and derailment should be identified and eliminated at the designing stage of a train to ensure its safe operation. In most of the earlier studies on hunting behaviour, a simplified model with a lower degree of freedom were considered, which resulted in incorrect results in some instances. In this study, a complete bond graph model of a railway vehicle with 31 degrees of freedom is presented to determine the response of a high-speed railway vehicle. For this purpose, two wheel–rail contacts grounded on a flange contact and Kalker's linear creep theory are implemented. The model is simulated to observe the effects of suspension elements on the vehicle's critical hunting velocity. It is observed that the critical hunting speed is extremely sensitive to the primary longitudinal and lateral springs. Other primary and secondary springs and dampers also affect the critical speed to some extent. However, the critical hunting velocity is insensitive to vertical suspension elements for both the primary and secondary suspensions. Also, the critical speed is found to be inversely related to the conicity of the wheel. [ABSTRACT FROM AUTHOR]

This research work is focused on the construction of an accurate longwave/shortwave radiation model on a tunnel greenhouse pseudo-bond graph model, widely used in Tunisia. This model includes sun position, useful incoming solar radiation model, sky longwave radiation model, inside longwave and shortwave radiation model. The key idea is to use bond graphs allowing a lumped modelling approach which is suitable for control applications. Furthermore, an evaluation of some longwave radiative model components was made, noting that these components are particularly sensitive regarding to the thermal behaviour of the model. Experimental tunnel greenhouse data are used as validation elements for the present model with globally good results. A comparative study was also performed between the present model and a previous bond graph model containing a simplistic radiative model. Practical simulation results show a clear improvement compared with the previous model. [ABSTRACT FROM AUTHOR]

The modelling in bond graph of a Skystream wind turbine composed by the blades, a permanent magnet synchronous generator (PMSG), three-phase rectifier, Boost converter and an inverter which is classified as a small-scale system is presented. Bond graphs permit to model systems formed by different energy domains. The Skystream turbine is a good case study to show that the bond graph model is presented in a unified representation approach. The electric power generation system based on this turbine is three-phase, the use of multibond graphs to model the PMSG, three-phase rectifier and inverter are proposed. However, the blades and Boost converter are modelled by single bond graphs. The mathematical representation of a section of a blade and the PMSG are obtained. In order to validate the simulation results obtained by bond graph models, an experimental study of the Skystream is compared with the complete simulation of the turbine. The motivation to develop these models in a bond graph approach is to design and build a low-cost wind turbine similar to the Skystream. Thus, the main contributions of this paper are: a bond graph model of the Skystream wind turbine, the PMSG, rectifier and inverter is modelled by multibond graphs. [ABSTRACT FROM AUTHOR]

The direct determination of the steady state response for linear time invariant (LTI) systems modeled by multibond graphs is presented. Firstly, a multiport junction structure of a multibond graph in an integral causality assignment (MBGI) to get the state space of the system is introduced. By assigning a derivative causality to the multiport storage elements, the multibond graph in a derivative causality (MBGD) is proposed. Based on this MBGD, a theorem to obtain the steady state response is presented. Two case studies to get the steady state of the state variables are applied. Both cases are modeled by multibond graphs, and the symbolic determination of the steady state is obtained. The simulation results using the 20-SIM software are numerically verified.

This paper presents a versatile approach to the synthesis and design of a bond graph model and a Kalman filter observer for an industrial back-support exoskeleton. Actually, the main purpose of developing a bond graph model is to investigate and understand better the system dynamics. On the other hand, the design of the Kalman observer always should be based on a model providing an adequate description of the system dynamics; however, when back-support exoskeletons are considered, the synthesis of a state observer becomes very challenging, since only nonlinear models may be adopted to reproduce the system dynamic response with adequate accuracy. The dynamic modeling of the exoskeleton robotic platform, used in this work, comprises an electrical brushless DC motor, gearbox transmission, torque sensor and human trunk (biomechanical model). On this basis, a block diagram model of the dynamic system is presented and an experimental test has been carried out for identifying the system parameters accordingly. Both the block diagram and bond graph dynamic models are simulated via MATLAB and 20-sim software (bond graph simulation software) respectively. Furthermore, the possibility of employing the Kalman filter observer together with a suitable linear model is investigated. Subsequently, the performance of the proposed Kalman observer is evaluated in a lifting task scenario with the use of a linear quadratic regulator (LQR) controller with double integral action. Finally, the most important simulation results are presented and discussed.

Proton Exchange Membrane (PEM) water electrolysis system is one of the promising technologies to produce green hydrogen from renewable energy sources (wind and solar). However, performance and dynamic analysis of PEM water electrolysis systems are challenging due to the intermittent nature of such sources and involved multi-physical behaviour of the components and subsystems. This study proposes a generic dynamical model of the PEM electrolysis system represented in a modular fashion using Bond Graph (BG) as a unified modelling approach. Causal and functional properties of the BG facilitate the formal PEM electrolyser model to adapt and to fit the different configurations of the electrolyser ranging from laboratory scale to industrial scale. The system-specific key parameter values are identified optimally for a laboratory-scale electrolyser system running on a multi-source energy platform using experimental data. The mean absolute percentage error between simulation and experimental data is found to be less than 5%. The performance characteristic curves of the electrolyser are predicted at different operating temperatures using the identified key parameters. The predicted performance is in good agreement with the expected behaviour of the electrolyser found in the literature. The model also estimates the different energy losses and the real-time efficiency of the system under dynamic inputs. With these capabilities, the developed model provides an economical mean for design, control, and diagnosis development of such systems.

This paper concentrates on the power flow and transmission efficiency of a two-side motors driving transmission system used in tracked vehicle. Based on the theoretical analysis of tracked vehicle's steering process, the theory of bond graph was applied in the efficiency analyses due to the properties of energy conservation and power fluxion. A bond graph model of dual planetary platoon power coupling mechanism was established. The kinematic and the dynamic characteristics of all components and the constraints between components were obtained with the constraint conditions of turning radius and speed. According to the criterion of power flow, the power flows of the transmission system were got under six different driving conditions. Based on the power flows, the transmission efficiency was obtained by the calculation method of planetary gear train's meshing efficiency, which was proposed by this paper. The results show that by using the bond graph theory, we can get all the possible power flows of the transmission system and its corresponding transmission efficiency. This method is more systematic and universal than the traditional methods, especially suitable for complex multi-input and multi-output gear transmission system.

We propose a detailed CellML model of the human cerebral circulation that runs faster than real time on a desktop computer and is designed for use in clinical settings when the speed of response is important. A lumped parameter mathematical model, which is based on a one-dimensional formulation of the flow of an incompressible fluid in distensible vessels, is constructed using a bond graph formulation to ensure mass conservation and energy conservation. The model includes arterial vessels with geometric and anatomical data based on the ADAN circulation model. The peripheral beds are represented by lumped parameter compartments. We compare the hemodynamics predicted by the bond graph formulation of the cerebral circulation with that given by a classical one-dimensional Navier-Stokes model working on top of the whole-body ADAN model. Outputs from the bond graph model, including the pressure and flow signatures and blood volumes, are compared with physiological data.