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Legged robots have capability of traversing on any type of terrain with much ease and stability compared to wheeled robots. The legged robots do not have continuous contact with ground, and thus, it is easy to avoid obstacles. The objective of this paper is to model and simulate a walking mechanism for quadruple model that is stable and is able to implement different types of gaits. The stability control of legged robot is of utmost importance as compared to wheeled robot as contact from ground is discontinuous due to lifting and placing of leg. The positing of legs relative to body of robot considerably affects the stability, and also the sequence and timing in which legs are moved and placed play important role in energy efficiency. Here, model of quadruped robot with four legs has been developed using bond graph technique. Results from simulation are discussed. The comparison of different gaits is made for energy efficiency. [ABSTRACT FROM AUTHOR]

In order to understand and to predict cable effects on structures, three-dimensional numerical models for a stranded cable and a beam–cable system consisting of a cantilever beam and two connected cables are presented. The multibond graph formalism is used to model the coupled cable–beam system, with the cable and beam substructures using 3D rigid lumped segments. The stranded cables are modelled considering the bending stiffness, tension and sag due to self-weight. The generally applicable cable-structure modelling approach in this paper is applied to vibration-based non-destructive evaluation of electrical utility poles, where simulated modal testing of the pole-conductor system is required. Experimental parametrization of a stranded cable is carried out using specially designed apparatus to accurately measure the bending stiffness at different tensions, and to measure the axial stiffness and axial damping. A reduced-scale lab set-up and finite element models are developed for verification of the numerical models. Experimental free and forced vibration testing is performed on individual cantilever beam and stranded cable subsystems, and on the coupled cable–beam system to verify the numerical models in the frequency and time domains. It is concluded that the 3D bond graph models can be used to understand the interaction between cable and structure, allowing prediction of the in-plane and out-of-plane natural frequencies and time response of the connected pole. It is also concluded that by adding the cable to the pole structure, some modes emerge in the eigenvalue solution of the system which may be categorized as cable-dominated modes, pole-dominated or hybrid modes. [ABSTRACT FROM AUTHOR]

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 howincrementalbond 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. [ABSTRACT FROM AUTHOR]

Nowadays, photovoltaic is becoming more popular, reliable, and widely used. Despite its popularity, there are several problems related to instability and non-availability in almost all the Photovoltaic applications. Various parameters cause those problems such as solar irradiation, temperature, the material used in the photovoltaic cells, as well as the battery's storage capacity, and the connecting cables. For a better understanding of those problems, it is needed to model photovoltaic installations trough Multi-physics modeling, which allows the simulation of photovoltaic installations and the impact quantification of each one of the parameters mentioned above. In this paper, a mathematical model based on graphical methodology (Bond Graph) for a 5 kW Photovoltaic Group is presented. The developed model demonstrates the effect of solar radiation and the ambient temperature on the output voltage, current, and power. This model is possible without going through an iterative process. In this work, all the photovoltaic group parameters are given according to ambient temperature, solar irradiation, materials of photovoltaic cells, and the conducting wires. The expected values for voltage and current have been successfully compared to the actual physical data. Good results have been demonstrated using RMSE, with values of 3.1775 V for voltage, and 0.04 A for current. [ABSTRACT FROM AUTHOR]

Automotive manufacturers have created vehicle models but these are somewhat complex and use black boxes with numerous tables and mappings. Each model is generally valid for its own field of use and can thus produce significant differences in results outside its specific field. Moreover vehicle behaviour requires detailing and analysis during precise manoeuvres called ‘life situations'. These ‘life situations' require different models to be set up. A complete vehicle model is necessary when attempting to reproduce simulated realistic behaviours for different manoeuvres. High modelling standards are also sought when vehicle systems such as steering, suspension or braking are approached. This paper presents bond graph modelling of an automotive vehicle with 16 degrees of freedom. Although not presented here, one purpose of such a model is dimensioning of different vehicle systems, in certain life situations, using an inverse approach. The vehicle body is modelled by a rigid body with six degrees of freedom. Each wheel has two degrees of freedom, one corresponding to vertical suspension deflection, the other to wheel axial rotation. Each front wheel has one additional degree of freedom corresponding to steering mobility. Vehicle components modelled and connected to the body model are thus four suspensions, wheels and steering system. Simulations of this model have been undertaken on 20Sim. They reveal good correlation with a model simulated on AMESim by automotive manufacturer PSA Peugeot Citroën, considered as the validation reference for this study. [ABSTRACT FROM AUTHOR]

In a steer-by-wire (SBW) system in a passenger vehicle, the conventional mechanical linkage between the steering wheel and the front wheel is replaced by electric wires. The SBW system consists of two parts: the steering-wheel system and the front-wheel system. The front-wheel system is the rack-actuating type. This paper proposes a concept for the control of the rack-actuating SBW system. In particular, the controller should behave similarly to a conventional (mechanically linked) steering system. In this paper, the rack-actuating SBW system was modelled using the bond graph method. The actuator controller was designed to minimize the reference signal error. The current research also considers the improvement in steering feel using feedback control of road information, in which the steering-wheel system's control algorithm used the torque map and transfer information of the road to the driver. Verification simulation and performance simulation showed that the rack-actuating SBW controller was available in this paper. [ABSTRACT FROM AUTHOR]

This paper describes a new Schemebuilder library developed for educational usage. Each component in the library has a simple model based on standard Bond Graph definitions, and Schemebuilder provides a higher level of interaction in which to use these models. The paper begins with a general overview of the Schemebuilder tool; a cross-domain example is then presented, followed by a discussion of the potential of Schemebuilder in teaching. [ABSTRACT FROM AUTHOR]

This paper addresses the fault diagnosis problem of uncertain systems in the context of Bond Graph modelling technique. The main objective is to enhance the fault detection step based on Interval valued Analytical Redundancy Relations (named I-ARR) in order to overcome the problems related to false alarms, missed alarms and robustness issues. These I-ARRs are a set of fault indicators that generate the interval bounds called thresholds. A fault is detected once the nominal residuals (point valued part of I-ARRs) exceed the thresholds. However, the existing fault detection method is limited to parametric faults and it presents various limitations with regards to estimation of measurement signal derivatives, to which I-ARRs are sensitive. The novelties and scientific interest of the proposed methodology are: (1) to improve the accuracy of the measurements derivatives estimation by using a dedicated sliding mode differentiator proposed in this work, (2) to suitably integrate the Fourier-Motzkin Elimination (FME) technique within the I-ARRs based diagnosis so that measurements faults can be detected successfully. The latter provides interval bounds over the derivatives which are included in the thresholds. The proposed methodology is studied under various scenarios (parametric and measurement faults) via simulations over a mechatronic torsion bar system. [ABSTRACT FROM AUTHOR]

Abstract: In this research paper, a mechatronics system such as a pan tilt platform (PTP) has been considered for motion control under intelligent controllers. A proportional-derivative (PD) controller is considered for comparison of results obtained from fuzzy and hybrid controllers. The trajectory following performance of the mechatronics system is found against these controllers. The results of simulations show that hybrid fuzzy controller reduce the tracking error effectively in lesser settling time. The intelligent controllers require knowledge base of error and derivative of error to compensate the PTP dynamics. The intelligent controllers have similar trends as the PD controllers and compensated both electrical and mechanical dynamics. The PD controller requires position measurement. The intelligent controllers have knowledge base consisting of position and velocity data. Thus intelligent controllers have position measurement along with knowledge base for position control system. The best results were achieved with hybrid fuzzy controllers. They meet the desired specifications. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

This paper presents a control algorithm for a steer-by-wire (SBW) system. In an SBW system in a passenger car, the usual mechanical linkage between the steering wheel and the front wheels is replaced with an electrical connection. An SBW system consists of two parts: the steering-wheel system and the front-wheel system. This research considers the tie-rod-actuating type of front-wheel system, in which two independently actuating motors control the front wheels. The steering-wheel and front-wheel motors are modelled, using the bond graph method for both, but controlled by different means. The steering-wheel system control algorithm used a torque map to generate reactive torque and damping. In the development of the tie-rod-actuating-type SBW system described herein, the Ackerman constraint was used for control of the two motors to improve stability and manoeuvrability. The validity of the system was verified with a full-car model. [ABSTRACT FROM AUTHOR]

Abstract: Water pumping using induction motors has become one of the most feasible photovoltaic (PV) applications. A bond graph model to enable testing the PV system performance by computer simulation was developed. The PV-powered water pumping system investigated in this paper consists mainly of a PV generator, DC–DC and DC–AC converters, and induction motor-pump. The DC–DC converter control strategy is based on pulse width modulation (PWM). However, the oriented field control is used for the induction machine control. Computer simulations were carried out for maximum power point tracking (MPPT). [Copyright &y& Elsevier]

A bond graph model of a mountain bike and rider is created to develop baseline predictions for the performance of mountain bikes during large excursion maneuvers such as drops, jumps, crashes and rough terrain riding. The model assumes planar dynamics, a hard-tail (front suspension only) bicycle and a rider fixed to the bicycle. An algorithm is developed to allow tracking of a virtual tire-ground contact point for events that separate the wheels from the ground. This model would be most applicable to novice mountain bikers who maintain a nearly rigid relationship between their body and the bicycle as opposed to experienced riders who are versed in controlling the bicycle independent of the body. Simulations of a steep drop are performed for various initial conditions to qualitatively validate the predictions of the model. Results from this model are to be compared to experimental data and more complex models in later research, particularly models including a separate rider. The overarching goals of the research are to examine and understand the dynamics and control of interactions between a cyclist and mountain bike. Specific goals are to understand the improvement in performance afforded by an experienced rider, to hypothesize human control algorithms that allow riders to perform manoeuvres well and safely, to predict structural bike and body forces from these maneuvers and to quantify performance differences between hard-tail and full suspension bicycles. [ABSTRACT FROM AUTHOR]