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1

Bond Graph Modeling of Muscle-Tendon Actuationof a Phalange

Uppal Sandeep Kuma, Vaz Anand

Computer Assisted Methods in Engineering and Science

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2022

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Vol. 29, no. 3

197--227

EN

In musculoskeletal actuation systems, it is essential to understand and analyze the exten-sion and force patterns generated in the muscle-tendon units (MTUs) responsible for themotion of a phalange. This work proposes a systematically developed bond graph modelfor the muscle-tendon actuation system for the desired motion of the phalange of thehand. The phalange is represented by a cylindrical rigid body, actuated by four MTUsattached to it symmetrically. The MTU is based on Hill’s muscle model. The role of thecentral nervous system (CNS) that commands desired motions to the phalange is emulatedthrough a virtual domain in the model. The virtual domain decides the activation patternof MTUs. Accordingly, the MTUs apply forces on the phalange to achieve the desiredmotion. Simulation results for important motions such as flexion-extension, adduction-abduction, and circumduction show that the model effectively captures the dynamics ofthe musculoskeletal actuation system.

2

Backlash fault suppression using LQ optimal control based rst controllers in wind turbine systems using bond graphs and matlab/simulink

Arab Mohamed, Lachouri Abederezak, Kerikeb Mohamed, Mehennaoui Lamine, Bouchareb Faouzi

Acta Mechanica et Automatica

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2021

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Vol. 15, no. 3

154--163

EN

The presence of backlash in wind turbines is a source of limitations as it introduces nonlinearities that reduce their efficiency in speed/torque control which affect the performance of the power quality. Because of production tolerances during rotation, the teeth contact is lost for a small angle; until it is re-established, it produces a backlash phenomenon. The desire to eliminate this phenomenon is often hard to realise due to the nonlinear dynamic behaviour, which arises with the presence of backlash fault in a system. Therefore, the goal of this study is to develop an LQ optimal control structure in a form of an R-S-T controller in order to reduce the disturbing torque transmitted inside the dead zone of a gearbox in the wind turbine system. The actual system is also developed to be used as a demonstration model at lectures or presentations. The efficacy of the proposed control is illustrated via simulations.

3

Diagnosis of hybrid systems through bond graph, observers and timed automata

Mhamdi Lotfi, Achbi Mohammed Said, Dhouibi Hedi, Kechida Sihem

Diagnostyka

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2020

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Vol. 21, No. 3

113--125

EN

Despite technological advances and progress in industrial systems, the fault diagnosis of a system remains a very important task. In fact an effective diagnosis contributes not only to improved reliability but also to a decrease in maintenance costs. This paper presents an approach to a diagnosis of hybrid systems thanks to the use of Bond Graphs, Observer and Timed Automata. Dynamic models (in normal and failing mode) are generated by an observer based methods as well as through state equations generated by the Bond Graphs model. The procedure of fault localization through a method based on the observer does not allow locating faults with the same signature of failure. Thus the diagnosis technique for the localization of these defects will be based on the time analysis using Timed Automata. The proposed approach is then validated by simulation tests in a two tanks hydraulic system.

4

Inverse kinematics of a spatial mechanismusing multibond graph

Maini Aman Kumar, Vaz Anand

Computer Assisted Methods in Engineering and Science

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2020

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Vol. 27, no. 1

71--85

EN

Various methods are available to compute kinematics and dynamics in the case of spa-tial mechanisms. These methods are cumbersome and laborious for large and multibodyspatial mechanisms. The bond graph technique is a powerful alternative tool for mode-ling. A four-link closed-chain 3R2S (3Revolute 2Spherical) spatial mechanism stands outamong the other four-link closed-chain spatial mechanisms due to its ability to be used ina number of applications. The main aim of this paper is to compute the inverse kinematicsof the mechanism using the bond graph structure of the system. In this paper, modeling ofa four-link closed-chain 3R2S spatial mechanism has been conducted using a multibondgraph approach. Inverse kinematics of the spatial mechanism, under various applications,has been directly obtained from the bond graph modeling. MATLAB coding for simula-tion has been done directly from the multibond graph without explicitly deriving systemequations. The simulation results have been analyzed and discussed using various plots.

5

Different dynamic formulations for a mechanism using Bond Graph

Maini Aman Kumar, Vaz Anand

Computer Assisted Methods in Engineering and Science

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2020

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Vol. 27, no. 4

241--264

EN

For modeling dynamics of mechanisms, various classical formulations are available in theliterature. The equations of dynamics given by various classical formulations can also bederived from the bond graph. The bond graph is a convenient graphical representation formodeling dynamics of physical systems in multi-energy domains.In this paper, various alternative causality assignment procedures in the bond graphare used to derive different classical formulations such as the Lagrange’s equations of thefirst kind (withmultipliers), Lagrange’s formulation of the second kind, and Hamiltonianformulations. An example of the quick return mechanism has been modeled using the bondgraph technique, and various alternative causality assignment procedures are applied toderive the various formulations. Simulation coding has been done using MATLAB andresults have been analyzed and discussed. The purpose of this paper is to show how thevarious formulations can be obtained from bond graph using various alternative causalityassignment procedures.