Méthodologie de modélisation des systèmes mécatroniques complexes à partir du multi-bond graph : application à la liaison BTP-fuselage d’un hélicoptère

Due to the operation of the rotor, the helicopter is subject to important vibrations affecting namely the fatigue of mechanical parts and the passengers comfort. The MGB-Fuselage joint equipped with the DAVI system is an anti-vibration system that helps to reduce, in a single frequency way, vibrations transmitted to the fuselage. Semi-active intelligent solutions are studied so that the filtering can be adjusted according to the vibration sources. Such studies suffer from a lack of tools and necessary methods, firstly, for the design of complex mechanical systems and secondly, for the development of an intelligent joint. This work proposes a modeling approach using a structural modeling tool : the multi-bond graph (MBG) which offers a global and modular view for the study of complex mechatronic systems such as helicopter. At first, an analysis of modeling tools leading to the selection of MBG is presented. Secondly, developments have focused on the MBG modeling of the 3D MGB-fuselage joint of an experimental setup which was designed and built in the laboratory. This joint is a mechanical system with kinematic loops. The equations of the dynamics of such system are a differential-algebraic system (DAE) requiring specific solving methods. The MBG model of the MGB-fuselage was simulated using the 20-sim software. The results were verified using the multibody software LMS Virtual Lab. A comparison of results obtained by the two methods led to a very good correlation to various cases of excitations of the MGB (pumping, roll, pitch). Thirdly, the MBG model was used for the establishment of semi-active control system. The model of the DAVI device also developed in 20-sim allows to adjust the position of the moving masses in operation so as to minimize the level of vibration of the fuselage. The control algorithm (gradient algorithm) enables to calculate the setpoint positions of the moving masses on the DAVI beaters. The position of the moving masses driven by an electric DC motor and a screw-nut system is then controlled to the setpoints generated by the control algorithm. Finally, the command could be implemented on a non-linear bond graph model which did not require a linearization to get a transfer function.De par le fonctionnement de son rotor, l'hélicoptère est le siège de vibrations mécaniques importantes impactant notamment la fatigue des pièces mécaniques et le confort des passagers. La liaison BTP-Fuselage équipé du système SARIB est un système anti-vibratoire qui permet d'atténuer mono-fréquentiellement les vibrations transmises au fuselage. Des solutions intelligentes semi-actives sont donc étudiées afin que la filtration soit réglable en fonction des vibrations excitatrices. Ce type d'études souffre, par contre, d'un manque d'outils et de méthodes indispensables, d'une part, à la modélisation de systèmes mécaniques complexes et d'autre part, à l'élaboration d'une liaison intelligente. Ces travaux proposent une démarche de modélisation à partir d'un outil de modélisation structurel tel que le multi-bond graph (MBG) permettant une vision global et modulaire pour l'étude de systèmes mécaniques complexes tels qu'on peut les trouver sur un hélicoptère. Dans un premier temps, une analyse des outils de modélisation conduisant au choix du MBG a été présentée. Dans un second temps, les développements ont porté sur la modélisation MBG de la liaison BTP/ Fuselage 3D d'un banc d'essai réel qui a été conçu et réalisé au sein du laboratoire. Cette liaison est un système mécanique cinématiquement bouclé. Les équations de la dynamique d'un tel système forment un système d'équations algébro-différentiel (DAE) nécessitant des techniques de résolution spécifiques. Le modèle MBG de la liaison BTP-fuselage entier a été simulé à l'aide du logiciel 20-sim. Les résultats obtenus ont été vérifiés à l'aide du logiciel multicorps LMS Virtual Lab. Une comparaison des résultats obtenus par les deux méthodes a donné, pour différents cas d'excitations de la BTP (pompage, roulis, tangage), une corrélation très satisfaisante. Dans un troisième temps, le modèle MBG a été exploité pour la mise en place d'un dispositif de contrôle semi-actif. Le modèle du dispositif SARIB développé également sous 20-sim permet de régler la position des masses mobiles en fonctionnement de manière à minimiser le niveau de vibratoire du fuselage. L'algorithme de contrôle (algorithme de gradient) permet de calculer les consignes de position des masses mobiles sur les batteurs SARIB. La position des masses mobiles actionnée par un moteur électrique à courant continu et un système vis-écrou est ensuite asservie aux consignes générées par l'algorithme de contrôle. Enfin, la commande a pu être mise en place sur un modèle bond graph non-linéaire qui n'a pas nécessité une linéarisation en vue d'une transformation en fonction de transfert

Nouvelle approche pour l’optimisation de systèmes mécaniques en vue de la récupération d'énergie vibratoire

La récupération d’énergie à partir des vibrations mécaniques est une préoccupation importante à l’heure actuelle car elle permet de rendre autonome les systèmes de surveillance vibratoire ou de contrôle de vibration (semi-actif). Cet article se positionne sur le thème de la récupération d’énergie vibratoire et plus particulièrement, dans la phase de conception d’un tel système, lors de l’étape de la « transformation et l’optimisation mécanique ». Dans ce sens, l’article propose une méthode d’aide à la conception des résonateurs équipant les systèmes de récupération. Cette méthode utilise les fonctions habituelles des interfaces (débattement, isolation) plus une fonction récupération d’énergie. La démarche intègre une étape supplémentaire aux démarches classiques de mise sous forme adimensionnelle de ces fonctions afin de minimiser le nombre de paramètres de plus haut niveau à utiliser lors d’une optimisation globale

Simulation of a helicopter’s main gearbox semiactive suspension with bond graphs

This paper presents a bond graph model of a helicopter’s semiactive suspension and the associated simulations. The structural and modular approach proposed with bond graph permits a systematic modeling of mechatronic multibody systems. This approach was carried out thanks to the use of the singular perturbation method, which is a variant of penalty formulation. The model is then built as an assembly of components or modules (rigid bodies and compliant kinematic joints) by following the structure of the actual system. The bond graph model of the passive suspension with fixed flapping masses has been verified with another multibody tool for three different excitations (pumping, roll, and yaw). Next, the passive model, augmented with electrical actuators and controllers, is called the semiactive suspension model. Simulations on the semiactive suspension model have been conducted.Chaire "dynamique des systèmes complexes" - Fondation EAD

Bond Graph Modeling and Simulation of a Vibration Absorber System in Helicopters

n the last 20 years, computer science has considerably progressed and there has been a resurgence of interest in bond graphs. The evolution of bond graph software has allowed for the full exploitation of its graphical aspects and for its simulation directly from the modeling environment without the need for the modeler to derive the associated dynamic equations. However, within this last decade, few simulations of complex multibody systems modeled with bond graphs have been conducted directly from a graphic software platform. In this context, the objective of this chapter is to show how bond graphs can be used to model and simulate a complex mechatronic system with bond graph simulation software. The multibody system studied in this chapter is a helicopter’s vibration absorber suspension. The structural and modular approach allowed by bond graphs permits a systematic modeling of mechatronic multibody systems. The model is then built as an assembly of components or modules (rigid bodies and compliant kinematic joints) by following the structure of the actual system. This approach was carried out with the use of the parasitic elements method. The bond graph model of the suspension has been verified with another multibody tool for three different excitations (pumping, roll, and yaw). The first part of this chapter will be dedicated to giving the reader an overview of the modeling of multibody systems with bond graphs. BG models of the rigid body and all the basic kinematic joints will be presented. The main existing methods (zero-causal paths ZCPs, Lagrange multipliers, and singular perturbation) for modeling and carrying out simulations of multibody systems will be recalled. The second part of this chapter will present a vector bond graph (also called multibond graph) model of a helicopter’s antivibratory system and the associated simulations. This system is a specific suspension of a helicopter, which filters the vibration coming from the rotor to the fuselage. It is a complex multibody system with four closed kinematic chains (CKC). The dynamic equations of such a CKC system are differential-algebraic equation systems (DAE) that are often difficult to treat and which require specific solving methods. The intention of writing this chapter was to give to bond graph practitioners a detailed and comprehensive method so as to model and conduct simulations of complex multibody systems directly from a bond graph modeling interface.Chaire "dynamique des systèmes complexes" - Fondation d'entreprises EAD

Design methodology of a complex CKC mechanical joint with a representation energetic tool multi-Bond graph: application to the helicopter

Due to the operation of the rotor, the helicopter is subject to important vibration levels affecting namely the fatigue of the mechanical parts and the passenger comfort. Suspensions between the main gear box (MGB) and the fuselage help to filter theses problematic vibrations. Their design can be difficult since the filtering should be efficient for different types of external forces (pumping force and roll/pitch torque) which may appear during the flight. As passive solutions classically show their limits, intelligent active solutions are proposed so that the filtering can be adjusted according to the vibration sources. Such studies still suffer from a lack of tools and methods, firstly, necessary to the design of complex mechanical systems (due to their multi-phase multi-physics multi-interaction characteristic, ...) and secondly, to develop of an intelligent joint. The main objective of this chapter is to provide a methodology for designing and analyzing an intelligent joint using an energetic representation approach: the multibond graph (MBG). This method is applied here to a complex mechanical system with closed kinematic chains (CKC) which is the joint between the main gear box (MGB) and the aircraft structure of a helicopter. Firstly, the MBG method is analyzed. Secondly, after a brief state of art of the MGB-Fuselage joint, developments focus on the 2D and 3D modeling of the MGB-Fuselage joint with a MBG approach. The 20-sim software is used to conduct the simulation of bond graph. Finally, the MBG models results are presented, illustrating the potential of the MBG tool to predict the dynamic of a complex CKC mechanical system.Chaire de la fondation d'entreprises EAD

An Energetic Approach to Aeroelastic Rotorcraft-Pilot Couplings Analysis

This paper describes an energetic method using multibond graphs to model multi-physical systems. Its potential in building physical meaningful graphs that represent equivalent mathematical models of classic analytical approaches is shown. An application to the study of an aeroelastic rotorcraft-pilot coupling is studied by analyzing the passive pilot behavior in the cyclic control loop. A rotorcraft in hover flight is simulated and perturbed on its rolling motion axis. Depending on the rotorcraft characteristics air resonance may occur, and the pilot may involuntarily excite the cyclic lever, increasing the rolling motion of the fuselage to an unstable point. Future work will explore eventual alternative solutions to notch filters to avoid passive pilot reinjection at low fuselage frequency modes by controlling for example the actuators of the swashplate through model inversion using the bond graph metho

The effects of social service contact on teenagers in England

Objective: This study investigated outcomes of social service contact during teenage years. Method: Secondary analysis was conducted of the Longitudinal Survey of Young People in England (N = 15,770), using data on reported contact with social services resulting from teenagers’ behavior. Outcomes considered were educational achievement and aspiration, mental health, and locus of control. Inverse-probability-weighted regression adjustment was used to estimate the effect of social service contact. Results: There was no significant difference between those who received social service contact and those who did not for mental health outcome or aspiration to apply to university. Those with contact had lower odds of achieving good exam results or of being confident in university acceptance if sought. Results for locus of control were mixed. Conclusions: Attention is needed to the role of social services in supporting the education of young people in difficulty. Further research is needed on the outcomes of social services contact

Methodology for modeling complex mecatronics systems with multi-bond graph : application to the helicopter

De par le fonctionnement de son rotor, l'hélicoptère est le siège de vibrations mécaniques importantes impactant notamment la fatigue des pièces mécaniques et le confort des passagers. La liaison BTP-Fuselage équipé du système SARIB est un système anti-vibratoire qui permet d'atténuer mono-fréquentiellement les vibrations transmises au fuselage. Des solutions intelligentes semi-actives sont donc étudiées afin que la filtration soit réglable en fonction des vibrations excitatrices. Ce type d'études souffre, par contre, d'un manque d'outils et de méthodes indispensables, d'une part, à la modélisation de systèmes mécaniques complexes et d'autre part, à l'élaboration d'une liaison intelligente. Ces travaux proposent une démarche de modélisation à partir d'un outil de modélisation structurel tel que le multi-bond graph (MBG) permettant une vision global et modulaire pour l'étude de systèmes mécaniques complexes tels qu'on peut les trouver sur un hélicoptère. Dans un premier temps, une analyse des outils de modélisation conduisant au choix du MBG a été présentée. Dans un second temps, les développements ont porté sur la modélisation MBG de la liaison BTP/ Fuselage 3D d'un banc d'essai réel qui a été conçu et réalisé au sein du laboratoire. Cette liaison est un système mécanique cinématiquement bouclé. Les équations de la dynamique d'un tel système forment un système d'équations algébro-différentiel (DAE) nécessitant des techniques de résolution spécifiques. Le modèle MBG de la liaison BTP-fuselage entier a été simulé à l'aide du logiciel 20-sim. Les résultats obtenus ont été vérifiés à l'aide du logiciel multicorps LMS Virtual Lab. Une comparaison des résultats obtenus par les deux méthodes a donné, pour différents cas d'excitations de la BTP (pompage, roulis, tangage), une corrélation très satisfaisante. Dans un troisième temps, le modèle MBG a été exploité pour la mise en place d'un dispositif de contrôle semi-actif. Le modèle du dispositif SARIB développé également sous 20-sim permet de régler la position des masses mobiles en fonctionnement de manière à minimiser le niveau de vibratoire du fuselage. L'algorithme de contrôle (algorithme de gradient) permet de calculer les consignes de position des masses mobiles sur les batteurs SARIB. La position des masses mobiles actionnée par un moteur électrique à courant continu et un système vis-écrou est ensuite asservie aux consignes générées par l'algorithme de contrôle. Enfin, la commande a pu être mise en place sur un modèle bond graph non-linéaire qui n'a pas nécessité une linéarisation en vue d'une transformation en fonction de transfert.Due to the operation of the rotor, the helicopter is subject to important vibrations affecting namely the fatigue of mechanical parts and the passengers comfort. The MGB-Fuselage joint equipped with the DAVI system is an anti-vibration system that helps to reduce, in a single frequency way, vibrations transmitted to the fuselage. Semi-active intelligent solutions are studied so that the filtering can be adjusted according to the vibration sources. Such studies suffer from a lack of tools and necessary methods, firstly, for the design of complex mechanical systems and secondly, for the development of an intelligent joint. This work proposes a modeling approach using a structural modeling tool : the multi-bond graph (MBG) which offers a global and modular view for the study of complex mechatronic systems such as helicopter. At first, an analysis of modeling tools leading to the selection of MBG is presented. Secondly, developments have focused on the MBG modeling of the 3D MGB-fuselage joint of an experimental setup which was designed and built in the laboratory. This joint is a mechanical system with kinematic loops. The equations of the dynamics of such system are a differential-algebraic system (DAE) requiring specific solving methods. The MBG model of the MGB-fuselage was simulated using the 20-sim software. The results were verified using the multibody software LMS Virtual Lab. A comparison of results obtained by the two methods led to a very good correlation to various cases of excitations of the MGB (pumping, roll, pitch). Thirdly, the MBG model was used for the establishment of semi-active control system. The model of the DAVI device also developed in 20-sim allows to adjust the position of the moving masses in operation so as to minimize the level of vibration of the fuselage. The control algorithm (gradient algorithm) enables to calculate the setpoint positions of the moving masses on the DAVI beaters. The position of the moving masses driven by an electric DC motor and a screw-nut system is then controlled to the setpoints generated by the control algorithm. Finally, the command could be implemented on a non-linear bond graph model which did not require a linearization to get a transfer function

Simulation of a helicopter’s main gearbox semiactive suspension with bond graphs

International audienceThis paper presents a bond graph model of a helicopter’s semiactive suspension and the associated simulations. The structural and modular approach proposed with bond graph permits a systematic modeling of mechatronic multibody systems. This approach was carried out thanks to the use of the singular perturbation method, which is a variant of penalty formulation. The model is then built as an assembly of components or modules (rigid bodies and compliant kinematic joints) by following the structure of the actual system.The bond graph model of the passive suspension with fixed flapping masses has been verified with another multibody tool for three different excitations (pumping, roll, and yaw). Next, the passive model, augmented with electrical actuators and controllers, is called the semiactive suspension model. Simulations on the semiactive suspension model have been conducted