Modeling and analysis of the vibration characteristics of a new type of in-arm hydropneumatic suspension of a tracked vehicle

We investigated the nonlinear elastic characteristic of an in-arm hydropneumatic suspension unit (ISU) as well as the damping characteristic of the controllable vane absorber. Due to the strong nonlinear characteristic of the ISU, simplify is needed to accurately model the vehicle. Based on the theory of multibody dynamics, a virtual prototype of the tracked vehicle was built, which includes the hydraulic system, the multi-dynamics of running gears and a road surface model. The virtual prototype is validated using both a static balancing test and a stiffness characteristics test. By simulating the road impact loading of the tracked vehicle when travelling on a trapezoidal US military road, the changes of the pitch angle and the acceleration of seats and centroid of the tracked vehicle was analyzed for two different damping ratios. We also determined key ride indicators for different speeds. The stiffness and damping characteristics of the ISU were tested in a bench experiment

Advanced suspension system using magnetorheological technology for vehicle vibration control

In the past forty years, the concept of controllable vehicle suspension has attracted extensive attention. Since high price of an active suspension system and deficiencies on a passive suspension, researchers pay a lot attention to semi-active suspension. Magneto-rheological fluid (MRF) is always an ideal material of semi-active structure. Thanks to its outstanding features like large yield stress, fast response time, low energy consumption and significant rheological effect. MR damper gradually becomes a preferred component of semi-active suspension for improving the riding performance of vehicle. However, because of the inherent nonlinear nature of MR damper, one of the challenging aspects of utilizing MR dampers to achieve high levels of performance is the development of an appropriate control strategy that can take advantage of the unique characteristics of MR dampers. This is why this project has studied semi-active MR control technology of vehicle suspensions to improve their performance. Focusing on MR semi-active suspension, the aim of this thesis sought to develop system structure and semi-active control strategy to give a vehicle opportunity to have a better performance on riding comfort. The issues of vibration control of the vehicle suspension were systematically analysed in this project. As a part of this research, a quarter-car test rig was built; the models of suspension and MR damper were established; the optimization work of mechanical structure and controller parameters was conducted to further improve the system performance; an optimized MR damper (OMRD) for a vehicle suspension was designed, fabricated, and tested. To utilize OMRD to achieve higher level of performance, an appropriate semi-active control algorithm, state observer-based Takagi-Sugeno fuzzy controller (SOTSFC), was designed for the semi-active suspension system, and its feasibility was verified through an experiment. Several tests were conducted on the quarter-car suspension to investigate the real effect of this semiactive control by changing suspension damping. In order to further enhance the vibration reduction performance of the vehicle, a fullsize variable stiffness and variable damping (VSVD) suspension was further designed, fabricated, and tested in this project. The suspension can be easily installed into a vehicle suspension system without any change to the original configuration. A new 3- degree of freedom (DOF) phenomenological model to further accurately describe the dynamic characteristic of the VSVD suspension was also presented. Based on a simple on-off controller, the performance of the variable stiffness and damping suspension was verified numerically. In addition, an innovative TS fuzzy modelling based VSVD controller was designed. The TS fuzzy modelling controller includes a skyhook damping control module and a state observer based stiffness control module which considering road dominant frequency in real-time. The performance evaluation of the VSVD control algorithm was based on the quarter-car test rig which equipping the VSVD suspension. The experiment results showed that this strategy increases riding comfort effectively, especially under off-road working condition. The semi-active control system developed in this thesis can be adapted and used on a vehicle suspension in order to better control vibration

Innovative magnetorheological devices for shock and vibration mitigation

Vibration and impact protection have been a popular topic in research fields, which could directly affect the passengers’ and drivers’ comfort and safety, even cause spines fracture. Therefore, an increasing number of vehicle suspensions and aircraft landing gears are proposed and manufactured. Magnetorheological fluids (MRFs), as a smart material, are growly applied into the above device owing to its unique properties such as fast response, reversible properties, and broad controllable range, which could improve the vibration/impact mitigation performance. MRF was utilized to achieve adaptive parameters of the vehicle suspensions by controlling the magnetic field strength of the MRF working areas. Generally, the magnetic field is provided by a given current, subsequently, it would consume massive energy from a long-term perspective. Thus, a self-powered concept was applied as well. This thesis reports a compact stiffness controllable MR damper with a self-powered capacity. After the prototype of the MR damper, its property tests were conducted to verify the stiffness controllability and the energy generating ability using a hydraulic Instron test system. Then, a quarter-car test rig was built, and the semi-active MR suspension integrated with the self-powered MR damper was installed on a test rig. Two controllers, one based on short-time Fourier transform (STFT) and a classical skyhook controller was developed to control the stiffness. The evaluation results demonstrate that the proposed MR damper incorporated with STFT controller or skyhook controller could suppress the response displacements and accelerations obviously comparing with the conventional passive systems

Towards an alternative version of the Hydractive CRONE car suspension

La suspension CRONE Hydractive, développée par l’équipe CRONE dans le cadre des suspensions de véhicules automobiles, présente des performances remarquables. En effet, l’association de l’approche CRONE, garantissant la robustesse du degré de stabilité aux variations de la masse suspendue, et de la stratégie Hydractive, permettant la commutation d’une architecture de suspension orientée confort vibratoire à une autre orientée comportement routier,permet la mise en défaut de la plupart des dilemmes inhérents aux architectures traditionnelles de suspension. La présente étude propose ainsi le développement d’une version alternative de la suspension CRONE par deux approches. Une première approche consiste en la mise en place d’une version passive métallique reposant sur l’utilisation des ressorts à lames en s’inscrivant dans une démarche de modernisation et d’optimisation des technologies historiques. La seconde approche, quant à elle, consiste à proposer le développement d’une version active pneumatique de la suspension CRONE. La modélisation complète de l’architecture « CRONE » orientée confort est alors proposée à travers celle de ses accumulateurs et gicleurs pneumatiques. Cette nouvelle version de suspension, en adoptant une technologie d’actualité de plus en plus répandue et pouvant bénéficier des développements du Véhicule Autonome Connecté, ouvre de nouvelles perspectives d’évolution de la suspension automobile.The Hydractive CRONE car suspension developed by the CRONE team provides outstanding performances. Indeed, the CRONE method ensures the robustness of the stability degree with respect to variations of the sprung mass, while the Hydractive strategy enables the switchover between a comfort-oriented architecture and a road-behavior-oriented one. The association of the CRONE method with the Hydractive strategy allows to circumvent most of the dilemmas that occur with traditional architecture suspensions. The present study aims to develop an alternative version of the CRONE suspension using two approaches. A first approach consists of the implementation of a passive metallic version based on leaf springs aiming the modernisation and optimisation of historical technologies. The second one, however, involves the use of a more relevant and increasingly widespread technology with the development of an active pneumatic version of the CRONE suspension. The complete modeling of the ``CRONE'' comfort-oriented architecture is then proposed through its pneumatic accumulators and nozzles. This new version, benefiting from the pneumatic active system and from the development of the Autonomous Connected Vehicle, opens up new prospects for the development of car suspensions

Vers une version alternative à la suspension CRONE Hydractive

The Hydractive CRONE car suspension developed by the CRONE team provides outstanding performances. Indeed, the CRONE method ensures the robustness of the stability degree with respect to variations of the sprung mass, while the Hydractive strategy enables the switchover between a comfort-oriented architecture and a road-behavior-oriented one. The association of the CRONE method with the Hydractive strategy allows to circumvent most of the dilemmas that occur with traditional architecture suspensions. The present study aims to develop an alternative version of the CRONE suspension using two approaches. A first approach consists of the implementation of a passive metallic version based on leaf springs aiming the modernisation and optimisation of historical technologies. The second one, however, involves the use of a more relevant and increasingly widespread technology with the development of an active pneumatic version of the CRONE suspension. The complete modeling of the ``CRONE'' comfort-oriented architecture is then proposed through its pneumatic accumulators and nozzles. This new version, benefiting from the pneumatic active system and from the development of the Autonomous Connected Vehicle, opens up new prospects for the development of car suspensions.La suspension CRONE Hydractive, développée par l’équipe CRONE dans le cadre des suspensions de véhicules automobiles, présente des performances remarquables. En effet, l’association de l’approche CRONE, garantissant la robustesse du degré de stabilité aux variations de la masse suspendue, et de la stratégie Hydractive, permettant la commutation d’une architecture de suspension orientée confort vibratoire à une autre orientée comportement routier,permet la mise en défaut de la plupart des dilemmes inhérents aux architectures traditionnelles de suspension. La présente étude propose ainsi le développement d’une version alternative de la suspension CRONE par deux approches. Une première approche consiste en la mise en place d’une version passive métallique reposant sur l’utilisation des ressorts à lames en s’inscrivant dans une démarche de modernisation et d’optimisation des technologies historiques. La seconde approche, quant à elle, consiste à proposer le développement d’une version active pneumatique de la suspension CRONE. La modélisation complète de l’architecture « CRONE » orientée confort est alors proposée à travers celle de ses accumulateurs et gicleurs pneumatiques. Cette nouvelle version de suspension, en adoptant une technologie d’actualité de plus en plus répandue et pouvant bénéficier des développements du Véhicule Autonome Connecté, ouvre de nouvelles perspectives d’évolution de la suspension automobile

Analyse de l’influence des non-linéarités dans l’approche CRONE : application en isolation vibratoire

The thesis deals with the synthesis and the realisation of a band limited fractional differentiator. The realisation is made thanks to a small number of resistive and capacitive cells (RC cells). The first part of this thesis is about some new methods to compute the physical parameters of the RC cells from the 4 high-level parameters of the band limited fractional differentiator. The specificities of a realisation using hydropneumatic technology are detailed. It is shown that, in vibration isolation, they lead to remarkable performances. The stability degree robustness and the rapidity robustness towards the variation of the sprung mass value are obtained in spite of non- linearities. Volterra serie expansion is used to study the non-linearities. The second part is about the application of the previous results to the automotive field. The design and the realisation of an hydractive CRONE suspension is proposed. An hydractive CRONE suspension is a suspension with several operating modes and which allows to obtain the stability degree robustness. The hydractive CRONE suspension is then test with a 14 degrees of freedom model of a car.Cette thèse traite de la synthèse et de la réalisation d’un intégrateur d’ordre non entier borné en fréquence. La réalisation est faite par un réseau constitué d’un faible nombre de cellules capacitives et dissipatives. La première partie de ce mémoire s’attache à développer des méthodes permettant de déterminer les paramètres physiques des éléments du réseau à partir des quatre paramètres de haut niveau qui caractérisent l’intégrateur d’ordre non entier à réaliser. Les spécificités liées à une réalisation en technologie hydropneumatique sont détaillées. Il est montré, dans un contexte d’isolation vibratoire, qu’elles conduisent à des performances remarquables de robustesse du degré de stabilité et de robustesse de la rapidité vis-à-vis des variations de la masse suspendue, et ce, malgré l’existence de non-linéarités. Les non-linéarités sont étudiées à l’aide des séries de Volterra. La seconde partie est consacrée à l’application au secteur de l’automobile des résultats de la première partie. La synthèse et la réalisation d’une suspension CRONE hydractive, suspension multi-états dont le mode souple assure la robustesse du degré de stabilité de la caisse vis-à-vis des variations de la masse suspendue, sont proposées et validées en simulation sur un modèle de véhicule à 14 degrés de liberté

Stability of the Hydractive CRONE suspension

National audienc

Analyse de l'influence des non-linéarités dans l'approche CRONE (application en isolation vibratoire)

Cette thèse traite de la synthèse et de la réalisation d un intégrateur d ordre non entier borné en fréquence. La réalisation est faite par un réseau constitué d un faible nombre de cellules capacitives et dissipatives. La première partie de ce mémoire s attache à développer des méthodes permettant de déterminer les paramètres physiques des éléments du réseau à partir des quatre paramètres de haut niveau qui caractérisent l intégrateur d ordre non entier à réaliser. Les spécificités liées à une réalisation en technologie hydropneumatique sont détaillées. Il est montré, dans un contexte d isolation vibratoire, qu elles conduisent à des performances remarquables de robustesse du degré de stabilité et de robustesse de la rapidité vis-à-vis des variations de la masse suspendue, et ce, malgré l existence de non-linéarités. Les non-linéarités sont étudiées à l aide des séries de Volterra. La seconde partie est consacrée à l application au secteur de l automobile des résultats de la première partie. La synthèse et la réalisation d une suspension CRONE hydractive, suspension multi-états dont le mode souple assure la robustesse du degré de stabilité de la caisse vis-à-vis des variations de la masse suspendue, sont proposées et validées en simulation sur un modèle de véhicule à 14 degrés de liberté.The thesis deals with the synthesis and the realisation of a band limited fractional differentiator. The realisation is made thanks to a small number of resistive and capacitive cells (RC cells). The first part of this thesis is about some new methods to compute the physical parameters of the RC cells from the 4 high-level parameters of the band limited fractional differentiator. The specificities of a realisation using hydropneumatic technology are detailed. It is shown that, in vibration isolation, they lead to remarkable performances. The stability degree robustness and the rapidity robustness towards the variation of the sprung mass value are obtained in spite of non- linearities. Volterra serie expansion is used to study the non-linearities. The second part is about the application of the previous results to the automotive field. The design and the realisation of an hydractive CRONE suspension is proposed. An hydractive CRONE suspension is a suspension with several operating modes and which allows to obtain the stability degree robustness. The hydractive CRONE suspension is then test with a 14 degrees of freedom model of a car.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF