References of "Kerschen, Gaëtan"
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See detailRobust mission design using invariant manifolds
Dell'Elce, Lamberto ULiege; Baresi, Nicola; Kerschen, Gaëtan ULiege et al

in Proceedings of the 67th International Astronautical Congress (2016, September 26)

Uncertainties in the dynamical system affect all real-life applications in astrodynamics. This is particularly true for satellites orbiting about small bodies owing to their irregular shapes and to the ... [more ▼]

Uncertainties in the dynamical system affect all real-life applications in astrodynamics. This is particularly true for satellites orbiting about small bodies owing to their irregular shapes and to the difficulties in characterizing their physical properties at the early stages of a dedicated spacecraft mission. Hence, accommodating uncertainty in the orbital design process may be extremely beneficial for the success of the mission. Here, in a Lyapunov stability perspective, the properties of the invariant manifolds are exploited to generate regions of the phase space where the motion is guaranteed to evolve despite the uncertainties in the system parameters and navigation errors. Specifically, the scenario approach is applied to tackle a semi-infinite optimization problem that locates these robust regions. The methodology is illustrated with the robust design of a inner retrograde orbit about the primary of (65803) Didymos as well as with a ballistic landing on the smaller secondary body. [less ▲]

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See detailSatellite Formation Control Using Continuous Adaptive Sliding Mode Controller
Cho, Hancheol ULiege; Kerschen, Gaëtan ULiege

in AIAA/AAS Astrodynamics Specialist Conference (2016, September)

The focus of this study is on the development of a robust controller with a simple gain adaptation for satellite formation control. The complete nonlinear dynamics of the motion of the follower satellite ... [more ▼]

The focus of this study is on the development of a robust controller with a simple gain adaptation for satellite formation control. The complete nonlinear dynamics of the motion of the follower satellite relative to the leader satellite is considered and the rigorous proof for the stability of the controlled formation system is given in the presence of unknown external disturbances and unknown mass of the follower satellite. Although the controller design is based on the concept of sliding mode control, the proposed control strategy is free from chattering and guarantees a finite-time convergence of the controlled system to the target area. Furthermore, a simple adaptive law to automatically update the control gain is suggested that does not require a priori knowledge of the uncertainties of the system. In addition, to guarantee the robustness from the beginning and to improve the transient performance, a new sliding surface is also constructed. Numerical simulations are carried out to demonstrate the effectiveness of the proposed adaptive controller to maintain a desired formation configuration by compensating for the initial offset errors and external disturbance effects including gravitational perturbations and atmospheric drag. [less ▲]

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See detailNonlinear vibration analysis of the SmallSat spacecraft: From identification to design
Detroux, Thibaut ULiege; Noël, Jean-Philippe ULiege; Masset, Luc ULiege et al

Conference (2016, September)

The objective of the present contribution is to introduce nonlinear experimental and numerical tools and methods applicable to real-life structures. The study is illustrated using the SmallSat spacecraft ... [more ▼]

The objective of the present contribution is to introduce nonlinear experimental and numerical tools and methods applicable to real-life structures. The study is illustrated using the SmallSat spacecraft developed by Airbus Defence and Space, which possesses several localized nonlinearities. The computation of nonlinear normal modes and bifurcations reveals that the satellite possesses complex dynamics including modal interactions, quasiperiodic oscillations and isolated resonances. [less ▲]

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See detail10 years of advances in nonlinear system identification in structural dynamics: A review
Noël, Jean-Philippe ULiege; Kerschen, Gaëtan ULiege

in Proceedings of ISMA 2016 - International Conference on Noise and Vibration Engineering (2016, September)

Nonlinear system identification is a vast research field, today attracting a great deal of attention in the structural dynamics community. Ten years ago, an MSSP paper reviewing the progress achieved ... [more ▼]

Nonlinear system identification is a vast research field, today attracting a great deal of attention in the structural dynamics community. Ten years ago, an MSSP paper reviewing the progress achieved until then concluded that the identification of simple continuous structures with localised nonlinearities was within reach. The past decade witnessed a shift in emphasis, accommodating the growing industrial need for a first generation of tools capable of addressing complex nonlinearities in larger-scale structures. The objective of the present paper is to survey the key developments which arose in the field since 2006 towards developing these tools. [less ▲]

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See detailPassive Linearization of Nonlinear System Resonances
Habib, Giuseppe ULiege; Grappasonni, Chiara ULiege; Kerschen, Gaëtan ULiege

Conference (2016, August 22)

In this work we demonstrate that the addition of properly-tuned nonlinearities to a nonlinear system can increase the range over which a specific resonance responds linearly. Specifically, we seek to ... [more ▼]

In this work we demonstrate that the addition of properly-tuned nonlinearities to a nonlinear system can increase the range over which a specific resonance responds linearly. Specifically, we seek to enforce two important properties of linear systems, namely the force-displacement proportionality and the invariance of resonance frequencies. Theoretical findings are validated through numerical simulations and experiments. [less ▲]

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See detailPassive linearization of nonlinear resonances
Habib, Giuseppe ULiege; Grappasonni, Chiara ULiege; Kerschen, Gaëtan ULiege

in Journal of Applied Physics (2016), 120

The objective of this paper is to demonstrate that the addition of properly-tuned nonlinearities to a nonlinear system can increase the range over which a speci c resonance responds linearly. Speci cally ... [more ▼]

The objective of this paper is to demonstrate that the addition of properly-tuned nonlinearities to a nonlinear system can increase the range over which a speci c resonance responds linearly. Speci cally, we seek to enforce two important properties of linear systems, namely the force-displacement proportionality and the invariance of resonance frequencies. Numerical simulations and experiments are used to validate the theoretical ndings. [less ▲]

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See detailPassive flutter suppression using a nonlinear tuned vibration absorber
Verstraelen, Edouard ULiege; Gourc, Etienne ULiege; Kerschen, Gaëtan ULiege et al

Poster (2016, July)

A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was ... [more ▼]

A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was turning the initial super-critical bifurcation into a sub-critical one. This work shows numerically that adding a nonlinear restoring force to the absorber can restore the su- percritical behaviour of the bifurcation and further reduce the post-instability limit cycle amplitude. [less ▲]

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See detailIdentification of nonlinear frequency responses and bifurcations from experimental data
Noël, Jean-Philippe ULiege; Gourc, Etienne ULiege; Grappasonni, Chiara ULiege et al

in Actes de CFA/VISHNO 2016 (2016, April)

The objective of the paper is to obtain the frequency response curves of nonlinear mechanical systems from broadband testing. The proposed approach consists in coupling an identification method with a ... [more ▼]

The objective of the paper is to obtain the frequency response curves of nonlinear mechanical systems from broadband testing. The proposed approach consists in coupling an identification method with a continuation method. Specifically, the frequency-domain nonlinear subspace identification (FNSI) method is first used to derive an experimental model of the structure in state-space from broadband measurements. The harmonic balance method coupled with arclength continuation then utilizes this experimental model to compute the frequency response curves of the system. The method is demonstrated using a numerical example. [less ▲]

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See detailA nonlinear state-space solution to a hysteretic benchmark in system identification
Noël, Jean-Philippe ULiege; Esfahani, Alireza; Kerschen, Gaëtan ULiege et al

Conference (2016, April)

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See detailChattering-free Sliding Mode Control for Propellantless Rendez-vous using Differential Drag
Cho, Hancheol ULiege; Dell'Elce, Lamberto ULiege; Kerschen, Gaëtan ULiege

in International Conference on Astrodynamics Tools and Techniques (2016, March)

This paper develops a differential drag-based sliding mode controller for satellite rendez-vous. It is chattering-free and avoids bang-bang type control to adjust the relative motion more efficiently. In ... [more ▼]

This paper develops a differential drag-based sliding mode controller for satellite rendez-vous. It is chattering-free and avoids bang-bang type control to adjust the relative motion more efficiently. In spite of uncertain nonlinear perturbations and disturbances, it is shown that the in-plane relative motion between two satellites can be effectively controlled by regulating the drag difference. An adaptive tuning rule is also presented such that the errors are suppressed to lie within a desired error box. The proposed controller is simple and easy to implement in a small satellite, and numerical simulations are carried out to demonstrate its effectiveness in a high fidelity environment. [less ▲]

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See detailObtaining nonlinear frequency responses from broadband testing
Gourc, Etienne ULiege; Grappasonni, Chiara ULiege; Noël, Jean-Philippe ULiege et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIV (2016, January)

The objective of the paper is to obtain the frequency response curves of nonlinear mechanical systems from broadband testing. The proposed approach consists in coupling an identification method with a ... [more ▼]

The objective of the paper is to obtain the frequency response curves of nonlinear mechanical systems from broadband testing. The proposed approach consists in coupling an identification method with a continuation method. Specifically, the frequency-domain nonlinear subspace identification (FNSI) method is first used to derive an experimental model of the structure in state space from broadband measurements. The harmonic balance method coupled with arclength continuation then utilizes this experimental model to compute the frequency response curves of the system. The method is demonstrated using a numerical example. [less ▲]

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See detailExperimental study of isolated response curves in a two-degree-of-freedom nonlinear system
Detroux, Thibaut ULiege; Noël, Jean-Philippe ULiege; Kerschen, Gaëtan ULiege et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIV (2016, January)

In the present paper, the observation and characterization of isolated response curves (IRCs) are experimentally reported in the case of a nonlinear system consisting of two masses sliding on an ... [more ▼]

In the present paper, the observation and characterization of isolated response curves (IRCs) are experimentally reported in the case of a nonlinear system consisting of two masses sliding on an horizontal guide. Transverse springs are attached to one mass to provide the nonlinear restoring force, and a harmonic motion of the complete system is imposed by prescribing the displacement of their supports. The existence of an IRC is related to a 3:1 internal resonance between the two modes of the system. The observed IRC is studied in detached and merged conditions using swept-sine excitations and system perturbations. [less ▲]

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See detailExperimental nonlinear identification of an aircraft with bolted connections
De Filippis, Giovanni; Noël, Jean-Philippe ULiege; Kerschen, Gaëtan ULiege et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIII (2016, January)

Aircraft structures are known to be prone to nonlinear phenomena, especially as they constantly become lighter and hence more flexible. One specific challenge that is regularly encountered is the modeling ... [more ▼]

Aircraft structures are known to be prone to nonlinear phenomena, especially as they constantly become lighter and hence more flexible. One specific challenge that is regularly encountered is the modeling of the mounting interfaces between aircraft subcomponents. Indeed, for large amplitudes of vibration, such interfaces may loosen and, in turn, trigger complex mechanisms such as friction and clearances. In this context, the present work intends to investigate the nonlinear dynamics of the Morane–Saulnier Paris aircraft, accessible at ONERA. This aircraft possesses multiple bolted connections between two external fuel tanks and wing tips. The objective of the paper is specifically to carry out an adequate identification of the numerous nonlinearities affecting the dynamics of this full-scale structure. Nonlinearity detection and the subsequent subspace-based parameter estimation have been performed on experimental data, collected during an on-ground test campaign. Nonlinearity detection is first achieved by the comparison of frequency response functions estimated at low excitation level, with those obtained at high amplitude level, yielding insight towards accurately characterizing the behavior of the bolted connections. Then, a nonlinear subspace identification method is applied to measured data to estimate the linear and nonlinear parameters of the structure and novel strategies and tools that overcome specific arisen problems are developed. [less ▲]

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See detailHysteresis identification using nonlinear state-space models
Noël, Jean-Philippe ULiege; Esfahani, Alireza; Kerschen, Gaëtan ULiege et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIV (2016, January)

Most studies tackling hysteresis identification in the technical literature follow white-box approaches, i.e. they rely on the assumption that measured data obey a specific hysteretic model. Such an ... [more ▼]

Most studies tackling hysteresis identification in the technical literature follow white-box approaches, i.e. they rely on the assumption that measured data obey a specific hysteretic model. Such an assumption may be a hard requirement to handle in real applications, since hysteresis is a highly individualistic nonlinear behaviour. The present paper adopts a black-box approach based on nonlinear state-space models to identify hysteresis dynamics. This approach is shown to provide a general framework to hysteresis identification, featuring flexibility and parsimony of representation. Nonlinear model terms are constructed as a multivariate polynomial in the state variables, and parameter estimation is performed by minimising weighted least-squares cost functions. Technical issues, including the selection of the model order and the polynomial degree, are discussed, and model validation is achieved in both broadband and sine conditions. The study is carried out numerically by exploiting synthetic data generated via the Bouc-Wen equations. [less ▲]

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See detailRobust Subspace Identification of a Nonlinear Satellite Using Model Reduction
Dossogne, Tilàn ULiege; Noël, Jean-Philippe ULiege; Kerschen, Gaëtan ULiege

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIV (2016, January)

The frequency-domain nonlinear subspace identification (FNSI) method has recently been successfully applied to large-scale nonlinear structures. One of the key features of FNSI is the nonlinear ... [more ▼]

The frequency-domain nonlinear subspace identification (FNSI) method has recently been successfully applied to large-scale nonlinear structures. One of the key features of FNSI is the nonlinear generalisation of the stabilisation diagram. However, as in linear system identification, the selection of the model order in the diagram is complicated by the presence of spurious poles, resulting from noise and modelling errors. Spurious poles have been shown to strongly perturb the estimation of the nonlinear coefficients. The present paper establishes a constructive procedure to discriminate between spurious and genuine poles. This procedure is derived in modal space and is based on a dominancy index and on model reduction techniques. It is demonstrated on a complete satellite structure possessing nonsmooth nonlinearities and high modal density. Spurious frequency variations in the nonlinear coefficients are proved to be effectively removed, significantly improving the quality of the overall identified model. [less ▲]

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See detailPerformance comparison between a nonlinear energy sink and a linear tuned vibration absorber for broadband control
Gourc, E.; Elce, L. D.; Kerschen, Gaëtan ULiege et al

in Conference Proceedings of the Society for Experimental Mechanics Series (2016), 1

The performance of a linear tuned vibration absorber (LTVA) and a nonlinear energy sink (NES) for the vibration mitigation of an uncertain linear primary system is investigated. An analytic tuning rule ... [more ▼]

The performance of a linear tuned vibration absorber (LTVA) and a nonlinear energy sink (NES) for the vibration mitigation of an uncertain linear primary system is investigated. An analytic tuning rule for the LTVA when the primary system contains uncertainty is derived. The behavior of the linear system coupled to the NES is analyzed theoretically. A tuning methodology for the NES in the deterministic as well as for the uncertain case is presented. © The Society for Experimental Mechanics, Inc. 2016. [less ▲]

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See detailChatter mitigation using the nonlinear tuned vibration absorber
Habib, G.; Kerschen, Gaëtan ULiege; Stepan, Gabor

in Proceedings of ISMA 2016 - International Conference on Noise and Vibration Engineering and USD2016 - International Conference on Uncertainty in Structural Dynamics (2016)

A passive vibration absorber, termed the nonlinear tuned vibration absorber (NLTVA), is designed for the suppression of chatter vibrations. Differently from most passive vibration absorbers proposed in ... [more ▼]

A passive vibration absorber, termed the nonlinear tuned vibration absorber (NLTVA), is designed for the suppression of chatter vibrations. Differently from most passive vibration absorbers proposed in the literature, the NLTVA comprises both a linear and a nonlinear restoring force. Its linear characteristics are tuned in order to optimize the stability properties of the machining operation, while its nonlinear properties are chosen in order to control the bifurcation behavior of the system and guarantee robustness of stable operation. In this work, the NLTVA is applied to turning machining. [less ▲]

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See detailEnforcing linear dynamics through the addition of nonlinearity
Habib, G.; Grappasonni, C.; Kerschen, Gaëtan ULiege et al

in Conference Proceedings of the Society for Experimental Mechanics Series (2016), 1

The current trend of developing more slender structures is increasing the importance of nonlinearities in engineering design, which, in turn, gives rise to complicated dynamical phenomena. In this study ... [more ▼]

The current trend of developing more slender structures is increasing the importance of nonlinearities in engineering design, which, in turn, gives rise to complicated dynamical phenomena. In this study, we evidence the somewhat paradoxical result that adding purposefully nonlinearity to an already nonlinear structure renders the behavior more linear. Isochronicity, i.e., the invariance of natural frequencies with respect to oscillation amplitude, and the force-displacement proportionality are two key properties of linear systems that are lost for nonlinear systems. The objective of this research is to investigate how these properties can be enforced in a nonlinear system through the addition of nonlinearity. To this end, we exploit the nonlinear normal modes theory to derive simple rules, yet applicable to real structures, for the compensation of nonlinear effects. The developments are illustrated using numerical experiments on a cantilever beam possessing a geometrically nonlinear boundary condition. © The Society for Experimental Mechanics, Inc. 2016. [less ▲]

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