| 1. |
- Besselink, Bart, et al.
(författare)
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Model Reduction for Nonlinear Systems by Incremental Balanced Truncation
- 2014
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Ingår i: IEEE Transactions on Automatic Control. - 0018-9286 .- 1558-2523. ; 59:10, s. 2739-2753
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the method of incremental balanced truncation is introduced as a tool for model reduction of nonlinear systems. Incremental balanced truncation provides an extension of balanced truncation for linear systems towards the nonlinear case and differs from existing nonlinear balancing techniques in the definition of two novel energy functions. These incremental observability and incremental controllability functions form the basis for a model reduction procedure in which the preservation of stability properties is guaranteed. In particular, the property of incremental stability, which provides a notion of stability for systems with nonzero inputs, is preserved. Moreover, a computable error bound is given. Next, an extension towards so-called generalized incremental balanced truncation is proposed, which provides a reduction technique with increased computational feasibility at the cost of a (potentially) larger error bound. The proposed reduction technique is illustrated by means of application to an example of an electronic circuit with nonlinear elements.
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| 2. |
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| 3. |
- Boere, Stijn, et al.
(författare)
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Tyre/road interaction model for the prediction of road texture influence on rolling resistance
- 2014
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Ingår i: International Journal of Vehicle Design. - 0143-3369 .- 1741-5314. ; 65:2-3, s. 202-221
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Tidskriftsartikel (refereegranskat)abstract
- A novel modelling approach to predict the influence of road texture on the rolling resistance of car tyres is presented where the large static tyre deformations and the small texture induced tyre vibrations are treated separately. The energy dissipation due to the large continuous cyclic deformation of the tyre cross section for a treadless tyre subject to nominal load on a smooth road is determined in a non-linear steady-state rolling analysis on an FEM tyre model. The additional energy dissipation resulting from the con tact forces and tyre vibrations due to the combined effect of the tread profile and the road texture, are determined based on a modal representation of the deformed tyre. The predicted rolling resistance coefficients are compared to experimental data. Although an offset in the absolute rolling resistance levels can be observed, the model predicts the correct trend regarding the increase of rolling resistance with increasing texture depth.
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| 4. |
- Glad, Torkel, 1947-, et al.
(författare)
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On Diffusion Driven Oscillations in Coupled Dynamical Systems
- 1999
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Ingår i: International Journal of Bifurcation and Chaos in Applied Sciences and Engineering. - 0218-1274. ; 9:4, s. 629-644
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Tidskriftsartikel (refereegranskat)abstract
- The paper deals with the problem of destabilization of diffusively coupled identical systems. It is shown that globally asymptotically stable systems being diffusively coupled, may exhibit oscillatory behavior. It is shown that if the diffusive medium consists of hyperbolically nonminimum phase systems and the diffusive factors exceed some threshold value, the origin of the overall system undergoes a Poincare-Andronov-Hopf bifurcation resulting in oscillatory behavior.
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| 5. |
- Hoeijmakers, Maarten, et al.
(författare)
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Accuracy assessment of thermoacoustic instability models using binary classification
- 2013
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Ingår i: International Journal of Spray and Combustion Dynamics. - : SAGE Publications. - 1756-8277 .- 1756-8285. ; 5:3, s. 201-223
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Tidskriftsartikel (refereegranskat)abstract
- We apply binary classification theory to assess the (in)stability prediction accuracy of thermoacoustic models. It is shown that by applying such methods to compare a large set of stability predictions and experiments it is possible to gain valuable qualitative insight in different aspects of prediction quality. The approach is illustrated with a 2-port model and a large experimental data set. The presented framework provides an unified and practical tool to answer questions such as (i) What is the chance that a stable prediction will be correct? and (ii) How conservative is the model? It is shown that the most suitable quality indicator is strongly dependent on the actual purpose of the model. The method provides a solid starting point for model comparison and optimization.
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| 6. |
- Hoeijmakers, Maarten, et al.
(författare)
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Flame dominated thermoacoustic instabilities in a system with high acoustic losses
- 2016
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Ingår i: Combustion and Flame. - : Elsevier. - 0010-2180 .- 1556-2921. ; 169, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- The thermoacoustic stability behaviour of a flame is experimentally investigated in the presence of large acoustic losses. Recently it has become clear that under such conditions an instability can occur due to an intrinsic local feedbackloop at the heat source. The experimental results confirm that despite significant acoustic losses, thermoacoustic instabilities can still be present. These findings imply that the effectiveness of passive thermoacoustic damping devices is limited by the intrinsic stability properties of the flame. (C) 2016 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 7. |
- Hoeijmakers, Maarten, et al.
(författare)
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Flames in context of thermo-acoustic stability bounds
- 2015
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 35, s. 1073-1078
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Tidskriftsartikel (refereegranskat)abstract
- Bounds are derived for the acoustic losses such that a thermoacoustic system with a given flame can be guaranteed to be stable. The analysis is based on the flame's acoustic input-to-output properties represented by its scattering matrix. The developed analytical and numerical techniques allow estimating the maximum reflection coefficients (equivalently - acoustic losses) which are sufficient to ensure stable operation of a given burner. It is shown that the calculated numerical upper-bound is less conservative than the analytical one. The frequency dependence of the required acoustic losses provides (i) a thermo-acoustic signature of the flame and (ii) guidelines for the proper design of the up-and downstream acoustics from the flame. The method is illustrated on two burners/flames of premixed multiple Bunsen type. The frequency dependence of the upper bounds allows to identify those frequency ranges where the flame is more likely to cause instability of the complete system.
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| 8. |
- Hoeijmakers, Maarten, et al.
(författare)
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Intrinsic instability of flame-acoustic coupling
- 2014
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180 .- 1556-2921. ; 161:11, s. 2860-2867
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Tidskriftsartikel (refereegranskat)abstract
- This paper shows that a flame can be an intrinsically unstable acoustic element. The finding is clarified in the framework of an acoustic network model, where the flame is described by an acoustic scattering matrix. The instability of the flame acoustic coupling is shown to become dominating in the limit of no acoustic reflections. This is in contrast to classical standing-wave thermoacoustic modes, which originate from the positive feedback loop between system acoustics and the flame. These findings imply that the effectiveness of passive thermoacoustic damping devices is limited by the intrinsic stability properties of the flame.
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| 9. |
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| 10. |
- Lopez Arteaga, Ines, et al.
(författare)
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Improved source reconstruction in Fourier-based Near-field Acoustic Holography applied to small apertures
- 2012
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Ingår i: Mechanical systems and signal processing. - : Elsevier BV. - 0888-3270 .- 1096-1216. ; 32, s. 359-373
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Tidskriftsartikel (refereegranskat)abstract
- It is well known that Fourier-based Near-field Acoustic Holography fails to produce good source reconstructions when the aperture size of the microphone array is smaller than the source size. In this paper this problem is overcome by pre-conditioning the spatial hologram data using Linear Predictive Border Padding (LPBP) before it is Fourier-transformed to the wave-number domain. It is shown that LPBP allows for very small aperture sizes with a good reconstruction accuracy. An exhaustive analysis of LPBP is presented based on numerical experiments and measured data. The numerical experiments are performed on two different source types: modal patterns and point sources. These two types of sources represent the two limit situations that one can find in practice: modal patterns have a tonal spectrum in the spatial wave-number domain and are relatively easy to reconstruct accurately, while point sources have a broad-band wave-number spectrum which makes them very challenging to reconstruct. In order to illustrate the accuracy of the method in practice, results of measurements on a hard disk drive are presented as well. For a given distance to the source, the position and size of the hologram plane apertures is varied and the reconstructed source information is compared to the original source data. The reconstructed sources are compared both qualitatively and quantitatively. The results show that LPBP is an efficient and accurate extrapolation method, which leads to accurate reconstructions even for very small aperture sizes.
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| 11. |
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| 12. |
- Ploeg, Jeroen, et al.
(författare)
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Guest Editorial Introduction to the Special Issue on the 2016 Grand Cooperative Driving Challenge
- 2018
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - Piscataway, NJ : IEEE. - 1524-9050 .- 1558-0016. ; 19:4, s. 1208-1212
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Tidskriftsartikel (refereegranskat)abstract
- Cooperative driving is based on wireless communications between vehicles and between vehicles and roadside infrastructure, aiming for increased traffic flow and traffic safety, while decreasing fuel consumption and emissions. To support and accelerate the introduction of cooperative vehicles in everyday traffic, in 2011, nine international teams joined the Grand Cooperative Driving Challenge (GCDC). The challenge was to perform platooning, in which vehicles drive in road trains with short intervehicle distances. The results were reported in a Special Issue of IEEE Transactions on Intelligent Transportation Systems, published in September 2012 [item 1 in the Appendix].
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| 13. |
- Pogromsky, Alexander, et al.
(författare)
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On Diffusion Driven Oscillations in Coupled Dynamical Systems
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The paper deals with the problem of destabilization of diffusively coupled identical systems. It is shown that globally asymptotically stable systems being diffusively coupled, may exhibit oscillatory behavior. It is shown that if the diffusive medium consists of hyperbolically nonminimum phase systems and the diffusive factors exceed some threshold value, the origin of the overall system undergoes a Poincare-Andronov-Hopf bifurcation resulting in oscillatory behavior.
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| 14. |
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| 15. |
- Tateo, F., et al.
(författare)
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Design and experimental validation of a plate with internally resonating lattices for low-frequency vibro-acoustic control
- 2020
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Ingår i: Euronoise 2015. - : DC/ConfOrg. ; , s. 995-1000
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Konferensbidrag (refereegranskat)abstract
- A flexible plate and an internal resonating lattice are combined in an assembly which is characterized by high damping performance and tuned vibration attenuation at low frequencies. The resonating lattice consists of an elastomeric frame equipped with a metallic inclusion which is designed to resonate at selected frequencies. The system achieves high damping performance by combining the frequency-selective properties of internally resonating structures, with the energy dissipation characteristics of their constituent material. Furthermore, tuning and modifying the layout of the resonant lattice allows for tailoring of the resonating properties so that vibration attenuation is obtained over desired frequency ranges. Experimental results show the performances of the resonant assembly and suggest its potential application in vibrations and noise reduction.
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| 16. |
- Wang, Yuquan, 1985-, et al.
(författare)
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Filling the gap between low frequency measurements with their estimates
- 2014
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Ingår i: Robotics and Automation (ICRA), 2014 IEEE International Conference on. - : IEEE conference proceedings. ; , s. 175-180
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Konferensbidrag (refereegranskat)abstract
- The use of redundant sensors brings a rich diver-sity of information, nevertheless fusing different sensors thatrun at vastly different frequencies into a proper estimate isstill a challenging sensor fusion problem. Instead of using thesize-varying measurements and thereby the size-varying filtersduring each sampling period, we propose to find a substitute ofthe unavailable low frequency measurements such that we canavoid using different sampling frequencies in one filter. In thegap between the sampling of two low frequency measurements,the use of these substitutes produces smoother estimates. In boththe proof of concept simulation and the localization experimentperformed on an indoor soccer robot, our proposed approachexhibits an improved performance compared to the size-varyingKalman filter methods.
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