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Leuven, Belgium

Stallaert B.,Catholic University of Leuven | Pinte G.,Flanders Technology Center | Sas P.,Catholic University of Leuven | Desmet W.,Catholic University of Leuven | Swevers J.,Catholic University of Leuven
Mechanical Systems and Signal Processing | Year: 2010

This paper describes the application of a novel design strategy for iterative learning and repetitive controllers for systems with a high modal density, presented in the companion paper, on two experimental case studies. Both case studies are examples of active structural acoustic control, where the goal is to reduce the radiated noise using structural actuators. In the first case study, ILC is used to control punching noise. An electrodynamic actuator on the frame of the punching machine is driven by the ILC algorithm which takes advantage of the repetitiveness of the consecutive impacts to reduce noise radiation. In the second case study, an RC algorithm is used to control the noise radiated by rotating machinery, which is often mainly periodic. A piezoelectric actuator incorporated in the bearing is driven by the RC algorithm which is capable of reducing harmonics of the rotational frequency of the shaft. Both applications show the practical usefulness of the novel design strategy. © 2009 Elsevier Ltd. All rights reserved. Source


Pinte G.,Flanders Technology Center | Stallaert B.,Catholic University of Leuven | Sas P.,Catholic University of Leuven | Desmet W.,Catholic University of Leuven | Swevers J.,Catholic University of Leuven
Mechanical Systems and Signal Processing | Year: 2010

This paper discusses the design and application of iterative learning control (ILC) and repetitive control (RC) for high modal density systems. Typical examples of these systems are structural and acoustical systems considered in active structural acoustic control (ASAC) and active noise control (ANC) applications. The application of traditional ILC and RC design techniques, which are based on a parametric system model, on systems with a high modal density has several important drawbacks: the design procedure is complex, the controllers require much computational power and the robustness of the controllers is low. This paper describes a novel strategy to design noncausal ILC and RC filters, which is especially suited for high modal density systems. Since it does not require a parametric system model, the novel strategy avoids several drawbacks of the traditional techniques: no cumbersome parametric model estimation is required; the ILC and RC controllers are robust to small changes of the poles and zeros of the controlled system; and the complexity of the ILC and RC control filters is restricted. A crucial element in the proposed strategy is the noncausal filtering in the ILC and RC controllers, which requires the availability of a trigger signal to announce a new ILC trial or RC period in advance. A numerical validation on a simulation model proves the potential of the developed strategy. © 2009 Elsevier Ltd. All rights reserved. Source


Zhao G.,Catholic University of Leuven | Pinte G.,Flanders Technology Center | Devos S.,Flanders Technology Center | Swevers J.,Catholic University of Leuven | Sas P.,Catholic University of Leuven
International Conference on Noise and Vibration Engineering 2012, ISMA 2012, including USD 2012: International Conference on Uncertainty in Structure Dynamics | Year: 2012

This paper presents an axisymmetric rotational inertia shaker for reducing the structure borne noise radiated by rotating machinery. This modular inertia shaker uses a piezostack to generate a compensating force on a rotating element by accelerating a ring shaped mass. The piezostack is controlled using an adaptive shunt circuit, which emulates the impedance of a variable inductance. The inertia shaker is tested on an experimental test bed where a disturbance force excites a rotating shaft, which is mounted in a frame. As a result, noise is radiated by a plate that is attached to the frame. The performance of the inertia shaker is first evaluated during non-rotating tests. When the virtual inductance is tuned optimally, a shaft vibration reduction of more than 12 dB and a corresponding noise reduction of 9 dB are obtained. Afterwards, the performance has also been checked during a rotating test. A comparable reduction as in the non-rotating tests is obtained when the piezostack is in the same direction as the disturbance force, while there is nearly no reduction when the piezostack is in the perpendicular direction to the disturbance. © (2012) by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved. Source


Ompusunggu A.P.,Flanders Technology Center | Ompusunggu A.P.,Catholic University of Leuven | Janssens T.,Catholic University of Leuven | Sas P.,Catholic University of Leuven
International Conference on Noise and Vibration Engineering 2012, ISMA 2012, including USD 2012: International Conference on Uncertainty in Structure Dynamics | Year: 2012

Wet friction clutches have become widely used in today's transmissions, e.g. automatic transmissions, dual clutch transmissions, etc. It is known that the central role of this particular component is strongly determined by its friction characteristics. While a clutch is in use, degradation inevitably takes place that consequently deteriorates its friction characteristics. However, to the authors knowledge, how the friction characteristics evolve with the clutch degradation progression is not fully understood yet. A profound understanding of the clutch friction characteristics during its lifetime can improve our knowledge, which enable us to model and simulate the dynamic engagement behavior of a clutch with the progression of the degradation. Eventually, the gained knowledge can aid in deriving physical features, which are useful for clutch monitoring, prognostics and adaptive control. This study aims at experimentally investigating the sliding friction characteristics of a wet friction clutch during its lifetime. More precisely, the objective of the study is to understand how the Stribeck and the frictional lag (i.e. sliding hysteresis) parameters evolve as the degradation progresses. For this purpose, a novel test procedure is proposed and the test is carried out on a fully assembled (commercial) clutch using a modified SAE#2 test setup. The clutch consists of a predefined number of commercial friction and separator discs and is lubricated with a commercial automatic transmission fluid (ATF). Furthermore, a systematic methodology for the identification of the Stribeck and the frictional lag parameters is proposed. The experimental results reveal that the identified parameters evolve deterministically during the clutch lifetime. © (2012) by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved. Source


Pinte G.,Flanders Technology Center | Devos S.,Flanders Technology Center | Stallaert B.,Catholic University of Leuven | Symens W.,Flanders Technology Center | And 2 more authors.
Journal of Sound and Vibration | Year: 2010

This paper presents an active bearing for reducing the radiated structure borne noise of rotating machinery. This modular bearing uses piezostacks to generate secondary forces in the vibration transmission path of the controlled structure. The bearing is tested on an experimental test bed comprising a rotating shaft, which is mounted in a frame. Noise is radiated by a plate that is attached to the frame. To evaluate different control approaches, a simplified model of the set-up was made. Based on the simulation results, a combination of feedback and repetitive control is implemented, using a force and acceleration measurement. This way, a noise reduction of more than 10 dB is achieved at the most important resonance frequencies of the system below 1 kHz. © 2009 Elsevier Ltd. All rights reserved. Source

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