Tesis sobre el tema "Active vibration reduction"
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Ganguli, ABHIJIT. "Chatter reduction through active vibration damping". Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210980.
Texto completoThe regenerative process theory explains chatter as a closed loop interaction between the structural dynamics and the cutting process. This is considered to be the most dominant reason behind machine tool chatter although other instability causing mechanisms exist.
The stability lobe diagram provides a quantitative idea of the limits of stable machining in terms of two physical parameters: the width of contact between tool and the workpiece, called the width of cut and the speed of rotation of the spindle. It is found that the minimum value of the stability limit is proportional to the structural damping ratio for turning operations. This important finding provides the motivation of influencing the structural dynamics by active damping to enhance stability limits of a machining operation.
A direct implementation of active damping in an industrial environment may be difficult. So an intermediate step of testing the strategy in a laboratory setup, without conducting real cutting is proposed. Two mechatronic "Hardware in the Loop" simulators for chatter in turning and milling are presented, which simulate regenerative chatter experimentally without conducting real cutting tests. A simple cantilever beam, representing the MDOF dynamics of
the machine tool structure constitutes the basic hardware part and the cutting process is simulated in real time on a DSP board. The values of the cutting parameters such as spindle speed and the axial width of cut can be changed on the DSP board and the closed loop interaction between the structure and the cutting process can be led to instability.
The demonstrators are then used as test beds to investigate the efficiency of active damping, as a potential chatter stabilization strategy. Active damping is easy to implement, robust and does not require a very detailed model of the structure for proper functioning, provided a collocated sensor and actuator configuration is followed. The idea of active damping is currently being implemented in the industry in various metal cutting machines as part of the European Union funded SMARTOOL project (www.smartool.org), intended to propose smart chatter control technologies in machining operations.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
Boffa, John. "Model Reduction of Large Structural Systems for Active Vibration Control". University of Technology, Sydney. Faculty of Engineering, 2006. http://hdl.handle.net/2100/338.
Texto completoHuyanan, Satienpong. "An active vibration absorber for chatter reduction in machining". Thesis, University of Sheffield, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486712.
Texto completoBoffa, John. "Model reduction of large structural systems for active vibration control /". Electronic version, 2002. http://adt.lib.uts.edu.au/public/adt-NTSM20060317.113054/index.html.
Texto completoGan, Zengkang. "Adaptive control of an active seat for occupant vibration reduction". Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.665426.
Texto completoMartinovic, Zoran N. "Sensitivity of active vibration control to structural changes and model reduction". Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53641.
Texto completoPh. D.
LI, MINGFENG. "ACTIVE VIBRATION CONTROL OF A GEARBOX SYSTEM WITH EMPHASIS ON GEAR WHINE REDUCTION". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1115131866.
Texto completoClements, Kristen Lynn. "Active control of an automobile suspension system for reduction of vibration and noise". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30359.
Texto completoThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 79-82).
A new method for controlling road noise transmitted through the suspension system of an automobile was developed, using a Lincoln LS automobile as the target vehicle. In this vehicle, road surface roughness generates vibrations that are transmitted into the automobile primary through a single bushing (the "point 4 bushing") on each of the front suspension control arms. An electromagnetic actuator was designed, built, and tested on a Lincoln LS with simulated roads noise. The actuator applies a force across the point 4 bushing, in response to accelerations of the vehicle frame, just inboard of the bushing, with the goal of reducing the net forces transmitted into the vehicle frame, which ultimately produce unwanted interior noise. Several tonal controllers were developed, each designed to operate in a narrow frequency band, and to eliminate the cross member (frame) vibration just inside the point 4 bushing. The tonal controllers were able to eliminate cross member vibration at the desired frequency. Eliminating the cross member vibration resulted in modest reductions interior sound levels. A successful vibration control system (in this vehicle) would need to eliminate cross member vibrations over frequency range 100 to 200 Hz. However, a broadband controller with this electromagnetic actuator system proved to be difficult, due to undesirable non-minimum phase dynamics.
by Kristen Lynn Clements.
S.M.
Curtis, A. R. D. "The theory and application of quadratic minimization in the active reduction of sound and vibration". Thesis, University of Southampton, 1988. https://eprints.soton.ac.uk/52272/.
Texto completoBecker, Jens. "Semi-active control of friction dampers and feedforward tracking control design for structural vibration reduction". Tönning Lübeck Marburg Der Andere Verl, 2009. http://d-nb.info/995846200/04.
Texto completoHuang, Haoyu. "A temperature controlled semi-active tuned mass damper using shape memory alloy for vibration reduction applications". Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720664.
Texto completoBrakna, Mohammed. "Sensor and actuator optimal location for dynamic controller design. Application to active vibration reduction in a galvanizing process". Electronic Thesis or Diss., Université de Lorraine, 2023. https://docnum.univ-lorraine.fr/ulprive/DDOC_T_2023_0152_BRAKNA.pdf.
Texto completoThe aims of the present PhD thesis are to determine a model that is both sufficiently accurate and numerically exploitable to propose optimal placement of sensors and actuators for active vibration control in a galvanizing line. A continuous hot-dip galvanizing process consists in covering a metal (here: a steel band) by a protective layer of zinc which avoids the corrosion due to the air. The thickness of this layer must be constant to guarantee the mechanical properties and surface condition of the product. In a galvanizing line, the moving steel strip is heated and then immersed in a liquid zinc bath before being wiped out by nozzles projecting air. The air flow, as well as the rotation of the driving rolls, among other things, creates vibrations affecting the wiping process and thus the regularity of the zinc deposit. Active control is therefore necessary, for example by means of electromagnets placed on either side of the moving steel strip. In a first step, a behavioral model of the steel strip taking into account the presence and propagation of vibrations was obtained by spatial discretization of a partial differential equation. This state space model was validated in simulation and experimentally on a pilot galvanizing line of ArcelorMittal Research in Maizières-lès-Metz. Once this model is established, the objective of the study is to find the optimal placement of sensors, to measure the vibrations of the strip as efficiently as possible, but also of actuators to minimize the amplitude of these vibrations by an appropriate control law. These problems of optimal placement are at the heart of the issues of active vibration control and are found in many fields of application. An optimal placement method based on Gramian maximization has been proposed in order to reduce the impact of disturbances on the system. Different control strategies have been considered such as (i) observed state feedback based on Kalman filter and LQ regulator; and (ii) extended observed state feedback to improve the results by also taking into account the disturbance estimation provided by a PI (proportional-integral) observer. Simulation and experimental results illustrate the thesis contributions
Wang, Peng. "Active vibration control in a specific zone of smart structures". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEC007/document.
Texto completoThis research aims at solving a particular vibration control problem of smart structures. We aim at reducing the vibration in a specific zone of the smart structure under the disturbance that covers a wide frequency band. Moreover, at this specific zone, neither actuation nor sensing is possible.Here we face several main challenges. First, we need to control the vibration of a specific zone of the structure while we only have access to measurements at other zones. Second, the wide bandwidth of the disturbance implies that numerous modes should be controlled at the same time which requires the use of multiple actuators and sensors. This leads to a MIMO controller which is difficult to obtain using classical controller design methods. Third, the so-called spillover problem must be avoided which is to guarantee the closed-loop stability when the model-based controller is applied on the actual setup. To tackle these challenges, we investigate two control strategies: the centralized control and the distributed control.For centralized control, we propose a methodology that allows us to obtain a simple MIMO controller that accomplishes these challenges. First, several modeling and identification techniques are applied to obtain an accurate low-order model of the smart structure. Then, an H_∞ control based synthesis method with a particularly proposed H_∞ criterion is applied. This H_∞ criterion integrates multiple control objectives, including the main challenges. In particular, the spillover problem is transformed into a robust stability problem and will be guaranteed using this criterion. The obtained H_∞ controller is a standard solution of the H_∞ problem. The final controller is obtained by further simplifying this H_∞ controller without losing the closed-loop stability and degrading the performance. This methodology is validated on a beam structure with piezoelectric transducers and the central zone is where the vibration should be reduced. The effectiveness of the obtained controller is validated by simulations and experiments.For distributed control, we consider the same beam structure and the same control objectives. There exist methods aiming at designing distributed controllers of spatially interconnected system. This research proposes a FEM based method, combined with several model reduction techniques, that allows to spatially discretize the beam structure and deduce the state-space models of interconnected subsystems. The design of distributed controllers will not be tackled in this research
Beck, Benjamin Stewart. "Negative capacitance shunting of piezoelectric patches for vibration control of continuous systems". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45850.
Texto completoKim, Taeho y Monika Ivantysynova. "Active Vibration Control of Axial Piston Machine using Higher Harmonic Least Mean Square Control of Swash Plate". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199412.
Texto completoBai, Hao. "Machine learning assisted probabilistic prediction of long-term fatigue damage and vibration reduction of wind turbine tower using active damping system". Thesis, Normandie, 2021. http://www.theses.fr/2021NORMIR01.
Texto completoThis dissertation is devoted to the development of an active damping system for vibration reduction of wind turbine tower under gusty wind and turbulent wind. The presence of vibrations often leads to either an ultimate deflection on the top of wind tower or a failure due to the material’s fatigue near the bottom of wind tower. Furthermore, given the random nature of wind conditions, it is indispensable to look at this problem from a probabilistic point of view. In this work, a probabilistic framework of fatigue analysis is developed and improved by using a residual neural network. A damping system employing an active damper, Twin Rotor Damper, is designed for NREL 5MW reference wind turbine. The design is optimized by an evolutionary algorithm with automatic parameter tuning method based on exploitation and exploration
Sangili, Vadamalu Raja [Verfasser], Christian [Akademischer Betreuer] Beidl y Stephan [Akademischer Betreuer] Rinderknecht. "Estimation and Control Methods for Active Reduction of Engine-Induced Torsional Vibration in Hybrid Powertrains / Raja Sangili Vadamalu ; Christian Beidl, Stephan Rinderknecht". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2018. http://d-nb.info/1193177944/34.
Texto completoVadamalu, Raja [Verfasser], Christian [Akademischer Betreuer] Beidl y Stephan [Akademischer Betreuer] Rinderknecht. "Estimation and Control Methods for Active Reduction of Engine-Induced Torsional Vibration in Hybrid Powertrains / Raja Sangili Vadamalu ; Christian Beidl, Stephan Rinderknecht". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2018. http://d-nb.info/1193177944/34.
Texto completoMin, Byung-Young. "A physics based investigation of gurney flaps for enhancement of rotorcraft flight characteristics". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33851.
Texto completoFarah, Philippe-Siad. "Étude de la réduction des vibrations des machines synchrones". Grenoble INPG, 1995. http://www.theses.fr/1995INPG0087.
Texto completoKarim, Yassine. "Caractérisation robuste de liaisons amortissantes avec dispositifs piezo-électriques pour la réduction de vibrations de structures". Phd thesis, Conservatoire national des arts et metiers - CNAM, 2013. http://tel.archives-ouvertes.fr/tel-00953330.
Texto completoBrinkschulte, Lars, Marina Graf y Marcus Geimer. "Reinforcement learning: a control approach for reducing component damage in mobile machines". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71113.
Texto completoKartha, Satish Chandrashekhar. "Active, Passive and Active/Passive Control Techniques For Reduction of Vibrational Power Flow in Fluid Filled Pipes". Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/31156.
Texto completoMaster of Science
Opfer, Holger. "Active cancellation of 3D Tollmien-Schlichting waves in the presence of sound and vibrations". Doctoral thesis, Köln : Dt. Zentrum für Luft- und Raumfahrt e.V., Bibliotheks- und Informationswesen, 2002. http://www.gbv.de/dms/goettingen/370770838.pdf.
Texto completoBoultifat, Chaouki Nacer. "Contrôle acoustique actif du bruit dans une cavité fermée". Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2019. http://www.theses.fr/2019IMTA0134/document.
Texto completoThis thesis deals with active noise control (ANC) in a cavity. The aim is to mitigate the effect of a disturbing sound wave at some points or in a volume. This is achieved using ananti-noise generated, for example, by a loudspeaker. This study requires the use of dynamic models that report changes in pressure at points of interest in response to exogenous noises. Such models can be obtained by frequency identification of point-to-point responses or by using the underlying physical model (wave equation). In the latter case, the search for a low-complexity model (finite dimensional model) is often a prerequisite for the conceptual study of an active control system. The contributions of this thesis concern the development of different simplified models parameterized by the spatial position for acoustic systems, and the design of control laws for noise attenuation. The first part of the thesis is dedicated to the development of various simplified models of acoustic propagation system within a cavity. For that, the simplifications envisaged can be of spatial nature as much as frequential. We show in particular that it is possible, under certain conditions, to approximate the 3D system by a 1D system. This has been demonstrated experimentally on the prototype system, LS2NBox. The second part of the thesis deals with the design of control laws. First, the control strategies commonly used for ANC are compared. The effect of multi-objective H control at different spatial positions close to the attenuation points is analyzed. The possibility of perfect noise cancellation at one point is also discussed
Wei, Jyh-Yang y 魏志揚. "Vibration reduction and stability analysis of H_infinite active control systems". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/54949820670691377701.
Texto completo國立中興大學
土木工程學系
87
In this study,H-infinite control algorithm is applied to reduce the structural responses under seismic loads. Two kinds of controlled outputs, named “displacement controlled output” and “energy controlled output” are presented to design the optimal controller for structures equipped with active tendon systems. The value of parameters alpha and gamma are selected based on the desired control efficiency. The decrease of alpha or increase of gamma will result in larger control forces and better effectiveness in reducing structural responses. Larger has to be selected for stiff structures to achieve the same control effectiveness than flexible structures. The influence of structural modeling error on the accuracy of estimating controlled frequencies and damping ratios was also investigated. It is found that control system with displacement controlled output are primarily affected by the errors of structural fundamental period, whereas the “energy controlled output” systems are more sensitive to the errors of structural original damping ratio. In active control systems, control force execution time delay cannot be avoided. Small delay time not only can render the control ineffective, but also may cause the system instability. The maximum delay time for system instability increased with increasing structural original damping ratios or selecting smaller alpha in which the stability of control system are dominated by lower modes. In the final part of this thesis, an optimal time-delayed H-infinite control algorithm is developed for discrete-time systems. According to the proposed control algorithm, the structural system is assured to remain stable and the control effectiveness is not degraded even with the presence of time delay.
Fu, Yu-Ting y 傅俞婷. "Vibration Reduction of H-infinity Discrete-Time Active Control Systems with Time Delay". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/12101587003517304630.
Texto completo國立中興大學
土木工程學系所
98
In recent years, with numerous theoretical development and experimental verifications, both active and semi-active structural control systems have been accepted and implemented to control wind- or earthquake-induced vibration of buildings around the world. In addition, due to flexibility, reliability, and high speed, digital computers have been used for on-line signal processing and calculation of control forces in real-time control. Therefore, it is more logical and more realistic to formulate the control systems in discrete-time fashion prior to their implementation. In this study, an optimal discrete-time control algorithm is developed to reduce the structural seismic responses. Both sampling period and control force execution time delay are considered to derive the optimal state feedback gains. Discrete-time control forces are then calculated from the multiplication of output measurements by the pre-calculated time-invariant delayed gain matrix. Parametric studies of a single-degree-of-freedom (SDOF) system demonstrate the relationships of the delayed gains and the modal properties corresponding to the sampling period used and the intentionally added delay time. To achieve optimal control performance, the strategy to select both control parameters and was investigated extensively. Numerical verification results show that decrease in or increase in yields better control performance with an acceptable magnitude of control force. The selective ranges of and making a controlled system become overdamped or unstable were found. To assure system stability and better performance than LQR control, the upper and lower bounds of and are derived and illustrated graphically. An optimal design flowchart is also proposed.
XUE, WEN-ZHENG y 薛文証. "Study on the reduction of mast vibration and radar interference by active control system". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/66085440420911201966.
Texto completoThakkar, Dipali. "Helicopter Vibration Reduction Using Single Crystal And Soft Piezoceramic Shear Induced Active Blade Twist". Thesis, 2005. https://etd.iisc.ac.in/handle/2005/1477.
Texto completoThakkar, Dipali. "Helicopter Vibration Reduction Using Single Crystal And Soft Piezoceramic Shear Induced Active Blade Twist". Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1477.
Texto completoChen, Lin-Hung y 陳林宏. "Studies on Active and Passive Constrained Layer Damping for the Vibration Reduction of Cylindrical Shells". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/01040505749418225219.
Texto completo國立臺灣科技大學
機械工程系
87
This investigation presents vibration response of cylindrical shells with passive and active constrained layer damping (CLD) treatments. The research topics include cylindrical shell with passive constrained layer damping (PCLD), active constrained layer damping (ACLD) and active control (AC). A thin shell theory in conjunction with the Donnell-Mushtari-Vlasov assumptions is employed to yield models for all cases. The assumed-mode method follows to discretize the energy expressions and subsequently yields the equations of motion. As to ACLD, it is formed from PCLD by replacing with the constraining layer, a piezoceramic-based (PZT) self-sensing actuator. The proportional plus the derivative (PD) and the positive position feedback (PPF) control laws are discussed in ACLD and AC cases. To yield the equations of motion of AC case, one simply lets the viscoelastic material (VEM) vanish from the ACLD case. The numerical results emphasize not only the effects of treatment length, of constraining layer (CL) thickness and stiffness, and of VEM thickness for PCLD, but also the comparison of PD and PPF controls, for ACLD and AC. The effect of VEM layer to control force reduction is discussed as well. The results of this research, to the knowledge of the author, are original and provide the engineers useful information about damping effects due to various parameters for PCLD, ACLD and AC treatments and the comparison in between.
Sangili, Vadamalu Raja. "Estimation and Control Methods for Active Reduction of Engine-Induced Torsional Vibration in Hybrid Powertrains". Phd thesis, 2018. https://tuprints.ulb.tu-darmstadt.de/9007/7/Vorlage_Dissertation_a5.pdf.
Texto completoYang, Tzu-Hung y 楊子弘. "The Study of Using Hybrid Shape Memory Helical Spring in the Vibration Reduction of Semi-Active Suspension Platform". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/98650449250197470740.
Texto completo大葉大學
機械與自動化工程學系
97
In this study, the natural frequency and the associated damping capacity of a platform suspended by four helical springs were investigated at different controlled temperatures. The helical spring was fabricated with multiple layers of pyro condensation polymeric sleeve wrapped outside a superelastic NiTi core which has been heat-treated into helical configuration beforehand. The dynamic characteristics of the hybrid shape-memory helical spring was first investigated experimentally. It was found that the first natural frequency of the spring can be decreased to 50% of the frequency at room temperature when the temperature was raised to 90oC. On the other hand, a decrease in the damping capacity of the spring was found accompanying the increase in temperature. Then, the change in the natural frequency of a platform supported by four helical springs was studied. The prediction of the natural frequency of the first few lower modes of the sprung-mass correlated well with the result from measurement. Moreover, we demonstrated the displacement amplitude of vibration for the platform under eccentric loading of imbalance mass was reduced significantly with the control temperature raised to 90℃.
Ke, Jian-Cheng y 柯建呈. "Development of semi-active control for vibration reduction of structural systems using Duffing-like model and magnetorheological damper". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/896d6s.
Texto completoWrona, Stanisław. "Modelling and control of device casing vibrations for active reduction of acoustic noise". Rozprawa doktorska, 2016. https://repolis.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=37786.
Texto completoWrona, Stanisław. "Modelling and control of device casing vibrations for active reduction of acoustic noise". Rozprawa doktorska, 2016. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=37786.
Texto completoHsin-ChangLi y 李信昌. "A Study on the Characteristics and Reduction of Ground Vibrations Generated by Surface and Seismic Loads Acting on Layered Soils". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/02573003768243487832.
Texto completo國立成功大學
土木工程學系碩博士班
101
This thesis investigates the dynamic characteristics of wave propagation in elastic layered soils. Both the theoretical matrix and finite element methods are employed to simulate the three-dimensional (3D) wave propagation in elastic layered soils with a harmonic point load acting on the surface. Using various multi-layer soils in which harmonic point loads act on the ground surface in the horizontal or vertical directions, these two methods are adopted to solve the steady state solutions of both horizontal and vertical displacement distributions along the direction of wave propagation. In order to confirm the accuracy and reliability of the two assessment methods, it is necessary to compare their results, although few studies have undertaken this task. Moreover, in order to increase efficiency and reduce demands on the computer’s HD capacity, we utilize the theoretical matrix method to further investigate the vibration features of surface wave propagation, especially the irregular hump activity due to Love wave motion. With regard to validating the simulation results, an experimental approach is carried out by measuring the ground vibration from a high speed train. Two typical locations represented the layered and homogeneous soils respectively are selected to perform the tests. A series of test devices were installed to undertake the in situ measurements and analyses of the vibrations induced by a high speed train. The results reveal that low frequency waves might propagate farther than high frequency ones. Besides, SH propagations in layered soils could possibly generate irregular ground vibrations, which may threaten the safety of buildings. However, such irregular vibration phenomena would not occur in homogeneous soils. This study thus also considers how to reduce the ground vibration caused by various external loadings. In addition to a parametric study, a 3D time-domain finite element method is used to analyze the isolation efficiency of open trenches filled with different levels of water. The results indicate that the Y direction wave is difficult to reduce in the water trench, especially for low frequency waves. Meanwhile, field experiments with a full water trench are used to validate this finite element model, and the results show an acceptable level of agreement. Finally, this thesis also considers the safety of high speed trains affected by the ground vibration due to seismic wave propagating in layered soils. Since Taiwan in located in a high risk earthquake zone, we developed a finite element model to simulate the derailment of trains moving on embankments under seismic loading. The results show that the rail irregularities and the resonance between the train and earthquake play an important role in train derailment.