Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 8

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  plate vibrations
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
EN
The paper describes briefly some main aspects of the active feedback control system that has been developed and constructed for reduction of vibroacoustic emission of vibrating plate structures with arbitrary boundary conditions. Relations between the forms and frequency of the vibrations induced by an external harmonic excitation and the distribution of the generated acoustic pressure field are investigated using the developed numerical model based on indirect variational boundary element method. The aim of the control system is to minimize the sound pressure level in a given point of the ambient space. The system uses small, rectangle-shaped piezoelectric transducers as both sensors and actuators. The transducers are connected in a number of independent feedback loops, and the feedback gains are the control parameters which are optimized using the developed optimal control algorithm. The constructed active system has been tested for the stability and control performance during experimental research performed in an anechoic chamber. Results of experiments are presented in the paper, proving a high level of noise reduction and a good agreement with numerical predictions.
2
Content available remote Vibration Suppression of Composite Plate with MFC Active Elements
EN
Application of the Macro Fiber Composite (MFC) as active elements for suppression of composite plate vibrations is presented in this paper. Vibrations are reduced by the Nonlinear Saturation Control (NSC) method. Effectiveness of the algorithm is tested in Matlab package using a reduced model of a plate. The numerical results are verified experimentally.
4
Content available remote Predictive feedback approach to structural vibration suppresion
EN
The problem of active vibration control of a plate has been vastly researched and described in recent years. Theoretical and experimental results demonstrate the effectiveness of the designed controllers and indicate the potential of control techniques for reducing transient and steady state dynamics in structural acoustic systems. The examples from the computational studies, confirmed that vibration levels could be effectively reduced, however, the implementation procedures are not yet ideal, still exists the gap between experimental and simulations findings. To overcome this problem, autors propose extension for the Fuzzy-PID controller, with an on-line identification technique coupled with a control scheme, for a plate vibrationsupression. It is assumed, that the system to be regulated is unknown, the control schemes presented in this work have the ability to identify and suppress a plate vibrations with only an initial estimate of the system order. A prediction method implemented was designed using a neutral network (NN) identification algorithm, based on the well-known Runge-Kutta methods. This algorithm is similar to described by Wang and Lin [14], but it uses a copmutation structure of Runge-Kutta-3/8. with radial cosine basis neural network.
EN
In this paper, predictive feedback control is used to suppress circular plate vibrations. It is assumed that the system to be regulated is unknown. The plate is excited by a uniform force over the bottom surface generated by a loudspeaker. The axially-symmetrical vibrations of the plate are measured by the application of the strain sensors located along the plate radius and two centrally placed piezoceramic discs are used to cancel the plate vibrations. The control schemes presented in this work have the ability to predict the error sensor signals, to compute the control effort and to apply it to the actuator within one sampling period. For precise estimation of system behaviour the modified Runge-Kutta-3/8 neural network algorithm has been applied and tested. This control scheme is then illustrated through some numerical examples with simulations modeling the fuzzy predictive P-PI-PD controller and the improvement gained by incorporating a feed-forward path into the controller is demonstrated.
EN
This paper presents the problem of the active vibration control of a simply-supported circular plate. The plate is excited by an uniform force over the bottom surface generated by a lodspeaker. The axially-symmtrical vibrations of the plate are measured by the application of the four accelometers located along the plate radius. The mathematical model of the plate was obtained by using analytical methods, as well as, on a base of regisrtation of a system response on a fixed excitation (a parametric system identification procedure has been employed). Firstly, a modal model for the vibration of the considered structure is presented and the state realisation of the model is given. Secondly. the OE (Output Error) identification method is used to derive the reduced linear model in the form of a transfer function of the second order. The obtained model is used to develop the linear feedback control algorithm for the cancellation of vibration by using the point force provided by a shaker (SIMO system). Finally, the laboratory results obtained for the considered plate are presented. The results show that in the chosen low-frequency limit the designed structure of a closed-loop system provides a substantial vibration suppression.
EN
The paper presents a system identification and simulation of active vibration control for a clamped circular plate as well as its expermental implementation. The model is based upon the geometry and properties of an experimental set-up consisting of a hard-walled cylinder ith a thin plate at one end. The primary excitation is provided by a low frequency loudpeaker installed centraly at the bottom of the cylinder. Vibrations of the plate are measured by the application of several pairs of strain sensors located along the plate radius. The derived control action is applied to the plate by one shaker attached pointwise in its middle (SIMO system). In particular, obtained numerical values and structure of dynamical model are used to develop the P-PID control algorithm for vibration cancellation. Finally, the laboratory results obtained for the considered plate are presented.
EN
In this paper, the authors describe progress on the development of a hybrid (active/passive) scheme for use in adaptive structures. An aluminium plate is employed as the demonstrator. The technique is based upon the use of a finite element model of the plate, extended to include passive control in the form of viscoelastic and constraining layers. Experimental results are presented to demonstrate the validity of the finite element model of the plate. Onto this framework is superimposed an active control scheme, formulated in modal state space. Emphasis is placed upon model reduction to obtain a low-order controller and to minimise the spillover effects which are induced when such controllers are implemented. Through a series of numerical experiments, it is shown how the presence of passive control introduces damping to improve robustness of modal control strategies. The paper concludes with a discussion of issues which remain to be resolved.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.