Browsing by Subject "vibration control"

Now showing 1 - 14 of 14

Access status: Open Access ,
Active coil-core system as a part of rigid body support and its influence on the body vibrations
(2012) Kondratiuk, Mirosław; Gosiewski, Zdzisław; Ambroziak, Leszek
In the paper we took into account the influence of the actively controlled coil dampers introduced into vibrating body supports. The body was considered as moving mass centre of 3-degrees-of-freedom. Investigated object was located on four supports. Body dynamics was described by means of Newton and Euler equations. Body vibrations were caused by statically unbalanced rotor located inside the object. In the control system the coils with the movable cores were used as the executive elements (controllable stiffness). In the closed-loop system the PD regulators were introduced into each support. The coils current was controlled by means of pulse width modulated (PWM) generators. In the article we presented the time characteristics and the frequency responses of the investigated system. Differences between open (non-controlled) and closed-loop (actively controlled) system were shown. Responses to the rotor perturbations were also calculated. Finally, the main advantages and disadvantages of the proposed solution were discussed. The further work directions were also indicated.
Access status: Open Access ,
Experimental study of vibration control in a two-degree-of-freedom pitch-plane model of a magnetorheological vehicle suspension
(Wydawnictwa AGH, 2007) Martynowicz, Paweł; Sapiński, Bogdan
The paper concerns the vibration control in a two-degree-of-freedom model of vehicle suspension equipped with independently controlled MR dampers in front and rear sections. The suspension model was tested in open-loop and feedback system configurations under harmonic and square base excitations. The experiments were conducted on the specially designed laboratory setup with data acquisition and control system configured in MATLAB/Simulink environment. The obtained results reveal effectiveness of MR dampers in vibration isolation for a wide range of excitation frequencies.
Access status: Open Access ,
Experimental study of vibration control in a 3 DOF pitch-plane model of an MR vehicle suspension
(Wydawnictwa AGH, 2007) Sapiński, Bogdan; Martynowicz, Paweł
The paper is concerned with the experimental study of vibration control in a vehicle suspension model equipped with independently controlled magnetorheological (MR) dampers in front and rear sections of the vehicle body, and in the driver's seat suspension. Pitch-plane suspension model with one pitch degree of freedom (DOF) and two bounce DOFs was considered. The system was tested under harmonic excitations with an open loop and feedback. Performance of standard skyhook controller was compared with cascade controllers, in which the reference resistance forces determined by linear-quadratic or skyhook principles were fed to the inverse model of an MR damper. The tests were conducted in the experimental setup with measurement and control system configured in MATLAB/Simulink environment.
Access status: Open Access ,
Identification of flexible structure model for piezoelectric vibration control
(Wydawnictwa AGH, 2005) Gosiewski, Zdzisław
Modern structures are light and compliance. Therefore, they are strongly influenced by external and internal perturbations. To reduce the structure vibrations the active vibration controls systems are designed. When active control of flexible structures is sought, three items must be individually and simultaneously considered. 1) The creation of reduced-order models. 2) Placement of sensors and actuators. 3) Countermeasures for spillover. All these problems are particularly important in the case of active system with parameter-distributed piezoelectric sensors and actuators. The glued piezoelectrics and their amplifiers change the structure parameters and should be taken into account in the model of the open-loop system. In the paper we consider an identification method which leads directly to the reduced-order model of the open-loop system. Analytical and experimental investigations were carried out for flexible beam with fixed one end and with opposite free end. Piezoelectric strips were glued on both sides of the beam: one works as a sensor and second one as an actuator. It means that we have designed single input single output system. It is appeared that used amplifier works as a low-pass filter which cuts-off the high-frequency dynamic effects. The frequency response function (FRF) was recorded and model of open-loop system was adjusted to experimental results. Taking into account the theory of reduced-order model of flexible structures we can state that resonances are connected with poles while anti-resonances with zeros of system transfer function. The resonance and anti-resonance frequencies were used directly in the model while damping coefficients were calculated by using of the least-square sum method. In the next step some control laws were used to damp the vibration of the beam. The proper control law was chosen with help of computer simulations. The active control loop rapidly accelerates the vanishing of the impulse-excited transient vibrations of the structure. Experimental results confirmed the analytical considerations.
Access status: Open Access ,
Magnetic spring as the element of vibration reduction system
(2010) Snamina, Jacek; Habel, Piotr
The paper presents the operating principle, experiments and calculations of a magnetic spring. Force exerted by the magnetic spring is a result of interaction of magnetic fields formed by magnets and coils. The stiffness of the spring can be modified by changing the current in coils. The paper presents FE model of the spring. Static characteristic of the spring were determined using results of FE method calculations and experiments. The magnetic spring with switched stiffness was employed in one degree of freedom system.
Access status: Open Access ,
Magnetorheological dampers in vibration control of mechanical structures
(Wydawnictwa AGH, 2009) Sapiński, Bogdan
The paper summarizes the experimental data gathered during the laboratory tests of vibration control of three mechanical structures utilizing magnetorheological (MR) dampers. The author's research program involved the investigations of the structures. The first application refers to vibration control in a driver's seat suspension (structure 1). The control objective is to reduce vertical acceleration of the driver. The second application covers vibration control in a pitch plane vehicle suspension (structure 2). The control objective is to reduce vertical and angular accelerations of the vehicle. The third application concerns vibration control of a suspended cable (structure 3). The control objective is to reduce transverse free vibrations of the cable. The obtained results demonstrate system performance improvement achieved through the control of MR damper(s).
Access status: Open Access ,
Modelling and control of structure-acoustic interaction problems via piezoceramic actuators
(Wydawnictwa AGH, 2005) Leniowska, Lucyna
Active control of vibration suppression of a circular fluid-loaded plate is analytically studied. The purpose of this theoretical work is to present a general model of a planar vibrating structure located in a finite baffle and interacted with fluid as well as its time response on harmonic excitation when a control strategy is applied. The structure under study is a vibrating circular plate of radius a, having a constant thickness h, to which centrally placed circular shaped piezoeleetric ceramic patches of radius a1 a are bonded. They are used to cancel the plate vibrations and related sound field when a controlling voltage is applied. It was assumed, that the plate clamped at the edge is excited on one side by a uniform periodic force with a constant amplitude F0 and it radiates the acoustic waves into a surrounded fluid of density Po. The control problem lies in using piezoceramic actuators working in a pair to reduce the plate vibrations. For the system under consideration the state-space model is constructed. The modern control theory is then applied to the system model using a linear quadratic regulator (LQR). The simulations of the active attenuation of the plate vibrations were made with a MATLAB/Simulink computer program, The results demonstrate that it is possible to achieve a significant reduction of the vibration amplitude with the use of a pair PZT actuators.
Access status: Open Access ,
Skyhook vibration control with energy regenerative system
(Wydawnictwa AGH, 2009) Snamina, Jacek; Podsiadło, Andrzej Bogumił; Orkisz, Paweł
In the paper two-degree-of-freedom system with self-powered active control was considered. The skyhook control scheme was assumed in calculation. The DC motor was used as the energy regenerative damper that converts the vibration energy into electric energy. The regenerative energy was stored in capacitor or battery. The results of numerical simulation of the motion excited by random process were presented and the analysis of energy balance in the system was estimated.
Access status: Restricted ,
Sterownik drgającej belki wykonany w technologii FPGA
(Data obrony: 2017-01-19) Zielonka, Piotr
Wydział Elektrotechniki, Automatyki, Informatyki i Inżynierii Biomedycznej
Access status: Open Access ,
Suppression of vibration of a clamped beam via piezoceramics
(Wydawnictwa AGH, 2007) Starek, Ladislav; Šolek, Peter; Starek, Daniel; Stareková, Anna; Blesák, Peter
Contribution deals with the suppression of the resonance vibration of a clamped beam with sensors and actuators made of piezoceramics material. It will be discussed the problem of influencing of a response of vibration by higher frequencies so called control and observation spillover. The model of a beam with piesoceramics was designed in environment ANSYS. The properties of the model have been identified from the response on an unit step impuls (voltage). The control was realized by controller with PPF method. Simulation of control has been realized on the clamped beam in environment MATLAB. There was designed an experimental test bed for verification of the simulation results.
Access status: Open Access ,
The method of application of SEA in structural design process for reducing structure-borne noise in machinery. Part 1, General procedure
(Wydawnictwa AGH, 2009) Yamazaki, Toru; Kuroda, Katsuhiko
The paper focuses on the finding which parts of machinery should be modified in order to reduce the noise. The countermeasure is decided by being based on the theoretical formulation the statistical energy analysis (SEA). The proposed process is applied to determine the countermeasures to structure-borne noise in a commercial product (A4 laser printer). This study is the first report of a series to develop a process based on the SEA.
Access status: Open Access ,
The method of application of SEA in structural design process for reducing structure-borne noise in machinery. Part 2, Structural optimization of subsystems
(Wydawnictwa AGH, 2009) Kuroda, Katsuhiko; Kuratani, Fumiyasu|Yamazaki, Toru
This paper presents the formulation of the structural optimization method on the basis of statistical energy analysis. A4 laser beam printer consisting of eight finite elastic steel plates is considered as an example, where the mass is taken as a constraint function. Consequently, taking one CLF as the objective function, an optimization of the thickness of the shell elements is performed showing the efficiency of the structural optimization method.
Access status: Open Access ,
Vibration control capabilities of a cantilever beam with a magnetorheological fluid
(Wydawnictwa AGH, 2008) Sapiński, Bogdan; Snamina, Jacek
This paper presents an analysis of dynamic characteristics of a cantilever beam with a magnetorheological (MR) fluid. The beam consists of two aluminium outer layers and MR fluid layer placed between them. Due to MR fluid control capabilities both damping and stiffness of the beam can be changed simultaneously. The simple model of three-layered structure is assumed. Vibration characteristics of the beam are predicted for various magnetic field strength and a simple control algorithm based on switching of the beam stiffness is proposed. The results of calculations illustrate the vibration control capabilities of the MR adaptive beam at various level of magnetic strength.
Access status: Open Access ,
Vibration control of a fluid-loaded circular plate via pole placement
(Wydawnictwa AGH, 2008) Leniowska, Lucyna
This paper presents the application of active control system to reduce the vibration and the sound radiation of a circular plate which is fluid-loaded and clamped at a finite baffle. The plate is driven by a uniform harmonic primary force and controlled by a distributed secondary force generated by the piezodisks. The aim of the paper is to design a controller to modify the response of the plant in some desired fashion. The mathematical model of the system includes the influence the acoustic wave radiated by the plate, Kelvin-Voigt damping in the plate material and viscous fluid damping. For the considered system the transfer function of controller of 4th order, satisfying the polynomial Diofantine equation, is derived. The influence of the fluid-loading and damping effects on the system response are presented graphically and discussed. The results show that plate modes have been reduced very well by obtained controller for a few assumed values of damping coefficients.