Active Vibration Control for the Improvement of Sound Transmission Loss through a Square Plate

2002 ◽  
Vol 9 (4) ◽  
pp. 289-301 ◽  
Author(s):  
Kuo-Tsai Chen ◽  
Kuan-Tin Chiang ◽  
Sue-Min Huang ◽  
Bor-Chien Tsai

An active vibration control system is considered for the reduction of sound transmission through a square plate acted on by a reverberant field. The study includes the prediction of the resonant frequencies of the plate involved, the derivations of both the feedback adaptive control algorithm and the volume velocity cancellation technique adopted, and the experiment for active vibration control on the sound transmission through a plate. It is demonstrated that an improvement of the order of 6 decibels at 132 Hz is obtained. Also, increased transmission loss at lower resonant frequencies is possible.

Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley ◽  
Gregory J. Hiemenz

Novel semi-active vibration controllers are developed in this study for magnetorheological (MR) fluid-based vibration control systems, including: (1) a band-pass frequency shaped semi-active control algorithm, (2) a narrow-band frequency shaped semi-active control algorithm. These semi-active vibration control algorithms designed without resorting to the implementation of an active vibration control algorithms upon which is superposed the energy dissipation constraint. These new Frequency Shaped Semi-active Control (FSSC) algorithms require neither an accurate damper (or actuator) model, nor system identification of damper model parameters for determining control current input. In the design procedure for the FSSC algorithms, the semi-active MR damper is not treated as an active force producing actuator, but rather is treated in the design process as a semi-active dissipative device. The control signal from the FSSC algorithms is a control current, and not a control force as is typically done for active controllers. In this study, two FSSC algorithms are formulated and performance of each is assessed via simulation. Performance of the FSSC vibration controllers is evaluated using a single-degree-of-freedom (DOF) MR fluid-based engine mount system. To better understand the control characteristics and advantages of the two FSSC algorithms, the vibration mitigation performance of a semi-active skyhook control algorithm, which is the classical semi-active controller used in base excitation problems, is compared to the two FSSC algorithms.


2019 ◽  
Vol 24 (3) ◽  
pp. 608-615 ◽  
Author(s):  
Miroslav Pawlenka ◽  
Miroslav Mahdal ◽  
Jiri Tuma ◽  
Adam Burecek

This study concerns the active vibration control of journal bearings, which are also known as sliding bearings. The control system contains a non-rotating loose bushing, the position of which is controlled by piezoelectric actuators. For governing the respective orthogonal direction of the journal motion, the control algorithm realizes a proportional controller in parallel with a bandpass filter of the IIR type. The bandpass filter is of the second order and its centre frequency is self-tuned to be the same as the whirl frequency that results from the instability of the bearing journal due to the oil film. The objective of active vibration control is to achieve the highest operational speed of the journal bearing at which the motion of the rotor is stable. The control algorithm for the active vibration control is implemented in Simulink and realized in a dSPACE control system.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xing Shen ◽  
Yuke Dai ◽  
Mingxuan Chen ◽  
Lei Zhang ◽  
Li Yu

In wind tunnel tests, cantilever stings are often used as model-mount in order to reduce flow interference on experimental data. In this case, however, large-amplitude vibration and low-frequency vibration are easily produced on the system, which indicates the potential hazards of gaining inaccurate data and even damaging the structure. This paper details three algorithms, respectively, Classical PD Algorithm, Artificial Neural Network PID (NNPID), and Linear Quadratic Regulator (LQR) Optimal Control Algorithm, which can realize active vibration control of sting used in wind tunnel. The hardware platform of the first-order vibration damping system based on piezoelectric structure is set up and the real-time control software is designed to verify the feasibility and practicability of the algorithms. While the PD algorithm is the most common method in engineering, the results show that all the algorithms can achieve the purpose of over 80% reduction, and the last two algorithms perform even better. Besides, self-tuning is realized in NNPID, and with the help of the Observer/Kalman Filter Identification (OKID), LQR optimal control algorithm can make the control effort as small as possible. The paper proves the superiority of NNPID and LQR algorithms and can be an available reference for vibration control of wind tunnel system.


Author(s):  
Marek L. Szary ◽  
Maciej Noras

Electrorheological (ER) liquids possess the ability to change their physical properties like the apparent viscosity and modulus of elasticity under the influence of an external electric field. They serve successfully in the field of active vibration control—as well as in many other areas. In the Acoustic Laboratory at the College of Engineering, Southern Illinois University in Carbondale, research on the possibility of applying ER liquids to the control of a sound transmission loss (STL) was conducted. The STL was investigated for various kinds of ER suspensions in the frequency range 100 Hz to 2 kHz. An influence of the electric field density on the STL was different for normal and shear stress developed by DC voltage. In both cases the STL decreased with the increasing electric field density. These properties could be potentially useful in sound propagation control applications.


Author(s):  
Ali Fellah Jahromi ◽  
A. Zabihollah

A novel semi-active control system for suspension systems of passenger car using Magnetorheological (MR) damper is introduced. The suspension system is considered as a massspring model with an eight-degrees-of-freedom, a passive damper and an active damper. The semi-active vibration control is designed to reduce the amplitude of automotive vibration caused by the alteration of road profile. The control mechanism is designed based on the optimal control algorithm, Linear Quadratic Regulator (LQR). In this system, the damping coefficient of the shock absorber changes actively trough inducing magnetic field. It is observed that utilizing the present control algorithm may significantly reduce the vibration response of the passenger car, thus, providing comfortable drive. The new developed suspension system may lead to design and manufacturing of passenger car in which the passenger may not feel the changes in road profile from highly bumpy to smooth profile.


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