• Smart Structures and Systems
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• v.25 no.6
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• pp.643-655
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• 2020

Active control of nonlinear vibration of stiffened functionally graded (SFG) cylindrical shell is studied in this paper. The system is subjected to axial and transverse periodic loads in the presence of thermal uncertainty. The material composition is considered to be continuously graded in the thickness direction, also these properties depend on temperature. The relations of strain-displacement are derived based on the classical shell theory and the von Kármán equations. For modeling the stiffeners on the cylindrical shell surface, the smeared stiffener technique is used. The Galerkin method is used to discretize the partial differential equations of motion. Some comparisons are made to validate the SFG model. For suppression of the nonlinear vibration, the linear and nonlinear control strategies are applied. For control objectives, the piezoelectric actuator is attached to the external surface of the shell and the thin ring piezoelectric sensor is attached to the middle internal surface of shell. The effect of PID, feedback linearization and sliding mode control on the suppression of vibration for SFG cylindrical shell is presented.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.3
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• pp.309-316
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• 2011

This paper deals with the experimental study of the vibration suppression of the smart structures. First, a new high-speed active control system is presented using the DSP320C6713 microprocessor. A peripheral system developed is composed of a data acquisition system, A/D and D/A converters, piezoelectric (PZT) actuator/sensors, and drivers using PA 95 for fast data processing. Next, the processing time of the peripheral device is tested and the corresponding test results are provided. Since fast data processing is very important in the active vibration control of the structures, achieving the fast loop times of the control system is focused. The control algorithm using PPF in addition to FIR filter is implemented. Finally, numerous experiments were carried out on the aluminum plate to validate the superior performance of the vibration control system at different control loop times.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.248-253
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• 2013

The maximum speed is one of the most important performance in high speed railway vehicle. The higher the train speed is, the worse the ride comfort is, In order to solve this problem, a semi-active or active suspension can be applied to high speed railway vehicle. The variable damper with hydraulic solenoid valve is used in the semi-active suspension. But the variable damper with hydraulic solenoid valve requires tank for supplying fluid. The MR(Magneto Rheological) damper can be considered instead of hydraulic variable damper which needs additional device, i.e. reserver tank for fluid. In the case of active suspension, hydraulic actuator or electro-mechanical one is used to suppress the carbody vibration in railway vehicle. In this study the MR damper and electro-mechanical actuator was considered in secondary suspension system of high speed railway vehicle. The dynamic analysis was performed by using 10-DOF dynamic equations of railway vehicle. The performance of the semi-active suspension and active suspension system were reviewed by using MATLAB/Simulink S/W. The vibration suppression effect of semi-active and active suspension system were investigated experimentally by using 1/5-scaled railway vehicle model.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.9
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• pp.858-867
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• 2011

As applying an active control technique to a pneumatic vibration isolation system, the settling time for the payload excitation could be remarkably reduced as well as the improvement of isolation performance for the ground vibration. Some previous researches were dealt with the settling time through the simulation or experiment but, the discussion on the simulation or experimental results including moving parts, such as a XY-stage, on the isolation table rarely exists. As considering the moving part, the dynamic model could be time varying system and in such a case the force imposed on pneumatic vibration isolation table could be described by inertial forces of moving parts according to Newton's 3rd law, the action and reaction law. In this paper, the simulation procedure of the 3-DOF active pneumatic vibration isolation system including moving parts by TDC(time delay control) technique is proposed and the effectiveness through simulation results are also shown.

• Structural Engineering and Mechanics
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• v.38 no.2
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• pp.141-156
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• 2011

A cable stayed bridge under construction has low structural damping and is not as stable as the completed bridge. Control countermeasures, such as the installation of energy dissipating devices, are thus required. In this study, the general procedure and key issues on adopting an active control device, the active mass damper (AMD), for vibration control of cable stayed bridges under construction were studied. Taking a typical cable stayed bridge as the prototype structure; a lab-scale test structure was designed and fabricated firstly. A baseline FEM model was then setup and updated according to the modal parameters measured from vibration test on the structure. A numerical study to simulate the bridge-AMD control system was conducted and an efficient LQG-based controller was designed. Based on that, an experimental implementation of AMD control of the transverse vibration of the bridge model was performed. The results from numerical simulation and experimental study verified that the AMD-based active control was feasible and efficient for reducing dynamic responses of a complex structural system. Moreover, the discussion made in this study clarified some critical problems which should be addressed for the practical implementation of AMD control on real cable-stayed bridges.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.550-555
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• 2007

This paper is concerned with the active vibration control of building structure by means of the active tuned mass damper and the modified positive position feedback controller. To this end, one-degree-of-freedom spring-mass-damper system equipped with ATMD is considered. The stability condition for the addressed system when applying the proposed PPF controller is derived by Routh-Hurwitz stability criterion. The stability condition shows that the modified PPF controller is absolutely stable if the controller gain is positive, so that the modified PPF controller can be used without difficulty. Theoretical study shows that the modified PPF controller can effectively suppress vibrations as the original PPF controller does in smart structure applications. To investigate the validity of the modified PPF controller, a simple experimental structure with an ATMD system driven by DC motor was built. The modified PPF control algorithm was implemented on Atmel 128 microcontroller. The experimental result shows that the modified PPF controller can also suppress vibrations for the real structure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.2
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• pp.224-230
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• 2008

This paper is concerned with the active vibration control of building structure by means of the active tuned mass damper and the modified positive position feedback controller. To this end, one-degree-of-freedom spring-mass-damper system equipped with ATMD is considered. The stability condition for the addressed system when applying the proposed PPF controller is derived by Routh-Hurwitz stability criterion. The stability condition shows that the modified PPF controller is absolutely stable if the controller gain is positive. so that the modified PPF controller can be used without difficulty. Theoretical study shows that the modified PPF controller can effectively suppress vibrations as the original PPF controller does in smart structure applications. To investigate the validity of the modified PPF controller, a simple experimental structure with an ATMD system driven by DC motor was built. The modified PPF control algorithm was implemented on Atmel 128 microcontroller. The experimental result shows that the modified PPF controller can also suppress vibrations for the real structure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.7
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• pp.524-531
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• 2003

This paper presents an active vibration control of a flexible beam structure using a hybrid mount which consists of elastic rubber and Piezoelectric material. After identifying stiffness and damping properties of the rubber and piezoelectric elements, a mechanical model of the hybrid mount is established. The mount model is then Incorporated into the beam structure, and the governing equation of motion is obtained in a state space. A sliding mode controller is designed in order to actively attenuate the vibration of the beam structure subjected to high frequency and small magnitude excitations. The controller is experimentally realized and control responses such as acceleration of the beam structure and force transmission through the hybrid mount are evaluated. In addition. a comparative work is done between the passive and hybrid mount systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1573-1581
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• 1996

This paper present as experimental demonstratio of DSP and a sensory actuator that is used to actively control sound transmission/radiation through a vibrating plate. A plane acoustic wave incident on a clamped, thin circular plate was used as a noise source, and a sensory actuator bounded to the plate was used to control and sense vibration of the plate. The sound transmission reduction problem was tranformed as a structural vibration control problem that actively control the structural vibration modes coupled to acoustic modes. The results show that the first structural vibration mode is controlled with a reduction of 78 percent in the displacement and velocity of the plate. This corresponds to a 13dB reduction in the acoustic response. These experimental results indicate that a sensory actuator bounded to the plate can be employed to attenuate the sound transmitted to radiated from the plate.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.828-833
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• 2003

Rigid plate elastically supported at the edges is modeled and the performance of the optimal vibration control under sinusoidal excitation is tested. The controller based on the linear quadratic regulator with output feedback is designed to control the multi-degree of freedom vibration. Relative weighting parameters are considered as design constraints to determine the limitation of maximum control force and state parameters. Control force calculated by proportional output feedback of the displacement and velocity is used to suppress the vibration induced by the sinusoidal external force. The active vibration control of vibrating plate by the LQR controller is examined through the numerical simulations that show the effectiveness of optimal control scheme on the three degrees of freedom structure.