• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.664-669
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• 1998

This research is concerned with the active vibration controller design for smart structures by a modified LQG controller. The smart structure is defined as the structure equipped with smart actuators and sensors. Various analog and digital control, techniques aimed for the piezoceramic sensors and actuators have been proposed for the active vibration control of smart structures. In this paper, the modified LQG controller is developed for the active vibration suppression of smart structures to implement the predefined decay rate on modal displacements. The proposed modified LQG controller proved its effectiveness by experiments.

• Smart Structures and Systems
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• v.11 no.6
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• pp.623-635
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• 2013

This paper investigates application of a control algorithm called model predictive sliding mode control (MPSMC) to active vibration suppression of a cantilevered aluminum beam. MPSMC is a relatively new control algorithm where model predictive control is employed to enhance sliding mode control by enforcing the system to reach the sliding surface in an optimal manner. In previous studies, it was shown that MPSMC can be applied to reduce hysteretic effects of piezoelectric actuators in dynamic displacement tracking applications. In the current study, a cantilevered beam with unknown mass distribution is selected as an experimental test bed in order to verify the robustness of MPSMC in active vibration control applications. Experimental results show that MPSMC can reduce vibration of an aluminum cantilevered beam at least by 29% regardless of modified mass distribution.

• Journal of Mechanical Science and Technology
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• v.14 no.1
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• pp.57-64
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• 2000

Recent advances in the field of control theory have enabled us to design active vibration control systems for various structures. In many studies, the controller used to suppress vibration has been synthesized for the given mathematical model of structure. In these cases, the designer has not been able to utilize the degree of freedom to adjust the structural parameters of the control object. To overcome this problem, so called 'Structure/Control Simultaneous Optimization Method' is used. In this context of view, this paper is concerned with the active vibration control of bridge towers, platforms and ocean vehicles etc. Simultaneous design method is used to achieve optimal system performance. Here, a general framework for the simultaneous design problem of output feedback case is introduced based on LMI (Linear Matrix Inequality). The simulation results show that the proposed design method achieves desirable control performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1176-1182
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• 2010

Vibrations caused by automobile engine are absorbed mostly by a passive-type engine mount. However, user specifications for automobile vibrations require more stringent conditions and higher standard. Hence, active-type engine mount have been developed to cope with such specifications. The active-type engine mount consists of sensor, actuator and controller where a control algorithm is implemented. The performance of the active engine mount depends on the control algorithm if the sensor and actuator satisfies the specification. The control algorithm should be able to suppress persistent vibrations caused by the engine which are related to engine revolution. In this study, three control algorithms are considered for suppressing persistent vibrations, which are the positive position feedback control algorithm, the strain-rate feedback control algorithm, and the modified higher harmonic control algorithm. Experimental results show that all the control algorithms considered in this study are effective in suppressing resonant vibrations but the modified higher harmonic controller is the most effective controller for non-resonant vibrations.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.3
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• pp.437-445
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• 2008

This paper deals with the experimental assessment of the vibration suppression of the smart structures. First. we have presented a new high-speed active control system using the DSP320C6713 microprocessor. A peripheral system developed is composed of a data acquisition system, N/D and D/A converters, piezoelectric (PZT) actuator/sensors, and drivers for fast data processing. Next, we have tested the processing time of the peripheral devices, and provided the corresponding test results. Since fast data processing is very important in the active vibration control of the structures, we have focused on achieving the fast loop times of the control system. 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.

• Smart Structures and Systems
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• v.16 no.6
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• pp.1003-1021
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• 2015

MR dampers have been proposed for the control of cable vibration of cable-stayed bridge in recent years due to their high performance and low energy consumption. However, the highly nonlinear feature of MR dampers makes them difficult to be designed with efficient semi-active control algorithms. Simulation study has previously been carried out on the cable-MR damper system using a semi-active control algorithm derived based on the universal design curve of dampers and a bilinear mechanical model of the MR damper. This paper aims to verify the effectiveness of the MR damper for mitigating cable vibration through a full-scale experimental test, using the same semi-active control strategy as in the simulation study. A long stay cable fabricated for a real bridge was set-up with the MR damper installed. The cable was excited under both free and forced vibrations. Different test scenarios were considered where the MR damper was tuned as passive damper with minimum or maximum input current, or the input current of the damper was changed according to the proposed semi-active control algorithm. The effectiveness of the MR damper for controlling the cable vibration was assessed through computing the damping ratio of the cable for free vibration and the root mean square value of acceleration of the cable for forced vibration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.6 s.177
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• pp.1390-1397
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• 2000

This paper presents the multi-channel active vibration control of a flexible plate of the acoustically loaded enclosure. The flexible plate was excited acoustically with sinusoidal and white noise input. The control was performed by two piezo ceramic actuators and two accelerometers. The experimental results were compared with the single channel control results. In the case of white noise input, 20 dB of vibration reduction was achieved below 300Hz frequency range. The experimental results demonstrate that multi-channel filtered-x LMS algorithm is effective than single-channel filtered-x LMS algorithm in active vibration control of plate.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.407-412
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• 2009

In the present work, vibration control performance of active camera mount system for unmanned aero vehicle (UAV) is evaluated. An active mount featuring inertia type of piezostack actuator is designed and manufactured. Then, vibration control performances are experimentally evaluated. A camera mount system with four active mounts is constructed and mechanical model is established. The governing equation for the camera mount system is obtained and control model is constructed in state space model. Sliding mode controller which has inherent robustness to external disturbance is designed and implemented to the system. Vibration control performances are evaluated at each mount and center of gravity point. Effective vibration performances are obtained and presented in time and frequency domains.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.12
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• pp.1315-1321
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• 2009

In the present work, vibration control performance of active camera mount system for unmanned aero vehicle(UAV) is evaluated. An active mount featuring inertia type of piezostack actuator is designed and manufactured. Then, vibration control performances are experimentally evaluated. A camera mount system with four active mounts is constructed and mechanical model is established. The governing equation for the camera mount system is obtained and control model is constructed in state space model. Sliding mode controller which has inherent robustness to external disturbance is designed and implemented to the system. Vibration control performances are evaluated at each mount and center of gravity point. Effective vibration performances are obtained and presented in time and frequency domains.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.466-471
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• 2008

Structural vibration and noise are hot issues in underwater vehicles such as submarines for their survivability. Therefore, active vibration and noise control of submarine, which can be modeled as hull structure, have been conducted by the use of piezoelectric materials. Traditional piezoelectric materials are too brittle and not suitable to curved geometry such as hull structures. Therefore, advanced anisotropic piezoceramic actuator named as Macro-Fiber Composite (MFC), which can provide great flexibility, large induced strain and directional actuating force is adopted for this research. In this study, dynamic model of the smart hull structure is established and active vibration control performance of the smart hull structure is evaluated using optimally placed MFC. Actuating performance of MFC is evaluated by finite element analysis and dynamic modeling of the smart hull structure is derived by finite element method considering underwater condition. In order to suppress the vibration of hull structure, Linear-Quadratic-Gaussian (LQG) algorithm is adopted. After then active vibration control performance of the proposed smart hull structure is evaluated with computer simulation and experimental investigation in underwater. Structural vibration of the hull structure is decreased effectively by applying proper control voltages to the MFC actuators.