• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.875-878
• /
• 2005

This paper presents active control of aperture type near-field storage head. In order to achieve fast and accurate control, dual servo control algorithm is applied. Based on the big difference in time constant, we seperate two actuator and control independently. With the combination of fine and coarse actuator, gap is controlled within 100nm until the disk rotates upto 10 rpm speed. From the experimental results, the feasibility and performance of active gap control is proved.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.23 no.11 s.170
• /
• pp.1912-1921
• /
• 1999

The equipments mounted on guided-missile undertake heavy vibrational disturbance. Sometimes the equipments mounted on guided-missile go wrong so that the guided-missile flies over unintended place. For the vibration isolation of the equipments mounted on guided-missile, active vibration control was performed. In the case of active vibration technique, the stiffness matrix and the mass matrix are derived based on FEM (ANSYS5.0). Model reduction was carried out and, as a result, we got 7 DOF mass and stiffness matrix. For the sake of FEM model identification, modal experiment was carried out. With the help of Sensitivity Analysis, the natural frequencies of FEM were tuned to those of Experiment. In this work, the Sky Hook and the LQG control theory were adopted for v iteration control using stacked piezoactuator. Experiments were performed with changing excitation frequency from 10 Hz upto 200 Hz and we got frequency response function of guided-missile equipments. The magnitude of 3rd mode of guided-missile equipments is 8.6 % that of Uncontrolled in Skyhook controller and is 3.4 % that of uncontrolled in LQG controller.

• Proceedings of the KIEE Conference
• /
• 1996.11a
• /
• pp.317-319
• /
• 1996

In this paper, an active vibration control system using a voice coil type linear oscillating actuator(LOA) is studied to suppress structural vibration. Being compared with a hydraulic actuator, a LOA has simplified structure and requires a few elements in the driving system, so it has lots of merits with respect to economics and maintenance. The general mathematical dynamic model to obtain the algorithm for the realization of vibration active control system is treated. Actually, the performance test of the control system using LOA is carried out on a steel test structure under sinusoidal and white noise excitation. From this test it is conformed that acceleration level of test structure is reduced near the resonance region. In the future research on the application to large structures will be studied.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.257-262
• /
• 2000

This research is concerned with the active vibration control of slewing smart structures subjected to rotating disturbance. When cantilever beam rotates about axes perpendicular to the undeformed beam's longitudinal axis, it experiences inertial loading. Hence, the beam vibrates after the slewing ends. In this paper, the analytical model for a single slewing flexible beam with surface bonded piezoelectric sensor and actuator is developed using the Hamilton's principle with discretization by the assumed mode method. The theoretial model is verified by the experimental open loop frequency response data. The controller is designed for residual vibration suppression after slewing. The designed cotroller is a positive position feedback (PPF) controller for controlling the first mode vibration.

• Smart Structures and Systems
• /
• v.25 no.2
• /
• pp.229-240
• /
• 2020

In this research, toggled actuator forces were examined. For achieving to this object, an actuator was installed in a toggle pattern in a S.D.O.F frame and actuator forces were investigated thru a numerical analysis process. Within past twenty years, researchers tried to use strong bracing systems as well as huge dampers to stabilize tall buildings during intensive earthquakes. Eventually, utilizing of active control systems containing actuators to counter massive excitations in structures was emerged. However, the more powerful earthquake excitations, the more robust actuators were required to be installed in the system. Subsequently, the latter process made disadvantage to the active control system due to very high price of the robust actuators as well as their large demands for electricity. Therefore, through a numerical process (Part I), influence of toggled actuator pattern was investigated. The algorithm used in the system was LQR and ATmega328 was selected as a control platform. For comparison, active tendon control system was chosen. The final results show clearly that using the toggle pattern mitigates the required actuator forces enormously leading to deploy much lighter actuators.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.3
• /
• pp.284-292
• /
• 2008

The active control technique mostly uses the least-mean-square(LMS) algorithm, because the LMS algorithm can easily obtain the complex transfer function in real-time, particularly when the Filtered-X LMS(FXLMS) algorithm is applied to an active noise control(ANC) system. However, FXLMS algorithm has the demerit that stability of the control is decreased when the step size become larger but the convergence speed is faster because the step size of FXLMS algorithm is fixed. As a result, the system has higher probability which the divergence occurs. Thus the Co-FXLMS algorithm was developed to solve this problem. The Co-FXLMS algorithm is realized by using an estimate of the cross correlation between the adaptation error and the filtered input signal to control the step size. In this paper, the performance of the Co-FXLMS algorithm is presented in comparison with the FXLMS algorithm. Simulation and experimental results show that active noise control using Co-FXLMS is effective in reducing the noise in duct system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.598-603
• /
• 2007

The active control technique mostly uses the Least-Mean-Square (LMS) algorithm, because the LMS algorithm can easily obtain the complex transfer function in real-time, particularly when the Filtered-X LMS (FXLMS) algorithm is applied to an active noise control (ANC) system. However, FXLMS algorithm has the demerit that stability of the control is decreased when the step size become larger but the convergence speed is faster because the step size of FXLMS algorithm is fixed. As a result, the system has higher probability which the divergence occurs. Thus the Co-FXLMS algorithm was developed to solve this problem. The Co-FXLMS algorithm is realized by using an estimate of the cross correlation between the adaptation error and the filtered input signal to control the step size. In this paper, the performance of the Co-FXLMS algorithm is presented in comparison with the FXLMS algorithm. Simulation results show that active noise control using Co-FXLMS is effective in reducing the noise in duct system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.631-632
• /
• 2008

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.04a
• /
• pp.273-274
• /
• 2014

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.04a
• /
• pp.237-238
• /
• 2009