• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.1
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• pp.9-20
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• 2003

In this study, the performance of a semi-active suspension system for heavy duty tracked vehicles has been investigated. To this end, continuous and on-off Sky-Hook control law have been evaluated for a 1/4 car model. Simulation results show that the semi-active suspension system has potential to improve ride quality of the vehicle. And we proposed a method for improving of variable damper performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5A
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• pp.372-380
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• 2009

In this paper, we analyze the active RFID systems ISO/IEC 18000-7 and ISO/IEC 18000-4. In order to improve the coverage in sensor networks, which consist active RFID tag, we propose RFID multi-hop relay system using active RFID relay tag. To compare the performance between the existing ISO/IEC 18000-7 system and the proposed RFID multi-hop relay system, we introduce new system efficiency measure and sensitivity-based measure of achieved coverage. Also, we analyze the performance of the proposed system and compare it with that of the existing system through MCL (Minimum Coupling Loss) analysis and SLS (System Level Simulation) analysis.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.918-924
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• 2009

This paper deals with the experimental assessment of the vibration suppression of the smart structures. First, we have presented the paper about the new high-speed active control system that we have developed using the DSP320C6713 microprocessor and a peripheral system composed of a data acquisition system, A/D and D/A converters, piezoelectric (PZT) actuator/sensors, and drivers using PA95. Since fast data processing is very important in the active vibration control of the structures, we utilized the fast processing DSP320C6713 microprocessor as a main processor to the controller and fast peripheral devices for fast control loop. To realize a fast active vibration control, we have analyzed and tested the processing time of the peripheral devices and provided the corresponding test results. Especially, we have focused on achieving the fast signal amplification of the PA95 device since it takes most of loop times of the control system. Finally, we performed numerous experiments of active vibration control of the aluminum plate to validate the superior performance of the developed control system based on previous mode tests of the plate.

• 한국벤처창업학회:학술대회논문집
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• 2007.11a
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• pp.263-276
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• 2007

In this paper, we summary known suggestion system which is useful a small and medium enterprise. We don't think suggestion system of a small and medium enterprise active. We reflect 2 points of suggestion system. We propose the Active Plan to Suggestion System for small and medium Enterprise which are (1) suggestion direction for enterprise future, (2) suggestion body for all employee included, (3) suggestion methods for all information shared.

• Proceedings of the Safety Management and Science Conference
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• 2007.11a
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• pp.341-350
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• 2007

In this paper, we summary known suggestion system which is useful a small and medium enterprise. We don't think suggestion system of a small and medium enterprise active. We reflect 2 points of suggestion system. We propose the Active Plan to Suggestion System for small and medium Enterprise which are (1) suggestion direction for enterprise future, (2) suggestion body for all employee included, (3) suggestion methods for all information shared.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.747-755
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• 2011

In this paper, we summary known suggestion system which is useful a small and medium enterprise. We don't think suggestion system of a small and medium enterprise active. We reflect 2 points of suggestion system. We propose the Active Plan to Suggestion System for small and medium Enterprise which are (1) suggestion direction for enterprise future, (2) suggestion body for all employee included, (3) suggestion methods for all information shared.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.345-350
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• 1996

The suspension system plays an important role in vehicle performance. To improve suspension characteristics related to riding comfort and handling stability simultaneously, active suspension system is developed. In this study, a hybrid control scheme is proposed, the idea of which is that the sliding mode control is applied to nonlinear hydraulic system and the skyhook control is applied for controlling the motion of the suspension system. The performance of the proposed control method is evaluated by simulation and experiment of a half car active suspension system.

• Journal of Power System Engineering
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• v.14 no.5
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• pp.56-62
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• 2010

In this paper, a recurrent cerebellar modulation articulation control (RCMAC) has been developed for improvement of noise attenuation performance in active noise control system. For the narrow band noise, a filter-x least mean square (FXLMS) method has bee frequently employed as an algorithm for active noise control (ANC) and has a partial satisfactory noise attenuation performance. However, noise attenuation performance of an ANC system with FXLMS method is poor for broad band noise and nonlinear path since it has linear filtering structure. Thus, an ANC system using RCMAC is proposed to improve this problem. Some simulations in duct system using harmonic motor noise and KTX cabin noise as a noise source were executed. It is shown that satisfactory noise attenuation performance can be obtained.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.74-80
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• 2013

This study describes structural reliability analysis of actively-controlled structure for which random vibration analysis is incorporated into the first-order reliability method (FORM) framework. The existing approaches perform the reliability analysis based on the RMS response, whereas the proposed study uses the peak response for the reliability analysis. Therefore, the proposed approach provides us a meaningful performance measure of the active control system, i.e., realistic failure probability. In addition, it can deal with the uncertainties in the system parameters as well as the excitations in single-loop reliability analysis, whereas the conventional random vibration analysis requires double-loop reliability analysis; one is for the system parameters and the other is for stochastic excitations. The effectiveness of the proposed approach is demonstrated through a numerical example where the proposed approach shows fast and accurate reliability (or inversely failure probability) assessment results of the dynamical active control system against random seismic excitations in the presence of parametric uncertainties of the dynamical structural system.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1613-1626
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• 2002

This paper presents hybrid control of an active suspension system with a full-car model by using H$\sub$$\infty$/ and nonlinear adaptive control methods. The full-car model has seven degrees of freedom including heaving, pitching and rolling motions. In the active suspension system, the controller shows good performance: small gains from the road disturbances to the heaving, pitching and rolling accelerations of the car body. Also the controlled system must be robust to system parameter variations. As the control method, H$\sub$$\infty$/ controller is designed so as to guarantee the robustness of a closed-loop system in the presence of uncertainties and disturbances. The system parameter variations are taken into account by multiplicative uncertainty model and the system robustness is guaranteed by small gain theorem. The active system with H$\sub$$\infty$/ controller can reduce the accelerations of the car body in the heaving, pitching and rolling directions. The nonlinearity of a hydraulic actuator is handled by nonlinear adaptive control based on the back-stepping method. The effectiveness of the controllers is verified through simulation results in both frequency and time domains.