• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1459-1464
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• 1996

The most important parameter for hydraulic active suspension system is to sustain desirable vehicle maneuvering stability and ride comfort without increasing consumption power. The performance of hydraulic active suspension system depends on damping force of body damping valve and piston damping valve. Hydraulic actuator design and damping valve parameter selection are essential and basic procedure to design hydraulic active suspension system. This paper is on computer simulation with use of mathematical model that was delivered from dynamic characteristic of hydraulic actuator, as know basic damping characteristics of hydraulic active suspension system. The aim of this paper is to select the system parameter that affect mainly hydraulic active suspension, and identify the validity on the system parameter selection.

• 대한기계학회논문집A
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• 제26권4호
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• pp.683-692
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• 2002

The most important parameter for hydraulic active suspension system is to sustain desirable vehicle maneuvering stability and ride comfort without increasing power consumption. The performance of hydraulic active suspension system depends on damping force of body damping valve and piston damping valve. Hydraulic actuator design and damping valve parameter selection are essential and basic procedure to design hydraulic system. This paper is on computer simulation with use of mathematical model that was delivered from dynamic characteristic of hydraulic actuator, as know basic damping characteristics of hydraulic active suspension system. The aim of this paper is to select the system parameter that affect mainly hydraulic active suspension, and identify the validity on the system parameter selection.

• Smart Structures and Systems
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• 제3권4호
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• pp.405-422
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• 2007

A new hybrid damping technique for vibration reduction in flexible structures, wherein a combination of layers of hard passive damping alloys and active (smart) magnetostrictive material is used to reduce vibrations, is proposed. While most conventional vibration control treatments are based exclusively on either passive or active based systems, this technique aims to combine the advantages of these systems and simultaneously, to overcome the inherent disadvantages in the individual systems. Two types of combined damping systems are idealized and studied here, viz., the Noninteractive system and the Interactive system. Frequency domain studies are carried out to investigate their performance. Finite element simulations using previously developed smart beam elements are carried out on typical metallic and laminated composite cantilever beams treated with hybrid damping. The influence of various parameters like excitation levels, frequency (mode) and control gain on the damping performance is investigated. It is shown that the proposed system could be used effectively to dampen the structural vibration over a wide frequency range. The interaction between the active and passive damping layers is brought out by a comparative study of the combined systems. Illustrative comparisons with 'only passive' and 'only active' damping schemes are also made. The influence and the mode dependence of control gain in a hybrid system is clearly illustrated. This study also demonstrates the significance and the exploitation of strain dependency of passive damping on the overall damping of the hybrid system. Further, the influence of the depthwise location of damping layers in laminated structures is also investigated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.938-944
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• 1994

Active damping has been shown to offer increased suspension performance in terms of vehicle isolation, suspension packaging, and road-tire contract force. Many semi-active damping strategies have been introduced to approximate the response of active damping with the modulation of passive damping parameters. This study investigates the characteristics of semi-active suspension control through the simulation of passive, skyhook active, and semi-active damping models. A quarter car model is studied with the conrolled damping replacing both passive and active damping. A new semi-active scheme is suggested to eliminate the abrupt changes in semi-active damping force. It is shown that the new strategy performs almost identically to the so called "force controlled" semi-active law without steep changes in damping force or body acceleration.eleration.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.150-158
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• 2002

Through experimental works, the damping force vibration problem was investigated, which results from valve and surge pressure in the oil return line of the hydraulic circuit of an active suspension system in a passenger cu. Experiments were carried out under passive system, where an orifice valve was closed and non-active system, where an orifice valve was opened, using a pressure control valve controlled by solenoid. The effects of parameters of the valve overlap and accumulator on smoothing surge pressure was elucidated. It was proved that the apparent variation of damping force due to the overlap amount of pressure control valve is the most important factor to control the damping force variation. The procedure of the experimental works shows the development process of a proportional pressure control valve in the hydraulics system of an active suspension system of passenger car.

• 한국소음진동공학회논문집
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• 제14권3호
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• pp.193-200
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• 2004

The Active Constrained Layer Damping(ACLD) combines the simplicity and reliability of passive damping with the low weight and high efficiency of active control to attain high damping characteristics. The proposed ACLD treatment consists of a viscoelastic damping which is sandwiched between an active piezoelectric layer and a host structure. In this manner, the smart ACLD consists of a Passive Constrained Layer Damping(PCLD) which is augmented with an active control in response to the structural vibrations. The arc type shell model is introduced to describe the interactions between the vibrating host structure, piezoelectric actuator and viscoelastic damping. The system is modeled by applying ARMAX model and changing a state-space form through the system identification method. An optimum control law for the piezo actuator is obtain by LQR(Linear Quadratic Regulator) method. The performance of the ACLD system is determined and compared with PCLD in order to demonstrate the effectiveness of the ACLD treatment. Also, the actuation capability of a piezo actuator is examined experimentally by varying thickness of viscoelastic material(VEM).

• 전력전자학회논문지
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• 제23권6호
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• pp.440-445
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• 2018

This study proposes a novel control and design method for a grid-connected inverter with an LCL filter without damping. The current resonance phenomenon must be considered when designing the grid-connected inverter system with an LCL filter. Passive or active damping is used in the inverter system to reduce the resonant current. However, passive damping reduces the efficiency of the system, and active damping methods are complex. If the resonant frequency is in a specific region, then the system will be unstable. This study examines the process of stabilizing the entire region without resonant damping. The validity of the proposed method is verified through simulation and experimentation.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.280-286
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• 2018

A sensorless active damping scheme for LCL filters in grid-connected parallel inverters for battery energy storage systems is proposed. This damping method is superior to the conventional notch filter and virtual damping methods with respect to robustness against the variation of the resonance of the filter and unnecessary additional current sensors. The theoretical analysis of the proposed damping method is explained in detail, along with the characteristic comparison to the conventional active damping methods. The performance verification of the proposed sensorless active damping method shows that its performance is comparable to that of the conventional virtual damping method, even without additional current sensors. Finally, simulation and experimental results are provided to examine the overall characteristics of the proposed method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1032-1038
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• 2002

The Active Constrained Layer Damping(ACLO) combines the simplicity and reliability of passive damping with the low weight and high efficiency of active control to attain high damping characteristics. The proposed ACLD treatment consists of a viscoelastic damping which is sandwiched between an active piezoelectric layer and a host structure. In this manner, the smart ACLD consists of a Passive Constrained Layer Damping(PCLD) which is augmented with an active control in response to the structural vibrations. The Arc type shell model is introduced to describe the interactions between the vibrating host structure, piezoelectric actuator and visco damping, The system is modeled by applying ARMAX model and changing a state-space form through the system identification method. An optimum control law for piezo actuator is obtain by LQR(Linear Quadratic Regulator) Method. The performance of ACLD system is determined and compared with PCLD in order to demonstrate the effectiveness of the ACLD treatment, Also, the actuation capability of a piezo actuator is examined experimentally by using various thickness of Viscoelastic Materials(VEM).

• International Journal of Railway
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• 제2권4호
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• pp.147-151
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• 2009

Railway vehicles equipped with semi-active suspension system can improve the ride quality of car bodies. Semi-active suspension system is usually applied onto high speed train, and therefore higher running safety requirement is proposed. The influence of semi-active suspension system on safety of vehicles running on straight line and curve line is studied, and the influences of sky hook damping coefficient and system time-delay on operation safety of cars fitted with semiactive suspension system is analyzed. The results show that the vehicles equipped with semi-active suspension system, not only the vibration of car body is decreased, it can also give little influence on running safety of cars, as a result, it will not endanger the running safety of cars.