• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.394-399
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• 1997

This paper presents a new concept of a semi-active suspension system for a commercial vehicle seat. The proposed suspension system features an ER(electro-rheological) damper which can produce continuously tunable damping forces by control electric fields. A dynamic model of the ER damper is first achieved by incorporating Bingham property of the ER fluid, followed by the formulation of governing equations of motion for the suspension system. A sliding mode controller is then designed on the basis of the hyper-plane sliding mode scheme. The effectiveness of the proposed control system is evaluated by investigating control performance for vibration isolation.

• 한국자동차공학회논문집
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• 제12권3호
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• pp.159-169
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• 2004

In this study, integration control of air-cell seat and semi-active suspension is proposed to minimize the road-tyre force which can cause uncomfortable feeling to rider. The proposed integration control with sliding perturbation observer is consisted of air-cell seat control which uses the force generated by air-cell and the sky-hook control. The air-cell seat itself has been modeled as a 1 degree of freedom spring-damper system. The actual characteristics of the air-cell have been analyzed through experiments. In this paper, we introduces a new robust motion control algorithm using partial state feedback for a nonlinear system with modelling uncertainties and external disturbances. The major contribution of this work is the development and design of robust observer for the state and the perturbation. The combination skyhook controller and air-cell controller using the observer improves control performance, because of the robust routine called Sliding Observer Design for Integration Control of Air-Cell Seat and Semi-active Suspension. The simulation results show a high accuracy and a good performance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.783-784
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• 2011

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2962-2964
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• 2005

Magneto-Rheological (MR) fluid is suspension of fine magnetic particles in a liquid carrier such as silicon oil or water. MR fluid exhibits solid-like mechanical behavior into chain or clusters with high yield stress when magnetic field is applied to the particles. The response of MR fluids is very quick and reversible after removal of the field. MR Fluids have high yield stress (up to 5kPs) and operate in low voltage power supply. Recently, MR damper using MR fluids was open used in vibration control system such as structural devices, seat vibration controllers and helicopter rotor systems, but it is too big in size and heavy. Therefore, it is not appreciate to rehabilitation devices such as prosthetic limbs.

• 대한기계학회논문집 C: 기술과 교육
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• 제3권2호
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• pp.131-140
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• 2015

하반신 마비환자가 스키를 탈 수 있도록 고안된 모노스키는 스키 플레이트 위에 좌석이 설치된 형태의 썰매이다. 스키를 탈 때 설면으로부터 전달되는 충격은 정상인의 경우 다리관절의 거동에 의하여 흡수되지만 모노스키의 경우에는 좌석에 탑승한 인체에 그대로 전달된다. 상용화된 대부분의 모노스키에는 이를 보완하기 위하여 스키 마운트와 시트 간에 링크 메커니즘과 충격완충장치가 설치되어 있다. 본 연구에서는 유압 실린더가 장착된 모노스키의 주행 시뮬레이션을 수행하고 불규칙한 표면 주행 중 발생하는 진동 충격 가속도를 분석하여 탑승자의 안락감을 평가할 수 있는 모델을 개발하였다. 안락감 평가방법은 국제 규격인 BS6841 을 사용하였다. 개발 모델을 이용하여 유압 완충장치의 노즐조절에 따른 안락감을 평가하였다.

• 동력기계공학회지
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• 제6권2호
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• pp.33-39
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• 2002

Commercial vehicles are mostly subjected to relatively rougher ground environment than passenger vehicles. Many driver's seats of commercial vehicles have suspension system with spring and dampers. Then, impact or vibrative forces transmitted from the vehicle to the driver can be attenuated. This study deals with a ride evaluation method using sky-hook control algorithm for the suspension dampers. Vibration amplitude transmissibilities were compared between passive dampers and semi-active dampers with sky-hook control method.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.141-148
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• 2005

In order to reduce the time and costs of improving the performance of vehicle suspensions, the techniques for optimizing damping and air spring characteristic were proposed. A full vehicle model for a bus is constructed with a car body, front and rear suspension linkages, air springs, dampers, tires, and a steering system. An air spring and a damper are modeled with nonlinear characteristics using experimental data and a curve fitting technique. The objective function for ride quality is WRMS (Weighted RMS) of the power spectral density of the vertical acceleration at the driver's seat, middle seat and rear seat. The objective function for handling performance is the RMS (Root Mean Squares) of the roll angle, roll rate, yaw rate, and lateral acceleration at the center of gravity of a body during a lane change. The design variables are determined by damping coefficients, damping exponents and curve fitting parameters of air spring characteristic curves. The Taguchi method is used in order to investigate sensitivity of design variables. Since ride and handling performances are mutually conflicting characteristics, the validity of the developed optimum design procedure is demonstrated by comparing the trends of ride and handling performance indices with respect to the ratio of weighting factors. The global criterion method is proposed to obtain the solution of multi-objective optimization problem.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2007년도 추계학술발표논문집
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• pp.315-318
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• 2007

최근 자동차안전기준이 중요시되면서 안전에 대한 관심이 높아지고 있다. 본 연구는 FMVSS301 및 자동차안전기준 제 91조에 해당하는 시험조건으로 후방추돌시 인체상해를 방지하기위해 뎀퍼가 장착된 자동차시트의 메카니즘을 설계 및 해석을 하였다.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.193-200
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• 2002

Simple spring-damper-mass models have been widely used to investigate whole-body vortical biodynamic response characteristics of the seated vehicle driver. Most previous models have not considered the effect of wobbling masses; i.e. heart, lungs, liver, intestine, etc. In this study, 4 -DOF seated driver model including one non-rigid mass representing wobbling visceral mass, 5-DOF model including intestine, and 10-DOF model including five lumbar vertebral masses were proposed. The model parameters were identified by a combinatorial optimization technique. simulated annealing method. The objective function was chosen as the sum of error between model response of seat-to-head transmissibility and driving point mechanical impedance and those of experimental data for subjects seated erect without backrest support. The model response showed a good agreement with the experimental response characteristics. Using a 10-DOF model, calculated resonance frequency of lumbar spine at 4Hz was matched well with experimental results of Panjabi et al.

• 드라이브 ㆍ 컨트롤
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• 제13권2호
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• pp.10-18
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• 2016

A front-end loader (FEL) mounted on an agricultural tractor is one of the most commonly used implements to mechanize routine agricultural tasks. When the FEL is used with a loaded bucket, careful operation is required to maintain safety and avoid spillage when the tractor passes a bump because a change in the gravity center of the tractor due to varied loadings can affect the stability of the tractor. Use of a boom suspension system consisting of accumulators and orifice dampers can be instrumental in reducing pitching vibrations while increasing the handling performance of the FEL-mounted tractor. The objective of this research was to reduce bump shocks by adding an orifice and a flow control valve to the original hydraulic circuit composed solely of accumulators. A simulation study was performed using the SimulationX program to investigate the effects of an accumulator and an orifice-throttle damper on bump shocks. Results showed that the peak pressure on a boom cylinder and the vertical acceleration of a bucket were significantly affected by use of both an accumulator and an orifice damper. In a field test conducted with a 75-kW tractor, the peak pressure of the boom cylinder, and the root mean square (RMS) vertical acceleration of the bucket and seat were reduced by on average, 23.0, 42.2, and 44.9% respectively, as compared to those measured with the original accumulator system, showing that an improved design for the accumulator hydraulic circuit can reduce bump shocks. Further studies are needed to design a tractor suspension system that includes the effects of cabin suspension and tires as well as dynamic analysis.