• Proceedings of the KSME Conference
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• 2001.06b
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• pp.584-589
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• 2001

This paper presents the dynamic parameter design optimization of a suspension seat system using the genetic algorithm. At first, an equivalent 1-D.O.F. mass-spring-damper model of a suspension seat system was constructed for the purpose of its vibration analysis. Vertical vibration response and transmissibility of the equivalent model due to base excitations, which are defined in the ISO's seat vibration test codes, were computed. Furthermore, seat vibration test, that is ISO's damping test, was carried out in order to investigate the validity of the equivalent suspension seat model. Both analytical and experimental results showed good agreement each other. For the design optimization, the acceleration transmissibility of the suspension seat model was adopted as an object function. A simple genetic algorithm was used to search the optimum values of the design variables, suspension stiffness and damping coefficient. Finally, vibration ride performance test results showed that the optimum suspension parameters gives the lowest vibration transmissibility. Accordingly the genetic algorithm and the equivalent suspension seat modelling can be successfully adopted in the vibration ride quality optimization of a suspension seat system.

• Journal of KSNVE
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• v.5 no.1
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• pp.67-73
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• 1995

In earth moving construction equipment used for rough and dangerous works, seat suspension system is the only means for reducing the vibration transmitted to the operator. Thus ISO(International Organization for Standardization) 7096 suggests a recommendation for the vibration characteristics of the seat suspension system in order to protect the human beings from excessive vibrationl. In this research, a new mechanical type seat suspension system is designed and a mathematical model, effective design parameters of the seat suspension system are determined and concept design strategy is presented.

• Journal of Biosystems Engineering
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• v.34 no.5
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• pp.315-324
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• 2009

Various types of vibration are transmitted to operators of agricultural tractors while working in the field. Most harmful vibration to human body is ride vibrations with low frequency ranging from 1 to 10 Hz, caused by rough terrain. These ride vibration has vertical and rotational components. This study was conducted to develop an active seat suspension system with two degrees of freedoms, enabling effectively reduce vibrations in vertical and pitch motions. Therefore, a mechanism for the active seat suspension was developed, and an electro-hydraulic servo system and a controller to drive the active seat suspension system were also developed in this study. A simulation model was developed to evaluate how the active seat suspension system effectively reduce the vibrations transmitted to the base of seat. Active seat suspension was optimized to enhance the performance using the developed simulation model. The performance of the seat suspension system was evaluated according to the test codes described in EEC78/764 in order to investigate the feasibility of application to agricultural tractors. The result showed that the developed active seat suspension system could reduce the magnitude of vertical vibration up to 80% for the input vibrations according to the test codes described in EEC78/764. The system could reduce the rotational displacement of ${\pm}\;2.5$ degrees up to 50% for the pitch vibration on the average in the frequency range of 1 to 2 Hz.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.5
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• pp.127-134
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• 2000

This paper presents the development of a semi-active seat damper using MR fluids and the performance analysis of seat suspension system with a MR seat damper. An annular orifice type MR seat damper is proposed for a seat suspension of a commercial vehicle. After formulating the governing equation of motion, then an appropriate size of the seat damper is designed and manufactured. Following the evaluation of field-dependant damping force characteristics, the controllability of the damping force is experimentally demonstrated in time domain by adopting PID controller. A semi-active seat suspension with the proposed MR damper is constructed and its dynamic model is established. Subsequently, vibration control capability of the semi-active suspension system is investigated by employing the sky-hook controller.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.619-624
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• 2004

This paper applies the fuzzy logic controller to a semiactive seat suspension system in order to obtain the better ride comfort in constraint of specific rattle space. The seat suspension system used for this research is a scissors-type one with the MR (Magnetic Rheological) fluid damper. Since a seat suspension system with a driver can not be exactly modeled, it is effective to control with the fuzzy logic controller. The rule was carefully tuned to effectively reduce the vibration transmitted to a driver. The on-road ride was realized on a hydraulic excitor and the result shows that the fuzzy controller has reduced the vibration of a seat suspension system compared to the continuous skyhook controller.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.572-577
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• 2005

This paper applies the fuzzy logic controller to a semiactive seat suspension system in order to obtain the better ride comfort in constraint of specific rattle space. The seat suspension system used for this research is a scissors-type one with the MR (Magneto Rheological) fluid damper. Since a seat suspension system with a driver can not be exactly modeled, it is effective to control with the fuzzy logic controller. The rule was carefully tuned to effectively reduce the vibration transmitted to a driver. The on-road ride was realized on a hydraulic excitor and the result shows that the fuzzy controller has reduced the vibration of a seat suspension system compared to the continuous skyhook controller.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1199-1205
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• 2011

In the present work, a seat suspension system adopting semi-active damper is evaluated for driver's ride quality. A cylindrical type of ER(electrorheological) damper is designed and manufactured for the seat suspension of heavy vehicles. The governing equation is derived under consideration of human vibration. A sliding mode controller is then synthesized and experimentally realized on the manufactured ER seat suspension while a driver is sitting on the controlled seat. Ride quality is evaluated by fatigue decreased proficiency boundary, vibration dose value and crest factor utilizing weighted-acceleration according to ISO2631.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.3
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• pp.7-13
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• 1998

This paper presents a new concept of a commercial vehicle seat suspension system. The proposed suspension system features an ER(electro-rheological)damper which can produce continuously tunable damping forces by control elecric 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 The effectiveness of the proposed ER seat suspension system is evaluated by investigating vibration with respect to sinusoidal inputs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.821-822
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• 2012

• Journal of Power System Engineering
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• v.3 no.3
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• pp.91-96
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• 1999

This study is about the design and analysis ot a suspension damper for truck driver's seat to improve the ride comfort. Trucks are usually subjected to hostile driving environments. Therefore, many truck driver's seat have suspension seats to isolate the vibration from the cab floor panel. Because the vehicle suspension system can reduce the primary vibration from the ground, only low frequency vibration can be transmitted to the driver's seat. But, this low frequency vibration can be harmful to the driver. The seat damper is very critical element to improve the ride comfort for the driver. In this study, a four-stage damper is designed and analyzed for the vibration capability. The damping coefficient of this damper can lie manually controlled in response to the road and driving environment.