• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.683-690
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• 2012

In this work, the semi-active control of a large-sized bus suspension system with an MR damper was studied. An MR damper model that can aptly describe the hysteretic characteristics of an MR damper was adopted. Parameter values of the MR damper model were suitably modified by considering the maximum damping force of a passive damper used in the suspension system of a real large-sized bus. In addition, a fuzzy logic controller was developed for semi-active control of a suspension system with an MR damper. The vertical acceleration at the attachment point of the MR damper and the relative velocity between sprung and unsprung masses were used as input variables, while voltage was used as the output variable. Straight-ahead driving simulations were performed on a road with a random road profile and on a flat road with a bump. In straight-ahead driving simulations, the vertical acceleration and pitch angle were measured to compare the riding performance of a suspension system with a passive damper with that of a suspension with an MR damper. In addition, a single lane change simulation was performed. In the simulation, the lateral acceleration and roll angle were measured in order to compare the handling performance of a suspension system using a passive damper with that of a suspension system using an MR damper.

• 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.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.11-17
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• 2015

Recently, the in-wheel motor vehicle is rapidly developed to solve energy exhaustion and environmental problems. Especially, it has the advantage of independently driving the torque control of each wheel in the vehicle. However, due to the weight increase of wheel, the comfort of vehicle riding and performance of road holding become worse. In this paper, to compensate the poor performance, a simultaneous control of the driving torque and semi-active suspension system is investigated. A vehicle model is generated using CarSim Software and validated by field tests. Co-simulation of CarSim and MATLAB/Simulink with control logics is carried out, and it is found that simultaneous control of the driving torque and semi-active suspension system can improve driving stability and durability of the in-wheel motor system.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.56-62
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• 2001

In this paper, skyhook control of a semi-active ER(Electro-Rheological) damper is investigated. The strength of the ER damper is controlled by a high voltage power supply. This paper deals with a two-degree-of-freedom suspension using the damper with ERF for a quarter vehicle system. The control law for semi-active suspensions modeled in this study is developed using skyhook and Linear Quadratic Regulator(LQR) optimal control method. Computer simulation and experimental results show that the semi-active suspension with ERF damper has good performances of ride quality.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.3
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• pp.120-129
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• 2001

A two-degree-of-freedom quarter-car model is used as the basis for LQ and the proposed controller design for a semi-active suspension. The LQ controller results in the best rms performance trade-offs(as defined by performance index) between ride, handling and packaging requirements. In LQ controller, however, the conflict between road holding and ride comfort remains. The adaptive semi-active suspension control based on the road frequency are introduced in this paper. With this method, the trade-off between road holding and ride comfort can be relaxed. The road frequency is estimated by wavelet transform if rattle space signal. The simulation results show that the proposed controller is superior to the conventional LQ controller.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.1
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• pp.17-23
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• 2004

The semi-active suspension system is getting widely adopted in passenger vehicles for its ability to improve ride comfort over the passive suspension system while not degrading driving safety. A key to the success is to develop practical controllers that yield performance enhancement over the passive damper under various driving conditions. To this end, several control strategies have been studied and evaluated in this research in consideration of practical aspects such as nonlinearity and dynamics of the damper. From simulation results. it has been observed that, with the proposed control schemes, ride comfort can be significantly upgraded while suppressing degradation of driving safety.

• Journal of Power System Engineering
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• v.6 no.2
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.775-780
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• 2011

This paper represents the study on the development of semi-active bicycle suspension system. The road vibration and transmissibility of front suspension are obtained by driving test on proving ground. The numerical simulation is evaluated by dynamic system modeling and equation of motion. The numerical simulation are performed to estimate the optimal damping force for minimal vibration transmission. And oscillating displacement is calculated and analyzed. Therefore the stoke which convert the damping characteristics is suggested from the driving test and numerical simulation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.47.5-47
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• 2001

In this paper. a road-adaptive LQG control for the semiactive Macpherson strut suspension system of hydraulic type is investigated. A new control oriented model, which incorporates the rotational motion of the unsprung mass, is introduced. A semi-active suspension controller adapting to road variations is proposed. First, based on the extended least squares estimation algorithm, a LQG controller adapting to the estimated road characteristics is designed. Through the computer simulations, the performance of the proposed semi-active suspension is compared with that of a non-adaptive one. The results show better control performance of the proposed system over the compared one.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.2187-2195
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• 1997

A semi-active suspension test system was designed and built for the experimental study. Vehicle parameters were estimated through tests and a quarter-car model was validated by comparing computer simulation results and laboratory test results. Alternative semi-active suspension control laws have been tested using the test system. Modulable damper used in this study is a "reverse" damper with 42 states which is controlled by a stepper motor. Experimental results have shown that semi-active suspensions have potential to improve ride quality of automobiles.tomobiles.