• Proceedings of the KSR Conference
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• 2011.10a
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• pp.69-74
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• 2011

In the curving detection method by using an accelerometer, the ride comfort in the first car is worse than one in the others due to spend the time to calculate the tilting command and drive the tilting mechanism after entering in the curve. In order to enhance the ride comfort in the first car, the preditive curve detection method which predicts the distance from a train to the starting point of curve by using the GPS, Tachometer, Ground balise and position DB for track. In this study, we predicted and evaluated the ride comfort for predictive curve detection method in transient curves according to the shape and dimension of transient curve and the various driving speed. Also, we predicted the improvement of the ride comfort for predictive curve detection method by comparing with the result of the ride comfort for predictive curve detection method and for curve detection method using an accelerometer in the short transient curve.

• Journal of Biomedical Engineering Research
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• v.44 no.2
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• pp.157-165
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• 2023

The purpose of this study was to evaluate the importance of developing slim seats with ergonomic design to improve seat comfort and expand the interior space. Two seats were used for the experiment: a sample seat designed based on hip shape and spinal alignment and a normal seat with a flat design without curves. Subjects sat in both the sample seat and a normal seat applied to the vehicle simulator and the experiment was conducted. The next part of the experiment was conducted in two different postures: a driving posture and a relaxed posture. The subjects filled out a comfort questionnaire immediately after sitting and after 30 minutes. The results showed that the comfort in the sample seat was found to be more comfortable than the normal seat. However, no significant difference was noted for the relaxation posture. Pressure distribution was also recorded immediately after sitting and after 30 minutes. In the case of pressure distribution, it was confirmed that the pressure in the sample seat was more evenly distributed in both the driving and relaxed postures than in the normal seat. The results showed that the ergonomically designed sample seat greatly improved seating comfort and pressure distribution compared to the normal seat, which is a general vehicle seat design.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.1-8
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• 1999

This study was conducted to collect data concerning the preferred driving postures and adopted seat adjustment levels and to grasp relationships among drivers' body sizes, postural angles, and adopted seat positions and angles. Also optimum driving posture and seat adjustment level estimation models were constructed. An experiment was conducted to investigate observed optimum driving posture, and seat adjustment level. Thirty-six subjects (male=20, female=16) was selected to include a wide range of percentiles in the dimensions important for automotive driving workstation design and to be representative of the automotive driving population in Korea. New guidelines and estimation models for optimum postural comfort were developed. There were significant differences between male and female in postural angles but not in seat adjustment levels. Taller subjects preferred a more open and reclined posture. Estimation models enable us to estimate the quantitative optimum driving posture and seat adjustment level with some drivers' physical dimensions.

• Advances in Automotive Engineering
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• v.1 no.1
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• pp.1-20
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• 2018

The aim of this study is the optimization of the parameters of interconnected Hydro-Pneumatic (HP) suspension system of a three-axle vehicle for ride comfort and handling. For HP suspension systems of equivalent vertical stiffness and damping characteristics, interconnected HP suspension systems increase roll and pitch stiffness and damping characteristics of the vehicle as compared to unconnected HP suspension systems. Thus, they result in improved handling and braking/acceleration performances of the vehicle. However, increased roll and pitch stiffness and damping characteristics also increase roll and pitch accelerations, which in turn result in degraded ride comfort performance. Therefore, in order to improve both ride comfort and vehicle handling performances simultaneously, an optimum parameter set of an interconnected HP suspension system is obtained through an optimization procedure. The objective function is formed as the sum of the weighted vertical accelerations according to ISO 2631. The roll angle, one of the important measures of vehicle handling and driving safety, is imposed as a constraint in the optimization study. Upper and lower parameter bounds are used in the optimization in order to get a physically realizable parameter set. Optimization procedure is implemented for a three-axle vehicle with unconnected and interconnected suspension systems separately. Optimization results show that interconnected HP suspension system results in improvements in both ride comfort and vehicle handling performance, as compared to the unconnected suspension system. As a result, interconnected HP suspension systems present a solution to the conflict between ride comfort and vehicle handling which is present in unconnected suspension systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.102-109
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• 2003

Safety and comfort are importance concepts for designers of vehicle seats and instrument panels. There have been a lot of researches on comfortable sitting postures, however, relatively a few researchers have tried to find a desirable driving posture in consideration of both comfort and safety. This study investigates a relationship between comfort and safety of sitting posture of a driver. Since a seat is closely related to comfort, the angular data of comfortable sitting posture were obtained through the correlation between the seat and the driver. In order to acquire the data of safe sitting posture, computer simulations were performed for various seatback angles. Based on comparing and analyzing the data obtained, the optimal sitting posture is suggested for both comfort and safety aspects.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1736-1740
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• 2003

There have been various studies to find out the correlation between subjective and objective evaluation ride comfort in vehicle. To be proper, subjective evaluation considers the signal pattern of vibration generated by vehicle. In this study, driving test is carried out to extract the correlation between subjective evaluation by subjects and vibration signals measured on the seat when a test vehicle is passing over test bumpers, which have two sorts of width change and height change respectively. A unique reference bumper is used to be compared with the relative comfort of test bumpers.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.57-61
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• 2011

The bimodal tram was designed to drive on the dedicated track as well as on the public road. The position and speed are automatically controlled on the dedicated track by the onboard computer, whereas they are manually controlled by driver like motor vehicles on the public road. The ride comfort the passengers feel and the effect of the vibration generated during driving on the passenger's health, comfortableness and motion sickness were evaluated with driving the bimodal tram prototype in automatic and manual mode, respectively. The test was done in automatic mode on the test track with various load conditions while it was done in manual mode on the public road with empty load.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1624-1630
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• 2011

Currently the train operating environment to affect track irregularity is changed rapidly such as speed-up, linear improvement and rolling stack upgrade. The recent track maintenance criteria of track irregularity was quoted from past Japan's, and the needs of revision of criteria are increased because of the rapid change in train operating environment. In case of enhance the track irregularity criteria, it secure driving safety and riding comfort but maintenance cost are increase. And also decrease ballast durability by frequent corrective work. In case of mitigate the criteria, it decrease driving safety and riding comfort, but save the maintenance cost. The study for enacting rational criteria did not carry out so far. In this study, survey the domestic and international track irregularity and case study for track irregularity inspection results and maintenance history for guideline of enacting irregularity criteria study.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.20-26
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• 1997

A System for reducing vehicle body roll by active control is developed. The stabilizer bar with hydraulic rotary actuator produces anti-roll moment which suppresses roll tendency. This reduction of roll improves the driving safety as well as the ride comfort. Vehicle test data shows considerable reduction of roll angle during steady-state turning. Also improvement of ride comfort is achieved by making the actuator freely rotatable, i.e. by connecting all chambers of actuator in normal driving conditions. A control algorithm using steering wheel angle and vehicle speed signal as input valve is applied. It is compared with signal of the G-sensor.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.128-137
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• 2003

Continuously variable damper can yield diverse damping forces for a single damping velocity. It is widely used in the semi-active suspension system since, with right control logics, it can enhance ride comfort compared to the passive damper while not degrading driving safety. A key to the successful design of the continuously variable damper is the knowledge of its complex and nonlinear characteristics. In this paper, research has been done for analyzing characteristics of the continuously variable damper. Various damper components have been investigated and their effects upon the force-velocity characteristics of the damper have been examined. The effects of the damper characteristics change upon ride comfort and driving safety have also been investigated by numerical simulations.