• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.25 no.12
• /
• pp.888-894
• /
• 2015

A new method for the simulation of the vehicle's interior road noise is proposed in the present study. The road noise model can synthesize road noise of a vehicle for varying driving speed within a range. In the proposed method, interior road noise is considered as a stochastic time-series, and is modeled by a nonstationary parametric model via two steps. First, each interior road noise signal, obtained from constant speed driving tests performed within a range of speed, is modeled as an autoregressive model whose parameters are estimated by using a standard method. Finally, the parameters obtained for different driving speeds are interpolated based on the varying driving speed to yield a time-varying autoregressive model. To model a full band road noise, audible frequency range is divided into an octave band using a wavelet filter bank, and the road noise in each octave band is modeled.

• Journal of the Korean Society of Industry Convergence
• /
• v.22 no.5
• /
• pp.575-582
• /
• 2019

Advanced driving assist system can support safety of driver and passengers which may require vehicle dynamics states as well as road geometry. It is essential to have in real-time estimation of related variables and parameters. Among the road geometry parameters, road slope angle which can not be measured is essential parameter in pose estimation, adaptive cruise control and others on sag road. In this paper, Kalman filter based method for the estimation of the vehicle dynamics and road slope angle using a nonlinear vehicle model is proposed. It uses a combination of Kalman filter as Cascade Extended Kalman Filter. CEKF uses measured vehicle states such as yaw rate, longitudinal/lateral acceleration and velocity. Unknown vehicle parameters such as center of gravity and inertia are obtained by 2 D.O.F lateral model and experimentally. Simulation and Experimental tests conducted with commercialized vehicle dynamics model and real-car.

• Journal of Climate Change Research
• /
• v.4 no.4
• /
• pp.359-369
• /
• 2013

In this paper, correlations between driving parameters and $CO_2$ of light-duty vehicles have been analyzed. Three test vehicles equipped with PEMS (Portable Emission Measurement System) have been driven in real-road in urban areas of Seoul. Averaged vehicle speed, RPA(Relative Positive Acceleration) and stop ratio have been selected as main driving parameters. The analysis have been conducted in interrupted and uninterrupted road types. Averaged values in various driving conditions have been calculated with distance based moving averaging window method. The multiple linear regression method have been applied to account for correlation between driving parameters and $CO_2$ emissions. This approach has shown statistically that $CO_2$ emission per distance (g/km) have tendencies to be increased as decreased averaged vehicle speed and increased RPA and stop ratio. Compared with uninterrupted traffic, interrupted traffic have shown the lower vehicle speed and the higher RPA and stop ratio. These characteristics of driving parameters in interrupted traffic should cause the higher $CO_2$ emission per distance.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.19 no.2
• /
• pp.101-106
• /
• 2024

For the commercialization of automated vehicles, it is necessary to create various scenarios that can evaluate driving safety and establish a data system that can verify them. Depending on the vehicle's ODD (Operational Design Domain), there are numerous scenarios with various parameters indicating vehicle driving conditions, but no systematic methodology has been proposed to create and combine scenarios to test them. Therefore, projects are actively underway abroad to establish a scenario library for real-world testing or simulation of autonomous vehicles. However, since it is difficult to obtain data, research is being conducted based on simulations that simulate real road. Therefore, in this study, parameters calculated through individual vehicle trajectory data extracted based on roadside CCTV image-based driving environment DB was proposed through the extracted data. This study can be used as basic data for safety standards for scenarios representing various driving behaviors.

• Journal of Korea Multimedia Society
• /
• v.25 no.2
• /
• pp.421-431
• /
• 2022

The purpose of this research is to determine the point of fixation of the driver during the process of driving. Based on the results of this research, the driving instructor can make a judgement on what the trainee stare on the most. Traffic accidents have become a serious concern in modern society. Especially, the traffic accidents among unskilled and elderly drivers are at issue. A driver should put attention on the vehicles around, traffic signs, passersby, passengers, road situation and its dashboard. An eye-tracking-based application was developed to analyze the driver's gaze behavior. It is a prototype for real-time eye tracking for monitoring the point of interest of drivers in driving practice. In this study, the driver's attention was measured by capturing the movement of the eyes in real road driving conditions using these tools. As a result, dwelling duration time, entry time and the average of fixation of the eye gaze are leading parameters that could help us prove the idea of this study.

• International Journal of Highway Engineering
• /
• v.17 no.5
• /
• pp.57-66
• /
• 2015

PURPOSES: Nighttime driving is very different from daytime driving because drivers must obtain nighttime sight-distances based on road lights and headlights. Unfortunately, nighttime driving conditions in Korea are far from ideal due to poor lighting and an insufficient number of road lights and inadequate operation and maintenance of delineators. This study is conducted to develop new standards for nighttime road visibility based on experiments of driver perception for nighttime visibility conditions. METHODS : In the study, perception level and satisfaction of nighttime visibility were investigated. A total of 60 drivers participated, including 34 older drivers and 31 young drivers. To evaluate driver perceptions of nighttime road visibility, fuzzy set theory was used because the conventional analysis methods for driver perception are limited in effectiveness for considering the characteristics of perception which are subjective and vague, and are generally expressed in terms of linguistic terminologies rather than numerical parameters. RESULTS : This study found that levels of nighttime visibility, as perceived by drivers, are remarkably similar to their satisfactions in different nighttime driving conditions with a log-function relationship. Older drivers evaluated unambiguously degree of nighttime visibility but evaluations by young drivers regarding it were unclear. CONCLUSIONS : A minimum value of brightness on roads was established as YUX 30, based on final analyzed results. In other words, road lights should be installed and operated to obtain more than YUX 30 brightness for the safety and comfort of nighttime driving.

• International Journal of Precision Engineering and Manufacturing
• /
• v.8 no.3
• /
• pp.3-7
• /
• 2007

There have been numerous studies directed toward the development of driving mechanisms for off-road mobility and rescue robots. To achieve surveillance, reconnaissance, and rescue, it is necessary for robots to have a driving mechanism that can handle off-road environments, We propose a new type of single-track driving mechanism with a variable geometry for a rescue robot, This mechanism has a symmetric configuration so that the robot can advance in two directions and also remain operable when overturned. By transforming its geometry, the robot can reduce energy consumption in steering and rotating as well as maximize its ability to climb obstacles such as stairs. The robot is also designed to have a compact size and low center of gravity to facilitate driving when on a set of stairs. In this paper, we analyzed the design parameters of the robot for the four phases of climbing stairs and determined the specifications needed to enhance its adaptability.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.5
• /
• pp.188-195
• /
• 2000

This study was conducted to develop the mathematical model and the computer simulation program(TPPMWV) for predicting the tractive performance of off-road wheeled vehicles operated on various soil conditions. The model takes into account main design parameters of a wheeled vehicle, including the radius and width of front and rear tires, the weight of vehicle, wheelbase and driving type(4WD, 2WD). Soil characteristics, such as the peressure-sinkage and shearing characteristics and the response to repetitive loading, are also taken into consideration. The effectiveness of the developed model was verified by comparing the predicted drawbar pulls using TPPMWV with measured ones obtained by field tests for two different driving types of wheeled vehicle. As a results, the drawbar pulls predicted by the TPPMWV were well matched to the measured ones within the absolute errors of 5.25%(4WD) AND 9.42%(2WD)for two different driving types, respectively.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.6
• /
• pp.207-213
• /
• 1999

In this study, the possibility of estimation of friction coefficient between tire and road surface using running car data are checked. To get necessary data, such as tire and car velocities and braking force, a test car is driven with certain magnitude of decelerations from pre-set initial velocities to stop . The data are used to estimate friction coefficient with property chosen parameters , e.g,, driving stiffness, pressure distribution functions, etc. Experimental results show that running data car be used with properly chosen parameters to estimate friction coefficient.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.11
• /
• pp.1096-1103
• /
• 2010

This paper proposes CDC (Continuous Damping Control) algorithm and verifies in multi-body dynamic vehicle. In order to distinguish a road profile on driving, waviness calculated by the filtered vertical-accelerations of sprung and unsprung masses is introduced. Sky-hook control is used at a low waviness road and constant damping level control is used at a high waviness road, where the hard damping level is determined by waviness, roll rate, acceleration, and deceleration. The damping levels of ride, anti-roll, anti-squat, and anti-dive modules are calculated by tuning parameters which is dependent upon vehicle velocity. Therefore this high tunable algorithm is useful to improve the ride and handling performance under various driving conditions. In the simulations, tire and dampers are modelled by SWIFT (Short Wavelength Intermediate Frequency Tire) model and 1st order delay model, and results are compared with conventional damper's.