• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.76-85
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• 1997

The understeer characteristics of four wheel steering system(4WS system) in a high speed region have a negative effect upon the yaw velocity, leading to a decrease in the handling ability of vehicle. As a result, even if the side slip angle of vehicle can be kept up a minimum, a driver must compensate a decrease in yaw velocity by increasing the steering wheel angle in order to track the desired vehicle path. In this study, to keep the side slip angle of vehicle at zero and achieve a suitable yaw velocity in vehicle motion, a full active 4WS system(FA 4WS system) with actively steerable front and rear wheels is presented based on a nonlinear vehicle model and a model following control of yaw velocity. And the analysis results show the fat that, besides the excellent stability of vehicle, the FA 4WS system is able to realize better handling performance of vehicle than the previous 4WS systems in the high speed region.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.405-416
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• 2015

This paper developed a method analyze drivers' response characteristics using spectral analysis with car following data. Cross-correlation function and cross spectrum are produced by Fourier transform from speed fluctuations of leading vehicle and following vehicle during the designated time ${\tau}$. Based on the analysis data, a process to calculate the reaction time and stimulus-adaption index of following vehicle was developed and 170 cases of field data was applied. It was reported average of 0.654 and 2.091 seconds of stimulus-adaption index and reaction time respectively. In conclusion, the developed indexes might contribute to enhance vehicle control of autonomous vehicle more efficient and safer.

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.83-90
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• 2006

The purpose of this paper is to describe the design and implementation of an unmanned ground vehicle, called the TailGator at CIMAR (Center for Intelligent Machines and Robotics) of the University of Florida. The TailGator is a gas powered, four-wheeled vehicle that was designed for the AUVSI Intelligent Ground Vehicle Competition and has been tested in the contest for 2 years. The vehicle control model and design of the sensory systems are described. The competition is comprised of two events called the Autonomous Challenge and the Navigation Challenge: For the autonomous challenge, line following, obstacle avoidance, and detection are required. Line following is accomplished with a camera system. Obstacle avoidance and detection are accomplished with a laser scanner. For the navigation challenge, waypoint following and obstacle detection are required. The waypoint navigation is implemented with a global positioning system. The TailGator has provided an educational test bed for not only the contest requirements but also other studies in developing artificial intelligence algorithms such as adaptive control, creative control, automatic calibration, and internet-base control. The significance of this effort is in helping engineering and technology students understand the transition from theory to practice.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.9-15
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• 2012

The purpose of this study was to investigate the effects of the secondary tasks such as sending text message (STM) and searching navigation (SN) on skin conductance level (SCL) and driving performance of relatively aged and high-experienced drivers. The subjects included 26 taxi drivers; 12 males aged $56.3{\pm}4.4$ with $28.4{\pm}6.4$ years of driving experiences and 14 females aged $55.5{\pm}3.5$ with $19.4{\pm}5.0$ years of driving experiences. All subjects were instructed to keep a constant following distance (30m) from the car ahead and a given vehicle speed (80km/h or 100km/h) in a driving simulator. The relative change of SCL, vehicle velocity deviations, and average following distances were measured during driving only and driving with secondary tasks. The relative change of SCL, average following distance, and vehicle velocity deviation were more increased during the driving with secondary tasks than driving only. The relative change of SCL, vehicle velocity deviation, and average following distance were more affected by driving with 100km/hr than 80km/hr of a given vehicle speed. Secondary tasks increased a work load of drivers in term of SCL change, and decreased driving performance in terms of the vehicle velocity deviation and average following distance.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.4
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• pp.11-21
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• 2000

The travel behavior should be analysed microscopically for the traffic management of urban street. The car following theory which found out the correlation between the lead and the following vehicles is being widely used as basic data in many fields. As the vehicle position and its speed information can be received by GPS, this technique is recently applying to the various fields. For the case study the travel data were collected with two vehicles equipped with GPS receiver. The moving distance was calculated by the collected location data every 2 seconds and the speed variation was checked. And this study analysed and compared the acceleration and deceleration speed between the lead and the following vehicle. Finally, Regression model about the relationship between the acceleration and deceleration speed and the acceleration and deceleration distance was constructed. This model could be helpful for the road design and the regulation for the safe traffic management.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.4
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• pp.57-61
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• 2002

We design Collision Avoidance System using model vehicle. The purpose of this system(Collision Avoidance System) is to maintain continuously constant distance between a forward running vehicle and a following automatic guided vehicle(AGV). For this system, we design modeling of vehicle and observe this through simulation. By sing super sonic sensors to measure the distance between vehicles and controller using 80c196kc for changing velocity of motor, we design Collision Avoidance System as maintaining continuously constant distance between vehicles.

• The Transactions of the Korea Information Processing Society
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• v.3 no.5
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• pp.1037-1045
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• 1996

In this paper, the parallel model for stereo camera is employed to find the heralding angle and the distance between a leading vehicle and the following vehicle, BART(Binocular Autonomous Research Team vehicle). Two TDNNs (Time Delay Neural Network) such as S-TDNN and A-TDNN are introduced to control BART. S-TDNN controls the speed of the following vehicle while A-TDNN controls the steering angle of BATR. A human drives BART to collect data which are used for training the said neural networks. The trained networks performed the vehicle tracking function satisfactorily under the same driving conditions performed by the human driver. The neural network approach has good portability which decreases costs and saves development time for the different types of vehicles.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.8
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• pp.627-636
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• 2021

This paper deals with a study for the guidance control of reusable launch vehicle. For this purpose, modeling of the equation of motion of a reusable launch vehicle with 6 degrees of freedom was performed. With this model, an optimal re-entry path was created and a path-following guidance control simulation was performed to follow the optimal re-entry path. For the design of the path-following guidance controller, the attitude controller applying a time-delay technique that is resistant to modeling uncertainty, disturbance and failure. And the nonlinear path-following guidance law were used. Guidance control simulation using a classical PD controller was performed and compared with the guidance control simulation of a reusable launch vehicle applying a time delay technique.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.856-864
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• 2008

This paper describes a vehicle low speed driving assistant (VLDA) system that is composed of laser scanner. This vehicle is designed for following lead vehicle (LV) without driver's operation. The system is made up several component systems that are based on unmanned ground vehicle (UGV). Each component system is applied to use advanced safety vehicle developed to complete UGV system. VLDA system was divided into vehicle control system and obstacle detecting system. The obstacle detecting system calculate distance and angle of LV and transmit these data to vehicle control system using front, left and right laser scanners. Vehicle control system makes vehicle control values such as steering angle, acceleration and brake position and control vehicle's movement with steering, acceleration and brake actuators. In this research, we designed VLDA system like as low speed cruise control system and test it on real road environments.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.176-187
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• 1995

The problem of designing intelligent cruise control system for a longitudinal motion of an automobile, which is powered by internal combustion engines coupled to an automatic multispeed transmission, is considered. The basic concept is a vehicle-following system which maintains desired spacing between vehicles. This system actuates throttle with the information of the spacing error so as to maintain proper spacing and improve passenger ride comfort. In designing the controller, a modified controller, i.e, PID gain scheduling and fuzzy controller with fuzzy compensator was developed in order to overcome the nonlinearities of the automobile and obtain better performance. The computer simulation results illustrate that the better vehicle responses were obtained with the modified fuzzy controller and, under this controller, the vehicle responses were found to be relatively insensitive to parameter variations.