• International Journal of Precision Engineering and Manufacturing
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• 제5권3호
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• pp.26-34
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• 2004

This paper examines the usefulness of a Brake Steer System(BSS), which uses differential brake forces for steering intervention in the context of Intelligent Transportation Systems(ITS). In order to help the car to turn, a yaw moment control was achieved by altering the left/right and front/rear brake distribution. This resulting yaw moment on the vehicle affects lateral position thereby providing a limited steering function. The steering function achieved through BSS was used to control lateral position in an unintended road departure system. A 8-DOF nonlinear vehicle model including STI tire model was validated using the equations of motion of the vehicle. Then a controller was developed. This controller, which is a PID controller tuned by Ziegler-Nichols, is designed to explore BSS feasibility by modifying the brake distribution through the control of the yaw rate of the vehicle.

• Proceedings of the KIEE Conference
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.451-454
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• 1995

Increasing the transfortation efficiency is very important issue in railway system. Speed-up of train and shortage of headway can be its solution. Headway can vary with blocksection length, characteristics of the railway and signalling systems. Safety braking distance needed for passenger's safety is very important factor in block section division method. In this study, basic block section division program was developed with the differential ratio of braking distance resulted by grade value of the track. More complete block section division program is going to be developed by the help of experienced experts.

• Journal of Auto-vehicle Safety Association
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• 제10권4호
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• pp.13-24
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• 2018

According to DEKRA (a Germany Certification and Inspection Agency)'s accident rate analysis by vehicle defect factor, as a result of analysis of the causes of accidents by flaws, it was found that braking devices accounted for 41%. Defects in the braking system are closely related to the accident, so it is very important to find faulty brking systems to ensure safety. The EU and USA uses ISO brake tester and the Korea is brake teater is first introduse in Japan for vehicle inspection and maintanance. KOTSA introduce the ISO brake tester in order to promote the advanced standardization of the inspection equipment and inspection tecnology, and examined the detection characteristics and applied it to the improvement direction of the brake tester to secure the driving safety.

• Journal of Auto-vehicle Safety Association
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• 제15권1호
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• pp.63-68
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• 2023

A study on the need for a safety system using driver's biometric information, vehicle automatic emergency braking system, and the e-call system that in the event of an unexpected situation such as loss of driving ability due to sudden physical abnormality of elderly drivers and drivers with health problems, and the improvement of laws for the spread of this system were studied.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.585-588
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• 1997

This paper presents a construction method of logic-based switching control system which operates in widely changing environments. The logic-based switching controller is composed of a family of candidate controllers together with a supervisor. The system does not require any identification schemes of environments. Switching from one candidate controller to another is carried out based on monitoring the output of the system. The basic ideas of adaptation are as follows: (1)each candidate controller is prepared for each environment in advance; (2)the supervisor applies a sequence of speculative controls to a plant with candidate controllers just after the control has started and just after the change of the environment has been detected. It is important that each candidate controller can keep the system stable during a sequence of speculative controls, and the most appropriate candidate controller for the environment to which the system is exposed can be selected before the last speculative control is ended. An application to an antiskid braking system clarifies the effectiveness of the proposed method.

• Journal of the Korean Society of Industry Convergence
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• 제20권4호
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• pp.313-323
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• 2017

As vehicles become more intelligent this is focused on ways to enhance safety and convenience for both drivers and passengers. In particular, x-by-wire systems that replace rigid mechanical components with dynamically configurable electronic elements are being developed to expand intelligent functions, such as adaptive cruise control or lane departure warning system. Because the malfunction of safety-related modules controlling critical functions, such as brakes, throttle, and steering in x-by-wire systems, can cause injury or death, safety and reliability are the most critical issue for automotive vendors and parts manufacturers. In an effort to develop better and effective brake-by-wire system, this paper presents EMB system by using the low speed electric vehicle, which is not required large braking force, with motor controller. In addition, we design performance evaluation system of EMB with 1/4 low speed electric vehicle model and suggested EMB is evaluated through the performance evaluation system.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제60권9호
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• pp.1715-1720
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• 2011

Studies suggested an increase in the competitiveness and roles of mainline railways like speed and accessibility improvement, as a fundamental direction of the National Transport Network Plan. At this point, topics presented especially for strengthening the role of human and environment centered transportation: as to the greatly improved speed competitiveness, there are an operational speed above 180km/h ~ 200km/h and traveling within 2 ~ 3 hours among big cities. As to accessibility improvement, there are accessibility to main railway stations within 30 minutes, and the improvement of accessibility, safety, eco-friendliness, amenity etc. As a part of these suggestions, field specific plans were proposed for the establishment of expressed mainline railway network in Korea such as train's, civil structures, trolley lines etc. In this paper we analyzed the conventional lines and systems to figure out whether to change details in terms of H/W of signaling system. Additionally, we reviewed the compatibility or difference of signalling system depending on train's speed. With this result, we deduced the number of virtual blocks specific to the speed of 180km/h, 200km/h and 230km/h, which were showed for the speed improvement considering each variable like blocks, braking distance etc. In this way, we suggested the railway signal system establishment plan considering safety operation.

• Journal of Institute of Control, Robotics and Systems
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• 제21권3호
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• pp.224-232
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• 2015

In order to develop an active safety system which avoids or mitigates collisions with preceding vehicles such as autonomous emergency braking (AEB), accurate state estimation of the nearby vehicles is very important. In this paper, an algorithm is proposed using 3 dynamic models to better estimate the state of a vehicle which has various dynamic patterns in both longitudinal and lateral direction. In particular, the proposed algorithm is based on the Interacting Multiple Model (IMM) method which employs three different dynamic models, in cruise mode, lateral maneuver mode and longitudinal maneuver mode. In addition, a Probabilistic Data Association Filter (PDAF) is utilized as a data association algorithm which can improve the reliability of the measurement under a clutter environment. In order to verify the performance of the proposed method, it is simulated in comparison with a Kalman filter method which employs a single dynamic model. Finally, the proposed method is validated using radar data obtained from the field test in the proving ground.

• Proceedings of the KSR Conference
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.941-947
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• 2008

In the braking of a railroad car, mechanical brake systems using wheel tread and brake disk are applied as well as electrical brake systems by regenerator and rheostat. During disk braking, kinetic energy of the vehicle is converted into thermal energy through friction between disk and brake pad. And it causes high temperature concentration and generates thermal crack on the brake disk surface. In this study, comparative test process for heat-resistance of candidate materials was designed for development of brake disk materials having high heat-resistance. We also verified the efficiency of the process by experiments using conventional brake disk materials.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제62권3호
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• pp.424-430
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• 2013

This paper presents a new design works for the braking chopper system which is included in the propulsion system of KTX high speed train. Due to the current fed type synchronous motors used in the propulsion system, some different behaviors are shown comparing to the voltage type other chopper systems. Specially this chopper system acts either braking controlling or regenerative power controlling system with a parallel resistive load in the propulsion system. In this paper, an improved simple high power IGBT brake chopper system has proposed which is able to be replaced with an existing complicated GTO chopper system. The analytical approaches to the parallel load type current chopper system and the propper snubber circuits calculation were explained in this paper to control new chopper system. In addition, the thermal resistance of the cooling system for power dissipation of IGBT modules was calculated also. Finally several PC simulations have been done to clarify its availability.