• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.113-113
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• 2000

A robust adaptive technique for the longitudinal control of a platoon of automated vehicles is presented. A nonlinear model is used to represent the vehicle dynamics of each vehicle within the platoon. The external disturbance such as wind gust and a disturbance term due to engine transmission variations and so on are considered. The state observer is used to avoid direct measurement of the relative velocity or acceleration between the controlled and leading vehicles or the controlled vehicle's acceleration. It is shown that platoon stability can be recovered in operation even if a speed dependent spacing policy is adopted, which incorporates a constant time headway in addition to the constant distance. The simulation results demonstrate excellent tracking even in the presence of disturbances.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.8
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• pp.390-396
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• 2003

This paper is focused on an optimal block sectioning technique which are widely used in conventional railway system. We studied braking distance with pure train braking performance to generalize train braking. We tried to apply the braking distance to wayside signaling system to decide optimal block sectioning to reduce headway. The braking distances are obtained for 2 aspects, 3 aspects, 4 aspects and n aspects such that step speed control, are longer than the pure braking distance. We found an optimal solution with the generalized n aspects, and a minimum block distance for ATO mode.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.1
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• pp.68-75
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• 1998

The Intelligent Cruise Control system, ICC, is a driver assisting system for controlling relative speed and distance between two vehicles in the same lane. The ICC may be considered as an extension of a traditional cruise control, not only keeping a fixed speed of the vehicle, but correcting the speed also to that of a slower one ahead. This paper presents a real-time self-tuning fuzzy control algorithm to develop ICC. The self-tuning fuzzy control law is adopted to reduce the effects of nonlinearities of the vehicle and various road environments. In the self-tuning algorithm an interior penalty method is applied to preserve the inherent order of membership functions and is modified as an on-line algorithm for real time application. Via simulations, the performance of the suggested control algorithm is compared with a PID and a fuzzy control without self-tuning. The suggested control algorithm is implemented on PRV III and the results of the test driving on a local road are given.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.359-362
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• 2002

Presently metro in our country has higher rate of passengers as a public transportation of urban area than other transportations. And road is under very restrictive condition to be expanded in many aspects because the streets are completely choked. Therefore increase of capacity in metro and reduction of headway has been seriously required and utmost efforts has been taken by related fields to meet the requirements. The concept of CBTC system came out from this background. CBTC system can be implemented to detect t location without using the track circuits. It h advantages in aspects of signalling equipments and maintenance. This study investigated exa radio communication system and applicable norms in other countries. And it also revie suggestion for the establishment of radio freq radio network to be considered for application control system by radio under Korean metro env

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.82-87
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• 2005

The new technology with Wireless LAN (WLAN) is implemented to the railway system, which is attached importance to safety and reliability. Railway control system based on WLAN that is called CBTC (Communication Based Train Control) is being developed by the advanced nations in this field and The system is applied to a new train line and a renovation for outworn equipment. The CBTC system has many merits about increase of capacity, reduction of headway and cost reduction etc.. Therefore, that is come into spotlight to the advanced railway company and the companies have being developed the system. So, we have developed the CBTC system for standardization and localization of the railway signal system.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.478-483
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• 2002

Presently metro in our county has higher rate of passengers as a public transportation of urban area than other transportations. And road is under very restrictive condition to be expanded in many aspects because the streets are completely choked. Therefore increase of capacity in metro and reduction of headway has been seriously required and utmost efforts has been taken by related fields to meet the requirements. The concept of CBTC system came out from this background. CBTC system can be implemented to detect the train location without using the track circuits. It has many advantages in aspects of signalling equipments build-up and maintenance. This study investigated examples of radio communication system and applicable standard norms in other countries. And it also reviewed the suggestion for the establishment of radio frequency and radio network to be considered for application train control system by radio under Korean metro environment.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.1
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• pp.31-37
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• 2001

A robust adaptive technique for the longitudinal control of a platoon of automated vehicles is presented. A nonlinear model is used to represent the dynamics of each vehicle within the platoon. The external disturbances such as wind gust and a disturbance term due to engine transmission variations and so on are considered. The state observer is used to avoid direct measurement of the relative velocity or acceleration between the controlled and leading vehicles or the controlled vehicles's acceleration. The proposed controller guarantees to recover platoon stability in operation even if a speed dependent spacing policy is adopted, which incorporates a constant time headway in addition to the constant distance. It is shown that the proposed observer is exponentially stable, and the at the robust adaptive controller is stable. The simulation results demonstrate excellent tracking even in the presence of disturbances.

• International Journal of Automotive Technology
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• v.7 no.5
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• pp.603-608
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• 2006

As an important and relatively easy to implement technology for realizing Intelligent Transportation Systems(ITS), Adaptive Cruise Control(ACC) automatically adjusts vehicle speed and distance to a preceding vehicle, thus enhancing driver comfort and safety. One of the key issues associated with ACC development is usability and user acceptance. Control parameters in ACC should be optimized in such a way that the system does not conflict with driving behavior of the driver and further that the driver feels comfortable with ACC. A driving simulator is a comprehensive research tool that can be applied to various human factor studies and vehicle system development in a safe and controlled environment. This study investigated driving behavior with ACC for drivers with different driving styles using the driving simulator. The ACC simulation system was implemented on the simulator and its performance was evaluated first. The Driving Style Questionnaire(DSQ) was used to classify the driving styles of the drivers in the simulator experiment. The experiment results show that, when driving with ACC, preferred headway-time was 1.5 seconds regardless of the driving styles, implying consistency in driving speed and safe distance. However, the lane keeping ability reduced, showing the larger deviation in vehicle lateral position and larger head and eye movement. It is suggested that integration of ACC and lateral control can enhance driver safety and comfort even further.

• Science of Emotion and Sensibility
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• v.6 no.3
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• pp.1-11
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• 2003

The purpose of the present driving simulation study was to examine the effect of cellular-phone use on driving performance when required driving speeds were systematically varied(60, 80, 100, or 120km/h) while either using cellular-phones(experimental condition; Hands-Free or Hands-Held) or not(control condition). Driving performance was measured both by longitudinal vehicle control(i.e., variabilities in driving speed and headway) and lateral vehicle control(variabilities in lane position). The results can be summarized as followings: (1) The significant difference in driving speed variation between the two cellular-phone usage conditions was found only at relatively higher driving speed conditions(i.e., over 80km/h). (2) Only in the experimental condition where cellular-phone was required to be used while driving, the magnitudes of variation in driving speed, headway and lane position were gradually increased as the required driving speeds were increased(this tendency was not found in control condition). And. (3) the dependent measures of this study appeared to suggest that cellular-phone usage itself (rather than the types of cellular-phone) had significant impact on driving performance. Finally, implication and issues related to this study were discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.496-500
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• 1998

Not merely running at the designated constant speed as the classical cruise control, the adaptive cruise control (ACC) maintains safe headway distance when the front is blocked by other vehicles. One of the most essential part of ACC System is the range sensor which can measure the position and speed of all objects in front continuously, ignore all irrelevant objects, distinguish vehicles in different lanes and lock on to the closest vehicle in the same lane. In this paper, the hierarchical object recognition algorithm (HORA) is proposed to process raw scanning laser data and acquire valid distance to target vehicle. HORA contains two principal concepts. First, the concept of life quantifies the reliability of range data to filter off the spurious detection and preserve the missing target position. Second, the concept of conformation checks the mobility of each obstacle and tracks the position shift. To estimate and predict the vehicle position Kalman filter is used. Repeatedly updated covariance matrix determines the bound of valid data. The algorithm is emulated on computer and tested on-line with our ACC vehicle.