Adaptive Sliding Mode Traffic Flow Control using a Deadzoned Parameter Adaptation Law for Ramp Metering and Speed Regulation

Xin Jin,Myunghwan Eom,Dongkyoung Chwa 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

In this paper, a novel traffic flow control method based-on ramp metering and speed regulation using an adaptive sliding mode control (ASMC) method along with a deadzoned parameter adaptation law is proposed at a stochastic macroscopic level traffic environment, where the influence of the density and speed disturbances is accounted for in the traffic dynamic equations. The goal of this paper is to design a local traffic flow controller using both ramp metering and speed regulation based on ASMC, in order to achieve the desired density and speed for the maintenance of the maximum mainline throughput against disturbances in practice. The proposed method is advantageous in that it can improve the traffic flow performance compared to the traditional methods using only ramp metering, even in the presence of ramp storage limitation and disturbances. Moreover, a prior knowledge of disturbance magnitude is not required in the process of designing the controller unlike the conventional sliding mode controller. A stability analysis is presented to show that the traffic system under the proposed traffic flow control method is guaranteed to be uniformly bounded and its ultimate bound can be adjusted to be sufficiently small in terms of deadzone. The validity of the proposed method is demonstrated under different traffic situations (i.e., different initial traffic status), in the sense that the proposed control method is capable of stabilizing traffic flow better than the previously well-known Asservissement Lineaire d"Entree Autoroutiere (ALINEA) strategy and also feedback linearization control (FLC) method.

Adaptive Sliding Mode Traffic Flow Control using a Deadzoned Parameter Adaptation Law for Ramp Metering and Speed Regulation

Jin, Xin,Eom, Myunghwan,Chwa, Dongkyoung The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

In this paper, a novel traffic flow control method based-on ramp metering and speed regulation using an adaptive sliding mode control (ASMC) method along with a deadzoned parameter adaptation law is proposed at a stochastic macroscopic level traffic environment, where the influence of the density and speed disturbances is accounted for in the traffic dynamic equations. The goal of this paper is to design a local traffic flow controller using both ramp metering and speed regulation based on ASMC, in order to achieve the desired density and speed for the maintenance of the maximum mainline throughput against disturbances in practice. The proposed method is advantageous in that it can improve the traffic flow performance compared to the traditional methods using only ramp metering, even in the presence of ramp storage limitation and disturbances. Moreover, a prior knowledge of disturbance magnitude is not required in the process of designing the controller unlike the conventional sliding mode controller. A stability analysis is presented to show that the traffic system under the proposed traffic flow control method is guaranteed to be uniformly bounded and its ultimate bound can be adjusted to be sufficiently small in terms of deadzone. The validity of the proposed method is demonstrated under different traffic situations (i.e., different initial traffic status), in the sense that the proposed control method is capable of stabilizing traffic flow better than the previously well-known Asservissement Lineaire d'Entree Autoroutiere (ALINEA) strategy and also feedback linearization control (FLC) method.

대형차량을 고려한 교차로 신호제어

최형도(HyeongDo Choi),조영태(YoungTae Jo),전수빈(SooBin Jeon),정인범(InBum Jung) 한국정보과학회 2013 정보과학회 컴퓨팅의 실제 논문지 Vol.19 No.6

최근 IT기술은 빠른 속도로 발전하며, 다른 분야와 접목되고 있다. 이런 상황에서 교통과 IT기술이 접목되어 지능형 교통시스템(ITS:Intelligent Transportation Systems)이라는 새로운 교통제어시스템이 등장한다. 지능형 교통시스템은 교통 전반에 걸쳐서 적용되고 있는데, 그 중 하나가 교차로 신호제어이다. 기존의 교차로 신호제어를 살펴보면 고정식 신호제어와 감응식 신호제어로 나누어볼 수 있다. 고정식 신호제어와 감응식 신호제어는 각각의 장단점이 존재하지만, 현재는 실시간 교통상황에 대처가 유리한 감응식 신호제어가 많이 연구 되고 있다. 이러한 감응식 신호제어 연구는 차량정보 습득의 기술적 문제로 인해 대형차량을 고려하지 않고 알고리즘을 설계하였었다. 이에 본 논문에서는 교차로 전체 차량 소통 량 증가와 평균 차량대기 시간 감소를 목적으로 CSCH(Crossroad Signal Control for Heavy goods vehicles) 알고리즘을 제안한다. 실험 결과 CSCH 알고리즘이 적용된 경우, 기존의 신호제어 알고리즘들에 비해 총 교통 소통 량이 증가하고, 평균 차량대기시간이 감소하여 교통흐름의 효율성이 증가한 것을 확인할 수 있다. Information technologies (IT) have been developed rapidly in the last decade of this century. Recently, the information technologies start combining with other technologies such as nano-technology, bio-technology and so on. Intelligent transportation systems (ITSs) is the one of the combined technologies which is convergence of transportation system and information technologies. ITS affect the first period of traffic, crossroad signal control is one of them. The existing crossroad signal control is divided into static signal control and actuated signal control. Static signal control and Actuated signal control have merits and demerits, but most signal control is study about actuated signal control. This Actuated signal control research was designed without considering heavy goods vehicles because of technical problem with vehicle information collection. Therefore, in this paper, we suggest CSCH(Crossroad Signal Control for Heavy goods vehicles) algorithm with the purpose of crossroad total vehicle flow increased and average vehicle waiting time reduced. The result shows that when adopting the CSCH algorithm, comparing to the existing signal control algorithm, the total vehicle flow increased and average vehicle waiting time decreased. Thus, we find that efficiency of traffic flow increased.

Scalable Network Architecture for Flow-Based Traffic Control

Jongtae Song,Soon Seok Lee,Kug-Chang Kang,Noik Park,Heuk Park,Sunghyun Yoon,Kyung Gyu Chun,Mi Young Chang,Young Sun Kim,Jinoo Joung 한국전자통신연구원 2008 ETRI Journal Vol.30 No.2

Many control schemes have been proposed for flowlevel traffic control. However, flow-level traffic control is implemented only in limited areas such as traffic monitoring and traffic control at edge nodes. No clear solution for end-to-end architecture has been proposed. Scalability and the lack of a business model are major problems for deploying end-to-end flow-level control architecture. This paper introduces an end-to-end transport architecture and a scalable control mechanism to support the various flow-level QoS requests from applications.

Driver Centric Decentralized Controller Design in Traffic Flow

Shigeru Yamamoto,Eiji Sakaguchi 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

In this paper, we consider a decentralized control problem for suppressing the traffic jam phenomenon in traffic flow. To analyze the phenomenon, we use the so-called optimal velocity model. In the model, the optimal velocity function which is a nonlinear function of the headway of the preceding vehicle describes driver’s characteristics. Without affecting the characteristics, all vehicles in traffic flow should be stabilized in a decentralized fashion. In this paper, we apply washout control which is a high pass filter based control method. We derive a stability condition and illustrate the effectiveness with several simulations.

교통조건에 따른 간선도로변 도로교통소음 특성에 관한 실험적 연구

조창근(Chang-Geun Cho) 한국생활환경학회 2010 한국생활환경학회지 Vol.17 No.5

Noise barrier has the limitation of reducing the road traffic noise in low frequency bands because of its diffraction phenomenon. In order to maximize the noise reduction performance of noise barrier, it is necessary that diffracted noise in low frequency bands should be effectively reduced. The purpose of this study is to investigate the characteristic of traffic noise in main roads and frequency characteristic of it for designing noise barrier by active noise control. Field measurement of road traffic noise at 1~5 m high from the ground on the 6 roads was carried out, and the variation characteristic by traffic flow condition was analyzed in this study. As a result, the road traffic noise showed high in mid and high frequency bands and the highest in 1 ㎑. Especially, the noise showed very high levels in 1 ㎑ in case of high speed of vehicles. Dominant frequency of the noise was appeared in low frequency bands under 100 ㎐, especially in 50~87.5 ㎐. It is thought that low frequency badns under 100 ㎐ should be considered to make noise source for active noise control. It is necessary that passive noise control should be applied for reducing the noise in mid and high frequency bands of 1 ㎑ in designing noise barrier. In addition, active noise control technique should be applied for decreasing the noise in low frequency bands under 100 ㎐ in order to maximize the noise reduction performance of noise barrier.

A Dynamic Control Method for Cavs Platoon Based on the MPC Framework and Safety Potential Field Model

Linheng Li,Jing Gan,Xu Qu,Wenqi Lu,Peipei Mao,Bin Ran 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.5

Safety and efficiency have always been significant challenges to the development of road traffic. Detailed vehicle motion information is the prerequisite for achieving optimal control of the platoon and improving traffic safety and efficiency. The connected and automated vehicles (CAVs) system has offered unprecedented opportunities for the real-time collection and processing of these detailed vehicle motion data. Based on the model predictive control (MPC) framework and safety potential field (SPF) model, we developed an alternative CAVs platoon dynamic control method. The SPF model was applied to describe the road risk distribution under the complex driving environment and was embedded in the MPC framework to optimize the vehicle dynamics from the perspective of capacity, safety, and energy-saving. Also, some experiments were performed to verify the validity of our platoon control strategy. Compared with the fixed time-headway strategy, our proposed strategy can increase the traffic capacity by about 24.4%, while ensuring safety and improving fuel economy. The results indicate that the novel CAVs platoon control methodology proposed in this paper can be potentially applied to alleviate various traffic problems (e.g., traffic congestion, traffic accidents, and high emissions).

도시고속도로 가변속도제어 운영방안과 효과분석

임관수,남두희 대한교통학회 2011 대한교통학회지 Vol.29 No.2

This paper discusses operational technique and effectiveness of Variable Speed Limits system that is implemented to control the traffic-flow on the Naebu Expressway. As the first step of the analysis, traffic data collected from vehicle detectors are corrected and smoothed. Applying a pattern analysis technique to the traffic data, the weekday traffic is classified into four different groups, and median of each group is calculated. Using three state variables, i.e., diverted traffic volume, average density and average speed, the conditions of roadway segments are determined. Computational outputs resulted from the application of the proposed model to the scenarios show that implementation of Variable Speed Limits system improved both safety and efficiency of the expressway. For the operational strategy, this paper also presents the change rate of the speed limit, and the effective duration of the speed limit according to the entering traffic volume. 본선 교통류 제어 방안 중 가변속도제어 모형을 제시하고 서울 내부순환로를 중심으로 효과를 검증하였다. 차량검지기로부터 수집된 데이터 보정 및 평활화 수행후 패턴분석을 통해 도시고속도로의 평일 상태를 4가지로 분류하고 중심 값을 산출하였다. 그리고 분석단위의 상태를 판단하기 위한 상태변수로 전이교통량, 평균밀도, 평균속도를 설정하였으며 제시된 모형과 시나리오에 근거하여 검증한 결과 안전성 및 효율성을 향상시킬 수 있었다. 또한 유입교통량에 따라 가변속도제어의 감속 정도와 유효 적용시간을 산출하였다.

자동화 컨테이너 터미널의 AGV 교통흐름 동적 최적화

김후림(Hoolim Kim),최이(Ri Choe),박태진(Taejin Park),류광렬(Kwang Ryel Ryu) 한국정보과학회 2010 정보과학회 컴퓨팅의 실제 논문지 Vol.16 No.5

본 논문에서는 자동화 컨테이너 터미널에서 컨테이너를 운반하는데 사용되는 무인 운반 차량(AGV)의 교통흐름을 동적으로 최적화하는 방안을 제안한다. 터미널 환경은 다수의 차량이 한정된 영역 내에서 주행하므로 높은 생산성을 위해서는 차량 사이의 간섭 및 병목현상을 최소화하도록 교통흐름을 제어해야 한다. 제안 알고리즘은 터미널 환경의 동적 변화에 대응하여 유전알고리즘을 이용하여 AGV의 교통흐름을 최적화한다. 알고리즘의 속도향상을 위해 이전에 수행한 최적화 결과를 활용하는 방안이 시도되었다. 시뮬레이션 실험을 통해 제안 알고리즘의 성능을 확인하였다. In this paper, a method that dynamically adapts the traffic flow of automated guided vehicles (AGVs) used in automated container terminals to the changing operational condition is presented. In a container terminal, the AGVs are vulnerable to traffic congestion because a large number of AGVs operate in a limited area. In addition, dynamically changing operational condition requires the traffic flow of AGVs to be continuously adjusted to keep up with the change. The proposed method utilizes a genetic algorithm to optimize the traffic flow. Exploiting the dynamic nature of the problem an approach that reuses the results of the previous search is tried to speed up the convergence of the genetic algorithm. The results of simulation experiments show the efficiency of the proposed method.

종단간 네트워크 시스템에서 전송율 기반 TCP 혼잡제어

배용근(Young geun Bae),윤찬호(Chan ho Yoon),김광준(Gwang jun Kim) 한국전자통신학회 2006 한국전자통신학회 논문지 Vol.1 No.2

본 논문에서는 전송 율 기반 흐름과 혼잡 제어를 이용한 종단 간 네트워크 시스템을 통한 양방향 TCP연결의 성능을 개선한다. TCP 패킷과 승인에 의해 버퍼를 공유하는 것은 ACK 압축이라는 결과를 초래하며, ACK 프레임 압축은 소스가 집단적으로 도착할 때 승인하며 불공정성과 처리 율 감소를 초래한다. 양방향 트래픽 때문에 발생한 처리 율 감소는 중요하다. 적절한 윈도의 크기를 가진 대칭적인 연결인 경우에서 연결의 효율은 2.0Mbps, 5.0Mbps, 7.5Mbps 세 가지 레벨의 백그라운드 트래픽에 대해서 약 20%정도의 성능이 개선된다. 반면에 지터의 처리율은 소스 노드와 목적 노드 사이에 왕복 지연 시간이 적기 때문에 약 50%정도 감소되는 것을 알 수 있다. 또한 처리 율 곡선이 2.5Mbps, 5Mbps, 7,5Mbps 백그라운드 트래픽에 대한 TCP 혼잡 회피를 위해 제안된 전송 율 기반 알고리즘에 의해 개선되어짐을 알 수 있다. In this paper, we improve the performance of bidirectional TCP connection over end-to-end network that uses transfer rate-based flow and congestion control. The sharing of a common buffer by TCP packets and acknowledgement has been known to result in an effect called ack compression, where acks of a connection arrive at the source bunched together, resulting in unfairness and degraded throughput. The degradation in throughput due to bidirectional traffic can be significant. For example, even in the simple case of symmetrical connections with adequate window size, the connection efficiency is improved about 20% for three levels of background traffic 2.5Mbps, 5.0Mbps and 7.5Mbps. Otherwise, the throughput of jitter is reduced about 50% because round trip delay time is smaller between source node and destination node. Also, we show that throughput curve is improved with connection rate algorithm which is proposed for TCP congestion avoidance as a function of aggressiveness threshold for three levels of background traffic 2.5Mbps, 5Mbps and 7.5Mbps.