摘要：随着我国社会经济快速展开，城市人口数量不断加大，城市化进程加快推进，城市交通问题将是我国社会经济发展面临的一个大问题。交通便捷与否是权衡一个城市经济发展水平与生活环境的重要依据，如何有效利用城市交通资源和提高交通效率将是未来研究的重点方向。目前,我国大部分中小型城市依旧在使用定时控制的交通信号灯系统，而这些城市往往人口数量比较多，这样的交通现状势必会导致城市交通效率低下，影响人们的日常生活。为了解决这样一个问题，研究一套智能交通信号控制系统以缓解城市交通压力，变得更加具有现实意义。

本论文介绍了利用PLC实现智能交通延时过程。该智能系统由车流量检测与智能控制两大部分组成。论文的重点部分是如何实现车流量的检测和智能延时控制，在车流量检测中采用目前使用最广的传感器地感线圈来探测车道内的通过，在车道两端埋设地感线圈来检测车流的驶入和驶出，然后将信息通过PLC端口传给PLC中的计数器以计算当前车道的滞留量，通过与设定经验值对比，自动调节该车道绿灯延长时间，提高绿信比和交通效率，减少交通拥堵。本论文经过对交通信号灯的控制要求的剖析，运用西门子S7-200的控制能力，实现了十字路口交通灯的合理控制的功能。

关键词：PLC；智能交通系统；智能控制；地感线圈

Abstract：With the continuous development of China's social economy, the increasing number of urban population, urbanization process is accelerating, urban traffic problems will be China's social and economic development is facing a big problem. Whether traffic is convenient or not is an important index to measure the level of urban development and living environment. How to make effective use of urban traffic resources and improve traffic efficiency will be the focus of future research. At present, most of China's small and medium-sized cities are still using the timing control of the traffic signal system, and these cities tend to population more, this traffic situation is bound to lead to urban traffic efficiency is low, affecting people's daily life. In order to solve such a problem, it is more practical to study a set of intelligent traffic signal control system to alleviate the urban traffic pressure.

This paper introduces the intelligent delay signal system of crossroads controlled by PLC technology and small programmable controller (S7-200 PLC). This intelligent traffic light system includes traffic flow detection and intelligent control, at the same time through the PLC communication port will PLC interconnection, to achieve multi-junction traffic information sharing. The key part of the paper is how to achieve the traffic flow detection and intelligent delay control, in the traffic flow detection using the most widely used sensors to detect the passage of the coil to pass through the lane at both ends of the ground to detect the coil to detect traffic And then pass the information through the PLC port to the PLC in the counter to calculate the current lane retention, by comparing with the set experience value, automatically adjust the lane green light to extend the time to improve the green letter ratio and traffic efficiency , To reduce traffic congestion. Based on the analysis of the control requirements of traffic lights and the control performance of Siemens S7-200, this paper realizes the reasonable control function of traffic lights at crossroads.

Key words: PLC; intelligent transportation system; intelligent control;

目录

第一章绪论 1

1.1研究背景、目的及意义 1

1.2城市交通发展现状 2

1.2.1国内城市交通信号控制系统的现状