随着经济的发展，城市车辆的数量迅速增加，十字路口的交通信号灯已经成为城市交通控制的主要手段，而交通灯控制的智能化大大提高了十字路口的交通能力。随着PLC的发展，PLC在工业领域起到很重要的作用，由于PLC对使用环境有很强的适应性，同时内部定时器资源十分丰富，可以对交通信号灯进行精确控制，基于PLC的交通灯智能控制系统在交通控制领域起到很重要的作用。城市中的交通灯的红绿灯周期通常是固定值，在车流量高峰期，往往不能及时疏导交通，造成交通拥挤等现象。在本文中，主要介绍了传感器技术、车流量检测技术、PLC的软硬件、特点及应用等。智能控制系统是通过传感器检测车流量，根据车流的变化而改变交通信号灯的周期。主要方法是通过传感器测量十字路口各方向一定距离路段的车辆数，由传感器对车辆计数并输送到PLC，车流量分为小、中、大三个等级，并在PLC内与设定的参考车流量做对比，从而决定各个方向的绿灯通行信号的时间，最终使得交通信号灯的红绿灯周期由车流量决定，大大提高了十字路口车辆的通行能力。关键词（本论文范文的主要论点）：PLC；交通灯；智能控制 AbstractWith the development of economic, there is a rapid increase in the number of urban’s vehicle, the traffic light on the crossrods have been an important way of traffic control, and the intelligent of the traffic light control system has greatly improved the traffic capacity of crossroads. With the development of PLC, it is playing an important role in the industry. the PLC has adapted to the environment with flexibility, while it’s timer resources is very rich,it can be precisely controlled on traffic lights, the PLC-based intelligent traffic lights control system is playing a very important role in the field.The cycle of traffic lights is often a fixed value, the peak of the traffic is often not timely flow, causing traffic congestion and other phenomena. This issue mainly introduced the technology of sensor, traffic detection, PLC’s software, hardware, characteristics and applications. This system detect the traffic through the sensor, and change the cycle of traffic light according to the traffic timely. The main way is useing the sensor to measure the vehicle’s number in a certain distance in front of every drection on the crossroad, then record the vehicle’s number, and input to the PLC,the PLC will divided every derection’s traffic into three levels: small, medium, large,and compare to the reference traffic, then decide the time of green light in all directions, and make the cycle of traffic light change according to the traffic flow ,and greatly improve the traffic capacity of the crossroads. Keywords: PLC; traffic light; intelligent control system
目 录
第一章 绪论..........................................................................................................................1
1.1交通灯智能控制的国内外现状与发展......................................................................1
1.2 本文的研究内容、目的和意义.................................................................................2
第二章 基础知识.................................................................................................................3
2.1 车流量检测技术.........................................................................................................3
2.2 PLC简介......................................................................................................................4
2.2.1 PLC的特点及应用.............................................................................................4
2.2.2 PLC的基本结构.................................................................................................5
2.2.3 PLC的工作原理.................................................................................................6
2.2.4 PLC的编程语言……………………………………………………………….7
第三章 控制系统的设计...................................................................................................8
3.1 控制系统总体方案设计..............................................................................................8
3.2 车流量检测..................................................................................................................8
3.2.1 传感器的选择.....................................................................................................8
3.2.2 环形线圈的工作原理.........................................................................................9
3.2.3 传感器的型号及参数.........................................................................................9
3.2.4 传感器的敷设与接线.......................................................................................11
3.3 PLC.............................................................................................................................13
3.3.1 PLC的型号选择................................................................................................13
3.3.2控制系统的电路................................................................................................15
第四章 控制系统的程序设计........................................................................................17
4.1 程序的控制原理........................................................................................................17
4.2 交通信号灯的时序图................................................................................................19
4.3 程序的梯形图设计....................................................................................................20
4.4 系统的运行结果........................................................................................................25
第五章 总结与展望...........................................................................................................31
致谢…………….....................................................................................................................32
参考文献…………………………………………….……………………………………...33
附录一 程序梯形图…………………………………………………….…………….….34
附录二 程序指令表…......………………………………………………………………...40
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