Traffic signal control system design system program introduction

Talking about the design of traffic signal control system, with the development of society and the improvement of human living standards, the number of cars has increased. With the development and application of DEA technology, EDA technology is becoming more and more important in the fields of electronic information, communication, automation, control and computer applications. With the continuous increase of DEA in the technology market and the talent market, the problem of transportation is becoming more and more prominent. It is no longer feasible to rely on manpower to direct traffic. Therefore, it is more and more urgent to design traffic lights to complete this demand. To ensure Pedestrians and vehicles at intersections pass smoothly and smoothly, often using electronically controlled traffic signals. Traffic Light Control System Design Urban intersection traffic signal control systems are generally divided into three types: fixed-cycle signals, multi-period and micro-computer-type signals without cable coordination, and networked adaptive multi-phase intelligent signals. Which type is used should be determined according to its application and characteristics. Among them, the first type has been widely used due to its low cost, simple design, and convenient installation and maintenance. The following are traffic lights designed with digital electronics: red light indicates that the road is forbidden; yellow light indicates parking; green light indicates permission to pass. The traffic light controller controls the traffic at the intersection of two main roads. There are many vehicles at the intersection. The straight-line signal and the left-turn signal are displayed separately. The transit time of the two main roads a and b is equal, and the green light indicating the straight line is bright for 30 s, indicating the left. The turn green light is on for 12 s. When the green light changes to red light, the yellow light is on for 3 s, so that the vehicle can stop in the parking line, and the corresponding yellow light of the last 3 s of the red light signal is also on, in order to prompt the driver to prepare for the start. . Sensors are provided at both main road junctions to detect the presence or absence of vehicle traffic. When the two main roads have vehicles, they are automatically in the green light of the main road, the red light of the main road b, and then the traffic is switched in turn. When the main road a has no vehicles, it is automatically in the main road b green light, the main road a red light state; and vice versa, to improve the traffic efficiency.

Keywords: traffic light control system; frequency divider; signal controller; VHDL language

Overview of traffic signal control system design

1 Overview

With the development of social economy, urban traffic problems have attracted more and more attention. The coordination of the relationship between people, vehicles and roads has become one of the important issues that the traffic management department needs to solve. The urban traffic control system is a computer integrated management system for urban traffic data monitoring, traffic signal control and traffic guidance. It is the most important component of the modern urban traffic monitoring command system. With the increasing number of urban motor vehicles, many large cities such as Beijing, Shanghai, and Nanjing have experienced traffic overload. Therefore, since the late 1980s, these cities have built urban expressways and completed the construction of expressways. In the early days, they also effectively improved traffic conditions. However, with the rapid growth of traffic volume and the lack of systematic research and control of highways, highways have not fully played their intended roles. The structural characteristics of urban expressways also determine that the traffic conditions of urban expressways are bound by the traffic conditions of the coupling between expressways and ordinary roads. Therefore, how to adopt appropriate control methods, make the best use of the urban highways that cost huge amounts of money, ease the traffic congestion of the main roads and ramps, and the surrounding areas of the city, and become more and more urgently needed to be solved by the transportation management and urban planning departments. The main problem.

2 Design requirements

Design a traffic light control system at the intersection. Use the LED light-emitting diodes on the experimental platform to display the direction in which the vehicle passes (a group of east and west and north and south), and use the digital tube to display the remaining time in that direction. Requirement: The working order is red for 45 seconds in the east-west direction. The green light is bright in the north and south directions in the first 40 seconds, and the yellow light is on in the last 5 seconds. Then the red light in the north-south direction is on for 45 seconds, the green light in the east and west directions is bright in the first 40 seconds, and the yellow light is on in the last 5 seconds. Repeat in order. In case of emergency, it is allowed to keep a green light or a red light in a certain direction. In addition, the specific situation is red light in both directions, and the vehicle is forbidden. For example, in a vicious traffic accident at a crossroad, there are two digital tubes in both directions. The direction lighting time is displayed in time.

3 overall concept

(1) The function that the traffic light controller should have

The traffic flow between the east and west directions is about the same, so the durations of red, yellow and green lights are the same. The red light is 45 sec, the yellow light is 5 sec, the green light is 40 sec, and the current state (red, yellow, green) is indicated by a digital tube. time. In addition, an emergency state is designed. When an emergency occurs, the two directions are prohibited from passing, indicating a red light. After the emergency is removed, recount and indicate the time.