智能交通信号控制外文翻译.docx

1、智能交通信号控制外文翻译现代控制理论 题 目 智能交通信号控制 学生姓名 学 号 学 院 专 业 指导教师 二一 三 年 12 月 15 日Intelligent Traffic Signal Control Using Wireless Sensor Networks Vignesh.Viswanathan and Vigneshwar. Santhanam Abstract:The growing vehicle population in all developing and developed countries calls for a major change in the exis

2、ting traffic signaling systems. The most widely used automated system uses simple timer based operation which is inefficient for non-uniform traffic. Advanced automated systems in testing use image processing techniques or advanced communication systems in vehicles to communicate with signals and as

3、k for routing. This might not be implementable in developing countries as they prove to be complex and expensive. The concept proposed in this paper involves use of wireless sensor networks to sense presence of traffic near junctions and hence route the traffic based on traffic density in the desire

4、d direction. This system does not require any system in vehicles so can be implemented in any traffic system easily. This system uses wireless sensor networks technology to sense vehicles and a microcontroller based routing algorithm for traffic management. Keywords:Intelligent traffic signals, inte

5、lligent routing, smart signals, wireless sensor networks. I. INTRODUCTION The traffic density is escalating at an alarming rate in developing countries which calls for the need of intelligent traffic signals to replace the conventional manual and timer based systems. Experimental systems in existenc

6、e involve image processing based density identification for routing of traffic which might be inefficient in situations like fog, rain or dust. The other conceptual system which is based on interaction of vehicles with traffic signals and each other require hardware modification on each vehicle and

7、cannot be practically implemented in countries like India which have almost 100 million vehicles on road 1. The system proposed here involves localized traffic routing for each intersection based on wireless sensor networks. The proposed system has a central controller at every junction which receiv

8、es data from tiny wireless sensor nodes placed on the road. The sensor nodes have sensors that can detect the presence of vehicle and the transmitter wirelessly transmits the traffic density to the central controller. The controller makes use of the proposed algorithm to find ways to regulate traffi

9、c efficiently. II. THE NEED FOR AN ALTERNATE SYSTEM The most prevalent traffic signaling system in developing countries is the timer based system. This system involves a predefined time setting for each road at an intersection. While this might prove effective for light traffic, heavy traffic requir

10、es an adaptive system that will work based on the density of traffic on each road. The first system proposed for adaptive signaling was based on digital image processing techniques. This system works based on the captured visual input from the roads and processing them to find which road has dense t

11、raffic. This system fails during environmental interaction like rain or fog. Also this system in testing does not prove efficient. The advanced system in testing at Pittsburgh 2 involves signals communicating with each other and also with the vehicles. The proposed system does not require a network

12、between signals and vehicles and is a standalone system at each intersection. III. THE PROPOSED SYSTEM This paper presents the concept of intelligent traffic routing using wireless sensor networks. The primary elements of this system are the sensor nodes or motes consisting of sensors and a transmit

13、ter. The sensors interact with the physical environment while the transmitter pages the sensors data to the central controller. This system involves the 4 x 2 array of sensor nodes in each road. This signifies 4 levels of traffic and 2 lanes in each road. The sensors are ultrasonic or IR based optic

14、al sensors which transmits status based on presence of vehicle near it. The sensor nodes transmit at specified time intervals via ZigBee protocol to the central controller placed at every intersection. The controller receives the signal and computes which road and which lane has to be given green si

15、gnal based on the density of traffic. The controller makes use of the discussed algorithm to perform the intelligent traffic routing. IV. COMPONENTS INVOLVED IN THE SYSTEM The proposed system involves wireless sensor networks which are comprised of three basic components: the sensor nodes or motes,

16、power source and a central controller. The motes in turn are comprised of Sensors and transceiver module. The sensors sense the vehicles at intersections and transceiver transmit the sensors data to the central controller through a wireless medium. The Power source provides the power needed for the

17、sensor nodes and is mostly regenerative. The central controller performs all the computations for the sensor networks. The controller receives the input from all sensors and processes simultaneously to make the required decisions. A.Sensors Sensors are hardware devices that produce a measurable resp

18、onse to a change in a physical condition like temperature or pressure. Sensors measure physical data of the parameter to be monitored. The continual analog signal produced by the sensors is digitized by an analog-to-digital converter and sent to controllers for further processing. A sensor node shou

19、ld be small in size, consume extremely low energy, operate in high volumetric densities, be autonomous and operate unattended, and be adaptive to the environment. As wireless sensor nodes are typically very small electronic devices, they can only be equipped with a limited power source of less than

20、0.5-2 ampere-hour and 1.2-3.7 volts. Sensors are classified into three categories: passive Omni-directional sensors; passive narrow-beam sensors; and active sensors 3. The sensors are implemented in this system placed beneath the roads in an intersection or on the lane dividers on each road. The sen

21、sors are active obstacle detectors that detect the presence of vehicles in their vicinity. The sensors are set in four levels on each road signifying four levels of traffic from starting from the STOP line. The fourth level indicates high density traffic and signifies higher priority for the road to

22、 the controller. The sensors required for obstacle detection can be either ultrasonic or Infrared LASER based sensors for better higher efficiency. B. Motes A mote, also known as a sensor node is a node in a wireless sensor network that is capable of performing some processing, gathering sensory inf

23、ormation and communicating with other connected nodes in the network. The main components of a sensor node are a microcontroller, transceiver, external memory, power source and one or more sensors 3. Fig. 1 Block Diagram of a Mote C. Need for Motes The primary responsibility of a Mote is to collect

24、information from the various distributed sensors in any area and to transmit the collected information to the central controller for processing. Any type of sensors can be incorporated with these Motes based on the requirements. It is a completely new paradigm for distributed sensing and it opens up

25、 a fascinating new way to look at sensor networks. D. Advantages of Motes The core of a mote is a small, low-cost, low-power controller. The controller monitors one or more sensors. It is easy to interface all sorts of sensors, including sensors for temperature, light, sound, position, acceleration,

26、 vibration, stress, weight, pressure, humidity, etc. with the mote. The controller connects to the central controller with a radio link. The most common radio links allow a mote to transmit at a distance of about 3 to 61 meters. Power consumption, size and cost are the barriers to longer distances.

27、Since a fundamental concept with motes is tiny size and associated tiny cost, small and low-power radios are normal. As motes shrink in size and power consumption, it is possible to imagine solar power or even something exotic like vibration power to keep them running. It is hard to imagine somethin

28、g as small and innocuous as a mote sparking a revolution, but thats exactly what they have done. Motes are also easy to program, either by using serial or Ethernet cable to connect to the programming board or by using Over the Air Programming (OTAP). Fig. 2 Block Diagram of the Proposed System E. Tr

29、ansceivers Sensor nodes often make use of ISM band, which gives free radio, spectrum allocation and global availability. The possible choices of wireless transmission media are radio frequency (RF), optical communication and infrared. Lasers require less energy, but need line-of-sight for communicat

30、ion and are sensitive to atmospheric conditions. Infrared, like lasers, needs no antenna but it is limited in its broadcasting capacity. Radio frequency-based communication is the most relevant that fits most of the WSN applications. WSNs tend to use license-free communication frequencies: 173, 433,

31、 868, and 915 MHz; and 2.4 GHz. The functionality of bothtransmitter and receiver are combined into a single deviceknown as a transceiver 3. To bring about uniqueness in transmitting and receiving toany particular device various protocols/algorithms are devised. The Motes are often are often provide

32、d with powerful transmitters and receivers collectively known as transceivers for better long range operation and also toachieve better quality of transmission/reception in any environmental conditions. F. Power Source The sensor node consumes power for sensing, communicating and data processing. More energy is required for data communication than any other process. Power is stored either in batteries or capacitors. Batteries, both rechargeable and non-rechargeable, are the main source of power supply for sensor nodes. Cur