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Wednesday, 24 April 2013

REAL -TIME TRAFFIC SIGNALING SYSTEM IN FPGA


Developing a sophisticated traffic monitoring and control system would result in an effective solution to this problem. In a conventional traffic light controller, the traffic lights change at constant cycle time. Hence it does not provide an optimal solution. Many traffic light controllers implemented in current practice, are based on the 'time-of-the-day' scheme, which use a limited number of predetermined traffic light patterns and implement these patterns depending upon the time of the day. These automated systems do not provide an optimal control for fluctuating traffic volumes.
 A traffic light controller based on fuzzy logic can be used for optimum control of fluctuating traffic volumes such as over saturated or unusual load conditions. The objective is to improve the vehicular throughput and minimize delays. The rules of fuzzy logic controller are formulated by following the same protocols that a human operator would use to control the time intervals of the traffic light. The length of the current green phase is extended or terminated depending upon the 'arrival' i.e. the number of vehicles approaching the green phase and the 'queue' that corresponds to the number of queuing vehicles in red phases. A prototype system for controlling traffic at an intersection is designed using Simulink and Matlab tool. The decision on the duration of the extension is taken using the Matlab tool. This decision is based on the Arrival and Queue of vehicles, which is imported in Matlab from VB6 environment. The time delay experienced by the vehicles using the fixed as well as fuzzy traffic controller is then compared to observe the effectiveness of the fuzzy traffic controller.
Here we make use of a matlab based system to find the volume of vehicles in each side of a junction. The images to be processed are collected from a Wireless camera mounted above the traffic light control unit. These images are sent to a matlab based system, where they are iterated towards some pre stored images in the data base to analyze the traffic volume.
After reaching a conclusion, the predicted information regarding the volume are sent to an embedded unit wirelessly. We make use of a protocol named ZIGBEE, an advance version of Bluetooth to transmit this information to the embedded unit
ZigBee is a wireless technology developed as an open global standard to address the unique needs of low-cost, low-power, wireless sensor networks. The standard takes full advantage of the IEEE 802.15.4 physical radio specification and operates in unlicensed bands worldwide. The specification is a packet-based radio protocol that meets the needs of low-cost, battery-operated devices. The protocol allows devices to intercommunicate and be powered by batteries that last years instead of hours.
After receiving the volume estimation from the PC, via Zigbee, the FPGA unit generates pulses, in accordance with the information from MATLAB which determines the time duration of traffic light.
In the normal working, i.e. if the volume is regular in junctions, the controller automatically generate uniform time signals for traffic light.

 

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