Design Of Freeway Accident Detection And Alarm System Based On Heterogeneous Network

The rapid development of freeway not only brings convenience for public transportation,but also causes a series of traffic safety problems.Existing freeway monitoring systems can not give a warning for the following vehicles to slow down or stop after the system detects the traffic accidents.In order to sound an alarm to void secondary accident after the system recognizes a traffic accident,a freeway accident accident detection and alarm system based on heterogeneous network is designed in this paper.This system can detect accidents information in real time,and publish alarm messages to the following vehicles through signal lamps along the freeway automatically.At the same time,this system sends the accident information to freeway monitoring center.This will make the rescue in time.The main contents of this paper are as followings:1.A freeway traffic accident detection and alarm system based on heterogeneous network is designed,aiming at the problem that the accident detection capacity of existing freeway transportation system is insufficient and secondary accident is difficult to prevent.And a traffic accident detecting strategy is designed.This system realizes the detection of press-key alarm and vehicles' hitting guardrails information.At the same time,early warning information can be displayed through the spot signal light automaticly or manually.2.According to the characteristics of freeway environment and system requirements,the communication scheme of this system is designed based on CAN bus and RS485 bus as well as GPRS communication and ZigBee wireless communication technology.The hardware structure of this system is constructed,including three layers: gateway layer,relay layer and control layer.And the hardware circuit of gateway node,relay node and control node are designed,whose core are STM32 or STC12 series microcontroller.3.The software program of heterogeneous network nodes are designed,achieving the accident perception and alarm function,as well as heterogeneous network data interaction.In gateway layer,the protocol conversion model and software program of gateway node are designed,and the data switching between CAN bus and GPRS module is realized.In relay layer,the software program of relay node is designed to realize the transportation of alarm messages and control instruction.In control layer,the communication protocol of RS485 bus is formulated.Combining the software of control node and relay node,accident detecting and alarm information transmission through RS485 bus are realized in real time.4.Using the Visual Studio 2015 development tool,a remote management platform based on C/S structure is designed,which realizes the function of displaying accident alarm information and issuing control instruction in the monitoring center.Combining the heterogeneous network hardware platform and remote management platform,a simulation environment of freeway is constructed in the lab,based on which the function of this system is tested.Test result shows that the accident detecting and alarming function are well achieved,and monitoring center's remote administration function is realized.