Design And Implementation Of OBD Vehicle Intelligent Monitoring System Under The Background Of Internet Of Vehicles

In the increasing trend of car ownership,problems such as vehicle system security,vehicle anti-theft,and vehicle exhaust pollution are becoming more and more significant.The technology of Internet of vehicles constructs the remote network structure connecting vehicles with the outside world,making it possible to remotely monitor the vehicle in real time.This paper aims at the shortcomings of current cars in terms of vehicle condition diagnosis,remote monitoring and anti-theft.Under the background of the Internet of vehicles,combined with GPS positioning,vehicle antitheft,OBD system diagnosis,embedded system development and other technologies,a real-time vehicle condition monitoring system with functions such as fault diagnosis,location tracking,anti-theft warning,and remote monitoring is developed.Firstly,according to the development status of technologies such as OBD systems,Internet of vehicles,vehicle terminal,and vehicle anti-theft systems at home and abroad,the main practical problems that need to be solved in the system development and design are summarized.Based on the demand analysis of the problem,the paper proposes the overall design of the vehicle status remote monitoring system composed of three parts: vehicle terminal,cloud server and smartphone terminal.The functional requirements,development environment and design scheme of the system are determined from two aspects of hardware and software.Secondly,this paper analyzes the working principle and standard interface of the OBD system,as well as various OBD-II communication protocols.In addition,the CAN bus and K-line two communication bus technologies,as well as the vehicle's original data flow and fault code information are studied in detail.Subsequently,the overall design block diagram of the hardware circuit of the vehicle terminal is constructed according to the hardware design scheme,and the hardware chip selection is determined,and the vehicle terminal hardware circuit schematic diagram and PCB layout design are completed.Among them,the core control circuit,GPS positioning circuit,OBD-II communication protocol drive circuit,wireless mobile communication circuit,step-down and stabilized voltage supply module circuit are designed in detail.Thirdly,according to the software design scheme,it forms the program design architecture of the lower computer of the vehicle terminal,as well as the functional program design block diagram of mobile APP and cloud server.The lower computer program of the vehicle terminal is developed in keil 5 integrated development environment with C language.A thread scheduling algorithm based on the ?C / OS-II operating system and an anti-theft warning algorithm for monitoring door status and vehicle position changes in real time were designed.The relevant program development such as the vehicle OBD communication protocol adaptation,the OBD / GPS data reading and analysis,and the data uploading are completed.The cloud server program has the functions of receiving,sending,and storing the data uploaded by the vehicle terminal.The mobile phone APP program obtains the vehicle terminal data through the cloud server,and develops the corresponding function display interface with the analysis of the vehicle data as the core.Finally,the OBD simulator is connected to the vehicle terminal instead of the real vehicle to test the overall function of the OBD vehicle intelligent monitoring system.The test results show that the system can effectively monitor the vehicle status,the overall function runs stably,and basically meets the initial design requirements.