Design And Implementation Of Vehicular Data Acquisition Terminal And Platform Of Cloud Monitoring Based On MQTT

With the continuous prosperity of China’s automotive industry and internet industry,the networking and digitisation of vehicles has become an important strategy for the transformation and upgrading of the automotive industry.Real-time data of vehicle is the basis for the realisation of applications of internet of vehicles.The on-board terminal is used to collect vehicle data,and the monitoring platform is used to monitor vehicles.Design and development of them is an important subject of automotive networking.Based on the current research status of on-board terminals and monitoring platforms,this thesis proposed a scheme based on the MQTT protocol.A vehicular data acquisition terminal and a cloud platform is designed and developed.This thesis covers the following main points.Firstly,this thesis studied the layered protocols of the on-board diagnostic system and analysed the OBD-II protocols based on the ISO 15765 protocol.The way of collecting real-time data from the vehicle is analysed.Key technologies such as GNSS and Wi Fi,4G and the MQTT communication protocol communication is examined.The scheme of the on-board terminal and the cloud platform is designed.Secondly,this thesis designed the hardware and software of the on-board terminal with the STM32F103ZET6 as the main controller.The development of the hardware includes the design of circuits such as the power supply circuit,the CAN bus driver circuit and circuits of communication modules.It also includes the PCB design of the on-board terminal.Software development includes porting Free RTOS and designing drivers for communication interfaces such as the CAN bus.It also includes tasks designed to request data via the OBD-II interface according to the request-response mechanism of the ISO15765 protocol.This thesis also designed MQTT communication program based on the ESP8266 and 4G module.According to the communication protocol,this paper built a MQTT message server,My SQL database and Node-RED in the cloud server and designed a vehicle data processing model based on Node-RED and My SQL database.Nodes designed to parse,compute and store data in Node-RED based on SAE J1979 protocol.Nodes designed to count the length of time of fatigued driving and to recognise rapid acceleration and deceleration behaviour.At the same time,the visual page of data monitoring is designed.Finally,the designed on-board terminal and data monitoring platform were tested.Using an fault diagnosis instrument and a USBCAN-II analyser,the system was tested in house and in real vehicle.The functionality of the terminal and cloud platform is verified.