Research And Implementation Of Frame Height Detection System Based On OneNET

From the birth of the first domestic passenger car in 1928,the development of passenger cars in China has a history of 90 years.Before the reform and opening up,only foreign passenger car chassis could be used to produce local passenger cars,to the first air-conditioned tourist bus after the reform and opening up.On the basis of satisfying the domestic market,China's current buses have been exported to overseas in large quantities,and they can compete with bus brands in other countries.These are the results of the continuous struggle of several generations of Chinese buses.In the inspection process of passenger cars,it mainly involves the inspection of the frame,including the inspection of the strength of the frame,the structure of the frame and the flatness of the frame.The frame carries the car's engine,transmission,clutch,and more.It is a substrate that carries various parts of the car.Take Yutong's ZK6148 HQ passenger car as an example,the total mass of the car has reached 15 tons,so higher requirements are placed on the load-carrying capacity of the frame.For designers of passenger cars,lowering the height of the frame can reduce the position of the center of mass of the entire vehicle,which is beneficial to improving the stability of the vehicle during driving.It can be said that the precise value of the frame amplitude height is directly related to the performance of the entire vehicle(handling,safety,comfort,reliability,service life).The commonly used detection method is: the inspector uses a ruler to measure the distance from the top to the bottom of the frame.This detection method takes a long time and the measurement results are not accurate enough.The measurement can only be performed when the passenger car is at a standstill,and it cannot achieve multi-point real-time measurement of the vehicle during the work process.In order to solve the problem of accurate collection and real-time collection of frame height,shorten the test time of passenger cars and the time to market of new models.This paper designs a mobile frame height detection system.First,ARM-STM32F103 is used as the core controller and vl53 lox laser pulse sensor is used to collect the height data of the six frames of the passenger car.Then a data processing method based on maximum entropy is used to eliminate the gross errors in the collected data,and the data collected by each node is fused.In addition to the advantages of higher accuracy,the fused data also has better representation.Finally,the upper computer software of the system is designed and implemented,and the Android APP realizes real-time display and storage of the collected data under the local area network.At the same time,the system is connected to China Mobile's Internet of Things platform OneNET,and users can remotely view the real-time data of the current frame height,at a glance the system operation status.In both local mode and OneNET mode,the frame height value and the standard deviation of the left front wheel at different points can be displayed at six points at the same time,which is convenient for the technician to adjust the body height according to the measured deviation data.The frame height detection system has undergone multiple functional tests,and each function runs steadily and meets the target requirements at the beginning of the design.At the same time,the system belongs to a new type of laser ranging detection system with modular design.Compared with traditional ranging solutions,the development cycle is short,the development cost is low,the operation is simple,and it can be suitable for monitoring in a variety of application scenarios.