Design And Optimization Of Coupler Height Measuring Device For Freight Car Based On STM32

Railway freight car is an important carrier of cargo transportation.It has the characteristics of large traffic volume,short transportation cycle and high safety.It plays a very important role in daily cargo transportation and national important strategic material transportation.Therefore,for a long time,railway departments have mostly adopted the mode of regular back-to-workshop maintenance to ensure the safety and reliability of transportation.As an important maintenance item,coupler height must ensure that the vertical height of coupler centerline from rail surface is within the specified precision range.At present,the widely used measuring ruler for coupler height measurement has some problems,such as inflexible operation,complicated calibration,timeconsuming and labor-intensive,and random errors caused by manual reading.In order to improve the above manual measurement problems,and gradually promote the on-demand return workshop maintenance mode based on the status monitoring of freight car coupler height,this thesis designed a kind of ultrasonic electronic coupler height measuring device based on STM32 single-chip computer,which can effectively improve the measurement time,and has the advantages of convenient use,economy and wide application prospect.With the development of the times and the progress of science and technology,the combination of ultrasonic technology and embedded technology has become increasingly mature in the application of short distance ranging.Combined with the actual application requirements,the overall design scheme of ultrasonic electronic coupler height measurement device was formulated,and specific software and hardware design and distance measurement accuracy optimization research was carried out.(1)In terms of hardware,the STM32F103ZET6,an enhanced control chip based on the ARM core architecture,was selected,and the design of the hardware circuit,including temperature and humidity acquisition,ultrasonic distance measurement,voice broadcast,SD card data storage,WIFI communication circuit and PCB,was completed;In terms of software,combined with the hardware circuit of the lower computer,the development of relevant software programs is completed.In order to better realize human-computer interaction,the upper computer develops the visual interface of PC and mobile phone respectively.Based on the TCP/IP protocol network architecture,the communication connection with the WiFi module of the lower computer is established,the data transmission and control command transmission are realized,and the design of electronic measurement device is completed.(2)Considering that the propagation speed of ultrasonic in the air is easily affected by the ambient temperature and humidity,and then affect the ranging accuracy,the design is based on multiple linear regression to establish an error optimisation compensation model to construct the correspondence between temperature and humidity,the range value before optimisation and the range value after optimization.The high regression significance of the model was also verified by means of an F-test,Combined with curve and data comparison,the relative error of ranging after optimization is no more than 1%,which meets the ranging accuracy requirement of electronic coupler height measuring device.(3)Based on the error compensation of ambient temperature and humidity ranging,a method of Improve chimp optimization algorithm and optimizing BP neural network model(IChOA-BP)is proposed.The improved algorithm introduces chaotic contrastive learning to improve initial population quality and diversity,adaptive t-distribution to increase the global exploitation ability and local search ability of the population,and a swarm individual memory strategy to balance the stochastic influence of individuals between populations.The simulation experiment is compared with three optimization algorithms.The results show that the prediction accuracy of the Improved chimp optimization algorithm is the highest,and the optimization model has high stability.The relative error of ranging after optimization by the IChOA-BP model does not exceed 0.5%,which further improves the distance measurement accuracy of electronic coupler height measuring device.(4)Based on the problem that the railway track height and the standard height errors also affect the ranging accuracy,a linear relationship between the measurement points and the errors is established by means of one-dimensional linear regression,which can be used to compensate for track errors in practical applications.Through the simulation experiment,the developed electronic measuring device for the height of freight car coupler has a ranging range of 150 cm and an accuracy of ±0.3cm,which is much higher than the requirements of field measuring range of 100 cm and an accuracy of ±1cm.At the same time,the upper computer of PC and mobile phone can easily realize the synchronous transmission and data visualization of lower computer data.The developed products have many advantages,such as high measurement accuracy,friendly human-computer interaction,remote monitoring,data traceability and so on.They can effectively improve the economic benefits of enterprises and have strong popularization.