Research Of The Testing System Of Automobile Brake Performance Test Bed Based On Virtual Instrument

Braking performance of automobile is one of the mainly character of the car,which is directly related to traffic safety and which is the mainly guarantee for Driving safety.Therefore,it is an important task for the Automotive Design Department and Automobile Use Department to improve the braking performance of the automobile.On the basis of improving the wheelset adjustment mechanism of the original brake test stand,this paper depend on the hardware platform of four wheel brake test bench、 LabVIEW and the software platform of virtual instruments has designed The Automobile braking performance testing system,which is easy to operate and practice.First of all,this paper has designed the Wheelbase regulating mechanism of the original four wheel brake test rig.The way to test the Braking performance of four wheels of a car can depend on Front and rear roller chain of Four wheel brake test rig of the original car,but in order to change the wheelbase,which has to increase tensioning device,change the chain between the frames before and after the connection or change the transmission chain with different length.In a word,it is more complicated.Therefore,the way of intermeshing with the spline shaft is put forward for the power transfer mechanism of the original test rig.At the same time,on the basis of reference mechanical design,this paper has completed the design calculation,modeling and drawing of the parts of the wheelbase adjustment mechanism.Secondly,the vehicle brake performance test system is built.,which is composed by hardware and software.The hardware configuration mainly includes the selection and installation of various sensors,the selection of data acquisition card,the design of signal conditioning circuit and purchasing corresponding industrial control machine.The software part includes the upper level management program and the hardware driver quantity.On the basis of LabVIEW software,the former designed the interface of landing interface,collection interface and data display,so as to realize the functions of signal acquisition,data processing and analysis,data storage and so on.The latter uses the form of dynamic link library(DLL)to call the upper management software to realize the functions of setting the working mode of the card,collecting and transmitting data.On the basis of the system hardware and software platform,combined with the knowledge of automobile theory,LabVIEW is used as the software platform to analysis the data for evaluating the parameters of automobile braking performance,which include speed,slip rate,brake pipe pressure,braking torque and ground adhesion rate,ground adhesion coefficient,etc.Finally,the debugging of hardware and software of the testing system is completed to verify the reliability of the testing system.At the beginning of the experiment,the experimental equipment,such as the oscilloscope and the signal generator,was selected to carry out a preliminary simulation experiment,which basically achieved the expected effect and can handle the data module.After that,the test system was transplanted to the site for bench test.The test results show that the wheelbase distance adjusting mechanism of the four wheel brake test rig can realize the adjustment of the wheelbase.The test system can give the test and analysis curve of the vehicle braking performance parameters in real time,and which can also realize the functions of data processing and analysis,displaying and storing data.The automobile brake test system was built in this paper is powerful and easy to operate.It can collect and analysis and the vehicle braking performance parameters.In addition,It can provide vehicle braking performance data for further research and analysis.Also,it can be further extended and applied.