Study On The Measuring And Controlling System Of Automobile ABS Tester Based On The Virtual Instrument

With the development of automobile transportation and the increase ofrunning velocity of automobile, security problem in running process is paid moreand more attention. Manipulating stability is improved greatly in the brakingprocess of automobile with ABS. As a result, automobile running security isensured in a certain extent. However, the use of vehicle and some other factorsmaybe result in the decline of automobile ABS' working performance ormalfunction that may lead to hidden fault deteriorating automobile running security.Therefore, it is necessary for the automobile ABS to be detected to find the faultand further maintain or replace so that people can take the above steps to preventthe traffic accident and the loss of lives and property.Detection methods for automobile ABS are either complicated in manipulatingprocess or only used to detect electro-circuit fault not to detect the comprehensiveperformance of automobile ABS.the primitive roller -tester for ABS can't simulatevarious road surface with certain attachment coefficient, so it is impossible ofdetecting rapidly and accurately and can't meet the detection requirement for highefficiency and intelligence even after updated. So it is significant to design a newtype of tester with advanced function for automobile ABS performance.The automobile ABS tester has some advanced performance as follows:1. Realizing adjustable rotative velocityAc. Motor, only used for constant speed condition, is widely applied intraditional tester of automobile braking performance which can't meet therequirement for adjustable rotative velocity of roller. Roller system is added with atransmission that achieves only stepped-speed in complicated mechanical structure.In the new tester system, Roller rotative velocity, namely, wheel rotativevelocity, is controlled accurately by adjusting the rotative velocity of electric motorthrough ac. frequency speed governor by means of controlling power-supplyfrequency of ac. Motor.2. Realizing simulating various road surface conditionsIn order to detect and evaluate the performance of automobile ABS on variousroad surfaces with certain attachment coefficient, it adopts magnetic particle clutchwhich is used to simulate various conditions of road surface and realizes detectionof automobile ABS performance on different road with different attachmentcoefficient.3. Realizing accurate and real-time compensation of automobile kinetic energyRotative kinetic energy of flywheel and roller of traditional tester ofautomobile braking performance is equal to the kinetic energy of automobile whenit runs on road. Kinetic energy to be simulated is various when the automobile isbraked at the same speed according to its quantity. Traditional tester of automobilebraking performance adopts several flywheels to meet the need of detection forautomobiles with different quantity. Automobile kinetic energy is not simulatedaccurately by the rotative kinetic energy of mechanical equipment with finiteinertia .It Realizes accurate and real-time compensation of automobile kineticenergy to improve measurement precision by using one flywheel and one motor.In this paper methods to achieve the functions above are studied thoroughly,And it applies virtual instrument (VI) technology in the testing and controllingsystem of automobile ABS tester. In view of velocity's changing rule whenautomobile is braked, virtual instrument testing and controlling system ofautomobile ABS tester is constructed in the controlling method ,which usescomputer and variable frequency speed control technology, powered asynchronousmotor, using magnetic particle clutch as power source, applying the abundanthardware source of industrial computer and based on developing platform ofLabVIEW.This paper involves mainly the following aspects:1. Tester of automobile ABS is redesigned to get improved and given thecontrolling model by analyzing the testing theory of automobile ABS tester;energycompensation stepped method is stated by analyzing the energy changing theory inbraking process on tester and its corresponding mathematic model is built.2. General hardware structure of testing and controlling system of tester isbuilt according to the requirement of automobile ABS tester. Functions and traits ofthe main implement parts like asynchronous motor, frequency converter andmagnetic particle clutch and so on are introduced and the product type is identified.At the same time, the working theory and performance of moment-speed sensorand multi-function data acquisition card are introduced briefly.3. Software system is designed. LabVIEW, as software platform, is used todevelop the testing program applying module programming theory. Softwarestructure of VI and its implement method are addressed, and various functionmodules' programming flow and the key technology are argued in detail.Application program software analyzes the signal gained by computer and providesthe testing result of automobile ABS.4. The testing system checkout is experienced through simulation. The resultof the simulation indicate the control means is feasible. It can simulate the differentroad with different attachment coefficient by controlling the magnetic particleclutch.The VI testing and controlling system in this paper should be improved infuture for some factors like time restrictions and financial shortage, and so on.