Development Of C8051F Microcontroller Road Friction Coefficient Measurement System

For the problem of the existing road friction coefficient measuring device canonly fixed-point testing,slow speed,low efficiency, the test result is affected bythe human factors issues, the subject developed a new road friction coefficientmeasurement device which based on embedded C8051F410technology, realizedthe on-line continuous measurement of road surface friction resistance and thewheel rotating pulse, calculate the frictional coefficient and the mean and variance,running speed, distance traveled, numerical, and real time displayed on the touchscreen.This subject describes the surface friction coefficient theory, system design,system hardware design and software design of four parts. This paper brieflyanalyses the road friction coefficient testing method commonly used at home andabroad and influence factors on friction coefficient. Based on the frictioncoefficient measurement principle, determine the hand pushing type road frictioncoefficient measuring device structure, proposed acquisition the friction whichtest wheel and the road surface friction generated, calculation of the measuredsurface friction coefficient method, and determine the design scheme of the systemThe hardware circuit concludes power module circuit design, signal samplingcircuit, a data storage circuit, serial communication circuit chip peripheral circuitis designed of module using C8051F410internal integrated A/D, UART, SPI,timing counter embedded, which realizes gather the LCD touch screen and themultiple types of data collection through serial interface together. The design ofsignal conditioning circuit adopts a differential input, reducing the common modeinterference in, improve the precision of sampling.Software design consists two parts of on-site embedded system and a touchscreen display. The lower position machine procedure mainly compete acquisition and storage of each sensor signal. The collection procedures using a statisticalalgorithm preceded a digital filtering, which improved sampling precision. Thesystem which has a friendly interface uses the touch screen as a host computer,data receiving and calculation of the friction coefficient, velocity and otherparameters, real-time display.This system realized all the predetermined function after the practicalapplication test, whose data approached with the others, and has the advantages ofsimple operation, high efficiency, convenient data processing method. The systemwill have a good application prospect.