The purpose of the experiment is to find out the variation of the slip rates of tractors on different types of roads on which they often run,such as cement road,gravel road,dirt road.The running speed of the tractor was measured by GPS,Doppler radar and the minimum wheel speed method,and the speed of the driving wheel of the tractor was measured by the encoders.PCI1740 data acquisition card was used to collect sensors data,and then the graphical programming software Labview was used to display and store rea...