Analysis of Wheel Performance (at Zero Slip Rate) Using the Wheel Soil System Constant.

A series of tests were conducted for driven rigid wheels on soft sand. The tests were performed at both positive and negative slip rates. For each slip rate the wheel load, the wheel sinkage, the input driving torque and the drawbar pull were measured. The system constant, is a combination of wheel dimensions and soil parameters, which can be used to develop methods for comparing the performance of various wheels. Theoretically, wheels which are designed and built with the same system constant should possess the same wheel performance parameters that is, they should sink to the same relative sinkage, support the same total weight and require the same tangential force in order to develop the same drawbar pull. Wheels with different system constants can be compared by normalizing their wheel performance parameters that is, dividing the actual performance parameter by the value of that wheels system constant. Thus all the performance parameters may be reduced to a common base for easy comparison. Wheel performance prediction equations were developed based on Bekkers pressure sinkage relationship. These equations give good results when compared with the actual experimental test measurements. Author