Side slip angle prediction model of an off-road tire on different terrains

In this paper, two mathematical models were developed to predict side slip angle for driven wheels of a prototype tractor. The independent variables involved moisture content, cone index, normal load, inflation pressure, angular velocity, and steer angle with three levels. Response Surface Method (RSM) was used to extract models and to analyze results. The tractor was driven in circular paths to the left side to apply all experimental treatments. Among different mathematical models, the linear models with coefficient of determination of 0.8978 and 0.8983 were chosen to predict side slip angle of the left and right wheels, respectively. The mathematical models analysis of variance showed that all factors had significant effect on tire side slip angle. In all experiments the inner wheel side slip angle was lower than that of the outer. An inverse effect for cone index and wheel normal load was observed while other factors effects were found to be direct. Also, the angular velocity had the highest impact on side slip angle for both rear wheels.