MODELING OF SLIP FOR WHEELED MOBILE ROBOTS

Wheeled Mobile Robots (WMRs) are known to be nonholonomic systems, and most dynamic models of WMRs assume that the wheels undergo rolling wi thout slipping. This paper deals with the problem of modeling and simu lation of motion of a WMR when the conditions for rolling are not sati sfied at the wheels. We use a traction model where the adhesion coeffi cient between the wheels of a WMR and a hard flat surface is a functio n of the wheel slip. This traction model is used in conjunction with t he dynamic equations of motion to simulate the motion of the WMR. The simulations show that controllers which do not take into account wheel slip give poor tracking performance for the WMR and path deviation is small only for large adhesion coefficients. This work shows the impor tance of wheel slip and suggests use of accurate traction models for i mproving tracking performance of a WMR.