Sliding mode avoidance in pasively articulated vehicles

The advantages of both structural simplicity and low resistance to movement are combined in passively articulated vehicles with independently powered wheels. The presence of the articulation in a vehicle enables it to move on straight or circular trajectories in the pure rolling mode, while the sliding mode motion may occur during the transition between the straight and the circular trajectory segments.. Certain difficulty of steering arises from the passivity of the articulation, which requires that the steering must be achieved exclusively through the differences in wheel velocities. This paper studies the movement of a vehicle with one passive articulation and two axles, having a total of four independently powered wheels, along straight and circular paths, and in particular, the condition of the pure rolling mode movement during the transition between straight and circular trajectory segments. The emphasis in this study is given to avoidance of the sliding mode motion through a non-linear feedback method for wheel velocity control.