Dynamics of a dual-unit articulated vehicle for path tracking control problem formulation

The dynamics of motion of a class of vehicles consisting of two one-axle wheeled units pivoted together are developed for the formulation of the path tracking control problem. This particular type of vehicle is frequently used for ore transportation in underground mines. Steering of this vehicle is performed through changing the angle between the two units by means of an actuator. In this paper the equations governing the motion and the tracking error dynamics in terms of the system inputs, namely the traction forces on the front and rear wheels and the actuator force for changing the angle between the two units, are derived. These equations are nonlinear and highly coupled. However, it may be deduced that from what normally appears in practice and for low operational speeds some acceptable assumptions may be made based upon which the formulation of the control problem and the synthesis of a controller becomes much simpler