CONTROL OF OSCILLATIONS IN ELECTRICALLY DRIVEN SKID STEER VEHICLES

摘要

This paper is concerned with the stabilization of skid steer wheeled vehicles. This type of vehicle is often characterized by a short wheelbase and without any suspension other than that of the wheels, and is therefore liable to rotational pitch oscillations. The objective of this paper is twofold. Firstly, the abovementioned oscillation phenomena are examined with a view to improve the understanding of its dependency on weight distribution, and traction characteristics of tire-surface contact. Secondly, a number of control strategies that dampens the oscillatory nature of the vehicle are derived and evaluated. The basic idea of the control strategy is to keep the angular pitch velocity at zero by increasing the motor torque when the vehicle is tilting forward and decreasing the motor torque when the vehicle is tilting backwards. The basic control design objective being to achieve the lowest possible mean square tracking error without letting the mean square input exceed its maximally permissible value. The results are experimentally evaluated by means of a small-scale vehicle.