VFO Control for Mobile Vehicles in the Presence of Skid Phenomenon

Abstract

Skid is a common phenomenon in real vehicles. Sometimes this effect is negligibly small and in a consequence can be omitted in a vehicle model preserving practically acceptable control performance. In a case of nonholonomic mobile robots it is equivalent to the rolling without slipping assumption. However, in many real-life situations the skid phenomenon influences vehicle motion in a such degree, that exclusion of it in a system model leads to significant control performance deterioration. The term skid used in this paper should be understood as a phenomenon of motion velocity disturbance, which for nonholonomic vehicles is connected with violating kinematic constraints. Wind blowing during aircraft flight, currents and waves during ship cruising, loosing adhesion between road surface and wheels during car ride or moving on sloping areas are examples of situations, where a skid phenomenon usually appears. To enhance tracking precision in these cases, control laws dedicated for mobile vehicles should be robust to skid-like disturbances. It is especially important when skidding is not vanishing and persistently disturbs vehicle motion.