A COMPARISON OF ALTERNATIVE INTERVENTION STRATEGIES FOR UNINTENDED ROADWAY DEPARTURE (URD) CONTROL

This paper investigates the use of several different inputs for the co ntrol of a vehicle, in the context of URD. In this investigation, the goal of the URD controller is to provide an intervention in the event of the vehicle leaving the road. ?he types of inputs that will be cons idered are (i) Four Wheel Steering, (ii) Front Wheel Steering, (iii) F our Wheel Brake Steering, (iv) Front Wheel Brake Steering, and (v) Rea r Wheel Brake Steering. The controller design is an LQ controller base d on the simplified dynamics of a 2 degree of freedom bicycle model. H owever, the analysis of the different strategies are performed on a 7 degree-of-freedom nonlinear vehicle model. The key contribution of thi s paper is the quantitative evaluation of the relative efficiencies of each of these input strategies being examined. Unlike most control sc hemes, the performance measure to be used will not be the output track ing error of the system. Instead, the metric of performance is the rat io of peak tire force used versus available tire force or, in other wo rds, the actuator response relative to the maximum available actuator capability.