New paradigms for the integration of yaw stability and rollover prevention functions in vehicle stability control

The integration of rollover prevention and yaw stability control objectives in electronic stability control has traditionally been done based on a priority calculation. This paper focuses on an integrated electronic stability control system wherein the objectives of yaw stability and rollover prevention are addressed simultaneously, rather than one at a time. First, we show that staying on a desired planar trajectory at a specified speed results in an invariant rollover index. This implies that rollover prevention can be achieved whenever there is a danger of rollover only by reducing vehicle speed, since changing the desired vehicle trajectory is not a desirable option. In this regard, it is shown that a vehicle which reduces its speed before entering a sharp curve performs significantly better than a vehicle that uses differential braking during the turn for yaw stability control.