VEHICLE ROLLOVER DETECTION INDEX

Vehicle rollover resistance can be enhanced using differential braking control, rear-wheel steering, front steering control, suspension damping control, or the combination of any of them. In each control action, the controller receives the vehicle dynamics information from various sensors, such as a yaw-velocity sensor, a lateral accelerometer, a roll-velocity sensor (if available), and suspension displacement sensors (if available), and determines a control action to be taken. A balance between controlling vehicle roll motion and vehicle yaw motion needs to be reached to achieve the optimal vehicle response. Therefore, detection of the current and impending vehicle situations, especially pertaining to the vehicle roll, is vital for the quality of control. Various methodologies have been developed in the past to detect vehicle situations that may lead to rollover. Generally, rollover detection is based on roll velocity sensor and roll angle estimation. In most of these methods, thresholds for roll velocity and roll angle are established to detect imminent rollover. Even though roll velocity and roll angle are the two most important elements in vehicle roll motion, they may not be sufficient to timely detect impending rollover. This paper proposes a vehicle rollover detection index that can be used in a control algorithm to enhance vehicle rollover resistance. It uses roll angle and velocity (measured or estimated), yaw velocity, vehicle speed, and lateral acceleration. Further enhancement to the proposed algorithm is then briefly discussed that includes the effect of vehicle lateral load transfer on the detection.