Vehicle Rollover Propensity Detection Based on a Mass-Center-Position Metric: A Continuous and Completed Method

Rollover index is an essential metric to detect vehicle rollover propensity, which is used to warn a driver or trigger an active rollover prevention system to perform corrective action. To give continuous and completed rollover information, this paper presents a novel rollover index based on a mass-center-position (MCP) metric. The MCP is first determined by estimating the positions of the center of mass of the vehicle, which consists of one sprung mass and two unsprung masses with two switchable roll motion models, before and after tire liftoff. The roll motion information can then be provided through the MCP continuously without saturation for both tripped and untripped rollovers. Moreover, to describe the completed rollover status, different criteria are derived from D'Alembert's principle and the moment balance conditions based on the MCP. In addition to tire liftoff, three new rollover statuses, 'rollover threshold,' 'rollover,' and vehicle jumping 'in the air,' can be all identified by the proposed criteria. Furthermore, the sensitivity analysis is conducted on some key parameters, such as the sprung/unsprung masses and the height of the center of gravity, to validate the robustness of the proposed detection method. Compared with an existing representative rollover index, lateral load transfer ratio, the fishhook maneuver simulation results in CarSim for an electric vehicle show that the MCP metric can successfully predict vehicle impending rollover status continuously and completely for both untripped and tripped rollovers.