A Study of the Properties That Influence Vehicle Rollover Propensity

Abstract

In this thesis, a vehicle’s load condition is varied to investigate its impact on roll stability and a stability threshold is derived empirically using vehicle simulation. A vehicle model is developed and simulated using MATLAB. Experiments performed by the National Highway Transportation and Safety Administration (NHTSA), are used to validate the simulation. Data from these experiments is also used to validate a stability threshold developed from the simulation. Scaled passenger vehicles in conjunction with computer simulation have proven to be a valuable tool in determining rollover propensity. The stability threshold is also validated by scaled vehicle experiments. This is made possible with the lower cost and increased safety of using a scaled vehicle versus full size passenger vehicles. A simple electronic stability control (ESC) is then developed to keep the scaled vehicle within the stability threshold. The ESC is tested using varying vehicle properties with a constant vehicle model to see how these property changes affect the ESC’s effectiveness to prevent rollover. The ESC is then implemented with an Intelligent Vehicle Model (IVM) which updates the controller’s vehicle model as vehicle properties such as loading conditions change. It is shown that an IVM greatly increases the success of ESC in keeping the vehicle in the stability region.