Untripped SUV Rollover Detection and Prevention

Abstract: Untripped SUV (Sport Utility Vehicle) rollovers are dangerous and possibly lethal accidents. This thesis address some issues in the detection and prevention of untripped SUV rollovers. Before a rollover can occur, the wheels on one side must lose road contact. The wheel lift-off situation is chosen as the critical situation to be avoided. If wheel lift-off is prevented, then rollover is prevented as well. A new kinetic energy based measure, that indicates an imminent wheel lift-off, is introduced. This measure is used by a gain scheduled LQ (Linear Quadratic) controller to prevent wheel lift-off. The LQ-controller outputs the desired changes of the forces acting on the chassis. These force changes are mapped to braking and traction system commands by a control allocator. Three different control allocation approaches were evaluated, including a new convex optimization approach. The convex optimization approach seems to work well. The controller is capable of preventing wheel lift-off in the simulated test cases, and the results are promising.