Switching strategies for narrow ground vehicles with dual mode automatic tilt control

Abstract

A tall and narrow type of commuter vehicle has an increased tendency to overturn during hard cornering when compared to conventional vehicles. This tendency can be mitigated by tilting it toward the inside of the turn. Two types of automatic tilting control strategies have been developed: Direct Tilt Control (DTC) and Steering Tilt Control (STC). At zero or low speeds, the DTC provides torque on the body to keep the body upright. The STC provides at high speeds lower perceived lateral acceleration and possibly a more natural feel for the passengers. The two types of tilt control cannot operate simultaneously without interfering with each other so here the problem of switching from one to the other without introducing disturbing transients is studied. In general, the switch from DTC to STC occurs as a specific speed is attained but we also show how the system can switch back to DTC for safety reasons under a low traction patch of roadway in a turn.