Proposal of driver assistance system for recovering vehicle stability from unstable states by automatic steering

Recently, the direct yaw-moment control system, in which braking or driving torque is distributed appropriately to the tires on either side, has been put to practical use. Such systems are called VDC (vehicle dynamics control) or VSC (vehicle stability control), and are available on the market. These systems aim to present the vehicle from falling into an unstable state, and cannot bring a destabilized vehicle back a stable state. On the other hand, it is a well-known fact that an expert driver can recover a vehicle from an unstable to a stable state. This report proposes an assistance system that recovers vehicle stability from an unstable state by means of automatic steering. In the proposed system, when the vehicle is in an unstable state, steering is carried out automatically by an optimal regulator, and when the vehicle recovers, it returns control to the driver. The issue of how to return control from automatic to manual is of particular interest.