Abstract
This paper proposes a driver assistance system with a dual control theoretic scheme, which tries to perform safety control of a vehicle as well as identification of the driver's cognitive state simultaneously. Suppose that a vehicle is going to deviate from the driving lane. When the system predicted that the vehicle's lane departure occurs in td seconds, the system implements a partial control (α%) as the control of the first stage to prevent the lane departure from occurring. The control of the first stage is powerful enough to keep the vehicle in the lane but not to bring the vehicle back to the center of the lane. If the driver does not implement himself/herself the remaining control within the time period of ti seconds, the system determines that the driver is in an off-normal cognitive state, and thus implements the remaining control (100-α%) as the control of the second stage. This paper shows a design of the dual control theoretic driver assistance with a steering torque control based on optimum control using a linear quadratic regulator, and validates the control model of the proposed system by a numerical simulation. This paper discusses the functions and characteristics of the safety control and the identification of the driver's cognitive state.
