  This paper addresses the shared lateral control for both lane-keeping and
obstacle avoidance tasks of a driver steering assist system (DSAS). In this
work, we propose a novel approach to deal with the interactions between the
human (driver) and the machine (DSAS) by introducing into the vehicle system a
fictive nonlinear term representing the driver activity. In this way, the
actions of the DSAS are computed according to the driver behaviors (actions and
intentions). Based on Takagi-Sugeno control technique together with Lyapunov
stability tools, the designed controller is able to handle a large range of
variation of vehicle longitudinal speed. In particular, this controller can
deal with the system state constraints and also the control input saturation.
As will be discussed later, the consideration of these constraints into the
control design improves significantly the closed-loop performance under various
driving situations. The interests of the proposed method are validated by
simulations.
