Impedance Control for Blending Driver and Automated Steering Commands in Lane Following Maneuvers

This paper presents a model-free control strategy for blending driver steering input and closed-loop path following control commands in automated lane following applications. An impedance controller is designed herein to respond to the measured driver steering torque and modify the reference steering angle to be tracked by the vehicle. A mathematical analysis is provided to prove that the vehicle trajectory remains bounded relative to the target trajectory for a given driver torque input and retains the same transient performance as the unmodified lane following controller. With this control strategy, a given steering effort translates to a steady and predictable offset relative to the target trajectory. Experimental results demonstrate that the proposed controller can deliver a desirable steering feel and is agnostic to the steering system design or the control implementation of the electronic power steering system for real world automated driving applications.