Pushing the limits: From lanekeeping to autonomous racing

The success of Electronic Stability Control (ESC) has demonstrated the potential life-saving benefits of vehicle control systems. Lanekeeping presents an obvious next step in vehicle control, but the performance of such systems must be guaranteed before lanekeeping can be viewed as a safety feature. This paper demonstrates that simple lookahead control schemes for lanekeeping are provably robust even at the limits of tire adhesion. By responding to the heading error relative to the desired path, these schemes provide the countersteer behavior necessary to compensate for rear tire saturation and stabilize the vehicle. Using a Lyapunov-based analysis, vehicle stability can be proven even with a highly saturated tire. Taking this a step further by developing a desired path based on the racing line, this lookahead controller can be coupled with longitudinal control based on path position and wheel slip to create an autonomous racecar. The performance of this algorithm shows the potential for lanekeeping control that can truly assist even the best drivers.