Slip Control for Vehicles Platooning via Second Order Sliding Modes

Recent research has demonstrated that longitudinal control strategies are useful in highway systems to regulate the spacing and velocity of vehicles. In this paper, a robust longitudinal control system for platoons of vehicles is designed. The proposed control scheme is composed of two different loops: the outer loop has to determine the traction force necessary to maintain the safety distance between the controlled vehicle and the preceding vehicle, while the inner loop is aimed at producing the desired traction force, calculated by the outer loop, by controlling the slip ratio. The unknown time-varying road conditions are taken into account by using an adaptive algorithm. The proposed controller enforces second order sliding modes, and, in contrast to conventional sliding mode controllers generates continuous control actions, thus resulting particularly suitable to be applied to automotive systems, where vibrations limitation is a crucial requirement.