Wheel Slip Regulation Using An Optimal Reference Slip Estimation Framework

Abstract

Wheel slip regulation algorithms constitute a significant part of active vehicle safety systems in heavy commercial road vehicles. Any wheel slip regulation algorithm designed for set-point tracking requires a reference operating wheel slip irrespective of its control strategy. This reference slip is unique to each tire-road interface and changes with tire normal load. The present work proposes the optimal reference slip as one that minimizes braking distance, and introduces a recursive algorithm for its estimation. It further proposes a framework for reference slip estimation and wheel slip control. The credibility of the framework was established by testing in a Hardware-in-Loop setup consisting of a pneumatic braking system and IPG TruckMaker ® , a high fidelity vehicle dynamics simulation environment. The algorithm estimated the reference slip corresponding to different tire-road interfaces and resulted in stable braking maneuvers with 7-17% reduction in braking distance.