Real-time vehicle parameter estimation and equivalent moment electronic stability control

Abstract

This paper presents a novel electronic stability control (ESC) strategy that is capable of adapting to changing vehicle mass, tyre cornering stiffnesses and road surface conditions. First a nonlinear reduced-order observer is used to estimate vehicle sideslip and axle slip angles. In addition, lateral forces are estimated providing a real-time characterisation of lateral force capability of the axles with respect to slip angle. A recursive least squares estimation algorithm is used to estimate cornering stiffness, which in turn provides a real-time indication of axle lateral force saturation. An algorithm calculates the reduction in yaw moment owing to axle lateral force saturation and determines an equivalent moment to be generated by differential braking on the opposite axle. Simulations demonstrate that the ESC strategy provides improved vehicle performance with regard to handling stability and is capable of adapting to changes in vehicle parameters.