Algorithms for a Vehicle Dynamics Monitoring System, Based on Model Reference Structure

Abstract

Vehicle control depends heavily on the knowledge of the vehicle operatingconditions. One of the most important parameters for its control is thetyre–road friction coefficient (µ). An appropriate way toestimate the vehicle operating conditions is the Model Reference Approach.This technique requires a model that provides estimated states which can becompared with the measured states, the difference is used to determine thereal operating conditions. This paper presents two different applications ofthe Model Reference Techniques to estimate tyre–road frictioncoefficient; these are based on the relation between tyre forces and slip,and on the vehicle lateral behaviour using an extended Kalman filter.Experimental data from the test vehicle confirms the good results obtainedin the friction estimation based on the tyre slip–force relation. Theestimation using an extended Kalman filter on lateral behaviour showsaccurate tracking. The next step to be taken is to integrate all thealgorithms in the test vehicle and to validate them for a wide range ofoperating conditions, in order to have reliable information for the activesystem control.