A Procedure to identify the handling characteristics of agricultural tyre through full-scale experimental tests

European standards will increase agricultural vehicles’ speed up to 80km/h on ordinary asphalt roads. Thus vehicle safety and cornering stability are becoming issues of fundamental importance. To address these issues at a design stage, mathematical models simulating the handling behaviour of agricultural vehicles are needed. For passenger cars, tyre model parameters used in such models are generally identified from indoor tests on a individual tyres. Size, dimension and amplitude of required forces make these experiments more challenging for agricultural tyres and thus they are generally not performed. The present paper presents a methodology to identify agricultural tyres’ handling characteristics based only on the measurements carried out on board vehicle (vehicle sideslip angle, yaw rate, lateral acceleration, speed and steer angle) during standard handling manoeuvres (step-steers, ramp-steers, sweep tests, etc.), instead than during indoor tests. In particular, MF-Tyre model parameters (including vertical load and pressure dependency) are identified by the developed algorithm, which is based on a constrained minimization approach. The proposed identification procedure was applied to the data collected on an instrumented high-range agricultural vehicle during a series of handling manoeuvres carried out at different inflation pressures.