New Procedures For Tyre Characteristic Measurement

Abstract

ABSTRACT The properties of tyres mainly influence the dynamic behaviour of vehicles in reality and in simulation. The slip-angle characteristic and the characteristic of the aligning moment play an important role with respect to cornering manoeuvres. Regarding the conditions of a tyre on a vehicle and the typical conditions of a tyre on a test-bench there are large differences. This is one reason for bad correlation of vehicle dynamic's measurement and simulation using measured tyre data. Therefore, it is important to measure the properties of tyres “as realistic as possible”. To realize this, new procedures are developed. Tyre model oriented measurements: some tyre models are developed to describe the established measurements. On the other hand tyre models can be used to create measurement procedures. Realistic measurements: tyre load, lateral force, driving velocity, camber angle is measured at a vehicle or simulated with a vehicle model. While tyre load, driving velocity and camber angle are variables to the test bench, slip angle is controlled by lateral force. This allows a reproduction of the real tyre behaviour on a car. Measurements with constant sliding velocity: the tyre characteristic is usually measured with constant driving velocity. This results in unrealistic high slip velocities. To avoid this, driving velocity is computed in such a way, that the sliding velocity remains constant. This additionally leads to realistic tyre temperatures. State space oriented measurements: considering the state space of wheel load and lateral force it can be shown, that only a few areas of the tyre characteristic measurement are covered during standard driving manoeuvres. The definition of procedures using a slip angle control measuring these important areas improves the measurements.