Abstract
Accuracy of vehicle simulations depends vitally on accuracy of the model parameters. Some of the most important tyre properties are difficult to measure without special devices. Cornering stiffness of the tyre dominates the response of the vehicle and it is obviously important parameter for the tyre model. Passenger car tyres can easily be measured using a test rig over the dynamometer drum. However, tyre cornering stiffness on ice or snow cannot be measured similarly. The same limitation stands for the tyres used in straddle carriers and tractors which don´t fit the typical test rig because of their size.
Measurement method of normalized cornering stiffness using vehicle measurements is studied. It is based on a phenomenon that the sign of vehicle slip angle is reversed at certain velocity in steadystate cornering. That velocity can be used to calculate normalized cornering stiffness of the tyre. The method was studied using vehicle simulation model and good accuracy was achieved.
For the validation of the method, two sets of tyres were measured in a tyre test rig on dynamometer drum. The same tyres were used in a test vehicle to measure the velocity at which the sign of slip angle is reversed. Test rig and vehicle dynamic measurements were correlating.
Possible sources of measurement errors were analysed while using the test rig and the vehicle. Different winter tyres were measured on ice and snow surfaces and the cornering stiffness of each tyre was calculated. Difference of axle and tyre cornering stiffness and its influence to the results is discussed.
This research is confirming the method to measure normalized cornering stiffness using vehicle measurements to be accurate. The presented method is not the best possible tool for tyre researchers, but it is simple and costeffective way to validate certain tyre parameters for vehicle simulation purposes.
Keywords:cornering stiffness, vehicle dynamics, tyre parameter, vehicle simulation