Optical position detection to measure tyre carcass deflections and implementation for vehicle state estimation
Ari Juhani Tuononen · Aaltodoc (Aalto University) · 2009
Future active safety systems for vehicles will need accurate information about the state of the vehicle. Tyre sensors certainly offer an interesting option to evaluate the operating state of an individual tyre. On the other hand, tyre behaviour in some driving conditions is not completely understood and tyre sensor measurements can contribute to the fundamentals of tyre research as well. This thesis discusses a method to measure the carcass deflection of a rolling tyre. Tyre force estimation algorithms are proposed and tested in real time with a low-cost micro-controller unit. The tyre force information is then exploited to estimate the lateral state of a car. In addition, the tyre sensor signals in aquaplaning are carefully studied and the hydrodynamic and viscous aquaplaning zones were separated from the data in post-processing. Another method was developed to estimate partial and full aquaplaning in real time. The results obtained support the development of more production-friendly tyre sensor concepts. The relations between carcass deflections and tyre forces that were obtained can be useful for completely different types of sensors. In addition, tyre behaviour in complex conditions can be measured and the results can validate tyre models.