Design and Assessment of a Machine Vision System for Automatic Vehicle Wheel Alignment

Indexed in ISI. Wheel alignment, consisting of properly checking the wheel characteristic angles against vehicle manufacturers' specifications, is a crucial task in the automotive field since it prevents irregular tyre wear and affects vehicle handling and safety. In the last years, systems based on Machine Vision have been widely studied in order to automatically detect wheel’s characteristic angles. In order to overcome limitations of existing methodologies, due to measurement equipment mounting onto the wheels, the present work deals with design and assessment of a 3D machine vision-based system for contactless reconstruction of vehicle wheels geometry, with particular reference to characteristic planes. Such planes, properly referred to a global coordinate system, are used for determining wheel angles. The effectiveness of the proposed method was tested against a set of measurements carried out using a commercial 3D scanner; the absolute average error in measuring toe and camber angles with the machine vision system resulted to be fully compatible with expected accuracy of wheel alignment systems.