Method and apparatus for measuring vehicle wheel roll radius

摘要

A method and apparatus are provided for determining a roll radius of a vehicle wheel for use in alignment and other diagnostic or maintenance operations. An optically scannable target is attached to a wheel of the vehicle. A first position measurement is made using a machine vision system, such as a three-dimensional aligner. The vehicle is rolled a short distance and a second position measurement is made. The linear and angular differences of the first and second position measurements are used to compute and store a roll radius value. Alignment values resulting from alignment of the motor vehicle are modified based on the roll radius value. A plane angle value may also be created and stored for use in adjusting the alignment values.