2012 Volume 6 Issue 9 Pages 935-949
From a traffic safety point of view, there is an urgent need for intelligent tires which can optimize braking control by estimating the slip ratio and friction coefficient between a road surface and an automobile tire. The present study develops concurrent monitoring of frictional and vertical loads applied to the tires from the inner tire strain data for estimating the road/tire friction coefficient, which enables optimization of vehicle control and implementation of a road condition warning system. The tire strain is obtained using a three-dimensional digital image correlation method with a single wireless CCD camera attached to the wheel rim inside the tire. The procedures of the applied load estimation decompose the measured strain into the frictional and vertical strain components using their symmetrical and anti-symmetrical characteristics. Static tire rotation tests were carried out, and the applied loads were estimated from the inner tire surface strain distribution. Compared with the actual applied loads measured from strain gages attached to the experimental apparatus, it was confirmed that the vertical and frictional loads can be estimated independently with adequate accuracy.
