Visual odometry for trailer off-tracking estimation

Abstract

Application of articulated and Long Combination Vehicles (LCVs) in challenging off-highway applications is possible with the use of path-following trailer steering. This requires an accurate estimate of trailer off-tracking, but it has been shown that that existing methods for this are not applicable on roads with low friction or significant camber or grade. Here we propose an off-tracking measurement concept using stereo visual odometry which is applicable to off-highway environments. Simulation results demonstrate the theoretical accuracy of the system as well as the effects of camera placement and stereo baseline. Rear-mounted cameras are shown to yield the best precision, with RMS off-tracking measurement errors of 7–36 mm, while side-mounted cameras offer practical benefits such as scope for multiple-trailer configurations. Integration drift errors were shown to be bounded in time due to the relative nature of the off-tracking measurement.