| Teck Chew Ng Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore, Martin Adams School of Electrical & Electronics Engineering,
Nanyang Technological University, Singapore and Javier Ibañez-Guzmán Renault - Research Division - Electronics Systems
Department, France |
| Autonomous Vehicle Following can be achieved if the poses of both
the follower and leader vehicles are continuously estimated. This can
be achieved by using a Bayesian estimation technique together with
a virtual trailer link model. The advantage of such a model is that the
follower vehicle will trail a virtual trailer, modeled as an attachment
to the leader vehicle, instead of the leader vehicle itself, so that a safe
spacing between the two vehicles is guaranteed. The key to a tractable
solution to this vehicle following problem is the justifiable assumption
that the pose of the follower vehicle is statistically independent of that
of the leader. This assumption is valid when conditioned on the history
of the follower vehicle’s inputs and the sensor observations made by
the follower vehicle. Hence, a factored solution to the joint estimate of
the follower and leader poses can be formulated. Due to the factored
solution, the pose of the follower vehicle is estimated separately using
a recursive estimator. In a separate estimator, the poses of the virtual
tailer and the leader vehicle are augmented in the tracking process
of the leader vehicle. The aim is to command the follower vehicle to
trail the estimated pose of the virtual trailer link model. The pose of
the virtual trailer is computed with an on-board sensor mounted on
the follower vehicle. A case study on the implementation of the proposed
formulation, using an Extended Kalman Filter as the main estimator,
is presented. First, simulation results are presented. To make
the simulation results comparable to the actual system, the variances
of sensor measurements are set according to real sensor data-sheet
values. Various types of vehicle maneuver, such as straight paths and
clothoids with left and right transition paths, are considered. Real experiments
are also carried out in a car park. A comparison of the
estimated paths and the best available ground truth is presented. The
path deviations of the proposed system are also compared with similar
systems in the literature. |
