Method for measuring a distance from a vehicle to a platform
A method for measuring a given distance between a vehicle and an upper surface of a platform includes projecting two or more beams by a detection system mounted on the vehicle. The beams lie in a single plane of projection towards the platform. For each beam, a distance is measured between the detection system and the platform along a respective direction of the beam. The measured distances not corresponding to the upper surface are excluded. A vertical distance between a vehicle marker and the upper surface of the platform is calculated from the distances that are not excluded.
1. A method of measuring a given distance between a vehicle and an upper surface of a platform, comprising
providing a detection system mounted on the vehicle,
projecting a plurality of beams by the detection system towards the platform, the beams all lying in a single plane of projection towards the platform, each of the beams emitted at a different angle between the beam and a vertical direction,
measuring, for each beam, a distance between the detection system and the platform along a respective direction of said beam detected by the detection system,
detecting an edge of the platform by comparing the measured distances,
excluding a first part of the measured distances, the first part comprising the measured distances not corresponding to the upper surface,
calculating a vertical distance between a marker of the vehicle and the upper surface of the platform from measured distances which do not included the first part,
wherein the vertical distance is calculated as a function of the measured distances for beams that are not excluded and the corresponding angle between each such beam and the vertical direction.
2. The measuring method according to claim 1 , wherein the beam is a laser beam.
3. The measuring method according to claim 1 , wherein the beam reaching the edge of the platform is the beam with the smallest measured distance between the detection system and the platform.
4. The measuring method according to claim 1 , wherein each measured distance is associated with an angle between the corresponding beam and the vertical, the excluded first part of the measured distances corresponding to a predefined range of angles whose upper limit is the angle of the beam reaching the edge of the platform.
5. The measurement method according to claim 1 , comprising a step of excluding a second part of the measured distances, the second part comprising measurements corresponding to the upper surface of the platform, and a step of calculating a horizontal distance between the marker of the vehicle and an edge of the platform from distances not included in the second part, each measured distance being associated with an angle to the vertical, the excluded second part of the measured distances corresponding to an angle interval with respect to the vertical, whose lower limit is the angle of the beam reaching the edge of the platform.
6. The measurement method according to claim 1 , comprising a step of excluding distance values between the detection system and the platform, said values not meeting at least one predefined criterion.
7. The measurement method according to claim 6 , wherein:
each measured distance is associated with an angle of the beam,
for each angle, a range of expected distances is predetermined, and
distances measured outside their distance interval are excluded in the value exclusion step.
8. The measuring method according to claim 1 , wherein each measured distance is associated with an angle of the beam, for each angle whose associated distance is not excluded, a vertical distance between the marker and the platform is calculated from the associated measured distance.
9. The measuring method according to claim 8 , wherein for each angle to the vertical whose associated distance is not excluded, the vertical distance between the marker and the platform is calculated by the following formula: H cl/q n =D n ×cos(∝ 0 +∝ n )−H cl/c where H cl/q n is the vertical distance between the marker and the point on the platform reached by the beam, α0 is the angle between the vertical and the beam reaching the edge of the platform, αn is the angle between the edge of the platform and the beam corresponding to the measurement, and H cl/q n is the vertical distance between the marker and the detection system.
10. The measuring method according to claim 1 , wherein the method detects the edge of the platform by (i) identifying a beam with the smallest measured distance between the detection system and the platform and (ii) comparing the measured distances.