Method for controlling the positioning of an autonomous forklift relative to an annular load to be lifted

A method for controlling positioning of an autonomous forklift relative to an annular load to be lifted and transported, the forklift comprising a vertically movable fork provided with at least one arm, and the method comprising:

• a step of acquiring at least one image of the annular load by means of at least one 3D camera rendering a point cloud of coordinates measured in a coordinate system associated with the 3D camera, the 3D camera being fastened to the autonomous forklift centered relative to the vertically movable fork and having a line of sight oriented forward along a longitudinal axis of the forklift;
• a step of digitally processing the image obtained in the acquisition step comprising:
• a sub-step of detecting at least one circle located on a front face of the annular load and corresponding to an outer diameter or inner diameter of the annular load,
• a sub-step of calculating an offset, in a plane perpendicular to the line of sight, between the center of the detected circle and a center of the 3D camera, the offset representing a centering error of the forklift relative to the annular load,
• a sub-step of determining a plane corresponding to the front face of the annular load, and
• a sub-step of calculating an angle between a normal to the determined plane and the line of sight of the 3D camera, the angle representing an angle error of the forklift relative to the annular load;
• and
• a step of stopping the forklift if at least one of the calculated angle error or centering error values is greater, as an absolute value, than a predefined limit value.