Method of mounting wheel to vehicle

A method of mounting a wheel, by a wheel mounting robot, to a vehicle conveyed along an assembly line, comprising the steps of:

• obtaining an image of a wheel hub by first imaging means disposed on one side of said conveyed vehicle;
• calculating approximate coordinates of the center of said wheel hub based on the image obtained by said first imaging means;
• locating second imaging means mounted on said wheel mounting robot so that respective said second imaging means are located in front of said wheel hub and symmetrically with respect to the center of said wheel hub, according to said approximate coordinates of the center of said wheel hub;
• calculating revised coordinates of the center of the wheel hub and a rotational displacement from a standard rotational position of the wheel hub, based on said images obtained by said second imaging means;
• extracting points recognized as the heads of hub bolts studded on said wheel hub based on each of said images obtained by said second imaging means;
• connecting said recognized points in each of said images with a curve to find a best fitted ellipse;
• finding a ratio of the lengths of the minor and major axes of said ellipse in each of said images to determine the direction of the normal of a hub bolt circle with respect to an optical axis of each of said second imaging means;
• determining a turning angle of the wheel hub toward the right or left with respect to a progressive direction of the vehicle based on said direction of the normal of the hub bolt circle determined for each of said second imaging means;
• and
• mounting the wheel to said wheel hub by said wheel mounting robot based on the revised coordinates of the center, rotational displacement, and turning angle of said wheel hub.