Optical navigation system for an automatic guided vehicle, and method

A navigation system for guiding an automatically guided vehicle having vehicle control means along a variable, pre-determined path defined by a plurality of fixed, spaced-apart points, and comprising:

• (a) a target positioned at each spaced-apart point defining the vehicle path, said target including a first vertical row of light sources for emitting a first series of converging light beams and a second vertical row of light sources horizontally spaced-apart from said first row of light sources for emitting a second series of light beams;
• (b) a light receiving camera and lens mounted on the vehicle for receiving said first and second series of horizontally spaced-apart light beams and focusing said first and second series of light beams on a detector, said detector having a vertically extending axis representing the path of the vehicle to the target, said first and second series of light beams being focused on said detector at two spaced-apart points on opposite sides of the vertically extending axis wherein a difference in distance from the vertical axis of the detector of said two spaced-apart points represents a deviation from the proper path of the vehicle to said target and an equality of distance of two said spaced-apart points to said vertically extending axis represents the proper path to the target, and the position of said first and second series of light beams and the vertical field of view of said lens being configured for receiving:
• (1) all of the light beams at a predetermined distance from the target;
• (2) light from a fewer number of light beams at a closer distance from the target;
• and
• (3) a light from a still fewer number of light beams at a still closer distance to the target, whereby the rate of the change in intensity of the light beams as the vehicle approaches the target is reduced to within a range usable by the camera;
• and
• (c) said detector including means for converting said first and second light beams into a signal representing a bearing of the vehicle from the target and outputting said signal to the vehicle control means for controlling the vehicle position in relation to the target.