Optical navigation system for an automatic guided vehicle, and method

• US 4,858,132 A
• Filed: 09/11/1987
• Issued: 08/15/1989
• Est. Priority Date: 09/11/1987
• Status: Expired due to Fees

• Current Assignee: Nationsbank Of North Carolina, N.A. (Bank of America Corp.)
• Original Assignee: Ndc Technologies Inc. (Nordson Corporation)
• Inventors: Holmquist, Fredrik
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/095,608
• Time in Patent Office: 704 Days
• Field of Search: 364/424.02, 364/444, 364/449, 358/103, 180/168, 180/169
• US Class Current: 701/28
• CPC Class Codes: G01S 3/784 using a mosaic of detectors
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00

Abstract

A navigation system for guiding an automatically guided vehicle along a variable, predetermined path defined by a plurality of fixed, spaced-apart points. A target is positioned at each spaced-apart point defining the target which includes first and light sources spaced horizontally apart. A light receiving camera and lens is mounted on the vehicle for receiving the first and second horizontally spaced-apart light beams and focusing the beams on a detector. The detector includes an access on which the light beams are focused. A difference in distance from the vertical axis of the detector of the two spaced-apart points represents a deviation from the proper path of the vehicle to the target and an equality of distance of the two spaced-apart points to the vertically extending axis represents the proper path to the target. A vehicle controller controls the vehicle position in relation to the target based on the information received by the camera and lens.

Claims

1. 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 light source for emitting a first light beam and a second light source horizontally spaced-apart from said first light source for emitting a second light beam;

(b) a light receiving camera and lens mounted on the vehicle for receiving said first and second horizontally spaced-apart light beams and focusing said beams on a detector, said detector having a vertically extending axis representing the path of the vehicle to the target, said 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

(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.

2. A navigation system according to claim 1, wherein said detector includes means for converting the light intensity of the first and second light beams into a signal level proportionate to the distance of the vehicle from the target.

3. A navigation system according to claim 1, wherein said lens includes a filter for filtering out visible light to focus said first and second light beams at said detector.

4. A navigation system according to claim 1, wherein said first and second light sources are adjustable to vary the distance therebetween for controlling the voltage level of the signal at which the detector directs the vehicle to perform a vehicle function.

5. 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.