Automated guided vehicle
First Claim
1. In an automated guided vehicle having a frame, drive means mounted on the frame for propelling the vehicle, and steering means associated with the frame for controlling the vehicle'"'"'s direction of travel, an improved guidance system for controlling the drive means and steering means so as to guide the vehicle along a predetermined path, the guidance system comprising:
- a plurality of targets mounted along the desired path;
sighting means mounted on the vehicle for determining the direction from the sighting means to a target, the sighting means including means for defining a reference line and for comparing the target direction to the reference line to determine a heading error angle;
control means responsive to the sighting means for activating the drive means or steering means as required to steer the vehicle along a path defined by said reference line, by substantially reducing the heading error angle to zero; and
positioning means for moving the sighting means laterally of the vehicle in one direction thereby deliberately inducing a non-zero heading error angle so that the control means will steer the vehicle in the opposite direction to regain a zero degree heading error angle, thereby causing the vehicle to move with the longitudinal center line of the vehicle being laterally offset and parallel to the reference line.
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Accused Products
Abstract
An unmanned, self-propelled vehicle in the nature of a mobile robot has an on-board computer that stores path and machine function instructions and activates the drive and steering systems so as to cause the machine to follow a desired path. A plurality of retroreflective targets are mounted along the desired path. They do not have to be mounted at a specific height or distance apart, nor need they be square to the path. An improved guidance system for keeping the vehicle on the prescribed path includes a laterally scanning laser transmitter-receiver mounted on the vehicle. An electromechanical tracking device controls the angle of elevation of the laser beam so as to keep it aimed at each target successively as the vehicle moves. The laser produces signals which steer the vehicle such that the laser transmitter and targets are kept aligned in a vertical plane. A positioning device can move the laser transmitter transversely on the vehicle so that the vehicle centerline may travel in the vertical plane of the laser or may travel in an offset line parallel to the vertical laser plane. Certain ones of the targets are bar coded and a target counter senses and counts them as the machine moves past them to keep track of where the vehicle is located along its desired path. A motion sensing system using reflective microwave sensors provides speed and distance information.
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Citations
20 Claims
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1. In an automated guided vehicle having a frame, drive means mounted on the frame for propelling the vehicle, and steering means associated with the frame for controlling the vehicle'"'"'s direction of travel, an improved guidance system for controlling the drive means and steering means so as to guide the vehicle along a predetermined path, the guidance system comprising:
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a plurality of targets mounted along the desired path; sighting means mounted on the vehicle for determining the direction from the sighting means to a target, the sighting means including means for defining a reference line and for comparing the target direction to the reference line to determine a heading error angle; control means responsive to the sighting means for activating the drive means or steering means as required to steer the vehicle along a path defined by said reference line, by substantially reducing the heading error angle to zero; and positioning means for moving the sighting means laterally of the vehicle in one direction thereby deliberately inducing a non-zero heading error angle so that the control means will steer the vehicle in the opposite direction to regain a zero degree heading error angle, thereby causing the vehicle to move with the longitudinal center line of the vehicle being laterally offset and parallel to the reference line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. In an automated guided vehicle having a frame, drive means mounted on the frame for propelling the vehicle, and steering means associated with the frame for controlling the vehicle'"'"'s direction of travel, an improved method of controlling the drive means and steering means so as to guide the vehicle along a predetermined path, the method comprising the steps of:
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placing a plurality of targets along the desired path; determining the direction from the vehicle to a target; defining a reference line; comparing the target direction to the reference line to determine a heading error angle; activating the drive means or steering means as required to steer the vehicle along a path defined by said reference line, by substantially reducing the heading error angle to zero; and moving the sighting means laterally of the vehicle in one direction thereby deliberately inducing a on-zero heading error angle so that the control means will steer the vehicle in the opposite direction to regain a zero degree handling error angle, thereby causing the vehicle to move with the longitudinal center line of the vehicle being laterally offset and parallel to the reference line. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification