04996468 is referenced by 118 patents and cites 20 patents.

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.

Title
Automated guided vehicle
Application Number
101508
Publication Number
4996468
Application Date
March 13, 1989
Publication Date
February 26, 1991
Inventor
Joseph G Kasper
Golden Valley
MN, US
Bruce F Field
Minneapolis
MN, US
Agent
Kinzer Plyer Dorn McEachran & Jambor
Assignee
Tennant Company
MN, US
IPC
G05D 1/03
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