General Electric Company

Michael P Robins

Malcolm T Roberts

Peter J Reeve

Ian E Sharrott

In a guidance system for guiding an automated vehicle around an area such as a warehouse, a scanning laser beam from a source mounted on the vehicle impinges upon reflectors located around the area. Each reflector incorporates an optical code which identifies that reflector. Laser light reflected back to the vehicle from the reflectors is used to control the movement and heading of the vehicle. The area is divided notionally into a number of equal sub-areas of predetermined dimensions, each having at least two differently-coded reflectors. The vehicle is first moved to a position from which it can scan initialization reflectors located at selected initialization positions. The navigation system determines the initial position of the vehicle relative to the initialization reflectors and, during subsequent movements of the vehicle around the area, measures the distances and directions travelled by the vehicle from the initial position so that the navigation system can determine in which sub-area the vehicle is located at any instant. Because the system always knows in which sub-area the vehicle is located, it is not necessary for every reflector to have a unique code, so some duplication of codes around the area can be tolerated, thereby increasing the number of available reflectors for a given number of code elements.

Automated vehicle control

A vehicle guidance system includes a computer for generating signals to control a number of vehicles to carry out movements within a predetermined area. Data identifying locations of notional points on the floor of the area are entered into the computer together with a look-up table specifying pairs of those points between which movements of vehicles may be required, and specifying which other of the movements between pairs of points must be considered as potential causes of collision between vehicles when any particular movement is to be effected. When a vehicle movement is requested, the computer determines from the table which other movements must be considered, and determines whether any such movements are being effected at that instant. If so, the computer inhibits the requested vehicle movement or, if not, it initiates the requested vehicle movement.

A vehicle control and guidance system in which a desired route for the vehicle is stored in the vehicle in the form of co-ordinates in a ground reference frame. The `vectors` between these junction points are divided by successive reference points into incremental vectors, the reference points being generated ahead of the vehicle at regular intervals. A dead reckoning system predicts the position of the vehicle at the end of each interval and this estimate is corrected, using a Kalman filter, by an independent fixed-target detection system using a scanning laser. The error between the estimated vehicle position and the local incremental vector provides a steering angle correction for the vehicle and the vehicle speed is dependent upon the lag of the vehicle behind the generation of reference points.

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Rugby, United Kingdom

Michael P Robins