Automated vehicle control

Abstract

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.