Position sensing system for a moving object wherein a lens focuses light onto a radiation sensitive matrix

Claim 1

An electro-optic position system for a mobile robot moving in a plane comprising at least one light source mounted in a fixed position and emitting light, a light receiver on said robot having a lens arrangement, means in said system for calculating the position of said robot relative to said light source, said light source so mounted and arranged whereby the radiation field of the light source covers the complete area within which said robot is capable of movement, said light receiver being provided with a matrix of radiation sensitive elements, said lens arrangement focusing incident light from said light source to a light spot on said matrix whereby said elements thus illuminated responding by emitting corresponding electric signals, means being provided for sensing the matrix to determine the position of said light spot from the element which unambiguously reacts to incident light, and calculating means for calculating the position coordinates of the robot in the plane of movement from the position of said unambiguously reacting element in said matrix, said calculating means being arranged to present the position coordinates in a polar form, and means being provided which during movement of the robot in a predetermined direction repeatedly compares each value of the polar angle coordinates with the immediately preceding value in order to detect and correct a turning of the robot relative to a predetermined direction.