Patent ID: 7853352
Filing Date: 2010-12-14
Classification: G05B

Abstract:
1. A method of self calibrating a positioning system for positioning an element in a working space, comprising the steps of: providing a system of actual coordinates, a system of nominal coordinates, and a set of conversion functions for converting between the actual and nominal coordinates, wherein each of said functions is determined by at least one conversion parameter; positioning a reference device by a work head at a plurality of different calibration locations in said working space by sequentially repositioning said reference device to one of said plurality of different calibration locations at a time, wherein said reference device comprises a plurality of discernable reference features arranged at substantially fixed relative positions; sensing, for each one of said plurality of different calibration locations at which said reference device is positioned, the position of at least any two of said reference features of said reference device in nominal coordinates by non-contact measurements using a camera connected to an image processing system; and selecting a numerical value for each of said conversion parameters such that the differences in relative positions of said reference features expressed in said actual coordinates are reduced for each one of said plurality of different calibration locations.