Image Number 4 for United States Patent #6236896.
A method of setting a coordinate system to an automatic machine with a stable accuracy in a non-contact manner. The desired coordinate system can be set even if it exists outside a moving range of the automatic machine. The operator operates a robot control device to move a robot to a first position A1 where a coordinate system setting jig is within the field of view of a camera supported by the robot. Matrix data [A1] representing the robot position A1 is stored and the jig is photographed by the camera. The image of a group of dots on the jig are analyzed by an image processor to obtain picture element values of the individual points. Based on the picture element values of the individual points and jig data (data of distances between and number of the points), matrix data [D1] representing a position and a posture of a coordinate system .SIGMA.c to be set with respect to a sensor coordinate system .SIGMA.s is obtained. In the same manner, a matrix data [D2] at a position A2 is obtained. According to a relationship [C]=[A1].multidot.[S].multidot.[D1]=[A2].multidot.[S].multidot.[D2], a matrix [C] is derived and stored as data for setting the coordinate system .SIGMA.c to the robot control device.