Control of an industrial robot

A method for controlling a working robot which has hand means adapted to hold a workpiece and move it with respect to a tool which is held in a stationary position so that a work is performed by the tool on the workpiece at a predetermined location, the method comprising steps of obtaining a position of a working end of said tool in first coordinates taken in said robot, operating said hand means to bring said workpiece to a first position wherein a first point on the workpiece is located with respect to said tool so that a desired work can be done by the tool on said first point and obtaining a first tool length vector in the first position in second coordinates having an origin in a point on said hand means, operating said hand means to bring said workpiece to a second position wherein a second point is located with respect to said tool so that a desired work can be done by the tool on said second point and obtaining a second tool length vector in the second position in said second coordinates, calculating a work distance on said workpiece along a path on which a work is to be performed, calculating based on said first and second tool length vectors and said work distance an intermediate tool length vector at an intermediate point on said path between said first and second points as a value in said second coordinates, converting said value of the intermediate tool length vector into a corresponding value on said first coordinates, and controlling said hand means in accordance with said corresponding value on said first coordinates.