Abstract: Method and apparatus in a robot installation for programmed control of a working tool to perform processing operations on an object by a movable servo-actuated robot arm system with more than six degrees of freedom and including a data memory for storing preprogrammed tool path data. A coordinate transformation module derives and stores in the memory the preprogrammed tool path data defined in an outer coordinate system without physical connection with the robot arm system. The robot arm system is subdivided into system parts movable relative to each other and each system part having at most six degrees of freedom, thereby enabling suitable coordinate transformation to an inner reference coordinate system associated with the robot arm. Sensor devices obtain positional data for each system part, apart from at least one system part connected with the inner reference coordinate system.