Abstract: In a method for manipulating paper roll heads by a multi-axis robot (8), heads are picked-up and transferred by the robot (8) from multiple stacks in accordance with stored data concerning the height and position of each stack as well as the dimension characteristics of the articles in the stack. At initial start-up, or immediately after a shut-down, previously stored information on the position or height of the stacks is considered not known by or otherwise unreliable by the robot (8) controller. That is, when the operation of the robot (8) is halted to accommodate replacement or replenishment of the head stacks, the stored parameter data for all stacks is set unknown. In accordance with its operating program, the system operation is restarted, the robot performs a slow-speed approach toward an uncalibrated stack, measures the stack data, that is, calibrates the stack height and position, and thus can perform the next stack approach through a normal transfer cycle on the basis of the measured data.

Abstract: The present invention relates to a method and assembly suited to determining the size and position of a head relative to a clamp when using an industrial multi-axis robot. The invention is based on moving the clamp by means of the robot advantageously past three sensor elements and providing the clamp with a target element suitable for aiding in the position detection of the reference point of the clamp at the instant the clamp moves past a first sensor element. The size and position of the head are determined on the basis of geometrical lines computed from the head edge intercept signals obtained by means of the sensor elements. The lengths of the geometrical lines are determined from the speed of the clamp and the time intervals of intersect instants counted by a control system counter card connected to said sensor elements.