Method to avoid singularity in a robot mechanism

Abstract

A method to avoid excessive rotational speeds, of the axes of a robot wrist, that result in the vicinity of a singularity in the path defined by consecutive points along which a tool held by a three-axis wrist mechanism of the robot moves. The speeds of the first and third axes are reduced within the allowable range of rotational speed for these axes, generally defined by the robot manufacturer, while maintaining constant the rotation about the intermediate or second joint. The rotational speed about each of these axes is determined as the tool moves between successive points on the path. Then, if necessary, the rotation of the second joint is decreased while maintaining constant the speeds about the first and third axes. Finally, the tool is maintained on the path by rotating the position of the tool without altering the reduced speeds of rotation about the axes.

Dependencies are inferred from the claim text.