Method of controlling robot movement

摘要

A method of controlling movement of a robot includes moving only the wrist portion about two of the wrist axes to achieve a repeated and cyclical movement, such as a back-and-forth movement of the tool relative to a preselected path. Since only the wrist is moved, the range of available tool positions can be determined. In most instances, the desired position of the tool as it deviates from the path is outside of the range of available tool positions, given that only the wrist will move. The method of this invention includes determining a target position within the range of available positions that best corresponds to the desired position of the tool. A unique inverse kinematics solution, which includes fixing one of the wrist axes, is used to determine the wrist orientation required to place the tool into the target position.