Industrial versatility of inverse kinematics algorithms for general 6R manipulators

Serial manipulators with six revolute joints are the most common type of robots applied in industry and are used for various stages in a production process such as welding or painting. Thereby, modern production processes require a continuous increase in manufacturing precision. Additionally the effort to react quickly to changes in the environment demands that the planning of the end-effector path and the associated calculations are executed online. Therefore, in modern robot controllers an exact, reliable, fast and efficient computation of the inverse kinematics (IK) is the basis to obtain these requirements. IK solutions specially tailored to a few well known robot structures fulfill these needs and are frequently used. However, they lack flexibility when the IK of a robot with an even slightly deviating structure has to be calculated. Hence, the IK for a manipulator with non-standard structure is often deduced by hand, which is generally a tricky and time consuming task. In this paper two important complete IK solutions for generally structured serial robots with six revolute joints (6R) are analyzed and the capability for their use in an industrial environment is discussed.