Algorithm and Application of Inverse Kinematics for 6-DOF Welding Robot Based on Screw Theory

In order to achieve efficient and reliable inverse kinematics for industrial robot, an inverse kinematics solution is proposed for common 6 DOF industrial robots with the structure characteristics that can be described as "the last three joints axes are intersect, joint 2 and 3 are parallel and non co-planar but perpendicular to joint 1".Taking the screw kinematics model, the solution is established by using geometry relation method and basic known Paden-Kahan sub-problems.Firstly, the 1st joint angle is solved by the geometrical relationship between the robot wrist point and first three joint axes, and the rest five joint angles are solved by transforming into three Panden-Kahan subproblem 1 and one sub-problem 2, so that the complete closed form solutions for inverse kinematics are provided.The accuracy and practicality of the algorithm are testified by the results in Vgroove welding experiment.