Inverse Kinematics of a 7-DOF Spray-Painting Robot with a Telescopic Forearm

Inverse kinematics is an important issue for redundant robot. This paper studies the inverse kinematics of a 7 degree of freedom (7-DOF) spray-painting robot with a telescopic forearm. The mapping relationship between the joint and the end-effector is studied and a method to find the solution of the inverse solution is proposed. The position of the end point of the painting gun are affected by five joints and the position of the two joints from the five joints are taken as independent variables. Except the two joints with their position taken as independent variables, the analytical solutions of other five joints are written as function of the two independent variables. An objective function that considers the joint limit is presented to optimize the two independent variables. The proposed method is compared with the direct Jacobian iteration method.