A Look-Ahead Trajectory Planning Algorithm for Spray Painting Robots with Non-spherical Wrists

This paper proposes an innovative trajectory planning algorithm aimed at limiting the speed and accelerations for robots for spray painting. The algorithm can be applied to robots that, due to their kinematic structure, do not offer a closed-form solution to the inverse kinematic problem. The trajectory planning problem is cast for a predefined path, which can be described by a B-splines. Such path is then described by a set of discrete samples, that are filtered to achieve end-effector speed and joint acceleration constraints. The proposed method has been applied to a commercially available painting robot equipped with a non-spherical wrist. The experimental results show a reduction of the joint speed, acceleration, and a sensible reduction of the motor efforts.