A new path-constrained trajectory planning strategy for spray painting robots

In this paper, a novel method for planning spray painting trajectories for industrial robots is presented. The proposed method takes as input an arbitrary parametric description of the end-effector path in the operative space. The method is aimed at providing feasible motion profiles without resorting to optimization routines and without the need for a dynamic description of the painting robot. The motion law is then defined by the algorithm to achieve end-effector speed limitation, in order to comply with the constraints imposed by the spray painting process and by the manipulator specifications. Subsequently, a sequence of look-ahead filtering operations on the speed profiles ensures joint acceleration limitation. The proposed method has been tested on an industrial painting robot, showing its effectiveness, which is experimentally evaluated against the results obtained with the original manufacturer’s proprietary planning method. The improvements include, other then the required end-effector speed and joint acceleration limitation, a sensible reduction of the cycle time, and of the torque effort requirement. The method is of simple implementation and can be useful for other robot-oriented industrial tasks.