Cartesian Path Planning for Arc Welding Robots: Evaluation of the Descartes Algorithm

Many industrial robot applications require fewer task constraints than the robot's degrees of freedom. For welding robots, for example, rotations of the welding torch around its axis do not negatively impact welding quality. Furthermore, the tool center point's Cartesian position and desired orientation as a function of time is often determined by the (manufacturing) process. Nevertheless, programming these robots can be time consuming. Reducing or eliminating this programming cost will allow robots to be used for producing small series. Recently, a promising software package for Cartesian path planning with the name Descartes was released by the ROS-Industrial community. To the authors' knowledge, an in-depth description of this algorithm and an experimental evaluation is lacking in literature. This paper describes the path planning approach used by the Descartes package. Moreover, the software's performance is evaluated for several key robot welding tasks and the encountered limitations are discussed. In addition, we show that the planner's performance can be improved by changing the cost function that the planner's graph search algorithm minimises.