Robotic Friction Stir Welding Path Planning with Deflection Compensation Using B-Splines

Abstract

Robotic Friction Stir Welding (RFSW) is an innovative process which allows the joining of aluminum materials with robots. The main drawback of using robots to perform friction stir welding is that the end effector of the robots deviates in position and orientation during welding. This is due to the high forces induced by the process and the weak stiffness of the robots. Thus, the compensation of the deviations must be taken into account in an RFSW path planning. In this paper, a methodology based on B-splines curves is proposed to generate offline a welding path with the compensation of the elastic deformation of a robot in order to achieve a high quality welding of three-dimensional workpieces. The methodology is validated on a Kuka robot KR500-2MT which performs a sinusoidal welding path defined on a cylindrical surface. The experiment shows the effectiveness of the methodology and allows to reduce significantly (about 88 %) the lateral end effector deviation.