Type and dimension synthesis of a portable all‐position welding robot

Purpose – The purpose of this paper is to develop a portable all‐position welding robot for the welding of intersected pipes. Design/methodology/approach – A complete procedure is adopted to conduct the design. The task and motion of the robot are analyzed and a mathematical description of the pose and position of the welding tool is given. Based on that, three representative types of robot are chosen in the type synthesis of mechanism. Two new indices proposed to evaluate required properties of the robot, along with the traditional dexterity index, are chosen to be the criteria in the dimension synthesis of mechanism. Through the optimization by genetic algorithm, the best robot in type and dimension is determined after comparison on their performances. Finally, the prototype is developed. Findings – The paper finds a new robot for welding intersected pipes. Originality/value – A new robot is introduced for the welding of intersected pipes. A complete design procedure is adopted to conduct the design. Two new indices are constructed for evaluating the required properties of this robot.