Highly flexible needle winding kinematics for traction stators based on a standard industrial robot

A challenge for many needle winding machines is programming via cam disks. The advantage of high flexibility in kinematics is nullified by a very inflexible motion programming. Furthermore, standard needle winding machines are special machines with complex and often expensive kinematics. To increase flexibility and to reduce the kinematics complexity a standard industrial robot was equipped to act as a manipulator of a needle winding machine. The system was designed to be able to manufacture traction stators with distributed windings. In this article the development of a standard industrial robot as a needle winding machine was presented and analyzed. A machine model for the manipulator was derived to investigate the kinematics in detail. Subsequently, a model of the dynamics was built up to investigate the acting forces during the winding process. A critical point of the robot system, the stiffness, was analyzed as well. During the winding process the needle has to be positioned accurately, although a force through wire tension acts permanently on the needle. While entering the slot, the orientation of the needle has to be precise, to prevent collisions with the stator stack. The challenge of an accurate positioning of the needle was analyzed by simulation.