Realization of NURBS path interpolator based on an open architecture robot controller

This paper implements a real-time NURBS (Non-Uniform Rational B-Spline) path interpolator for a six-axis arc welding robot. An open architecture robot controller is used as the testbed. The NURBS curve is calculated with an ICP (Iterated Closest Point)-based fitting algorithm. The reason that the end-effector velocity can be controlled in this motion interpolator is analyzed, and the situation is discussed when the velocity profile is a trapezoid which is commonly used in the end-effector movement. Finally, an example is given to prove the applicability of this method. After comparing with the commonly used point-to-point approximation technique, it can be observed that this method has great advantages.