Distributed-parameter control of geometry in rapid prototyping

This article introduces an analytical model of thermal rapid prototyping processes, using superposition of unit deposition distributions, composed of elementary ellipsoidal primitives. The real-time surface geometry model, with its parameters identified by in-process profile measurements, is used for Smith-prediction of the material shape. Thus, a distributed-parameter geometry control scheme is established to obtain a desired surface topology, by modulating the feed and motion of a moving source. This is based on dynamic geometry shaping by a real-time complex optimization technique. The methodology is tested in geometric command following on a robotic fused wire deposition station.