A Model Predictive Repetitive Process Control Formulation for Additive Manufacturing Processes

Abstract

Additive Manufacturing (AM) processes are a class of manufacturing processes in which parts are fabricated in a layer-by-layer fashion. The layer-by-layer fabrication method creates layer-to-layer dynamics. Implementing process control that neglects the layer-to-layer dynamics can lead to process instability. While repetitive process controllers which utilize only layer-to-layer feedback are a viable method, their usefulness is limited in that they are not well-suited for tracking non-periodic layer-domain references. However, since the entire reference signal is typically known a priori in AM process fabrications, a predictive control methodology can be useful for controlling fabrications in which the reference signal is non-periodic. In this paper a model predictive control formulation is extended to two-dimensions and utilized for repetitive process control Simulation results comparing open-loop and controlled fabrications for a Laser Metal Deposition process are given.