Adaptive Control with Variable Gain for Delay Systems: An Application in Metal Additive Manufacturing

Abstract

This paper proposes an Model Reference Adaptive Control with variable gain for linear systems with output delay and proves its global stability. The proposed algorithm is a modification of the MRAC for delay systems, which is reviewed here with its implementation details discussed. The variable gain, adapted using the Least Squares method, is a modification made with the intention of improving the performance of the MRAC at the beginning of adaptation, allowing for a faster transient. The proposed control is applied to a welding bead width control system in the context of additive manufacturing, where the deposition of a precise bead geometry is fundamental to the quality of the final part. The obtained results demonstrate performance improvement with the variable gain.