Design of a multivariable control system for an additive manufacturing process

Abstract

Additive Manufacturing, also known as 3D printing, has been used to build objects in different application fields because it allows the creation of complex geometries easily, rapidly, at low cost, and versatile compared to traditional manufacturing. However, these objects still present some drawbacks, such as poor surface finishes, low mechanical performance, high variability in the dimensions, and several others. These drawbacks can be associated with some challenges that Additive Manufacturing machines still have, such as the number of processable materials, dependence on human supervision, or the lack of a control system during the manufacturing process. The latter challenge mainly affects the machine's reliability and repeatability; therefore, this work aims to design and implement a multivariable closed-loop control system into an Additive Manufacturing process in order to supervise and control variables involved in the expected behavior of the manufacturing process. For this purpose, this dissertation presents a characterization of three different Additive Manufacturing techniques and an exploratory study of closed-loop controls system applied in Additive Manufacturing. In addition, the design and integration of a multivariable closed-loop control system into an Additive Manufacturing machine and a study of how the performance of the pieces is affected by this integration of closed-loop control systems are presented. The proposed approach of a multivariable closed-loop control system was integrated into a CORE XY Fused Filament Fabrication machine, which involved different feedback and control strategies, such as artificial intelligence control, and classic control, that allowed the creation of objects with better performance.