Estudo de estratégias de sensoriamento e controle para o ajuste de distância em um equipamento de manufatura aditiva

Abstract

Additive Manufacturing (AM) is a fabrication technology that builds three-dimensional objects by controlled addition of material in layers, distinguishing itself from conventional material removal methods such as milling and turning. The continuous improvement of AM systems and the understanding of the properties of produced parts are driving its adoption in sectors such as aerospace, medical, and automotive, which require complex geometries and production of small and medium batches. AM techniques are classified based on various criteria, such as the type of material and the state of the raw material. One highlighted technique is Directed Energy Deposition (DED), which allows the addition of metallic material in layers using a high-power laser, melting the powder to create precise and customizable parts. Other variations are also presented, such as Electron Beam Melting (EBM) and Wire Arc Deposition (EAD), which use different energy sources to melt the material. The objective of this project is to propose a distance control system during the DED process, using temperature and intensity signals captured by a pyrometer. Specifically, the project aims to investigate the correlation between the working distance and temperature signals, identify the dynamic system, model it, and develop a controller that allows real-time adjustments of the laser position, ensuring proper control of the distance during deposition. During the development of the system, thermal sensor calibration tests and deposition trials were conducted, analyzing the relationship between distance and temperature signals. From this analysis, it was possible to identify a suitable model to represent the dynamics between these parameters, with an ARMAX model being chosen for its adequacy and performance. For system control, a discrete-time transfer function approach was used, with a cascade control structure employing Proportional-Integral (PI) controllers, demonstrating versatility for practical application.