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Model-Based Feedforward Control of Part Height in Directed Energy Deposition

Control of the geometric accuracy of a metal deposit is critical in the repair and fabrication of complex components through Directed Energy Deposition (DED). This paper developed and experimentally evaluated a model-based feedforward control of laser power with the objective of achieving the target...

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Autores principales: Wang, Qian, Li, Jianyi, Nassar, Abdalla R., Reutzel, Edward W., Mitchell, Wesley F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7826930/
https://www.ncbi.nlm.nih.gov/pubmed/33440854
http://dx.doi.org/10.3390/ma14020337
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author Wang, Qian
Li, Jianyi
Nassar, Abdalla R.
Reutzel, Edward W.
Mitchell, Wesley F.
author_facet Wang, Qian
Li, Jianyi
Nassar, Abdalla R.
Reutzel, Edward W.
Mitchell, Wesley F.
author_sort Wang, Qian
collection PubMed
description Control of the geometric accuracy of a metal deposit is critical in the repair and fabrication of complex components through Directed Energy Deposition (DED). This paper developed and experimentally evaluated a model-based feedforward control of laser power with the objective of achieving the targeted part height in DED. Specifically, based on the dynamic model of melt-pool geometry derived from our prior work, a nonlinear inverse-dynamics controller was derived in a hatch-by-hatch, layer-by-layer manner to modulate the laser power such that the melt-pool height was regulated during the simulated build process. Then, the laser power trajectory from the simulated closed-loop control under the nonlinear inverse-dynamics controller was implemented as a feedforward control in an Optomec Laser-Engineered Net Shape (LENS) MR-7 system. This paper considered the deposition of L-shaped structures of Ti-6AL-4V as a case study to illustrate the proposed model-based controller. Experimental validation showed that by applying the proposed model-based feed-forward control for laser power, the resulting build had 24–42% reduction in the average build height error with respect to the target build height compared to applying a constant laser power through the entire build or applying a hatch-dependent laser power strategy, for which the laser power values were obtained from experimental trial and error.
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spelling pubmed-78269302021-01-25 Model-Based Feedforward Control of Part Height in Directed Energy Deposition Wang, Qian Li, Jianyi Nassar, Abdalla R. Reutzel, Edward W. Mitchell, Wesley F. Materials (Basel) Article Control of the geometric accuracy of a metal deposit is critical in the repair and fabrication of complex components through Directed Energy Deposition (DED). This paper developed and experimentally evaluated a model-based feedforward control of laser power with the objective of achieving the targeted part height in DED. Specifically, based on the dynamic model of melt-pool geometry derived from our prior work, a nonlinear inverse-dynamics controller was derived in a hatch-by-hatch, layer-by-layer manner to modulate the laser power such that the melt-pool height was regulated during the simulated build process. Then, the laser power trajectory from the simulated closed-loop control under the nonlinear inverse-dynamics controller was implemented as a feedforward control in an Optomec Laser-Engineered Net Shape (LENS) MR-7 system. This paper considered the deposition of L-shaped structures of Ti-6AL-4V as a case study to illustrate the proposed model-based controller. Experimental validation showed that by applying the proposed model-based feed-forward control for laser power, the resulting build had 24–42% reduction in the average build height error with respect to the target build height compared to applying a constant laser power through the entire build or applying a hatch-dependent laser power strategy, for which the laser power values were obtained from experimental trial and error. MDPI 2021-01-11 /pmc/articles/PMC7826930/ /pubmed/33440854 http://dx.doi.org/10.3390/ma14020337 Text en © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Wang, Qian
Li, Jianyi
Nassar, Abdalla R.
Reutzel, Edward W.
Mitchell, Wesley F.
Model-Based Feedforward Control of Part Height in Directed Energy Deposition
title Model-Based Feedforward Control of Part Height in Directed Energy Deposition
title_full Model-Based Feedforward Control of Part Height in Directed Energy Deposition
title_fullStr Model-Based Feedforward Control of Part Height in Directed Energy Deposition
title_full_unstemmed Model-Based Feedforward Control of Part Height in Directed Energy Deposition
title_short Model-Based Feedforward Control of Part Height in Directed Energy Deposition
title_sort model-based feedforward control of part height in directed energy deposition
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7826930/
https://www.ncbi.nlm.nih.gov/pubmed/33440854
http://dx.doi.org/10.3390/ma14020337
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