Extrusion Based Additive Manufacturing Using Explicit Model Predictive Control
Freeze-form Extrusion Fabrication (FEF) is a recent additive manufacturing process that fabricates ceramics using ram-based paste extrusion in a freezing environment. Previously, controlling the flow of the paste in FEF processes was accomplished through ram velocity or extrusion force control. However it has been shown that using a combination of both can lead to faster and more consistent extrusion. In this paper, in order to systematically combine the benefits of extrusion force and ram velocity control, a hierarchical control structure is suggested with an Explicit Model Predictive Controller in the lower level and a supervisory algorithm in the higher level. To increase the robustness of the lower level to system variations such as changes in paste material and nozzle geometry, these variations are considered as a disturbance and an adaptive disturbance estimation technique was incorporated. In the higher level, a decision algorithm intelligently switches between full emphasis on extrusion force tracking and full emphasis on ram velocity tracking. Performance of the proposed controller was evaluated experimentally. It was shown that the proposed method is more robust to paste variations during the process compared to previous FEF control methods.
H. Zomorodi and R. G. Landers, "Extrusion Based Additive Manufacturing Using Explicit Model Predictive Control," Proceedings of the 2016 American Control Conference (2016, Boston, MA), pp. 1747-1752, Institute of Electrical and Electronics Engineers (IEEE), Jul 2016.
The definitive version is available at https://doi.org/10.1109/ACC.2016.7525169
2016 American Control Conference, ACC (2016: Jul. 6-8, Boston, MA)
Mechanical and Aerospace Engineering
Intelligent Systems Center
International Standard Book Number (ISBN)
International Standard Serial Number (ISSN)
Article - Conference proceedings
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