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In-situ controller autotuning by Bayesian optimization for closed-loop feedback control of laser powder bed fusion process

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ADDITIVE MANUFACTURING 2025年 99卷

作者： Kavas, Baris Balta, Efe C. Tucker, Michael R. Krishnadas, Raamadaas Rupenyan, Alisa Lygeros, John Bambach, Markus Swiss Fed Inst Technol Dept Mech & Proc Engn CH-8092 Zurich Switzerland Inspire AG Control & Automat Grp CH-8005 Zurich Switzerland Swiss Fed Inst Technol Dept Informat Technol & Elect Engn Automat Control Lab CH-8092 Zurich Switzerland Zurich Univ Appl Sci ZHAW Ctr Artificial Intelligence Zurich Switzerland

Laser powder bed fusion (LPBF) additive manufacturing (AM) traditionally relies on static parameter assignment in an open loop, which can lead to defects when faced with complex thermal histories and process variability. closed-loop control offers a promising alternative that can enhance stability and mitigate defects. However, controller performance relies heavily on precise parameter tuning, a process that is typically manual and system-specific. This study employs Bayesian Optimization (BO) as an automated, sample-efficient method for tuning in-layer controllers in LPBF, leveraging the repetitive nature of the process for either online (in- process) or offline (pre-process) tuning. We experimentally apply BO to tune an in-layer PI controller to modulate laser power, assessing its performance on wedge geometries prone to overheating. The results show that BO significantly reduces overheating, outperforming uncontrolled settings. Notably, this study presents the first microstructural analysis of parts produced with in-layer controlled tuning, identifying lack-of-fusion porosities caused by the controller's corrective adjustments. In summary, BO demonstrates strong potential for automated controller tuning in LPBF, with implications for broader applications in AM, suggesting a path towards more adaptive and robust control across diverse machines and materials.

关键词： Laser powder bed fusion closed-loop feedback control In-layer control Bayesian optimization controller tuning

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closed-loop feedback control in Intelligent Wells: Application to a Heterogeneous, Thin Oil-Rim Reservoir in the North Sea

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SPE RESERVOIR EVALUATION & ENGINEERING 2015年第1期18卷 69-83页

作者： Dilib, F. A. Jackson, M. D. Zadeh, A. Mojaddam Aasheim, R. Arland, K. Gyllensten, A. J. Erlandsen, S. M. Univ London Imperial Coll Sci Technol & Med London SW7 2AZ England STATOIL Stavanger Norway Univ London Imperial Coll Sci Technol & Med Dept Earth Sci & Engn Geol Fluid Mech London SW7 2AZ England STATOIL Reservoir Technol Stavanger Norway STATOIL Res Dev & Innovat Petr Technol Stavanger Norway STATOIL Res Dev & Innovat Stavanger Norway STATOIL R&D Stavanger Norway

Important challenges remain in the development of optimized control strategies for intelligent wells, particularly with respect to incorporating the impact of reservoir uncertainty. Most optimization methods are model-based and are effective only if the model or ensemble of models used in the optimization captures all possible reservoir behaviors at the individual-well and -completion level. This is rarely the case. Moreover, reservoir models are rarely predictive at the spatial and temporal scales required to identify control actions. We evaluate the benefit of the use of closed-loop control strategies, on the basis of direct feedback between reservoir monitoring and inflow-valve settings, within a geologically heterogeneous, thin oil-rim reservoir. This approach does not omit model predictions completely;rather, model predictions are used to optimize a number of adjustable parameters within a general direct feedback relationship between measured data and inflow-control settings. A high-resolution sector model is used to capture reservoir heterogeneity, which incorporates a locally refined horizontal grid in the oil zone, to accurately represent the horizontal-well geometry and fluid contacts, and capture water and gas flow. Two inflow-control strategies are tested. The first is an open-loop approach, using fixed inflow-control devices to balance the pressure drawdown along the well, sized before installation. The second is a closed-loop, feedback-control strategy, using variable inflow-control valves that can be controlled from the surface in response to multiphase-flow data obtained down-hole. The closed-loop strategy is optimized with a base-case model, and then tested against unexpected reservoir behavior by adjusting a number of uncertain parameters in the model but not reoptimizing. We find that closed-loop feedback control yields positive gains in net-present value (NPV) for the majority of reservoir behaviors investigated, and higher gains than the open-loo

关键词： production optimization intelligent wells closed-loop feedback control

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Study on flight dynamics of flexible projectiles based on closed-loop feedback control

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AEROSPACE SCIENCE AND TECHNOLOGY 2019年 90卷 327-341页

作者： Hua Ruhao Yuan Xianxu Tang Zhigong Ye Zhengyin China Aerodynam Res & Dev Ctr State Key Lab Aerodynam Mianyang 621000 Sichuan Peoples R China China Aerodynam Res & Dev Ctr Computat Aerodynam Inst Mianyang 621000 Sichuan Peoples R China Northwestern Polytech Univ Xian 710072 Shaanxi Peoples R China

Since projectiles with large slenderness ratio are prone to elastic deformation, the effect of structural deformation is necessary to be taken into consideration for dynamic modeling. In order to obtain the precise aerodynamic performance and flight dynamic characteristics of flexible projectiles, a new numerical flight simulation system is developed based on computational fluid dynamics and generalized dynamic-mesh technique. Furthermore, flight dynamic stability of a typical flexible projectile is carried out in detail by introducing PID controller. By means of installing the sensors at various locations, the effect of different mode shapes on the characteristics of the closed-loop flight dynamic system is researched. Numerical results indicate that, when the disturbance due to elastic vibration is added into the mixed signals gained from the angular velocity/acceleration sensors, the feedback response of the closed-loop system becomes adversely divergent. In contrast, the stability of the closed-loop system is not sensitive to the elastic disturbance added to the centroid velocity and acceleration. Moreover, the stability of closed-loop system is much less affected by the unsteady aerodynamic loading due to elastic vibration than the interference of the elastic vibration on the dynamic signals detected by the sensors. The phenomenon can be explained by the requirement on the stability of the long and short period modes of flight dynamics, which can provide some guidance for the layout of the sensor and the design of control system of the projectiles with large slenderness ratio. (C) 2019 Elsevier Masson SAS. All rights reserved.

关键词： Flexible projectiles closed-loop feedback control Flight dynamics Computational fluid dynamics Multi-disciplinary coupling

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Bidirectional Neural Interface: closed-loop feedback control for Hybrid Neural Systems 37

Bidirectional Neural Interface: Closed-Loop Feedback Control...

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37th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society (EMBC)

作者： Chou, Zane Lim, Jeffrey Brown, Sophie Keller, Melissa Bugbee, Joseph Broccard, Frederic D. Khraiche, Massoud L. Silva, Gabriel A. Cauwenberghs, Gert Univ Calif San Diego Undergrad Bioengn Program San Diego CA 92092 USA Univ Calif San Diego Dept Bioengn & Ophthalmol La Jolla CA 92093 USA Univ Calif San Diego Inst Neural Computat La Jolla CA 92093 USA Univ Calif San Diego Dept Bioengn La Jolla CA 92093 USA

ISBN: (纸本)9781424492701

closed-loop neural prostheses enable bidirectional communication between the biological and artificial components of a hybrid system. However, a major challenge in this field is the limited understanding of how these components, the two separate neural networks, interact with each other. In this paper, we propose an in vitro model of a closed-loop system that allows for easy experimental testing and modification of both biological and artificial network parameters. The interface closes the system loop in real time by stimulating each network based on recorded activity of the other network, within preset parameters. As a proof of concept we demonstrate that the bidirectional interface is able to establish and control network properties, such as synchrony, in a hybrid system of two neural networks more significantly more effectively than the same system without the interface or with unidirectional alternatives. This success holds promise for the application of closed-loop systems in neural prostheses, brain-machine interfaces, and drug testing.

关键词： Bidirectional Neural Interface closed-loop feedback control Hybrid Neural Systems

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Two-dimensional phase imaging based on closed-loop feedback control

Two-dimensional phase imaging based on closed-loop feedback ...

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Conference on Optics and Photonics for Information Processing V

作者： Watanabe, Eriko Toshima, Miki Fujikawa, Chiemi Univ Electrocommun 1-5-1 Chofugaoka Chofu Tokyo 1828585 Japan Japan Womens Univ Bunkyo Ku Tokyo 1128681 Japan Tokai Univ Kanagawa 2591292 Japan

ISBN: (纸本)9780819487445

Quantitative phase microscopy with a closed-loop feedback control is described. The system is based on a Mach-Zehnder interferometer using a phase-locking technique and measures the change in optical path length while the sample is scanned across the optical axis. The important feature of this system is no need for any unwrapping process, which allows us to measure the sample with highly precise around 2 pi radian. The spatial resolution is estimated to be less than 1 mu m, which is limited by the Rayleigh criterion and the sample thickness. The path length resolution is estimated to be less than 1nm, which corresponds to the change in refractive index less than 10(-3) for the sample of 10 mu m thick. Precise measurements of quantitative phase images by a volume phase holographic grating or a multi-level zone plate array validate the principle and show the accuracy of the methods. The samples depending on wavelength with the pigment such as red blood cell and diatom cells are measured by different wavelength. We quantify its accuracy by measuring calibrated test samples. The technique is applicable to examination of limitation of passage culture, biological cell imaging for diagnosis.

关键词： phase imaging quantitative phase microscopy refractive index living cell volume phase holographic grating closed-loop feedback control Mach-Zehnder interferometer

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Layer-to-layer closed-loop feedback control application for inter-layer temperature stabilization in laser powder bed fusion

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ADDITIVE MANUFACTURING 2023年 78卷

作者： Kavas, Baris Balta, Efe C. Tucker, Michael Rupenyan, Alisa Lygeros, John Bambach, Markus Swiss Fed Inst Technol Dept Mech & Proc Engn Adv Mfg Lab CH-8092 Zurich Switzerland Inspire AG Control & Automat Grp CH-8005 Zurich Switzerland Swiss Fed Inst Technol Dept Informat Technol & Elect Engn Automat Control Lab CH-8092 Zurich Switzerland Zurich Univ Appl Sci ZHAW Ctr Artificial Intelligence Zurich Switzerland

In laser powder bed fusion (LPBF), part quality and process conditions are highly dependent on the interlayer temperature (ILT) of the exposure surface of printed parts. State-of-the-art closed-loop control applications do not stabilize ILT, which has a decisive influence on the resulting part properties. This paper presents a closed-loop control strategy for LPBF that stabilizes the ILT. The thermal balance is defined with respect to exposure area change in overhanging parts and a control strategy is proposed to maintain the thermal balance by actuating energy input. The proposed control strategy uses an off-axis thermal camera for interlayer temperature acquisition to update the laser power layer to layer. An online optimization-based controller that leverages the repetitive nature of the LPBF process is implemented for the task. The developed controller is validated by experiments with different overhanging geometries. Successful ILT stabilization for various overhanging angles shows the robustness of the controller for an extended number of layers. However, modulation of laser power alone is shown to be insufficient to maintain the ILT within the stable processing window due to excessive heat accumulation in the long term. Nevertheless, the results of this study demonstrate the feasibility of ILT stabilization via of closed-loop control in LPBF and the potential for significant improvements in stabilizing the properties of the printed parts.

关键词： Laser powder bed fusion closed-loop feedback control Layer-to-layer temperature control Interlayer Temperature stabilization

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Bidirectional Neural Interface: closed-loop feedback control for Hybrid Neural Systems

Bidirectional Neural Interface: Closed-Loop Feedback Control...

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Annual International Conference of the IEEE Engineering in Medicine and Biology Society

作者： Zane Chou Jeffrey Lim Sophie Brown Melissa Keller Joseph Bugbee Frédéric D. Broccard Massoud L. Khraiche Gabriel A. Silva Gert Cauwenberghs the undergraduate Bioengineering program at the University of California San Diego CA 92092 USA the Institute for Neural Computation and the Department of Bioengineering at the University of California San Diego CA 92093 USA the Department of Bioengineering and Ophthalmology at the University of California San Diego CA 92093 USA

ISBN: (纸本)9781424492695

关键词： Bidirectional Neural Interface closed-loop feedback control Hybrid Neural Systems closed-loop feedback control hybrid systems closed loop systems Neural Prostheses bidirection communication Biological Substance Abuse Detection Induction loop systems network parameters Bidirectional

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Game-theoretic demand-side management and closed-loop control for a class of networked smart grid

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IET control THEORY AND APPLICATIONS 2017年第13期11卷 2170-2176页

作者： Zhu, Bing Xia, Kewei Xia, Xiaohua Beihang Univ Sch Automat Sci & Elect Engn Res Div 7 Beijing 100191 Peoples R China Beihang Univ Sci & Technol Aircraft Control Lab Beijing 100191 Peoples R China Univ Pretoria Dept Elect Elect & Comp Engn ZA-0028 Pretoria South Africa

A new systematic scheme is proposed for demand-side management and control of a class of networked smart grid. The networked smart grid is modelled into an evolutionary game, and the theory of semi-tensor product is applied to analyse its dynamic behaviours. By using a newly defined stacked form of structural matrix, a closed-loop feedback control is designed to shape the structural matrix of the evolutionary game, such that the Nash equilibrium (with respect to minimum total cost) can be reached and maintained. Based on the proposed feedback control, a robust control can be designed for the smart grid to reach the Nash equilibrium in case of model uncertainties resulted from fake behaviours of some users. Examples are provided to illustrate the theoretical results.

关键词： game theory demand side management evolutionary computation closed loop systems smart power grids robust control game-theoretic demand-side management networked smart grid evolutionary game structural matrix closed-loop feedback control Nash equilibrium robust control

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Cost Optimization and Performance control in the Hybrid Multi-cloud Environment 25

Cost Optimization and Performance Control in the Hybrid Mult...

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Proceedings of the 16th ACM/SPEC International Conference on Performance Engineering

作者： Boris Zibitsker Alexander Lupersolsky BEZNext Chicago IL USA

ISBN: (纸本)9798400710735

Escalating cloud costs and unpredictable performance are major challenges for organizations, particularly when deploying Generative AI (GenAI) applications in hybrid multi-cloud environments-a market projected to reach nearly 20 trillion by *** paper introduces a novel systems approach to cost optimization, performance control, and FinOps decision-making through automated observability, advanced queueing network modeling, and gradient *** automation narrows the scope of the tuning efforts by focusing on the most resource-consuming and credit use applications, applications with the highest rate of performance and cost anomalies, applications with the highest frequency of failed queries, and applications with the highest volume of data spilled to local and remote *** and optimization determine the minimal configurations, resource allocation, workload management, and budgets needed to meet Service Level Goals (SLGs) for all business applications running on different cloud data platforms in the Hybrid Multi-Cloud environment. Modeling and optimization evaluate options and set cost and performance expectations for proposed *** comparing actual performance and costs with expectations, our approach enables closed-loop performance and cost control, mitigating the risks of unexpected financial and operational outcomes. The presented case studies highlight the value of our technology in optimizing application costs and controlling performance across diverse projects, including sizing new applications before cloud deployment, selecting appropriate cloud platforms, optimizing cloud migration strategies, and managing dynamic capacity in hybrid multi-cloud *** predictions demonstrated high accuracy, with the difference between measured and predicted costs within 10%.

关键词： closed-loop feedback control

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Internal sensory models allow for balance control using muscle spindle acceleration feedback

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Neural Networks 2025年

作者： Eric Maris

Motor control requires sensory feedback, and the nature of this feedback has implications for the tasks of the central nervous system (CNS): for an approximately linear mechanical system (e.g., a freely standing person, a rider on a bicycle), if the sensory feedback does not contain the state variables (i.e., joint position and velocity), then optimal control actions are based on an internal dynamical system that estimates these states from the available incomplete sensory feedback. Such a computational system can be implemented as a recurrent neural network (RNN), and it uses a sensory model to update the state estimates. This is highly relevant for muscle spindle primary afferents whose firing rates scale with acceleration: if fusimotor and skeletomotor control are perfectly coordinated, these firing rates scale with the exafferent joint acceleration component, and in the absence of fusimotor control, they scale with the total joint acceleration (exafferent plus reafferent). For both scenarios, a sensory model exists that expresses the exafferent joint acceleration as a function of the state variables, and for the second scenario, a sensory model exists that corrects for the reafferent joint acceleration. Simulations of standing and bicycle balance control under realistic conditions show that joint acceleration feedback is sufficient for balance control, but only if the reafferent acceleration component is either absent from the feedback or is corrected for in the computational system.

关键词： Internal model sensory model recurrent neural network balance control standing balance bicycle balance muscle spindles fusimotor control acceleration feedback exafference reafference closed-loop feedback control optimal feedback control linear quadratic Gaussian underactuated

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