研究者詳細 - 柿沼　康弘

論文 - 柿沼　康弘

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Acquired Angle Error Correction Based on Variation of an Angle Detection Signal Intensity in Rotary Encoders

Sato A., Kakinuma Y.

Journal of Manufacturing Science and Engineering 147 （ 1 ） 2025年01月

ISSN 10871357

Rotary encoders are used in various machines to measure the angular position of a rotating axis. Therefore, rotary encoders are required not only to be highly accurate, but also usable in various environments. When using a rotary encoder on a machine, acquired angle errors occur due to the eccentricity between the encoder and the machine, the deformation of the scale, and the shaft runout of the rotation axis. Various methods have been adopted to reduce such angle errors. However, these methods have problems such as the large size and high cost of the encoder, the necessity of additional devices for measuring, and increasing installation labor, so the environment in which they can be implemented is limited. In this study, we have proposed a method to correct the acquired angle errors based on variation of an angle detection signal intensity in the sensor head. This method can correct the errors on the machine without using multiple sensor heads or additional devices. The angle error estimated by this method is compared with that measured by the external equipment of a reference encoder. While the maximum angle error was 28.36″ without correction, the residual error with correction of the acquired error can be reduced to 1.75″ or less. From this result, the proposed method can improve the measurement accuracy of the rotary encoder already installed on the machine. Therefore, this method is an effective means for achieving both high rotational accuracy on machines and ease of correcting an error in rotary encoder machines.

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Thermal modeling techniques designed for high-speed directed energy deposition coatings

Takemura S., Miyata Y., Hirono Y., Kakinuma Y.

Journal of Advanced Mechanical Design, Systems and Manufacturing （一般社団法人日本機械学会） 19 （ 1 ） JAMDSM0012 - JAMDSM0012 2025年

ISSN 1881-3054

High-speed directed energy deposition (DED) offers advantages such as efficiency, thin coating layers, and reduced heat-affected zones, making it ideal for repairs and coating on existing parts across various industries. In the DED process, various deposition parameters are included and affect the thermal history. Moreover, a thermal history significantly affects the deposit's mechanical properties by varying metallographic structure. Therefore, thermal simulations of DED are highly demanded due to the time and cost challenges associated with experimenting across different process parameters. However, thermal simulations of DED have difficulties because of the process by which material and heat source are supplied from time to time to the melt pool. Many studies have been conducted on thermal simulations of DED, however, few studies focus on high-speed DED coating. Therefore, this research develops the thermal simulation techniques for high-speed DED coating by exploring five simple methods for element addition and heat input. The geometry of the workpiece model was simplified to reduce the simulation cost. Using the Ansys Parametric Design Language (APDL) software and the simplified workpiece model, we conducted thermal simulations and validated them against experimental data acquired from high-speed imaging and two-color temperature measurements. Through these methods, the study proposed the temperature comparison method of experiment and simulation results and identified the suitable method for element addition and heat input in high-speed DED coating that closely replicates the actual temperature within the coating layer. This method reduces the need for finer mesh, effectively lowering computational costs while maintaining accuracy. The findings provide insights into practical simulation practices for DED and contribute to enhancing parameter validation in additive manufacturing simulations, supporting further development in high-speed DED coating technology.

Entangled chip removal utilizing mass-spring model with mobile manipulator

Takahashi R., Kimura H., Kakinuma Y.

CIRP Annals 2025年

ISSN 00078506

This study aims to automate the removal of entangled chips in manufacturing environments using a mobile manipulator. Despite advancements in factory automation technology, this task often necessitates manual intervention. Accordingly, this study proposes a deformable chip model (based on a reconfigurable mass-spring system per frame), incorporating visual chip tracking data and force reactions. Consequently, to evaluate the removal state, an efficient removal strategy is derived by defining the instantaneous stiffness and energy absorption rate. Validation of system performance through two removal tests demonstrates the feasibility of automating entangled chip removal, contributing to enhanced operational efficiency in fully automated production lines.

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AI-based sensor layout for predicting thermal deformations of CFRP machine tools

Finkeldey F., Kato M., Wiederkehr P., Kakinuma Y.

CIRP Annals 2025年

ISSN 00078506

Using data-based approaches, accurate predictions of thermal deformations, which can significantly affect the quality of manufactured components, can be enabled. However, a sufficient amount of data with maximised information content is necessary for efficient training. In this paper, an approach for optimising sensor configurations for predicting thermal deformations is presented. From initially 300 temperature sensors, the number of required sensors was significantly reduced while maintaining predictive accuracy. Furthermore, a pattern for sensor placement was identified, providing the potential for an efficient sensor layout that enables cost-effective data acquisition and improved monitoring of machining and wear progression of machine tool components.

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セラミックスの研削加工における加工状態可視化マップ

市川茉莉, 中山誠士, 細川博史, 柿沼康弘

精密工学会学術講演会講演論文集（公益社団法人精密工学会） 2024A （ 0 ） 674 - 675 2024年08月

セラミックスの研削加工において，センサを用いて加工面に生じる異常を実時間検知できれば，不良品の早期発見やプロセス改善につなげることができる．本研究では，センサデータの解析手法として，加工状態可視化マップを提案した．センサデータを加工位置に対してマッピングすることで，工作物表面への影響を視覚的に捉える手法である．可視化マップと工作物の表面プロファイルの関係を調べ，その有効性を確認した．

Digital Twin in Process Planning of the Additive and Subtractive Process Chain for Laser Metal Deposition and Micro Milling of Stainless Steel

Denkena B., Wichmann M., Malek T., Nguyen H.N., Kato M., Isshiki K., Koike R., Kakinuma Y.

Journal of Manufacturing Science and Engineering 146 （ 7 ） 2024年07月

ISSN 10871357

Additive and subtractive (Add/Sub) manufacturing processes are increasingly being combined to produce complex parts with unique geometries and properties. However, the design of such combined processes is often challenging as it requires a deep understanding of the interaction between the different processes. On the other hand, digital twin (DT) technology has become a powerful tool in recent years for optimizing manufacturing processes. This article explores the use of the digital twin technology for a holistic process planning of combined additive and subtractive processes. The article describes the integration of laser metal deposition (LMD) and micro-milling prediction models of resulting geometry (width and height), hardness, and surface roughness into the digital twin. This is then used for combined process planning to achieve different target values regarding resulting geometry and surface roughness. For the planning of this combined process chain, further criteria such as tool life, energy, and process time are considered in the optimization, showing the potential for sustainable and efficient production. Sensorless cutting force estimation is also used to detect small cutting forces, with the potential to use this as a soft sensor for roughness estimation. The measured width, height, and roughness as a result of the process parameters suggested by the optimization algorithms showed a mean absolute percentage error (MAPE) of 4, 17, and 16%, respectively.

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指向性エネルギー堆積法を用いた高速コーティングの加工条件と熱履歴の伝熱解析による評価

竹村志帆, 柿沼康弘, 廣野陽子, 小田陽平

精密工学会学術講演会講演論文集（公益社団法人精密工学会） 2024S （ 0 ） 535 - 536 2024年02月

金属積層造形の一方式である指向性エネルギー堆積法（DED）を用いた高速コーティングは，高効率な金属皮膜技術として期待されている．しかし，DEDではレーザによる入熱や自己冷却が繰り返され，それらの熱履歴が機械的性質に複雑に影響するため，所望の機械的性質を得るためには熱履歴に対する加工条件の影響を調べる必要がある．本研究では，伝熱解析により高速コーティングによる被膜層や母材の熱履歴を評価する．

Experimental analysis of chemical removal effect in RISA grinding of optical glass

Shimodo K., Takamaru H., Chiba Y., Kato H., Nagano M., Fukuta M., Tanaka K., Watanabe K., Hamazono K., Kakinuma Y.

Procedia CIRP 123 304 - 309 2024年

ISSN 22128271

In the large-aperture lens manufacturing, not only high surface quality but also high productivity is required. From this perspective, Reaction-Induced-Slurry-Assisted grinding (RISA grinding), in which cerium oxide slurry is supplied instead of using general grinding fluid, has been developed to achieve high surface quality at high removal rate. However, the surface profile error becomes large due to chemical removal effect of the cerium oxide slurry. Therefore, the purpose of this study is to experimentally investigate the influence of the chemical removal effect on the surface profile error using AE signals and servo current signals in RISA grinding. First, relation between dwell time and removal depth is analyzed by conducting a basic grinding test without the workpiece rotation. The result shows that the actual removal depth increases with increase of dwell time despite applying the constant depth of cut. Then, zero-cut RISA grinding test is conducted. It is found that the removal process proceeds even though zero-cut grinding, and its removal rate varies according to the wheel feed rate. Furthermore, the amount of cerium oxide abrasives adhered to the grinding wheel can be estimated from the AE signals and servo current signals.

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Task Planning Optimization in Assisting Multiple NC Machine Tools Using AMR

Kusashio K., Yakoh T., Kakinuma Y.

Proceedings of the IEEE International Conference on Industrial Technology 2024年

ISSN 26410184

Although advanced manufacturing strategies such as Industry 4.0 are becoming popular, many small and medium-sized enterprises (SMEs) are still facing challenges in factory automation. One of the reasons is that factory automation may require significant system updates. A retrofittable system that handle versatile tasks is needed to facilitate easier integration in the manufacturing industry. This paper proposes a system that can assist multiple numerical control (NC) machine tools using an autonomous mobile robots (AMR). The tasks integrated are chip removal inside the NC machine tool's chuck, vibration analysis while the NC machine tool is processing and charging AMR. AMR has to perform these tasks within the production line's strict time constraints and AMR's battery constraint. The proposed system produced a feasible schedule of the tasks. Numerical simulation evaluated the feasibility of the produced schedule. The produced schedule was verified by performing in the real world.

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グレーボックスモデルを用いた切削力推定手法における摩擦補償と入力データの影響

齋藤嶺旺, 柿沼康弘

生産加工・工作機械部門講演会 : 生産と加工に関する学術講演会（一般社団法人日本機械学会） 2024.15 （ 0 ） A09 2024年

Various cutting-force estimation methods based on different disturbance observers have been proposed. However, each method has a modeling error, decreasing the estimation accuracy in a certain frequency band. In order to compensate for the modeling error and improve the performance, we have proposed that three different cutting estimation methods are integrated by using a neural network. In this study, the influence of friction compensation and input data on the cutting force estimation is analyzed. The results showed that estimation accuracy remarkably decreased when friction compensation was not implemented, and the accuracy decreased including the experimental conditions of interpolation and extrapolation experiment conditions when directly inputting servo informations to a neural network.

RISA研削における滞留時間と除去高さの関係

西口大樹, 下堂滉大, 千葉裕介, 加来剛, 福田将彦, 田中克敏, 柿沼康弘

生産加工・工作機械部門講演会 : 生産と加工に関する学術講演会（一般社団法人日本機械学会） 2024.15 （ 0 ） A32 2024年

RISA grinding method using cerium oxide slurry has been proposed for grinding optical glass lenses. While the surface quality can be maintained at high feed rate and depth of cut, there is a problem that the profile error increases toward the center of the workpiece. The workpiece is SSG and the grinding wheel is a resin diamond wheel. In this study, the relationship between dwell time and depth of cut is experimentally investigated, and dwell time control method is proposed to achieve a uniform depth of cut. This method changes the rotation speed of workpiece to keep the slurry dwell time constant regardless of the distance from the center of workpiece. The effectiveness of this method was evaluated through orbicular machining tests. With conventional RISA grinding, the grinding trace becomes deeper as it gets closer to the center of the workpiece. By using dwell time control, the depth of the grinding trace is almost the same regardless of the distance from the center.

Influence of metal structure on mechanical characteristics in high-speed coating layer fabricated via Directed Energy Deposition

Hashimoto M., Koike R., Kakinuma Y., Hirono Y., Mori T., Oda Y.

Procedia CIRP 124 227 - 230 2024年

ISSN 22128271

Directed energy deposition (DED) is an additive manufacturing process wherein a metal powder is fed through a nozzle onto a baseplate, melted, and solidified using a laser. Potential applications of DED have been actively discussed. In this study, laser-based DED (DED-LB) was applied as a high-speed metal-coating technique to a cylindrical pipe. The mechanical properties of DED-fabricated objects were strongly affected by processing parameters such as laser power, powder feed rate, and rotational speed of the cylindrical pipe when using 20MnCr5 and M2 as the coating materials. Hardness measurements showed that the hardness of 20MnCr5 increased with a high heat input, whereas that of M2 increased with a low heat input. The two metals exhibited opposite trends in terms of hardness variation because of the differences in their transformation points. This study analyzed a layer coated with DED-LB from the viewpoint of metal morphology.

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High-speed laser metal deposition(HS-LMD)による高硬度鋼コーティングの現象解析

柿沼康弘

天田財団助成研究成果報告書（公益財団法人天田財団） 37 （ 0 ） 334 2024年

ISSN 24340723

Dispersion Engineering of Crystalline Microresonators for Optical Frequency Comb Generation beyond C-Band

Takabayashi R., Kodama H., Tanikawa K., Kakinuma Y., Tanabe T., Fujii S.

16th Pacific Rim Conference on Lasers and Electro-Optics, CLEO-PR 2024 2024年

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Dispersion engineering of crystalline microresonators for optical frequency comb generation beyond C-band

Takabayashi R., Kodama H., Tanikawa K., Kakinuma Y., Tanabe T., Fujii S.

Conference on Lasers and Electro-Optics/Pacific Rim, CLEO-PR 2024 in Proceedings 2024 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR) 2024年

回転エンコーダにおける角度検出信号の強度変化を利用した角度誤差計測方法の提案

佐藤彰彦, 柿沼康弘

精密工学会学術講演会講演論文集（公益社団法人精密工学会） 2023A （ 0 ） 517 - 518 2023年08月

回転エンコーダは、回転スケールの偏心や変形によって角度誤差が生じる。このとき、回転スケールの円筒面に角度信号の検出面を有する場合、偏心や変形によって検出面とセンサヘッドとのギャップ量が変化するため、センサヘッドが検出する角度信号の強度が変化する。本研究では、回転エンコーダを構成するセンサヘッドでこの強度変化を検出し、回転スケールの偏心や変形の量を逆算することで角度誤差を計測する方法を提案する。

超高速レーザークラッディングにおけるレーザー再溶融処理の応用

橋本昌征, 小池綾, 柿沼康弘, 森貴則, 廣野陽子, 小田陽平

精密工学会学術講演会講演論文集（公益社団法人精密工学会） 2023A （ 0 ） 623 - 624 2023年08月

単結晶フッ化マグネシウムの楕円振動切削における振動条件と臨界切り込み深さの関係

児玉耀, 松田莞, 藤井瞬, 田邉孝純, 柿沼康弘

精密工学会学術講演会講演論文集（公益社団法人精密工学会） 2023S （ 0 ） 246 - 247 2023年03月

より優れた光コムや光センサの開発に向けて，高性能な微小光共振器が求められている．光学特性に優れた単結晶MgF2を超精密切削することで実現できる可能性があるが，硬脆材かつ異方性を有するため微小き裂のない表面品位を維持することが難しい．そこで，本研究では楕円振動切削を適用することで，臨界切り込み深さの向上を目指した．加工面や切りくず観察を通して，振動条件が臨界切り込み深さに与える影響を調べた．

Machine Learning-Based Shape Error Estimation Using the Servomotor Current Generated During Micro-Milling of a Micro-Lens Mold

Mizuhara K., Nakamichi D., Yanagihara W., Kakinuma Y.

International Journal of Automation Technology （富士技術出版株式会社） 17 （ 2 ） 92 - 102 2023年03月

ISSN 18817629

The demand for the mass production of micro-lens arrays (MLAs) is increasing. An MLA is fabricated through an injection molding process, and its mold is manufactured by a five-axis high-precision machine tool using a small diameter endmill. A visual exam-ination is not available to judge the quality of the mold while machining. Therefore, an effective process monitoring technology must be developed. A promising approach is to apply a servomotor current to in-process monitoring because as long as the servomotor works well, no external sensors, capital investment, or maintenance processes are required. From this per-spective, a machine learning-based shape error estimation method using only the servomotor current is proposed. To explore the relationship between the motor current generated during micro-milling and the shape error of the mold, the servomotor current in X-, Y-, and Z-axes was recorded, and the corresponding shape error of the MLA mold was measured after ma-chining. Input data were prepared by converting time-domain servomotor current data to frequency-domain data using short-time Fourier transform and reduc-ing the dimensions of the data via principal compo-nent analysis. In terms of a meaningful label for the output data, the average shape error in the machined area corresponding to each window was provided. The input/output relationships were used to train five dif-ferent machine learning models, and the accuracy of shape error estimation using each model was evalu-ated. In addition, the estimation accuracies using the X-, Y-, and Z-axes were compared to find the axis that senses the shape error with the highest accuracy. The results show that the non-linear method using the X-axis servomotor current information closest to the machining point achieved the highest shape error estimation accuracy.

Model-based analysis of temperature-dependent dynamics in CFRP spindle unit

Kato M., Kakinuma Y.

CIRP Annals 72 （ 1 ） 337 - 340 2023年01月

ISSN 00078506

The application of CFRP to machine tool structures can potentially improve their dynamic characteristics and energy efficiency owing to its highly specific material properties. The different thermal characteristics of CFRP and steel in spindle units likely induce unique thermal deformation, which affects the bearing dynamics. This research proposes a modeling method of CFRP spindle unit dynamics via generalized multipoint receptance coupling with contact characteristics at the spindle-holder interface. The temperature-dependent mechanical properties are analyzed by parameter identification from the model. The translational stiffness and damping of bearings in the CFRP spindle increase with temperature increase at high rotational speed.

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柿沼 康弘

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柿沼　康弘

論文 - 柿沼　康弘