NOZAKI, Takahiro

写真a

Affiliation

Faculty of Science and Technology, Department of System Design Engineering (Yagami)

Position

Associate Professor

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Career 【 Display / hide 】

  • 2012.04
    -
    2014.03

    The Japan Society for the Promotion of Science, Research Fellow (DC1)

  • 2014.04
    -
    2015.03

    Yokohama National University, Assistant Professor

  • 2015.04
    -
    2018.03

    Department of System Design Engineering, Keio University, Assistant Professor

  • 2018.04
    -
    2022.03

    Department of System Design Engineering, Keio University, Assistant Professor

  • 2019.10
    -
    2021.04

    Department of Mechanical Engineering, Massachusetts Institute of Technology, Visiting Scientist

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Academic Background 【 Display / hide 】

  • 2006.04
    -
    2010.03

    Keio University, Faculty of Science and Technology, Department of System Design Engineering

    University, Graduated

  • 2010.04
    -
    2012.03

    Keio University, Graduate School, Division of Science and Engineering, School of Integrated Design Engineering

    Graduate School, Completed, Master's course

  • 2012.04
    -
    2014.03

    Keio University, Graduate School, Division of Science and Engineering, School of Integrated Design Engineering

    Graduate School, Completed, Doctoral course

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Academic Degrees 【 Display / hide 】

  • Ph. D., Keio University, Coursework, 2014.03

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Research Areas 【 Display / hide 】

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Power engineering

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Control and system engineering

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Electron device and electronic equipment

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Research Keywords 【 Display / hide 】

  • Power Electronics

  • Robotics

  • Control Engineering

  • Electroaerodynamic Propulsion System

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Books 【 Display / hide 】

  • Force/Tactile Sensation for Contact Task

    K Ohnishi, T Nozaki, Y Saito, H Asai, T Kitamura, Emotional Engineering: Vol.10: Emotional Engineering as a Culture for 22nd Century Civilisation, 2025.01

    　View Summary

    The sensation of the contact is indispensable for the contact task. In this chapter, the instantaneous value of the force/tactile sensation is defined and quantified as the ratio of the force and the velocity. The absolute value is also defined by the rms value with the definition of the time window. This value is extended to the frequency domain with the four parameters, which are also the admittance of the contact object. The operating point of the contact task in the force–velocity plane should be the crossing point of the characteristics of the actuation and the mechanical load. This is the same as the coincidence of the force/tactile sensation with the admittance of the contact object. Since the admittance of the contact object is varied according to the motion, such a coincidence should be maintained by the feedback mechanism. As a result, the feedforward system to define the mission of the contact and the feedback system for the matching the admittance is the essential structure of the contact task. That is shown by the figures and the experimental results.

  • ハプティクスとその応用―力触覚の伝送・記録・再現・表示―

    2022.12

    Scope: 第Ｉ編　ハプティクスの原理、第2章　ハプティクス技術論

  • ハプティクスとその応用―力触覚の伝送・記録・再現・表示―

    2022.12

    Scope: 第IV編　ハプティクスの応用、第8 章　双腕型ロボット「GP-Arm

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Papers 【 Display / hide 】

  • ANEMONE: a framework for three-dimensional simulations of solid-state electroaerodynamic propulsion systems

    H Shibata, S Shimizu, T Nozaki

    Computer Physics Communications, 109749 315 2025.10

    ISSN  00104655

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    Solid-state electro-aerodynamic propulsion systems are devices that utilize atmospheric pressure corona discharge and have been actively researched in recent years as a means of achieving silent drones. However, these systems contain multiple, widely disparate time and spatial scales. Therefore, the governing equations of the systems, a three-component plasma fluid model that considers the presence of electrons, positive ions, and negative ions, constitute a stiff non-linear system of partial differential equations, challenging to solve. Here, we have developed an ANEMONE simulator capable of numerically estimating the corona inception voltage and energy conversion efficiency in three-dimensional solid-state electro-aerodynamic propulsion systems. Specifically, on the basis of the governing equations, we adopted the method of characteristics and the perturbation method to obtain the sub-problems. Furthermore, we have successfully obtained the integral equations, making the sub-problems easier to solve. Finally, we validated the prediction results based on the theoretical results in a previous study. Remarkably, ANEMONE is the first simulator in the world which predicted the two representative performance (i.e., the corona inception voltage and energy conversion efficiency) of fully three-dimensional propulsion systems. Program summary: Program Title: ANEMONE CPC Library link to program files: https://doi.org/10.17632/2sxsg2pmyp.1 Licensing provisions: MIT Programming language: C++ Nature of problem: Solid-state electro-aerodynamic propulsion system [1] ionizes the ambient air and can propel silent drones. For the rapid-prototyping of the system, it is important to utilize numerical simulation, but the spatial and temporal scales of the system are diverse; hence, the corresponding governing equations (e.g. the three-component plasma fluid model which can simultaneously consider electrons, positive and negative ions) are too stiff to solve. For example, the overall spatial scale of the system is the order of meters, while the scale of the electrodes is the order of micrometers. Moreover, the ions move between electrodes in the order of milliseconds, while the Maxwell dielectric relaxation time scale is in the order of nanoseconds. Solution method: For the issue of the spatial scales, we adopt a three-dimensional hierarchical Cartesian grid method together with the adaptive mesh refinement method. Moreover, this leads fully automatic mesh generation and ensures the grid convergence. For the issue of the temporal scales, we adopt the perturbation method [2] combined with the method of characteristics. This can decompose the original problem into many subproblems easy to solve. References: [1] Haofeng Xu, et al., Flight of an aeroplane with solid-state propulsion, Nature 563 (7732) (2018) 532–535. [2] Hisaichi Shibata, et al., Performance prediction of electrohydrodynamic thrusters by the perturbation method, Phys. Plasmas 23 (5) (2016).

  • On the integral form of a three-component plasma fluid model

    H Shibata, T Nozaki

    Physics of Plasmas 32 (6) 32 ( 6 )  2025.06

    ISSN  1070664X

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    Solid-state propulsion is a near-silent plasma thruster that can be mounted on drones. It generates thrust by inducing corona discharge between asymmetric electrodes, which ionizes the surrounding air and accelerates it as a plasma jet. For rapid societal implementation, numerical analysis is crucial and numerous studies have addressed this aspect. However, high-thrust solid-state propulsion systems, such as MSD (multistage ducted thrusters), exhibit complex plasma flows in which both positive and negative corona discharges occur simultaneously. Therefore, MSD analysis requires the adoption of a plasma three-component model that simultaneously accounts for electrons, positive ions, and negative ions. However, because this model involves phenomena with disparate time and spatial scales, it requires substantial computational costs. In this study, different from previous research, we attempt to reduce computational cost and enhance numerical stability by first transforming the partial differential equations representing the three-component model into ordinary differential equations using the method of characteristics and then expressing those in integral form through manual calculation. The derived integral solution was validated by comparing it with experimental results from negative corona discharge within a coaxial cylinder electrode and point-to-plate electrodes and negative corona discharge around a single-stage thruster, confirming that the simulation's predictive accuracy is reliable.

  • Thrust Control with Switching in Electrodynamic Propulsion Systems with Corona Discharge

    S Yashita, H Katagiri, T Kitamura, T Nozaki

    2025 IEEE International Conference on Mechatronics (ICM), 1-6  2025

    ISSN  2837-1143

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    Electroaerodynamics (EAD) is one phenomenon that manipulates gas with high voltage. Corona discharge is a typical example and is known to produce thrust quietly without moving parts. Therefore, it is expected to be utilized in various ways, such as a thrust source of drones. As thrust with corona discharge depends on the applied voltage, it is necessary to manipulate the applied voltage for thrust control. However, large-scale systems require several tens of kV, and there is little adequate research on these systems. Thus, an adequate switching method is essential, and it is also crucial to elucidate the effect of switching on thrust. Hence, this study conducted thrust control with corona discharge and analyzed the influence of switching on thrust. Specifically, a resistor is connected in series to the electrode, and a switching element is connected in parallel with the resistor. The proposed method stabilizes and limits the voltage applied to the switching element and effectively controls the thrust and the voltage applied to the electrode. Two experiments were conducted to reveal the electrical characteristics of the electrode in corona discharge and confirm the effectiveness of the proposal. The first experiment showed the potential of switching for the electrode with corona discharge on the collector side. Moreover, the second experiment demonstrated that the proposed switching method worked properly, and thrust can be controlled by changing the duty ratio of switching. The achievements of this study are expected to control levitation systems EAD, such as corona discharge, and realize stable control.

  • Positioning Control for Voice Coil Motor Using Unbalanced Multilevel Inverter Topology

    G Takei, H Obara, R Haneda, T Nozaki

    2025 IEEE International Conference on Mechatronics (ICM), 1-6  2025

    ISSN  2837-1143

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    This article proposes a new multi-level inverter (MLI) based on flying capacitor inverter (FCI), with focused on high-precision positioning control for a voice coil motor (VCM). Multi-level inverters (MLIs) have the characteristic that increasing the number of output voltage levels reduces the output voltage error. However, as the number of levels increases, the number of circuit elements increases, and the circuit becomes more complex. In addition, the output voltage amplitude for each level is constant in conventional inverters. As a result, such as high-precision positioning control of VCM, designing an appropriate inverter for a reference wave that contains a large amount of low-voltage components increases the number of circuit elements. Therefore, this paper proposes a MLI with two unbalanced dc-input voltages, referred to as unbalanced MLIs (UMLIs) hereinafter. This topology uses two different dc-input voltages, and it is possible to reduce the output voltage level in extremely low-voltage range compared to other voltage levels. Simulation results when the high-precision positioning control of the VCM confirm that the proposed UMLIs improves the control performance compared to the conventional FCIs with equal number of output voltage levels and uniform level widths.

  • Investigation of Relationship between Electrode Integration Method and Force-to-Volume Ratio in Force Generation System Using Corona Discharge

    H Katagiri, S Yashita, T Kitamura, T Nozaki

    2025 IEEE International Conference on Mechatronics (ICM), 1-6  2025

    ISSN  2837-1143

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    A force generation mechanism utilizing corona discharge has the advantages of being lightweight, compact, and having no moving parts. The general structure of an electrode used to generate corona discharge is a wire on the high-voltage side and a flat plate on the ground side. To gain greater force generated by corona discharge, it is necessary to install and integrate a large number of electrodes. However, if a large number of electrodes are integrated, the required volume will increase. Therefore, a method of integrating the electrodes to increase the force-to-volume ratio is needed. Therefore, this paper comprehensively examines the two-dimensional arrangement of electrodes on the ground side and investigates the relationship with the force-to-volume ratio. Specifically, the force-to-volume ratio was investigated when the ground side was made of hollow hexagons, squares, or triangles compared to the wire-plate electrode. Also, since it is known that the force is more significant when needles are used on the high-voltage side rather than wires, the high-voltage side was made into a needle for electrodes with hollow polygons. The experimental results show that the force-to-volume ratios of the needle-hollow polygon electrodes were larger when the applied voltage was low, around 20 kV, and that of the wire-plate electrode was larger when the applied voltage was higher than 30 kV. These results show the relationship between the method of integrating the electrodes and the force-to-volume ratio, which was unknown in corona discharge. They can be used as a reference in the design of actuators.

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Papers, etc., Registered in KOARA 【 Display / hide 】

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • Japan-U.S. International Joint Research and Development of a Solid-State Electroaerodynamic Propulsion System Using High Voltage

    2025.01
    -
    2027.12

    New Energy and Industrial Technology Development Organization, ＮＥＤＯ先導研究プログラム／エネルギー・環境分野における革新的技術の国際共同研究開発, Other, Principal investigator

  • Development of a robot for single-cell surgery with tactile feedback

    2024.06
    -
    2027.03

    Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory), No Setting

    　View Summary

    細胞やその小器官から情報を得る手段として、単一細胞手術が近年注目されている。しかし、これまでに研究されてきた方法では、人の手で直接複雑な操作を施すことはできない。本研究は、触覚フィードバック付き単一細胞手術用ロボットの開発を目的とし、研究代表者らが培ってきた力触覚伝送技術（リアルハプティクス）による超微小手術用ロボット開発のノウハウをもとに、まずは基礎的知見を得ることを目指す。本研究の遂行により、複雑な細胞手術や新たな細胞手術法の開発への道が開ける。さらに、細胞研究を起点に生命科学全体の体系や方向性を大きく変革させること、およびロボット工学へ再応用することが期待できる。

  • Development of dental implant drill with bone quality change detection mechanism

    2023.04
    -
    2027.03

    Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), No Setting

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    歯科インプラント治療は、天然歯への負担が少なく、咀嚼機能や審美性に多くの利点を持つ優れた治療法である。しかし、歯槽骨高の低い上顎臼歯部の埋入においては、上顎洞粘膜損傷の危険性を伴う。そこで本研究では、上顎洞底の皮質骨のみを貫通した時点で上顎洞粘膜の損傷なく停止する新たなサイナスリフトシステムを構築する。目的達成のためA. 切削抵抗とドリル形状・回転速度との関係性解明、B. 切削抵抗測定アルゴリズムの開発、C. 骨質変化検出機構の開発、D. ハンドピース型歯科インプラントドリル機器のハード製作、E. 自動停止制御の実装を実施したのち、F. in vivo 実証実験により、有用性を確認する。

  • 電気的特性に基づく再生誘導血小板の品質評価に基づくパーソナル治療薬の開発

    2023.04
    -
    2026.03

    Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), No Setting

    　View Summary

    血小板は核を持たないことから、再生医療材料の分野において、臨床応用面で有利である。皮下脂肪組織由来血小板は、iPS細胞由来血小板より、安全面・費用面で、より臨床応用のハードルが低い素材として注目されている。これまでの成果を元に、われわれはは、いち早く皮下脂肪組織由来血小板を創傷治癒薬として臨床応用するため、治験を前提としており、具体的な治験プロトコールの策定・必要な客観的評価基準の確立・治験で使用する脂肪細胞ソースの確保を進めている。本研究では、特に誘導血小板の製品としての品質保証による安全性を担保する技術開発を行い、第一種再生医療等技術として完成させる。

  • 安全で確実な山岳トンネル工事を実現する遠隔操作システムの開発

    2022.03
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    2027.03

    New Energy and Industrial Technology Development Organization, Intensive Support Program for Young Promising Researchers, Other, Principal investigator

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Awards 【 Display / hide 】

  • Best Paper Award (Engineering)

    2024.11, The Japan Society of Computer Aided Surgery

    Type of Award： Award from Japanese society, conference, symposium, etc.

  • The 36th Young Investigation Excellence Award

    2021.09, The Robotics Society of Japan

    Type of Award： Award from Japanese society, conference, symposium, etc.

  • Excellent Paper Presentation Award

    2021.03, The Institute of Electrical Engineers of Japan

    Type of Award： Award from Japanese society, conference, symposium, etc.

  • Best Paper Award

    2021.03, The 9th IIAE Int’l Conf. on Ind. Application Engineering 2021

    Type of Award： Award from international society, conference, symposium, etc.

  • Excellent Paper Presentation Award

    2021.01, The Institute of Electrical Engineers of Japan

    Type of Award： Award from Japanese society, conference, symposium, etc.

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Courses Taught 【 Display / hide 】

  • SEMINAR IN SYSTEM DESIGN ENGINEERING

    2025

  • POWER ELECTRONICS

    2025

  • LABORATORIES IN SYSTEM DESIGN ENGINEERING 2)

    2025

  • LABORATORIES IN SCIENCE AND TECHNOLOGY

    2025

  • INDEPENDENT STUDY ON INTEGRATED DESIGN ENGINEERING

    2025

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