• I am ...

    Yuki Okafuji / 岡藤勇希

    Ph. D. in Engineering / 博士(工学)


    Assistant Professor at Ritsumeikan University


    Human Robotics Lab.​



    E-mail: yokafuji [at] fc.ritsumei.ac.jp


    A study on the integration of Control Engineering and Psychology

    What kind of information do drivers perceive, and what strategy do they use for their driving?


    In order to answer these questions, driver behaviour such as steering input has been analysed through various psychology experiments. On the other hand, we can analyse driver behaviour without the experimental environments if driver's mathematical models can be constructed. We have constructed driver's mathematical model inspired by the knowledge of various results in the psychological experiments, and then we have analysed driver behaviour based on the driver's mathematical models. I believe we will be able to answer "What is human-like driving?" by these approaches which tackle with both the psychological experiments and the driver models.


    Briefly, it is interesting that we can construct a mathematical model that can represent driver behaviour. My research aim is to find new knowledge through the fusion of both Control Engineering and Perceptual Psychology.

    Optical Flow Control (Engineering)

    Humans can perceive the direction of self-motion based on optic flow, and they can track a target path by matching their direction to a point of "they want to go" on the target path. This is a human (animal)-like control method. Therefore, we made a mathematical model of optic flow and introduced this human-like method into the vehicle steering control based on a nonlinear control method. From the results of the simulations and vehicle experiments, we confirmed this method is effective for the automated steering controller and can reproduce human's steering behaviour in terms of steering accuracy.

    Examine Influence of Optic Flow (Psychology)

    From the results of our proposed method, we got a hypothesis: the usefulness of a region of optic flow (for instance, far and near, or central and peripheral vision) for driver's steering behaviour is not consistent. Then, we made a unique simulation environment which can selectively mask either the optic flow or the road edge information. Then, we verified how this two information affects the steering performance of the driver within the scope of Two-point steering model. Amazingly, a part of the results is the same as the results produced by the optical flow control. This conclusion could give us some intuition: driver models capturing driver characteristics can figure out new driver behaviour even if we do not conduct the psychological experiments.



    • June 2017 - November 2017, Visiting Researcher, University of Leeds, UK
    • August 2018 - September 2018, Research Intern, CyberAgent AI Lab
      研究インターン,株式会社サイバーエージェント AI Lab
    • April 2018 - September 2018, JSPS Research Fellow (DC2), Kobe University
      日本学術振興会 特別研究員(DC2)(受入研究機関:神戸大学)
    • October 2018 - March 2019, JSPS Research Fellow (PD), Ritsumeikan University
      日本学術振興会 特別研究員(PD)(受入研究機関:立命館大学)
    • October 2018 - March 2019, Research Scientist, CyberAgent AI Lab
      リサーチサイエンティスト,株式会社サイバーエージェント AI Lab
    • November 2018 -March 2019, Visiting Researcher, Osaka University
    • April 2019 - Current, Assistant Professor, Ritsumeikan University


    • April 2007 - March 2012, Associate's Degree, Department of Mechanical and Electrical Engineering, National Institute of Technology, Tokuyama College, Japan
      徳山工業高等専門学校 機械電気工学科
    • April 2012 - March 2014, Bachelor's Degree, Department of Mechanical Engineering, Faculty of Engineering, Kobe University, Japan
      神戸大学 工学部機械工学科
    • April 2014 - September 2015, Master's Degree, Department of Mechanical Engineering, Graduate School of Engineering, Kobe University, Japan
      神戸大学 工学研究科機械工学専攻 修士課程
    • October 2015 - September 2018, Ph. D. Degree, Department of Mechanical Engineering, Graduate School of Engineering, Kobe University, Japan
      神戸大学 工学研究科機械工学専攻 博士課程
    • April 2016 - September 2018, Research Student, Graduate School of Science and Engineering, Ritsumeikan University, Japan
      立命館大学 理工学研究科 特別研究学生
    • September 2016 - February 2017, Visiting Research Student, Institute for Transport Studies, Faculty of Environment, University of Leeds, UK


    1. Y. Okafuji, C. D. Mole, N. Merat, T. Fukao, Y. Yokokohji, H. Inou, and R. M. Wilkie, “Steering bends and changing lanes: the impact of optic flow and road edges on two point steering control”, Journal of Vision, Vol. 18. No. 14, 2018, DOI: 10.1167/18.9.14
    2. Y. Okafuji, T. Fukao, Y. Yokokohji, H. Inou, “Design of a preview driver model based on optical flow”, IEEE Transaction on Intelligent Vehicles, Vol. 1, No. 3, pp.266-276,2016, DOI: 10.1109/TIV.2017.2658188
    3. Y. Okafuji, T. Fukao, H. Inou, “Development of automatic steering system by modeling human behavior based on optical flow”, Journal of Robotics and Mechatronics, Vol. 27, No. 2, pp.136-145, 2015, DOI: 10.20965/jrm.2015.p0136
    4. 伊能寛,深尾隆則,戸塚誠司,岡藤勇希,”オプティカル・フロー・モデルを利用した操舵制御システムの開発”,自動車技術会論文集,Vol. 46, No. 2, pp.443-448, 2015

    International Conference

    1. [Oral] Y. Okafuji, T. Fukao, H. Inou, “Theoretical Interpretation of Driver’s Gaze Considering Optic Flow and Seat Position”, IFAC Symposium on Analysis, Design, and Evaluation of Human-Machine Systems, Tallinn, Estonia, September 16-19, 2019 (to appear)

    2. [Oral] C. Mole, G. Markkula, O. Giles, Y. Okafuji, R. Romano, N. Merat, R. Wilkie, “Drivers fail to calibrate to optic flow speed changes during automated driving”, Driving Assessment Conference, New Mexico, USA, June 24-27, 2019 (to appear)

    3. [Demo] Y. Okafuji, J. Baba, J. Nakanishi, “Face-to-Face contact method for humanoid robots using face position prediction”, ACM/IEEE International Conference on Human-Robot Interaction, Daegu, Korea, March 2019

    4. [Oral] Y. Okafuji, C. D. Mole, R. M. Wilkie, N. Merat, “Examining how driver steering behaviour is affected by optic flow after resuming control from a highly automated vehicle”, The Human Factors and Ergonomics Society Europe Annual Meeting (HFES Europe), Rome, Italy, September 2017
    5. [Oral] Y. Okafuji, T. Fukao, Y. Yokokohji, H. Inou, “Optical flow-based control for automatic steering systems”, 2015 IEEE/SICE International Symposium on System Integration (SII2015), Japan, December 2015, DOI: 10.1109/SII.2015.7405027
    6. [Oral] H. Inou, T. Fukao, S. Totsuka, Y. Okafuji, “Development of Automatic Steering System Based on Optical Flow Model”, 12th International Symposium on Advanced Vehicle Control (AVEC’14), Japan, September 2014

    Invited Talks

    1. 岡藤勇希,”オプティカルフローに着目した自動車制御と人間の行動解析”,日本バーチャルリアリティ学会 第14回テレイグジスタンス研究会,2019年7月 (to appear)
    2. 岡藤勇希,”オプティカルフローに基づいたドライバモデル・ドライバの特性解析に関する研究”,自動車技術会 第5回ヒューマンファクター部門委員会,2018年12月

    Technical Report

    1. 岡藤勇希,” 自動/手動運転の切り替わり時におけるオプティックフローに影響されるドライバの操舵特性の解析”, 神戸大学大学院工学研究科・システム情報学研究科紀要,第9号,2017
    2. 伊能寛,深尾隆則,戸塚誠司,岡藤勇希,”オプティカル・フロー・モデルを利用した操舵制御システムの開発”,デンソーテクニカルレビュー,Vol. 20, pp.123-130, 2015

    Domestic Conference (in Japan)

    1. [Poster] 岡藤勇希,​馬場惇,中西惇也,倉本到,”ヒューマノイドロボットのための顔位置予測を用いた人の顔追従制御”,HAIシンポジウム,2019年3月
    2. [Oral] 岡藤勇希,深尾隆則,伊能寛,”座席位置の影響を考慮したドライバの注視点に関する理論的解釈”,自動車技術会秋季大会学術講演会,2018年10月​
    3. [Poster] ​岡藤勇希,深尾隆則,横小路泰義,伊能寛,”車両の横方向制御の相関に関する考察”,ロボティクス・メカトロニクス講演会 (ROBOMECH2017),2017年5月
    4. [Oral] ​岡藤勇希,深尾隆則,横小路泰義,伊能寛,”オプティカルフローに基づく自動操舵のための実環境計測を考慮したシミュレータ構築”,システム制御情報学会研究発表講演会 (SCI’16),2016年5月
    5. [Oral] ​岡藤勇希,深尾隆則,横小路泰義,伊能寛,”カメラ運動を考慮したオプティカルフローに基づく自動操舵システム”,第58回自動制御講演会,2015年11月
    6. [Oral] ​岡藤勇希,深尾隆則,横小路泰義,伊能寛,”オプティカルフローに基づいた前方注視モデルの理解と応用”,システム制御情報学会研究発表講演会 (SCI’15),2015年5月
    7. [Poster]岡藤勇希,深尾隆則,伊能寛,”オプティカルフローに基づいた自動操舵システム”,ロボティクス・メカトロニクス講演会 (ROBOMECH2014),2014年5月

    8. [Oral] 伊能寛,深尾隆則,戸塚誠司,岡藤勇希,”オプティカル・フロー・モデルを利用した操舵制御システムの開発”,自動車技術会春季講演会,2014年5月



    1. March 2019, Most Impressive Poster Award in HAI Symposium 2018
      HAIシンポジウム2018 最優秀ポスター賞
    2. June 2017, Kobe University Outstanding Student Award
    3. May 2016, The Excellent Student Presentation in the 60th Annual Conference of the Institute of Systems, Control, and Information Engineers
      第60回システム制御情報学会研究発表講演会 SCI学生発表賞
    4. May 2016, ISCIE Encouragement Award from the Institute of Systems, Control and Information Engineers
      システム制御情報学会賞 奨励賞
    5. March 2016, Miura Prize (Excellent Postgraduate Student Award) from The Japan Society of Mechanical Engineers
      日本機械学会 三浦賞
    6. December 2015, IEEE/SICE International Symposium on System Integration, Best Paper Award Finalist
    7. March 2014, Isamu Yamashita Prize (Excellent Undergraduate Student Award) from The Japan Institute of Marine Engineering
      日本マリンエンジニアリング学会 山下勇賞​

    8. May 2014, JSAE Annual Congress (spring) Excellent Technical Paper Presentation Awards


    1. April 2018 - March 2019, JSPS Research Fellowship
      日本学術振興会 特別研究員奨励費
    2. April 2017 - March 2022,立命館大学R-GIRO「次世代人工知能と記号学の国際融合研究拠点」分担研究員
    3. September 2016 - February 2017, Kobe University, Graduate School of Engineering, Premium Program
      神戸大学大学院工学研究科 プレミアム・プログラム