Generalization of Uncertainty Models in Stochastic Optimal Control and Its Application to Robust Trajectory Design

• Project/Area Number: 19K15214
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 24010:Aerospace engineering-related
• Research Institution: Japan Aerospace EXploration Agency
• Principal Investigator: Ozaki Naoya 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 特任助教 (90836222)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000); Fiscal Year 2022: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2021: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 軌道力学 / 確率制御 / ロバスト制御 / ミッション設計 / Uncertainty / 不確定性 / 最適制御 / 軌道最適化 / 軌道 / Trajectory / Trajectory Optimization / Stochastic Control / Stochastic Cotnrol / 不確定性評価 / 微分動的計画法

Outline of Research at the Start

惑星探査ミッションにおいて，いかに不確定性を評価し，いかに予め対処策を施しておくかはミッションの成功率を高める上で重要な課題である．研究代表者らは，先行研究として，確率微分動的計画法(SDDP)を確立し，不確定性に対してロバストな軌道設計手法を実現した．しかし，先行研究のSDDPはガウス分布で表現可能な不確定性に限定されており，実ミッションへの適用性が乏しい．本研究では，ガウス分布以外の一般の確率分布の不確定性を扱うために，SDDPを拡張することを目的とする．また，2020年代初旬に打上げ予定の実ミッションの軌道設計問題に対して，提案手法を適用することで，その実用性・普遍性を確認する．

Outline of Final Research Achievements

In deep space exploration missions, evaluating the effects of uncertainties and designing trajectories that are robust against uncertainties is one of the most important issues to improve the success rate of space missions. In this study, we established a stochastic trajectory design method for spacecraft trajectory design problems that is robust against uncertainties by using the unscented transform. To further extend the uncertainty model, a robust orbital control method considering general stochastic models such as general gamma distribution is established using planetary orbit injection as an example problem. These robust trajectory design methods were applied to actual missions to be launched by JAXA, such as MMX (Martian Moons eXploration) mission and DESTINY+ (Demonstration and Experiment of Space Technology for INterplanetary voYage with Phaethon fLyby and dUst Science) mission, and their practicality was demonstrated.

Academic Significance and Societal Importance of the Research Achievements

軌道設計分野の研究において，不確定性が与える影響度を評価する研究は多いが，その不確定性の影響を考慮して軌道設計を行う研究は更に難易度が高く，研究例が少ない．一方，制御分野の研究においては，非線形確率制御問題を解くための手法は研究されているが，それらは制約条件・大規模最適化の観点から軌道設計問題への適用性が乏しい．本研究成果を通して，軌道設計分野において，「確率的軌道設計」という新たな研究分野が拓かれた．また，DESTINY+を始めとして，実ミッションの軌道設計に関しても，不確定性を考慮した軌道設計のニーズが加速している．本研究成果は，これらの実ミッションを実現する上でのキー技術となる．

Research Products

• [Journal Article] Mission design of DESTINY+: Toward active asteroid (3200) Phaethon and multiple small bodies (2022)
  • Author(s): Ozaki Naoya、Yamamoto Takayuki、Gonzalez-Franquesa Ferran、Gutierrez-Ramon Roger、Pushparaj Nishanth、Chikazawa Takuya、Tos Diogene Alessandro Dei、?elik Onur、Marmo Nicola、Kawakatsu Yasuhiro、Arai Tomoko、Nishiyama Kazutaka、Takashima Takeshi
  • Journal Title: Acta Astronautica Volume: 196 Pages: 42-56
  • DOI: 10.1016/j.actaastro.2022.03.029
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Asteroid Flyby Cycler Trajectory Design Using Deep Neural Networks (2022)
  • Author(s): Ozaki Naoya、Yanagida Kanta、Chikazawa Takuya、Pushparaj Nishanth、Takeishi Naoya、Hyodo Ryuki
  • Journal Title: Journal of Guidance, Control, and Dynamics Volume: 45 Issue: 8 Pages: 1496-1511
  • DOI: 10.2514/1.g006487
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Extended Robust Planetary Orbit Insertion Method Under Probabilistic Uncertainties (2020)
  • Author(s): Ozaki Naoya、Chikazawa Takuya、Kakihara Kota、Ishikawa Akihiro、Kawakatsu Yasuhiro
  • Journal Title: Journal of Spacecraft and Rockets Volume: 57 Issue: 6 Pages: 1153-1164
  • DOI: 10.2514/1.a34755
  • Peer Reviewed
• [Journal Article] Tube Stochastic Optimal Control for Nonlinear Constrained Trajectory Optimization Problems (2020)
  • Author(s): Ozaki Naoya、Campagnola Stefano、Funase Ryu
  • Journal Title: Journal of Guidance, Control, and Dynamics Volume: 43 Issue: 4 Pages: 645-655
  • DOI: 10.2514/1.g004363
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] EQUULEUS Trajectory Design (2020)
  • Author(s): Kenshiro Oguri, Kenta Oshima, Stefano Campagnola, Kota Kakihara, Naoya Ozaki, Nicola Baresi, Yasuhiro Kawakatsu, and Ryu Funase
  • Journal Title: The Journal of the Astronautical Sciences Volume: - Issue: 3 Pages: 950-976
  • DOI: 10.1007/s40295-019-00206-y
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Mission Analysis for the EM-1 CubeSats EQUULEUS and OMOTENASHI (2019)
  • Author(s): Stefano Campagnola, Javier Hernando-Ayuso, Kota Kakihara, Yosuke Kawabata, Takuya Chikazawa, Ryu Funase, Naoya Ozaki, Nicola Baresi, Tatsuaki Hashimoto, Yasuhiro Kawakatsu, Toshinori Ikenaga, Kenshiro Oguri, Kenta Oshima
  • Journal Title: IEEE Aerospace & Electro. Systems Magazine Volume: 34 Issue: 4 Pages: 38-44
  • DOI: 10.1109/maes.2019.2916291
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Rapid Response Flyby Exploration using Deep Space Constellation deployed on Asteroid Flyby Cyclers (2023)
  • Author(s): Naoya Ozaki, Ryuki Hyodo, Yuki Takao, Darryl Z. Seligman, Michael E. Brown, Sonia Hernandez, Makoto Yoshikawa, Masaki Fujimoto
  • Organizer: IAA Planetary Defense Conference 2023
  • Int'l Joint Research
• [Presentation] A HYBRID MULTIPLE-SHOOTING APPROACH FOR COVARIANCE CONTROL OF INTERPLANETARY MISSIONS WITH NAVIGATION ERRORS (2023)
  • Author(s): Nicola Marmo, Alessandro Zavoli, Naoya Ozaki, and Yasuhiro Kawakatsu
  • Organizer: AAS/AIAA Astrodynamics Conference
  • Int'l Joint Research
• [Presentation] 深宇宙コンステレーションによる小天体マルチフライバイ探査構想 (2022)
  • Author(s): 尾崎直哉，高尾勇輝, 兵頭龍樹, 嶌生有理，他
  • Organizer: 宇宙科学技術連合講演会
• [Presentation] Mission Design of DESTINY+: Toward Active Asteroid (3200) Phaethon (2022)
  • Author(s): Naoya Ozaki
  • Organizer: International Astronautical Congress
  • Int'l Joint Research
• [Presentation] Extended Robust Planetary Orbit Insertion Method Under Probabilistic Uncertainties (2020)
  • Author(s): Naoya Ozaki, Takuya Chikazawa, Kota Kakihara, Akihiro Ishikawa and Yasuhiro Kawakatsu
  • Organizer: AIAA Scitech 2020 Forum
  • Int'l Joint Research
• [Presentation] Exploration of Long Time-of-Flight Three-Body Transfers Using Deep Reinforcement Learning (2020)
  • Author(s): Kanta Yanagida, Naoya Ozaki, Ryu Funase
  • Organizer: AIAA Scitech 2020 Forum
  • Int'l Joint Research
• [Presentation] Operations-driven Low-Thrust Trajectory Optimization with Applications to DESTINY+ (2020)
  • Author(s): Diogene A. Dei Tos, Takayuki Yamamoto, Naoya Ozaki, et al.
  • Organizer: AIAA Scitech 2020 Forum
  • Int'l Joint Research
• [Presentation] Tube Stochastic Optimal Control with Imperfect Information: Application to Navigation and Guidance Analyses (2020)
  • Author(s): Kota Kakihara, Naoya Ozaki, Akihiro Ishikawa, Takuya Chikazawa, Ryu Funase
  • Organizer: AIAA Scitech 2020 Forum
  • Int'l Joint Research
• [Presentation] DESTINY+ Low thrust trajectory design from Earth orbit to Asteroids flyby (2019)
  • Author(s): Takayuki Yamamoto, Naoya Ozaki, et al.
  • Organizer: 70th International Astronautical Congress
  • Int'l Joint Research
• [Presentation] Robust Planetary Orbit Insertion Algorithm Using Resonant Orbit Considering Missed-Thrust Uncertainty (2019)
  • Author(s): Naoya Ozaki, Takuya Chikazawa, Yasuhiro Kawakatsu
  • Organizer: Joint Symposium of 32nd ISTS & 9th NSAT
  • Int'l Joint Research