Transactions of the Japan Society for Aeronautical and Space Sciences最新文献_第8页

µm-class Control of Relative Position and Attitude for a Formation Flying Synthetic Aperture Telescope with Micro-satellites 微卫星编队飞行合成孔径望远镜相对位置和姿态的µm级控制

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/TJSASS.64.101

Ryo Suzumoto, S. Ikari, N. Miyamura, S. Nakasuka

{"title":"µm-class Control of Relative Position and Attitude for a Formation Flying Synthetic Aperture Telescope with Micro-satellites","authors":"Ryo Suzumoto, S. Ikari, N. Miyamura, S. Nakasuka","doi":"10.2322/TJSASS.64.101","DOIUrl":"https://doi.org/10.2322/TJSASS.64.101","url":null,"abstract":"Earth remote sensing from geostationary orbit (GEO) can realize high temporal resolution; however, the spatial resolution is commonly worse than observation from low Earth orbit. In order to achieve high-frequency and high-resolution GEO remote sensing, a “Formation Flying Synthetic Aperture Telescope (FFSAT)”with multiple micro-satellites has been proposed. The FFSAT greatly improves the spatial resolution using a synthetic aperture technique. Therefore the relative positions and attitudes between the optical units of each satellite must be controlled with an accuracy better than 1/10 of the observation wavelength. However, even mm-class accuracy control has not been demonstrated on orbit. As a first practical application of the FFSAT, a forest fire monitoring mission using infrared rays is being considered, in which control accuracy requirement is relaxed as its wavelength is longer than visible light. We proposed a point spread function optimization method for controlling formation flying with an accuracy of approximately 1–1,000 times the wavelength (1 μm–1mm) in the absence of sensors, which can measure absolute distance with μm-accuracy. The effectiveness of the method was demonstrated through simulations in which the satellites’ system and the optical system are coupled. The simulation results show that the method can control the formation within the wavelength order.","PeriodicalId":54419,"journal":{"name":"Transactions of the Japan Society for Aeronautical and Space Sciences","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68662531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Effect of Cutbacks on Tip Leakage Flow and Film-Cooling Effectiveness of a Turbine Blade Tip under Relative Moving Condition 相对运动条件下切量对涡轮叶片叶尖泄漏流动及气膜冷却效果的影响

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/tjsass.64.293

F. Cheng, Jing-zhou Zhang, Jingyang Zhang, Yuyan Zhang

引用次数: 1

Spatio-Temporal Path Planning for Lunar Polar Exploration with Robustness against Schedule Delay 基于时序延迟鲁棒性的月球极地探测时空路径规划

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/tjsass.64.304

H. Inoue, S. Adachi

{"title":"Spatio-Temporal Path Planning for Lunar Polar Exploration with Robustness against Schedule Delay","authors":"H. Inoue, S. Adachi","doi":"10.2322/tjsass.64.304","DOIUrl":"https://doi.org/10.2322/tjsass.64.304","url":null,"abstract":"This paper presents a method to obtain a robust optimal path in an environment with time-varying safety features, such as in the lunar polar region. In designing the path for planetary exploration rovers, we must consider various safety conditions, such as terrain hazards, illumination, and communication visibility to the Earth. Some of the safety features are time-varying, and the optimal path should be searched for both the spatial direction and the temporal direction. In addition, there is no guarantee that all of the sequences will be successfully executed on time due to misoperation, failures, or trou-ble. Therefore, a path that is robust against the delay must be planned so as to guarantee safety even when behind schedule. The authors propose an algorithm called “ Robust Spatio-Temporal Path Planner for the Planetary Rover (R OBUST -STP3R) ” to obtain a path that is robust against schedule delay in a time-varying environment. This method de ﬁ nes a cost function that consists of the distance as well as the region type cost. To add robustness against schedule delays, the authors consider a weighted summation of the time-varying region type cost with regard to the temporal direction. The e ﬀ ectiveness of the proposed method is demonstrated through use in a simulated lunar polar exploration exercise.","PeriodicalId":54419,"journal":{"name":"Transactions of the Japan Society for Aeronautical and Space Sciences","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68663503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Safety Analysis of Reduced Route Spacing for RNP 2 under Radar Environment 雷达环境下RNP - 2减小路由间距的安全性分析

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/TJSASS.64.165

Ryota Mori

引用次数: 0

Performance of a Miniature Hall Thruster and an In-house PPU 微型霍尔推力器和内部PPU的性能

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/TJSASS.64.189

Masatoshi Chono, N. Yamamoto, R. Tsukizaki, Takato Morishita, K. Kubota, Shinatra Cho, K. Kinefuchi, Toru Takahashi

引用次数: 2

Temperature Measurement of HEK-X Expansion Tube Flow by Laser Absorption Spectroscopy 激光吸收光谱法测量HEK-X膨胀管流动温度

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/TJSASS.64.193

M. Matsui, R. Kobayashi, Takashi Okamoto, Kazuhiko Yamada, H. Tanno

引用次数: 2

CFD Study on Penetration of Sonic Boom Applying a Wavy-Water Model 基于波浪-水模型的音爆侵彻CFD研究

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/tjsass.64.273

Po-Hsun Chen, Kojiro Suzuki

{"title":"CFD Study on Penetration of Sonic Boom Applying a Wavy-Water Model","authors":"Po-Hsun Chen, Kojiro Suzuki","doi":"10.2322/tjsass.64.273","DOIUrl":"https://doi.org/10.2322/tjsass.64.273","url":null,"abstract":"The penetration of sonic booms into the ocean and an estimation of the extent of their in ﬂ uence are important topics for supersonic and hypersonic aviation. Most prior studies were conducted assuming a ﬂ at-water surface. However, it is known that the e ﬀ ect of the surface waviness is not negligible in the case of real ocean environments. In the present study, the numerical method analyzes the two-dimensional ﬂ ow ﬁ eld of sonic boom propagation across the air and water is proposed. When the ﬂ ight Mach number of an aircraft is higher than 4.4, the underwater ﬂ ow ﬁ eld becomes supersonic, and a sonic boom is generated there. The numerical results show that, in the underwater subsonic regime, the penetrating waves have the form of evanescent waves under either ﬂ at or wavy water surface, but the waviness-induced ripples with the smaller decay rate are responsible for deeper penetration. In contrast, in the supersonic underwater ﬂ ow, the surface waviness hardly a ﬀ ects the penetration depth of underwater sonic booms, although it can slightly weaken the boom intensity. The e ﬀ ect of the amplitude of surface waviness on the underwater penetrating wave was also investigated. :","PeriodicalId":54419,"journal":{"name":"Transactions of the Japan Society for Aeronautical and Space Sciences","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68663254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Abstracts of the Papers Published in Journal of the Japan Society for Aeronautical and Space Sciences (Vol. 69, No. 4, Aug. 2021) 《日本航空航天学会学报》(第69卷第4期，2021年8月)论文摘要

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/tjsass.64.292

引用次数: 0

Aeroacoustic Fields of Supersonic Twin Jets at the Ideally Expanded Condition 理想膨胀条件下超音速双射流的气动声场

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/tjsass.64.312

Y. Ozawa, T. Nonomura, Y. Saito, K. Asai

引用次数: 6

Research on the Influence of Key Parameters on the Aerodynamic Characteristics of Shaftless Ducted Rotors 关键参数对无轴导管转子气动特性的影响研究

IF 1.1 4区工程技术

Transactions of the Japan Society for Aeronautical and Space Sciences Pub Date : 2021-01-01 DOI: 10.2322/tjsass.64.40

Suiyuan Shen, Qing-Hua Zhu, Jinfa Xu

{"title":"Research on the Influence of Key Parameters on the Aerodynamic Characteristics of Shaftless Ducted Rotors","authors":"Suiyuan Shen, Qing-Hua Zhu, Jinfa Xu","doi":"10.2322/tjsass.64.40","DOIUrl":"https://doi.org/10.2322/tjsass.64.40","url":null,"abstract":"The shaftless ducted rotor (SDR) is a new type of ducted rotor system built using a ducted-rotor-motor integration design. Based on unstructured sliding grid technology, the e ﬀ ects of four key parameters, such as rotor disk height, number of blades, the center hole radius and the blade root mounting angle, on the aerodynamic characteristics of the SDR were investigated. The calculation results show that the thrust performance gradually improves as the rotational speed increases. It is di ﬀ erent from traditional ducted rotors where the rotor is installed near the lip of the duct to obtain the optimal aerodynamic performance, the rotor of the SDR is installed away from the duct entrance to obtain the best aerodynamic performance. Additionally, the number of blades is increased to improve peak thrust and ducted thrust performance; however, this results in decreasing the power load. The central hole radius of the SDR should not be too small, as this can result in an excessive blocking e ﬀ ect when the central air ﬂ ow passes through the paddle. Finally, when the rotational speed is con-stant, increasing the blade root mounting angle results in a large increase in thrust, but this decreases the power load as well.","PeriodicalId":54419,"journal":{"name":"Transactions of the Japan Society for Aeronautical and Space Sciences","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68663770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2