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Physics-based model for boundary layer transition prediction in a wide speed range

Chinese Journal of Aeronautics 2022年第9期35卷 143-159页

作者： Zaijie LIU Yuhan LU Sheng WANG Qiang WANG Chao YAN School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083 China Research Institute of Navigation and Control Technology Beijing 100089China China Academy of Aerospace Aerodynamics Beijing 100074China

A new physics-based model employing three transport equations is developed for the simulation of boundary layer transitions in a wide speed range. The laminar kinetic energy is used to represent pretransitional streamwise velocity fluctuations, taking account of different instability modes. The fluctuation velocity components normal to the streamwise direction are modeled by another transport equation. Transition is triggered automatically with the development of the pretransitional velocity fluctuations. In the fully turbulent region, the model reverts to the k-ω turbulence model. Different test cases, including subsonic, supersonic and hypersonic flows around flat plates, airfoils and straight cones, are numerically simulated to validate the performance of the model. The results demonstrate the excellent predictive capabilities of the model in different paths of transition. The model can serve as a basis for the extension of additional transition mechanisms,such as rotation and curvature effects, roughness-induced transition and crossflow-induced transition.

关键词： Boundary layer High-speed Physics-based Transition model Transitional flow

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High-Precision Matching of Multisource Remote Sensing Images Considering Geometric Constraints

High-Precision Matching of Multisource Remote Sensing Images...

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2024 Applied Optics and Photonics China: Optical Sensing, Imaging technology, and Applications, AOPC 2024

作者： Kong, Xianghao Hu, Baiyang Wu, Qiong Chen, Zhuoyi Yang, Hua Gao, Kun China Academy of Space Technology Beijing100094 China Key Laboratory of Photoelectronic Imaging Technology and System Ministry of Education of China Beijing Institute of Technology Beijing100081 China China Ordinance Industry Navigation and Control Technology Research Institute Beijing100089 China

ISBN: (数字)9781510687820

ISBN: (纸本)9781510687813

The traditional correlation coefficient matching method can achieve good image matching results for multi-source satellite images under plain terrain conditions. However, satellite images under mountainous and other complex terrain conditions are prone to mismatches. This article proposes a global probability relaxation automatic matching algorithm that takes into account geometric constraints. Based on the correlation coefficient criterion, combined with least squares matching and coarse to fine matching strategies, the algorithm utilizes the global probability relaxation conditions considering geometric constraints to achieve high-precision matching of multi-source images. A DEM automatic extraction algorithm based on this method is designed. The results of the multi-source image matching and the automatic generation of DEM by using this method are analyzed to validate the effectiveness of the algorithm. © 2024 SPIE.

关键词： Image matching

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A New Star Location Method Based on Rectangular Hole Fraunhofer Diffraction

A New Star Location Method Based on Rectangular Hole Fraunho...

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2024 International Conference on Optoelectronic Information and Optical Engineering, OIOE 2024

作者： Chen, Zhuoyi Yang, Jiyuan Wu, Qiong Kong, Xianghao Yang, Hua Gao, Kun China Academy of Space Technology Beijing100094 China Key Laboratory of Photoelectronic Imaging Technology and System Ministry of Education of China Beijing Institute of Technology Beijing100081 China China Ordinance Industry Navigation and Control Technology Research Institute Beijing100089 China

ISBN: (数字)9781510680470

ISBN: (纸本)9781510680463

The traditional star sensor uses the pupil function of the lens to produce circular aperture Fraunhofer diffraction to form the diffuse spot, then enlarges the diffuse diameter by defocusing, and finally uses Gaussian fitting to determine the centroid of the star point. Compared with the traditional star sensor, this paper designs a new star location method based on rectangular hole Fraunhofer diffraction. The method first changes the optical system structure of the star sensor, so that the pupil function produces Fraunhofer diffraction image on the focal plane of the optical lens at infinite distance, and then directly determines the centroid of the star point through Gaussian fitting. Finally, the reliability of this method is verified by simulating random error. The Gaussian fitting algorithm of the new star sensor has higher accuracy, less computation burden and higher accurate reliability. Experiments show that the localization accuracy of this method can reach 0.007 pixels. © 2024 SPIE.

关键词： Location

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System Level Calibration Method for Drift of Rotary Accelerometer Gravity Gradiometer 30

System Level Calibration Method for Drift of Rotary Accelero...

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30th Saint Petersburg International Conference on Integrated navigation Systems, ICINS 2023

作者： Da, Li Chengsuo, Li Wei, Gao Zhong, Li Zishan, Zhang Yuan, Yuan Laboratory of Science and Technology on Marine Navigation Control of China State Shipbuilding Corporation Tianjin Navigation Instrument Research Institute Tianjin China Harbin Engineer University College of Intelligent Systems Science and Engineering Harbin China Tianjin Navigation Instrument Research Institute Tianjin China SUN YAT-SEN University School of Geospatial Engineering and Science Zhuhai China Laboratory of Science and Technology on Marine Navigation Control of China State Shipbuilding Corporation Tianjin China

ISBN: (纸本)9785919950950

This paper proposes a system level calibration method for the successive startup error of the signal drift measured by a rotating accelerometer gravity gradiometer. Firstly, based on the measurement principle of a rotating accelerometer gravity gradiometer and the transformation relationship of the gravity gradient tensor matrix between different coordinate systems, a gravity gradient drift calibration equation was established. Secondly, the calibration equation was rewritten in a recursive form, and the optimal estimation of the drift of the gravity gradient instrument was solved through recursive least squares. Based on this, a system level calibration method for gravity gradient drift was proposed by driving the instrument stabilization platform to achieve the rotation of the sensor along the geographical direction. Finally, the effectiveness of instrument system level calibration was verified through comparative experiments conducted on two gravity gradiometers at multiple locations. The experimental results showed that the method proposed in this article can achieve high-precision system level calibration of the drift of gravity gradiometers, with a calibration accuracy better than 1E, and has engineering significance. © 2023 Concern CSRI Elektropribor, JSC.

关键词： Calibration

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Fault diagnosis of Electro-hydrostatic actuators based on CWT and CNN-Transformer 3

Fault diagnosis of Electro-hydrostatic actuators based on CW...

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3rd International Conference on Intelligent Mechanical and Human-Computer Interaction technology, IHCIT 2024

作者： Li, Jiatong Tu, Chaofan Wang, Xingjian Wang, Zhaoyang Xiu, Wanbo School of Automation Science and Electrical Engineering Beihang University Beijing100191 China Laboratory of Science and Technology on Marine Navigation and Control China State Shipbuilding Corporation Tianjin300131 China China Tianjin Navigation Instrument Research Institute Tianjin300131 China

ISBN: (纸本)9781510683105

Electro-hydraulic actuator (EHA) system is a key component of the ship's electro-hydraulic control system, but the internal failure mechanism of EHA is extremely complex, and it is limited by insufficient detection methods in practical systems, making fault diagnosis of EHA a great challenge. To address this issue, this paper proposes a fault diagnosis method based on Continuous Wavelet Transform (CWT), Convolutional Neural Network (CNN) and Transformer. Firstly, the collected one-dimensional time series signal of the sensor is converted into a two-dimensional time-frequency map through CWT. Then, a hybrid module of CNN-Transformer is used to extract local and global fault features, and finally the classification results are output through softmax. Conduct EHA fault simulation experiments to validate the proposed method. The research results indicate that the proposed method has a fault diagnosis accuracy of 96.33%, achieving high-precision diagnosis of EHA faults. © 2024 SPIE.

关键词： Wavelet transforms

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Robust Adaptive control Using Nonlinear Quadratic Optimal controllers 63

Robust Adaptive Control Using Nonlinear Quadratic Optimal Co...

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63rd IEEE Conference on Decision and control, CDC 2024

作者： Li, Yan Wang, Zhong Liu, Yuxuan Lang, Jinxi Liu, Kai Northwestern Polytechnical University Department of Navigation Guidance and Control Xi'an710072 China University of Science and Technology Beijing School of Intelligence Science and Technology Beijing10083 China Military Research Institute Xi'an China

ISBN: (纸本)9798350316339

Optimal control-based robust controllers have been extensively studied to mitigate the impacts of disturbances. However, a common limitation of existing methodologies is the incorporation of disturbance information, such as upper bounds, directly into the cost function to design the controller. This practice restricts the applicability of such controllers primarily to problems where disturbance bounds are specified and known a priori. Recognizing the limitation, this paper proposes a novel robust optimal adaptive controller for nonlinear uncertain systems which is formulated without requiring knowledge of the bounds of uncertainty. By employing online parameter estimation, the considered design problem is converted into a nonlinear quadratic optimal control problem. Then an indirect Legendre-Gauss pseudospectral method (ILGPM) is developed to enable efficient numerical implementation. Numerical simulations illustrate the effectiveness of the proposed controller. © 2024 IEEE.

关键词： Cost functions

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Temperature-Dependent Noise Analysis of Angular Accelerometer Using Cross-Correlation Method

Temperature-Dependent Noise Analysis of Angular Acceleromete...

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Chinese Automation Congress (CAC)

作者： Kexuan Zhai Yufeng Yue Simai Wang Meiling Wang Department of Automation Institute of Navigation Guidance and Control Technology Beijing Institute of Technology Beijing China

ISBN: (数字)9798350368604

ISBN: (纸本)9798350368611

Noise characteristics significantly affect the accuracy of the angular accelerometers and limit their application in various fields. According to the working principle, noises are affected by both internal mechanisms and external environments, especially temperature. Therefore, in this paper, we propose a method to identify the temperature-dependent noise model of the angular accelerometers. First, the output signals of the angular accelerometers are collected at different temperatures using the temperature chamber. Then, a cross-correlation method is applied to reduce the noise caused by the vibration of the temperature chamber and obtain the self-noise of the angular accelerometers. Moreover, the obtained noise data is analyzed by the Allan variance method to construct the noise model. Experiments are carried out on two angular accelerometers under ten different temperatures within their operation range. The results show that the proposed method can effectively identify the noise model, and the temperature characteristics of these angular accelerometers' noise are investigated.

关键词： Accelerometers Vibrations Temperature distribution Noise Noise reduction Market research Data processing Reliability Time-domain analysis Spectral analysis

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Intelligent cooperative control method for flexible probe landing on small celestial bodies 74

Intelligent cooperative control method for flexible probe la...

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74th International Astronautical Congress, IAC 2023

作者： Lu, Bingjie Liang, Zixuan Zhu, Shengying School of Aerospace Engineering Beijing Institute of Technology Beijing100081 China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Beijing Institute of Technology Ministry of Industry and Information Technology Beijing100081 China

A novel flexible landing scheme is recently proposed to achieve soft landing on small celestial bodies. Limited by the special configuration and influenced by the flexible deformation, the attitude control of the flexible probe is challenging. To achieve a stable attitude maneuver, an intelligent cooperative control method is investigated for the flexible probe. Firstly, an equivalent model is established characterizing the flexible probe's attitude by the difference of the nodes' altitude. Then, a compensation-feedback control law of the nodes' altitude difference is designed. The compensation term trains a deep learning network to offset the internal force caused by the flexible deformation. The feedback term using a sliding mode control to converge on the desired nodes' altitude difference. Simple allocation law is given to coordinate the thruster of each node to execute the control command. Simulation results show that the proposed method can coordinate the limited control ability of the multiple thrusters. and control the probe's attitude steadily during the flexible landing. Copyright © 2023 by the International Astronautical Federation (IAF). All rights reserved.

关键词： cooperative control flexible probe intelligent attitude control small body landing

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Multi-Task Learning-Enabled Automatic Vessel Draft Reading for Intelligent Maritime Surveillance

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IEEE Transactions on Intelligent Transportation Systems 2024年第5期25卷 4552-4564页

作者： Qu, Jingxiang Liu, Ryan Wen Zhao, Chenjie Guo, Yu Xu, Sendren Sheng-Dong Zhu, Fenghua Lv, Yisheng Wuhan University of Technology Hubei Key Laboratory of Inland Shipping Technology School of Navigation Wuhan430063 China State Key Laboratory of Maritime Technology and Safety Wuhan430063 China National Taiwan University of Science and Technology Graduate Institute of Automation and Control and the Advanced Manufacturing Research Center Taipei10617 Taiwan Institute of Automation State Key Laboratory of Multimodal Artificial Intelligence Systems Chinese Academy of Sciences Beijing100190 China

The accurate and efficient vessel draft reading (VDR) is an important component of intelligent maritime surveillance, which could be exploited to assist in judging whether the vessel is normally loaded or overloaded. The computer vision technique with an excellent price-to-performance ratio has become a popular medium to estimate vessel draft depth. However, the traditional estimation methods easily suffer from several limitations, such as sensitivity to low-quality images, high computational cost, etc. In this work, we propose a multi-task learning-enabled computational method (termed MTL-VDR) for generating highly reliable VDR. In particular, our MTL-VDR mainly consists of four components, i.e., draft mark detection, draft scale recognition, vessel/water segmentation, and final draft depth estimation. We first construct a benchmark dataset related to draft mark detection and employ a powerful and efficient convolutional neural network to accurately perform the detection task. The multi-task learning method is then proposed for simultaneous draft scale recognition and vessel/water segmentation. To obtain more robust VDR under complex conditions (e.g., damaged and stained scales, etc.), the accurate draft scales are generated by an automatic correction method, which is presented based on the spatial distribution rules of draft scales. Finally, an adaptive computational method is exploited to yield an accurate and robust draft depth. Extensive experiments have been implemented on the realistic dataset to compare our MTL-VDR with state-of-the-art methods. The results have demonstrated its superior performance in terms of accuracy, robustness, and efficiency. The computational speed exceeds 40 FPS, which satisfies the requirements of real-time maritime surveillance to guarantee vessel traffic safety. © 2000-2011 IEEE.

关键词： Real time systems

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Mass Telemetry Cluster Storage and Autonomous Health Assessment System of Spacecraft control System in Orbit 2

Mass Telemetry Cluster Storage and Autonomous Health Assessm...

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2nd International Conference on Green Communication, Network, and Internet of Things, CNIoT 2022

作者： Cai, JunLiang Li, DaWei Ji, Ye Zhang, YuJia Yang, Fan Chang, Xiao Beijing Institute of Control Engineering Beijing100094 China Institute of Telecommunication and Navigation Satellites Beijing100094 China Beijing Sunwise Space Technology Ltd. Beijing100190 China

ISBN: (纸本)9781510662940

During the operation of spacecraft control system in orbit, a large amount of telemetry data will be generated. These data can characterize the operation performance of spacecraft control system and have high analytical value, which can identify the health status and operation performance of spacecraft from the telemetry in orbit. This paper presents a cluster storage system and an autonomous health assessment system. Simulation analysis and practical application show that the system supports the efficient storage of more than 800 spacecraft telemetry data, realizes the data elimination of 99.3% accuracy, realizes the fault self-diagnosis of 98.7% accuracy, can complete a comprehensive health assessment of the spacecraft in 3.5 seconds, and automatically generates the evaluation report. © 2023 SPIE.

关键词： Digital storage

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