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SSRN 2022年

作者： Ren, Ke Di, Yuelan Wang, Gang Wang, Liping Wang, Haidou Rong, Yiming School of Mechatronics Engineering Harbin Institute of Technology Harbin150001 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China Department of Equipment Support and Remanufacturing Army Academy of Armored Forces Beijing100072 China Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Department of Mechanical Engineering Tsinghua University Beijing100084 China

Precise control of energy and mass utilization is essential for the process design and optimization of powder-based laser-directed energy deposition (L-DED). However, fully comprehending the actual changes in the energy and the mass, which have complex nonlinear relationships with all inputs, is still challenging. In powder-based L-DED, the energy absorptivity is closely related to the powder catchment efficiency, owing to the effects of the laser incidence angle and the material properties. In this study, a forward calculation model was established for the utilization of energy and mass in powder-based L-DED without data regression of experimental measurements. Interactions between the laser, powders, and substrate were analyzed in detail in terms of three major effects: energy absorption of the substrate, powder catchment, and deposition shape variation. A secondary correction of the incidence angle was included in the geometric change of the deposited passes, and the boundary shift of the molten pool, which resulted from the melting point differences of the dissimilar deposited and substrate materials, was considered. The model prediction results matched the multipass deposition experimental results well. The average prediction error validated that the catchment efficiency did not exceed 5.2%. The scanning speed and the powder feed rate showed the largest effects on the energy absorptivity, which varied in the range of approximately 40%–65%. The developed model presents good universality and can be fundamental for understanding the forming mechanism, optimizing the process, and predicting the deposition quality of powder-based L-DED. © 2022, The Authors. All rights reserved.

关键词： Catchments

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Aviation Plug Clustering Based Fault Detection Method Using Hyperspectral Image

Aviation Plug Clustering Based Fault Detection Method Using ...

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第三十九届中国控制会议

作者： Miao Zhang Jiawen Feng Sicong Niu Yi Shen Department of Control Science and Engineering Harbin Institute of Technology

Through clustering the hyperspectral image and registering with plug standard template for the fault plug pin detection is proposed in this *** method firstly searches for the center and radius of the hyperspectral image of plug and obtains the image only containing the chassis and the *** this paper,k-means clustering is used to finely cluster the plug *** registering with the standard plug template,the fault pin is *** key of this method is to use the spectral resolution of hyperspectral which can distinguish different substances *** can also solve the problems that the pin and the chassis are similar in color and the plug frame is too high causing a lot of shadow on the *** clustering accuracy is greatly improved in this *** the plug detection,the traditional method is to edge detect the aviation plug square *** fault pin is detected by identifying the parameters and registering with the plug standard ***,since the position of the square frame is estimated,there is a large error in the detection *** the experiments,two main detection methods are compared and the results show that the proposed method in the paper has higher accuracy.

关键词： K-means clustering fault detection hyperspectral image edge detection

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Localization of Low-Frequency Magnetic Beacons Based on Genetic Algorithm

Localization of Low-Frequency Magnetic Beacons Based on Gene...

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第三十九届中国控制会议

作者： Jiaxin Song Danfeng Sun Zhiyuan Zhao Huajun Zhou Hongwei Xia Guangcheng Ma Department of control science and engineering Harbin Institute of Technology Shanghai Aerospace Control Technology Institute School of Energy Science and Engineering Harbin Institute of Technology

An autonomous positioning method utilizing the separated magnetic beacons model based on Genetic Algorithm(GA) is proposed in this paper. The low frequency alternating magnetic signal has high penetration ability. Taking advantage of this characteristics, stable positioning service in a severe environment is possible, in which the Global Positioning System(GPS) is not reliable due to multipath effects and non-line-of-sight conditions. The analytical method needs quadrant distinction and is difficult to position points close to the coordinate axis. While using the new method proposed in this paper, the defects are effectively ameliorated. Validated by both theoretical deduction and numerous simulations, the positioning method based on GA has been tested showing accurate localization results for a wide-range measurement.

关键词： Low-frequency magnetic field localization genetic algorithm

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Discrete-time Contractive MPC-based Sliding Mode Tension control for the Deployment of Space Tethered Satellite

Discrete-time Contractive MPC-based Sliding Mode Tension Con...

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第32届中国控制与决策会议

作者： Xiaolei Li Xiangyu Shao Xiaowei Deng Guanghui Sun Department of Control Science and Engineering Harbin Institute of Technology

This paper develops a novel discrete-time sliding mode tension control strategy based on the contractive MPC scheme,for the deployment of space tethered satellite system with input *** deriving the discrete-time Euler-Lagrange equation,the discrete-time nonlinear model is constructed for space tethered satellite ***,the proposed discrete-time sliding surface is strictly nonlinear and ***,the contractive MPC controller is designed to drive the sliding mode asymptotically converge to the sliding surface,which makes it possible to prove the exponential stability of the proposed ***,considering the limited input,a novel control structure with input compensation is raised to obtain a preferable ***,simulation studies are conducted to investigate the influences of contractive MPC and input compensation on the discrete-time sliding mode,validating the effectiveness of the proposed control strategy.

关键词： Space tethered satellite Discrete-time system Contractive model predictive control Sliding mode control

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Novel Detection Method on Polarization Spectral Imaging in Handwriting Identification

Novel Detection Method on Polarization Spectral Imaging in H...

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第三十九届中国控制会议

作者： Miao Zhang Sicong Niu Jiawen Feng Yi Shen Department of Control Science and Engineering Harbin Institute of Technology

This paper proposes a novel dection method for determining the sequence of seal and signature based on polarization spectral *** order to solve the problem of serious loss of information,great influence by the environment and poor judgment accuracy in the current method,we used the polarization hyperspectral feature vector of the target band with strong information to carry out correlation analysis,and judged the order of seal and signature by rank *** results show that this detection method is very effective and has a faster and more sensitive effect on handwriting identification,which is suitable for both evenly distributed and uneven handwriting,

关键词： Polarization hyperspectral imaging image fusion dynamic threshold rank correlation

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Orbital rendezvous performance comparison of differential geometric and ZEM/ZEV feedback guidance algorithms

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Astrodynamics 2019年第1期3卷 79-92页

作者： Pengyu Wang Yanning Guo Bong Wie Department of Control Science and Engineering Harbin Institute of TechnologyHarbin150001China Department of Aerospace Engineering Iowa State UniversityAmesIA50011USA

In this paper,the performance of two distinct classes of feedback guidance algorithms is evaluated for a spacecraft rendezvous problem utilizing a continuous low-thrust propulsion *** are the DG(Differential Geometric)and ZEM/ZEV(Zero-Effort-Miss/Zero-Effort-Velocity)feedback guidance *** though these two guidance algorithms do not attempt to minimize the onboard fuel consumption orΔV directly,theΔV requirement is used as a measure of their orbital rendezvous performance for various initial conditions and a wide range of the rendezvous time(within less than one orbital period of the target vehicle).For the DG guidance,the effects of its guidance parameter and terminal time on the closed-loop performance are evaluated by numerical *** the ZEM/ZEV guidance,its nearfuel-optimality is further demonstrated for a rapid,short-range orbital rendezvous,in comparison with the corresponding open-loop optimal ***,the poorΔV performance of the ZEM/ZEV guidance for a slow,long-range orbital rendezvous is remedied by simply adding an initial drift *** ZEM/ZEV feedback guidance algorithm and its appropriate variants are then shown to be a simple practical solution to a non-impulsive rendezvous problem,in comparison with the DG guidance as well as the open-loop optimal guidance.

关键词： differential geometric guidance ZEM/ZEV feedback guidance orbital rendezvous initial drift phase

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Temperature dependence of the rain-gas and snow-gas partition coefficients for nearly a thousand chemicals

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Chemosphere 2024年 362卷 142565页

作者： Yang, Pu-Fei Ma, Wan-Li Xiao, Hang Hansen, Kaj M. Wang, Liang Sun, Jing-Jing Liu, Li-Yan Zhang, Zi-Feng Jia, Hong-Liang Li, Yi-Fan State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology Harbin150090 China Harbin150090 China Harbin150090 China Department of Environmental Science Aarhus University Roskilde4000 Denmark Key Laboratory of Urban Environment and Health Ningbo Observation and Research Station Institute of Urban Environment Chinese Academy of Sciences Xiamen361021 China Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control CAS Haixi Industrial Technology Innovation Center in Beilun Ningbo315800 China Laboratory of Marine Ecological Environment Early Warning and Monitoring Third Institute of Oceanography Ministry of Natural Resources Xiamen361005 China College of Environmental Science and Engineering Dalian Maritime University Dalian116026 China IJRC-PTS-NA TorontoONM2J 3N8 Canada

Compared to the particle-gas partition coefficients (KPG), the rain-gas (KRG) and snow-gas (KSG) partition coefficients are also essential in studying the environmental behavior and fate of chemicals in the atmosphere. While the temperature dependence for the KPG have been extensively studied, the study for KRG and KSG are still lacking. Adsorption coefficients between water surface-air (KIA) and snow surface-air (KJA), as well as partition coefficients between water-air (KWA) and octanol-air (KOA) are vital in calculating KRG and KSG. These four basic adsorption and partition coefficients are also temperature-dependent, given by the well-known two-parameters Antoine equation logKXY = AXY + BXY/T, where KXY is the adsorption or partition coefficients, AXY and BXY are Antoine parameters (XY stand for IA, JA, WA, and OA), and T is the temperature in Kelvin. In this study, the parameters AXY and BXY are calculated for 943 chemicals, and logKXY can be estimated at any ambient temperature for these chemicals using these Antoine parameters. The results are evaluated by comparing these data with published experimental and modeled data, and the results show reasonable accuracy. Based on these coefficients, temperature-dependence of logKRG and logKSG is studied. It is found that both logKRG and logKSG are linearly related to 1/T, and Antoine parameters for logKRG and logKSG are also estimated. Distributions of the 943 chemicals in the atmospheric phases (gas, particle, and rain/snow), are illustrated in a Chemical Space Map. The findings reveal that, at environmental temperatures and precipitation days, the dominant state for the majority of chemicals is the gaseous phase. All the AXY and BXY values for logKSG, logKRG, and basic adsorption and partition coefficients, both modeled by this study and collected from published work, are systematically organized into an accessible dataset for public utilization. © 2024 Elsevier Ltd

关键词： Rain

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Effects of air relief openings on the mitigation of solitary wave forces on bridge decks

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Journal of Hydrodynamics 2019年第3期31卷 594-602页

作者： Sheng-chao Xiao An-xin Guo Ministry-of-Education Key Laboratory of Structural Dynamic Behavior and Control School of Civil Engineering Harbin Institute of Technology Harbin 150090 China Department of Civil Engineering The University of Queensland Brisbane 4072 Australia

For inverted T-type bridge decks, the air entrapped in the chambers between adjacent girders could increase the wave forces and lead to the destruction of the bridge decks. This paper studies the effects of the air relief openings (ARO) on the mitigation of the solitary wave-induced forces on the bridge decks. Hydrodynamic experiments are conducted for three inverted T-type decks with four, five, and six girders with different wave properties and deck clearances. The open source computational fluid dynamics toolbox OpenFOAM is adopted to conduct numerical simulations for the effects of the AROs. Since the numerical results correlate well with the measurements, the mechanism of the wave-structure interaction can be revealed by the numerical flow fields. Furthermore, the relationship between the shape and the volume of the ARO and the wave forces on the bridge decks, as well as the contribution of each ARO to the effect of the wave force mitigation, is also obtained from the numerical results of the OpenFOAM. Experimental and numerical results demonstrate that the AROs could effectively reduce the vertical wave forces on the bridge decks. The effects of the AROs increase with the increase of the volume of the ARO, while the shape of the ARO has no effect on the reduction of the wave forces.

关键词： Air entrapped hydrodynamic experiment solitary wave forces bridge decks OpenFOAM

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Aviation Plug Clustering Based Fault Detection Method Using Hyperspectral Image

Aviation Plug Clustering Based Fault Detection Method Using ...

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Chinese control Conference (CCC)

作者： Miao Zhang Jiawen Feng Sicong Niu Yi Shen Department of Control Science and Engineering Harbin Institute of Technology Harbin China

ISBN: (数字)9789881563903

ISBN: (纸本)9781728165233

Through clustering the hyperspectral image and registering with plug standard template for the fault plug pin detection is proposed in this paper. This method firstly searches for the center and radius of the hyperspectral image of plug and obtains the image only containing the chassis and the pin. In this paper, k-means clustering is used to finely cluster the plug pin. After registering with the standard plug template, the fault pin is detected. The key of this method is to use the spectral resolution of hyperspectral which can distinguish different substances accurately. It can also solve the problems that the pin and the chassis are similar in color and the plug frame is too high causing a lot of shadow on the image. The clustering accuracy is greatly improved in this paper. For the plug detection, the traditional method is to edge detect the aviation plug square frame. The fault pin is detected by identifying the parameters and registering with the plug standard template. However, since the position of the square frame is estimated, there is a large error in the detection results. In the experiments, two main detection methods are compared and the results show that the proposed method in the paper has higher accuracy.

关键词：

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A Cross-block Connection Network for Retinal Vessel Segmentation

A Cross-block Connection Network for Retinal Vessel Segmenta...

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IEEE International Symposium on Industrial Electronics (ISIE)

作者： Shaochong Liu Shen Yin Hao Luo Minglei Li Xiang Li Department of Control Science and Engineering Harbin Institute of Technology Harbin China

ISBN: (数字)9781728156354

ISBN: (纸本)9781728156361

The appearance and structure of retinal vessels is one of the diagnostic criterias for ophthalmic, cardiovascular and cerebrovascular diseases, which makes the segmentation of retinal vessels worthwhile in clinical medicine. Retinal images have low contrast, complex tissue structures, and diverse pathological conditions. Due to the difficulty to accurately and effectively identify these information, existing segmentation methods often have neglection on subtle vessels and have blurry segmentation on overlap area. This paper proposed a new vascular segmentation method based on deep learning. Considering the necessity of feature extraction from multi-aspect and multi-level, a cross-block dense connection was proposed to improve the feature identify and extract ability. It use additional mapping to connect and share features between different blocks of the network. Further, the residual connection is used inside the block to solve the degradation problem. Powerful extraction capability enables the network to obtain ideal segmentation results with less parameters, which immensely reduces the computing resource consumption of the network. Extensive experiments demonstrate that our approach achieves better performance based on multiple criteria with a much faster speed.

关键词： Feature extraction Convolution Image segmentation Decoding Retina Data mining Image coding

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