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International Conference on (ICEPT) Electronic Packaging Technology

作者： Bin Zhou Jianxin Qiao Yunkang Su Dapeng Liu Wentao Huang Longqiu Li State Key Laboratory of Robotics and System Key Laboratory for Microsystems and Microstructure Manufacturing Harbin Institute of Technology Harbin China School of Mechanical and Electrical Engineering Harbin Institute of Technology Harbin China

Complicated service environment such as thermo-mechano-electrical coupling field and limited solder height have brought great challenges to the reliability of flip chips packaging and hindered the chip integration process. In this work, mechanical properties of 3.0Ag-0.5Cu(SAC305) solder under different service environment and height were investigated at macroscopic and microcosmic level. The flip chip shear test is realized on the universal test machine use the proposed fixture. The shear strength shows declining trend with the increment of coupling fields and solder heights. The underlying mechanism of strength loss is thermal softening effect and reduction rate could reach 42.77% at most. The Scanning Electron Microscopy (SEM) is used to analysis the fracture morphology and intermetallic compound (IMC) layer. The shear strength was negatively correlated with the thickness of IMC layer, and was positively correlated with fractal dimension of fracture morphology. The result shows that the thickness of IMC layer is the highest while the field is thermo-mechano-electrical and the solid height is 398μm. Meanwhile, the fractal dimension of fracture morphology is the lowest.

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OAMatcher: An Overlapping Areas-based Network for Accurate Local Feature Matching

arXiv

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arXiv 2023年

作者： Dai, Kun Xie, Tao Wang, Ke Jiang, Zhiqiang Li, Ruifeng Zhao, Lijun State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150006 China SenseTime Group Inc. Beijing100080 China

Local feature matching is an essential component in many visual applications. In this work, we propose OAMatcher, a Tranformer-based detector-free method that imitates humans behavior to generate dense and accurate matches. Firstly, OAMatcher predicts overlapping areas to promote effective and clean global context aggregation, with the key insight that humans focus on the overlapping areas instead of the entire images after multiple observations when matching keypoints in image pairs. Technically, we first perform global information integration across all keypoints to imitate the humans behavior of observing the entire images at the beginning of feature matching. Then, we propose Overlapping Areas Prediction Module (OAPM) to capture the keypoints in co-visible regions and conduct feature enhancement among them to simulate that humans transit the focus regions from the entire images to overlapping regions, hence realizeing effective information exchange without the interference coming from the keypoints in non-overlapping areas. Besides, since humans tend to leverage probability to determine whether the match labels are correct or not, we propose a Match Labels Weight Strategy (MLWS) to generate the coefficients used to appraise the reliability of the ground-truth match labels, while alleviating the influence of measurement noise coming from the data. Moreover, we integrate depth-wise convolution into Tranformer encoder layers to ensure OAMatcher extracts local and global feature representation concurrently. Comprehensive experiments demonstrate that OAMatcher outperforms the state-of-the-art methods on several benchmarks, while exhibiting excellent robustness to extreme appearance variants. The source code is available at https://***/DK-HU/OAMatcher. © 2023, CC BY.

关键词： Image enhancement

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PetLock:A Genderless and Standard Interface for the Future On-orbit Construction

arXiv

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arXiv 2022年

作者： Li, Yuntao Xu, Zichun Yang, Xiaohang Zhao, Zhiyuan Zhao, Jingdong Liu, Hong State Key Laboratory of Robotics and System Harbin Institute of Technology Heilong Jiang Harbin China

Modular design is the foundation of on orbit construction technology of large space facilities in the future. Standard interface is the key technology of modular design of the future space robotic systems and space facilities. This paper presents the designed and tested of PetLock, a standard and genderless interface which can transfer mechanical loads, power and data between the future modular space robotic manipulator and spacecraft. PetLock adopts a completely genderless design, including connection face, locking mechanism, data and power interface. The connection surface provides a large translation and rotation misalignment tolerance, due to its 120-degree symmetrical and 3D shape design. The locking mechanism features the three locking pins retraction structure design, which is simple and reliable. POGO pin connectors in the center of the interface provides the power and data transfer capabilities. Due to the advantages of high locking force, large tolerance, high reliability and low cost, PetLock has the very big application potential in future on orbit construction missions. Copyright © 2022, The Authors. All rights reserved.

关键词： Fits and tolerances

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Layered structural engineering of Bi 2 O 3 /PP and WO 3 /PP composites for γ-ray shielding in high energy range: anisotropic attenuation mechanisms via Monte Carlo simulation and experiments

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Journal of Materials Research and Technology 2025年 36卷 10324-10336页

作者： Xiangjie Duan Jie Zhao Shuaida Song Na Zhou Jizhuang Fan Bo Tian Yunchen Du State Key Laboratory of Space Power-Sources School of Chemistry and Chemical Engineering Harbin Institute of Technology Harbin 150001 People's Republic of China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150006 People's Republic of China Heilongjiang Institute of Atomic Energy Heilongjiang Academy of Sciences Harbin 150081 People's Republic of China

The development of non-toxic and flexible polymer-based shielding composites has become a research hotspot due to the severe harm of γ ray to living organisms, mechanical equipment, and environment. However, the γ-ray shielding performance of polymer-based composites in high-energy range remains unsatisfactory. Herein, FLUKA Monte Carlo simulations capable of visualizing γ-photon transport behaviors are investigated in Bi 2 O 3 /PP and WO 3 /PP multi-layer composites with various layered configurations. The simulation results reveal significant anisotropic attenuation effects on shielding characteristics caused by layered configurations and incident path of γ-photons relative to the interface position. Subsequently, single-layer, AB, and sandwich-like ABA composites with a fixed thickness of 2.0 mm are experimentally fabricated via melt-mixing and hot press methods. At 1332 keV, sandwich-like WPPBPPWPP composite (WO 3 /PP outer layers + Bi 2 O 3 /PP core) achieves linear attenuation coefficients and radiation protection efficiency of 0.31 cm −1 and 6 %, respectively, which are 29 % higher than those of single-layer composite. These improvements originate from multiple scattering induced by interlayer interface. Additionally, layered configurations with externally placed high-density fillers (WO 3 ) and internally placed high atomic number fillers (Bi 2 O 3 ) further promote γ-photon attenuation in high-energy range. Experimental results validate the anisotropic shielding trends observed in MC simulations. Moreover, multi-layer composites demonstrate significantly improved energy storage capacity, thermal stability, and oxidation resistance while maintaining comparable to those of single-layer composites. This work provides a scalable strategy for developing non-toxic and flexible shielding materials applicable in nuclear protection, medical devices, and aerospace systems, where lightweight and efficient radiation attenuation are critical.

关键词： Polymer-based composites Multi-layer structural engineering γ-Ray shielding Monte Carlo simulation Anisotropy attenuation Heterogeneous interface

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High-density Baropodometry Platform Based on Vision Based Tactile Sensing 46

High-density Baropodometry Platform Based on Vision Based Ta...

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46th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2024

作者： Dong, Yueshi Ren, Jieji Zhang, Ningbin Zhao, Weijing Zhou, Jian Gu, Guoying Shanghai Jiao Tong University School of Mechanical Engineering The State Key Laboratory of Mechanical System and Vibration Shanghai200240 China Department of Endocrinology and Metabolism Sixth People's Hospital Affiliated Shanghai Jiao Tong University School of Medicine Shanghai200240 China The Robotics Institute School of Mechanical Engineering Shanghai Jiao Tong University Shanghai200240 China

ISBN: (纸本)9798350371499

Plantar pressure distribution measurement is significant for healthy monitoring and disease diagnosis. However, existing equipment lack of high-density resolution and may lead under-diagnosed of small abnormal regions. To address problem, we propose a special high resolution and low cost Baropodometry based on vision based tactile sensing (VBTS). Specially, we design a measurement platform with larger-scale sensing range (280 mm x 150 mm) and high-density resolution (440 ppi). To achieve the homogeneous illumination for the measure area, we also propose normally distributed light sources around the platform, and delicately adjust the incident angle to optimize the reconstruction performance. Besides, we design a example-based method to calibrate the platform and build a look-up table to reconstruct the plantar geometry from observed image. Experiments show the high lateral resolution that can discriminate the details ( © 2024 IEEE.

关键词： Barometers

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High-Precision Tracking Control of Modular Dielectric Elastomer Actuators Through Kalman Filter Base Self-Adaptive Direct Inverse Hysteresis Compensation

High-Precision Tracking Control of Modular Dielectric Elasto...

引用

International Conference on Control and Automation (ICCA)

作者： Bohao Xiao Guoying Gu Jiang Zou State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai China Robotics Institute School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China

ISBN: (数字)9798350354409

ISBN: (纸本)9798350354416

This work proposes a Kalman filter based direct inverse hysteresis compensation approach for modularized dielectric elastomer actuators (DEAs) with rate-dependent viscoelasticity, mechanical vibration, and individual variation. To this end, we firstly investigate the dynamics of three modularized DEAs, including viscoelasticity, mechanical vibration, and their individual variation. Then, based on a rate-independent phenomenological hysteresis model, a direct inverse hysteresis compensation (DIHC) is established to eliminate the hysteresis effect. Further, a feedback controller is adopted to remove the creep and model uncertainty. Lastly, a Kalman filter is employed to automatically adjust the parameter of the DIHC, capable of achieving high-precision tracking control of modular DEAs within a wide frequency range. To verify the effectiveness of our control strategy, three modularized DEAs are employed to track periodical trajectories with different frequencies (in a range of 0.1Hz to 10Hz). The experimental results demonstrate that the Kalman filter based controller can fully eliminate the rate-dependent viscoelasticity, mechanical vibration, and individual difference, achieving high-precision tracking control of modular DEAs in a wide frequency range. The maximum error and root mean square error are reduced from 20.16% and 11.44% to 9.87% and 5.22%, respectively.

关键词： Vibrations Uncertainty Creep Soft robotics Trajectory Kalman filters Root mean square

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MECHANICAL CHARACTERISTICS ANALYSIS OF CORNER TENSIONED RECTANGULAR THIN MEMBRANES 1

MECHANICAL CHARACTERISTICS ANALYSIS OF CORNER TENSIONED RECT...

引用

1st International Conference on Mechanical system Dynamics, ICMSD 2022

作者： Li, Bingyan Peng, Tao Lin, Qiuhong Wang, Xiaoyu Cong, Qiang Tian, Xinqi Liu, Rongqiang Beijing Institute of Spacecraft Engineering Beijing100094 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China College of Mechanical and Electrical Engineering Harbin Engineering University Harbin150001 China

ISBN: (数字)9781839537837

ISBN: (纸本)9781839537837

This paper presents the calculation of the stress distribution of corner tensioned rectangular thin membrane based on the stress superposition method (SSM). By comparing with the results of finite element simulation, the theoretical results of stress distribution of tensioned membrane structure are verified. Based on SSM and free vibration calculation theory, the effects of tension boundary parameters on membrane stress distribution and models are investigated. The influence of corner tension on the mechanical characteristics is analyzed for the corner tensioned rectangular membranes with different aspect ratios. The formula for each order's fundamental frequency ratio of atmospheric to spatial environment is proposed. Conducting the dynamics experiment of a rectangular tensioned membrane, the theoretical analysis is verified by the experimental modal results. © 2022 IET Conference Proceedings. All rights reserved.

关键词： Stress concentration

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An Air Floating Suspension Microgravity Simulator for Multi Specification of Spaceborne SAR 2

引用

2nd China International SAR Symposium, CISS 2021

作者： Sun, Zhiyao Sun, Xiangyu Zhou, Qihua Zou, Bo Liu, Gangfeng Dong, Huijuan Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin China The Tenth Research Laboratory Shanghai Radio Equipment Research Institute Shanghai China

ISBN: (纸本)9787000000001

Microgravity Simulators are significant equipment for spaceborne synthetic aperture radar (SAR) on-ground test. Considering the diversity of spaceborne SAR specification as well as SAR's high working accuracy, this paper provides a novel air floating suspension microgravity simulator equipped with both active and passive gravity compensation mechanism, which realize the high-precision microgravity simulation of spaceborne SAR with different structures and kinematic characteristics. The simulator also provides adjustable frames to guarantee the simulation stability of the SAR in different poses. In addition, the simulator's corresponding horizontal tracking control system and vertical constant tension control system are also provided in this paper, which realize the tracking of the SAR movement. Finally, the simulation and experiment are provided to verify the effectiveness of the microgravity simulator. © 2021 SISE.

关键词： Synthetic aperture radar

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S2H-GNN: Learning Soft to Hard Feature Matching with Sparsified Graph Neural Network

S2H-GNN: Learning Soft to Hard Feature Matching with Sparsif...

引用

IEEE International Conference on Real-time Computing and robotics (RCAR)

作者： Tao Xie Ruifeng Li Zhiqiang Jiang Kun Dai Ke Wang Lijun Zhao Shuozhan Li State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Fujian (Quanzhou)-HIT Research Institute of Engineering and Technology Quanzhou China

In this work, we introduce a soft-to-hard network (S2H-GNN) for precise local feature matching between image pairs. The core of S2H-GNN is a weighted context aggregation algorithm that enables nodes to receive information from their neighbors in order to form a more global understanding. S2HGNN leverages a sparsified graph neural network to enhance the features, consisting of the following modules alternately: (1) Inducing Point Initial Module that uses cosine correlation to identify highly scored keypoints as Inducing points. (2) Message Passing Module that integrates the features of original keypoints into those of Inducing points, which are further leveraged to exchange messages through self attention and cross attention. (3) Attention Upsample Module that propagates the feature of Inducing points to that of original keypoints, obtaining discriminative feature representation. Additionally, we propose an assignment layer to obtain a soft assignment matrix, which views feature matching as a graphy matching problem. Finally, we introduce a novel gap loss to guide S2H-GNN in learning a discriminative cognition of matching and non-matching keypoints, ultimately obtaining the hard assignment matrix. Experimental results demonstrate that S2H-GNN achieves comparable or higher performance in image matching and homography estimation tasks.

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Heating Patterns and Temperature Distribution of Projectile Surface in Lunar Soil Penetration

SSRN

引用

SSRN 2024年

作者： Chi, Cheng Jiang, Shengyuan Chi, Guanxin Tang, Junyue Xiao, Junxiao Zhu, Jiachen Chi, Runqiang Fan, Jinbiao Huang, Zexi Deng, Zongquan State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China College of Mechanical Engineering Yanshan University Qinhuangdao066004 China National Key Laboratory for Electronic Measurement Technology North University of China Taiyuan030051 China

A large quantity of friction-induced heat is generated during penetration, notably increasing the projectile's surface temperature. Considering that the temperature variation depends on the physical properties of the penetrating target, this factor can be helpful for extraterrestrial object detection. This study studied the heat generation patterns and temperature distribution on the projectile surface when penetrating the lunar soil. For discrete medium penetration, large deviations appear in temperature prediction due to particle extrusion flow. Thus, we established a heat flux density model on the projectile surface by introducing a relative velocity factor for correction. The particle flow characteristics simulation and fitting model of the introduced factor were also obtained. We constructed a theoretical relationship between the resistance and stress model parameters through dynamic modeling. Experimental projectiles recording penetration acceleration and temperature at the points of interest on the projectile surface were designed and tested to obtain recorded data. The temperature field in this process was simulated in COMSOL software to calculate the projectile surface's heat flux density and temperature distribution. The results indicate that the developed model is effective. This research infers the physical characteristics of the penetrating target under given penetration conditions and provides more dimensional information for lunar soil exploration. © 2024, The Authors. All rights reserved.

关键词： Temperature distribution

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