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Quantitative study on energy distribution and mode conversion of ultrasonic guided waves interacting with stepped and tapered transition regions

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Applied Acoustics 2025年 236卷

作者： Tian, Yuan Yu, Ximing Guo, Yudong Zhao, Lin Liu, Menglong Guo, Haotian Zhang, Jifeng Zhou, Limin College of Aerospace and Civil Engineering Harbin Engineering University Harbin150001 China Wuhan Aviation Instrument Co. Ltd. Wuhan430074 China School of Robotics and Advanced Manufacturing Harbin Institute of Technology Shenzhen518055 China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China

Ultrasonic guided waves (UGWs) are extensively used in structural health monitoring and nondestructive testing, particularly for complex structures such as lap joints, icing plates, and composite interfaces. This study comprehensively investigates the mode conversion, reflection, and transmission of UGWs both at the stepped and tapered transition region, where geometric discontinuity causes energy redistribution among various modes of reflected and transmitted UGWs. The Frequency Domain Finite Element method is employed to quantitatively analyse the mode energy distribution across a frequency range of 0 ∼ 3 MHz, with Mode S0 as the incident UGW. The results demonstrate that the energy distribution of transmitted UGW modes follows the phase velocity matching principle, whereas the reflected UGW energy exhibits no discernible pattern. Both the linearly and curvedly tapered transition regions improve the energy transmission efficiency by mitigating mode mismatches. Furthermore, increasing the length-to-thickness ratio of linearly tapered transition enhances the energy transmission, reaching over 99% at all frequencies when the ratio exceeds 5. The validation is conducted with the Time Domain Finite Element method and experiment. These findings provide valuable insights for optimizing the selection of UGWs, improving the accuracy and effectiveness of monitoring at stepped and tapered structures. © 2025 Elsevier Ltd

关键词： Guided electromagnetic wave propagation

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Practical Applicability of PLA for Industrial Wireless Networks: Gaps and Directions

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IEEE Network 2025年

作者： Liang, Wei Wei, Fuyou Wang, Qi Zhan, Ming Wang, Ke Chinese Academy of Sciences State Key Laboratory of Robotics Shenyang Institute of Automation Shenyang110016 China Chinese Academy of Sciences Key Laboratory of Networked Control System Shenyang Institute of Automation Shenyang110016 China Chinese Academy of Sciences Institutes for Robotics and Intelligent Manufacturing Shenyang110169 China University of Chinese Academy of Sciences Beijing100049 China Shandong Normal University Jinan250014 China Taizhou University School of Electronics and Information Engineering Zhejiang Taizhou China

The rapid transformation of Industrial Cyber-Physical system (ICPS) has introduced significant cyber security challenges, particularly in the context of ICPS. Wireless networks are a critical component of these systems, but their open nature makes them vulnerable to security threats. Physical Layer Authentication (PLA) algorithms based on Channel State Information (CSI) are essential complements to existing security technologies in wireless networks. However, their practical application faces challenges such as restricted sampling rates and uneven sampling interval, which result in low-precision CSI, significant random phase offsets, and signal distortion. This study aims to explore the feasibility of deploying and applying existing representative algorithms on industrial wireless commercial devices. According to characteristics of authentication algorithms and the adopted authentication features, we selected five of the latest physical layer authentication algorithms including supervised, semi-supervised, and unsupervised algorithms and deployed them on commercial devices that comply with the WIA-FA standard. We conducted systematic experiments focusing on the motion parameters of devices, the CSI data sampling frequency, the interference caused by worker movement, the surface materials of the devices, and the types of attacks. This study explores the ability of these algorithms to resist attacks and environmental interference in commercial devices and industrial scenarios. Extensive experimental data were collected, and the results indicate that existing authentication algorithms still need improvement to meet the requirements of industrial applications. The experiment findings and the summarized application challenges of these algorithms provide significant guidance for future research and practical industrial implementations. © 1986-2012 IEEE.

关键词： Authentication

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Self-powered water condition monitoring system based on rotational electromagnetic generator

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Energy 2025年 326卷

作者： Zhou, Xu Mei, Mingqi Tang, Tianyi Li, Yunfei Wang, Zizhao Zhu, Yu Yan, Bin Lin, Hao Li, Zhen Liu, Huicong School of Mechanical and Electrical Engineering Jiangsu Key Laboratory of Embodied Intelligence Robot Technology Soochow University Suzhou215006 China College of Engineering Center for Agricultural Flexible Electronics Technology China Agricultural University Beijing100083 China Suzhou Water Meter CO. LTD Suzhou215000 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China

As a widely available clean energy source in nature, water flow energy provides a research avenue for energy harvesting and environmental monitoring. This work proposes a self-powered water condition monitoring system based on rotational electromagnetic generator (WCM-EMG). The WCM-EMG adopts a fully enclosed design that collects energy by converting water flow into rotational motion, eventually generating electrical output based on electromagnetic induction. Through the optimization of impeller parameters, WCM-EMG can obtain higher electrical output with lower water head loss. At a flow velocity of 1.5 m/s and load resistance of 25 Ω, the WCM-EMG generates a power output of 606 mW and power density of 0.93 mW/cm3 while the head loss is only 2.5 m. For one thing, the WCM-EMG achieves a high-power supply for self-powering of the temperature, pH and turbidity sensors. For another, by processing the frequency of the electrical signal of WCM-EMG, the self-sensing of water flow velocity can be realized in real-time. By harvesting the kinetic energy of fluid flow, this work offers an encouraging solution for developing integrated multi-parameter intelligent sensing system that encompasses energy harvesting, self-sensing and monitoring, enabling passive zero-carbon sensing in the Internet of Things (IoT). © 2025

关键词： Stream flow

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Lunar regolith simulant-derived 3D-printed geopolymers with optimized mechanical and thermal management properties

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Composites Part A: Applied Science and Manufacturing 2025年 196卷

作者： Sun, Yifan Ma, Siqi Chen, Qingze Chen, Guoliang He, Peigang Wang, Yaming Qiu, Jun Jia, Dechang School of Energy Science and Engineering Key Laboratory of Aerospace Thermophysics Harbin Institute of Technology Harbin150001 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Institute for Advanced Ceramics Key Laboratory of Advanced Structure-Function Integrated Materials and Green Manufacturing Technology Harbin Institute of Technology Harbin150080 China Guangdong Provincial Key Laboratory of Mineral Physics and Materials Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou510460 China

Lunar soil, as an in-situ resource, holds significant potential for constructing bases and habitats on the Moon. However, such constructions face challenges including limited mechanical strength and extreme temperature fluctuations ranging from −170 °C to +133 °C between lunar day and night. In this study, we developed a 3D-printed geopolymer derived from lunar regolith simulant with an optimized zig-zag structure, exhibiting exceptional mechanical performance and thermal stability. The designed structure achieved remarkable damage tolerance, with a compressive strength exceeding 12.6 MPa at ∼ 80 vol% porosity and a fracture strain of 3.8 %. Finite element method (FEM) simulations revealed that the triangular frame and wavy interlayers enhanced both stiffness and toughness. Additionally, by incorporating strategically placed holes and extending the thermal diffusion path, we significantly improved the thermal insulation of the structure, achieving an ultralow thermal conductivity of 0.24 W/(m K). Furthermore, an iron-free geopolymer coating reduced overheating under sunlight by 51.5 °C, underscoring the material's potential for space applications. © 2025 Elsevier Ltd

关键词： Compressive strength

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GNN-Assisted BiG-AMP: Joint Channel Estimation and Data Detection for Massive MIMO Receiver

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IEEE Transactions on Wireless Communications 2025年

作者： Liu, Zishen Wu, Nan He, Dongxuan Yuan, Weijie Li, Yonghui Quek, Tony Q. S. School of Information and Electronics Beijing Institute of Technology Beijing100081 China School of System Design and Intelligent Manufacturing Shenzhen Key Laboratory of Robotics and Computer Vision Southern University of Science and Technology Shenzhen518055 China School of Electrical and Information Engineering The University of Sydney SydneyNSW2008 Australia Singapore University of Technology and Design 487372 Singapore Department of Electronic Engineering Kyung Hee University Yongin17104 Korea Republic of

In this paper, we develop a graph neural network (GNN)-assisted bilinear inference approach to enhance the receiver performance of the MIMO system through message passing-based joint channel estimation and data detection (JCD). Specifically, based on the bilinear generalized approximate message passing (BiG-AMP) framework and conditional correlation of signal, we propose a GNN-assisted BiG-AMP (GNN-BiGAMP) approach, which integrates a GNN module into the data-detection-loop to compensate the inaccurate marginal likelihood approximation. By leveraging the coupling between the channel and received symbols, a bilinear GNN-assisted BiG-AMP (BiGNN-BiGAMP) JCD receiver is further proposed. This method incorporates two GNNs with similar graph representation into the bilinear posterior estimation loops, which not only compensates for approximation errors but also alleviates performance loss due to premature variance convergence, thereby enhancing the receiver performance significantly. To fully exploit the supervised information from channel estimation and data detection, we propose a multitask learning based training scheme, which coordinates GNNs with different tasks in two loops. Simulation results show that our proposed GNN-assisted JCD receivers significantly outperform other JCD counterparts in terms of both channel estimation and data detection. © 2025 IEEE. All rights reserved.

关键词： Graph neural networks

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Effect of head swing motion on hydrodynamic performance of fishlike robot propulsion

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Journal of Hydrodynamics 2016年第4期28卷 637-647页

作者：夏丹陈维山刘军考吴泽 School of Mechanical Engineering Southeast University State Key Laboratory of Robotics and System Harbin Institute of Technology

This paper studies the effect of the head swing motion on the fishlike robot swimming performance numerically. Two critical parameters are employed in describing the kinematics of the head swing： the leading edge amplitude of the head and the trailing edge amplitude of the head. Three-dimensional Navier-Stokes equations are used to compute the viscous flow over the robot. The user-defined functions and the dynamic mesh technology are used to simulate the fishlike swimming with the head swing motion The results reveal that it is of great benefit for the fish to improve the thrust and also the propulsive efficiency by increasing the two amplitudes properly. Superior hydrodynamic performance can be achieved at the leading edge amplitudes of 0.05L （ L is the fish length） and the trailing edge amplitudes of 0.08L. The unsteady flow fields clearly indicate the evolution process of the flow structures along the swimming fish. Thrust-indicative flow structures with two pairs of pressure cores in a uniform mode are generated in the superior performance case with an appropriate head swing, rather than with one pair of pressure cores in the case of no head swing. The findings suggest that the swimming biological device design may improve its hydrodynamic performance through the head swing motion.

关键词： fishlike swimming head swing motion hydrodynamic performance biological device design

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The energy-saving advantages of burst-and-glide mode for thunniform swimming

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Journal of Hydrodynamics 2018年第6期30卷 1072-1082页

作者： Dan Xia Wei-shan Chen Jun-kao Liu Xiang Luo School of Mechanical Engineering Southeast University State Key Laboratory of Robotics and System Harbin Institute of Technology

This paper explores the energy-saving advantages of the burst-and-glide swimming and compares it with the normal self-swimming for a thunniform swimmer. The virtual swimmer allows us to perform controlled numerical experiments by varying the swinging tail number and the duty cycle while keeping the other parameters fixed. 3-D Navier-Stokes equations are used to compute the viscous flow over the swimmer. The user-defined functions and the dynamic mesh technology are used to simulate the burst-and-glide swimming. The results show that with the increase of the swinging tail number or the duty cycle, the swimming velocity, the power and the efficiency all increase, but the velocity-power ratio decreases somewhat. Therefore, choosing smaller swinging tail number and duty cycle is beneficial in reducing the power and increasing the velocity-power ratio, and thus to obtain the same velocity, less power is consumed. And to swim the same distance, the energy can significantly be saved. The power consumption, the efficiency and the velocity-power ratio in the burst-and-glide case are 43.9%, 40.6% and 1.15 times of those in the normal swimming case, respectively. The flow structures clearly show the evolution process around the fish in the burst-and-glide swimming. The findings can be used to reasonably plan the swimming action and to take the advantage of the external flow field energy for the fishlike robot, to be more efficient and energy-saving.

关键词： Energy-saving advantages burst-and-glide mode normal self-swimming thunniform swimmer

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Study on the Behavior of Solar Array Deployment with Root Hinge Drive Assembly

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Chinese Journal of Aeronautics 2012年第2期25卷 276-284页

作者： DING Xilun LI Xin XU Kun YANG Qiaolong PU Hailing Robotics Institute Beihang University Beijing 100191 China Beijing Institute of Spacecraft System Engineering Beijing 100094 China

In this paper, a method of using a root hinge drive assembly （RHDA） to control the solar array deployment is provided and a multi-DOF mechanism dynamic model of the system is established. In this way, the root hinge torque can be calculated iteratively. Then taking the predicted torque as a reference, a RHDA is designed for a large multiple-stage packaging and deployable solar array system. The control effect of the drive assembly is validated by ground tests. The test results indicate that the solar arrays can be deployed smoothly, and the deployment velocities are restricted by the drive assembly as expected. During the tests, the RHDA output speed and output torque are obtained. In order to examine the impact force when the yoke is lock-up with a hard stop, dynamics simulations are performed according to the actual behavior. The simulation result indicates that the designed RHDA reduces the impact force significantly and improves the lock-up reliability effectively.

关键词： solar array root hinge drive assembly multi-DOF model dynamics simulation reliability lock-up

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Multi-sensor control for precise assembly of optical components

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Chinese Journal of Aeronautics 2014年第3期27卷 613-621页

作者： Ma Li Rong Weibin Sun Lining School of Mechatronic Engineering and Automation Shanghai University State Key Laboratory of Robotics and System Harbin Institute of Technology

In order to perform an optical assembly accurately, a multi-sensor control strategy is developed which includes an attitude measurement system, a vision system, a loss measurement system and a force sensor. A 3-DOF attitude measuring method using linear variable differential transformers （LVDT） is designed to adjust the relation of position and attitude between the spher- ical mirror and the resonator. A micro vision feedback system is set up to extract the light beam and the diaphragm, which can achieve the coarse positioning of the spherical mirror in the optical assembly process. A rapid self-correlation method is presented to analyze the spectrum signal for the fine positioning. In order to prevent the damage of the optical components and realize sealing of the resonator, a hybrid force-position control is constructed to control the contact force of the optical components. The experimental results show that the proposed multi-sensor control strategy succeeds in accomplishing the precise assembly of the optical components, which consists of parallel adjustment, macro coarse adjustment, macro approach, micro fine adjustment, micro approach and optical contact. Therefore, the results validate the multi-sensor control strategy.

关键词： Assembly Attitude measurement Force control Multi-sensor Vision

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Closed-Form Modeling and Analysis of an XY Flexure-Based Nano-Manipulator

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Chinese Journal of Mechanical engineering 2018年第1期31卷 176-186页

作者： Yan-Ding Qin Xin Zhao Bijan Shirinzadeh Yan-Ling Tian Da-Wei Zhang Institute of Robotics and Automatic Information System (Tianjin Key Laboratory of Intelligent Robotics) Nankai University Robotics and Mechatronics Research Laboratory Department of Mechanical and Aerospace Engineering Monash University School of Mechanical Engineering Tianjin University

Flexure-based mechanisms are widely utilized in nano manipulations. The closed-form statics and dynamics modeling is difficult due to the complex topologies, the inevitable compliance of levers, the Hertzian contact interface, etc. This paper presents the closed-form modeling of an XY nano-manipulator consisting of statically indeterminate symmetric(SIS) structures using leaf and circular flexure hinges. Theoretical analysis reveals that the lever’s compliance, the contact stiffness, and the load mass have significant influence on the static and dynamic performances of the *** are conducted to verify the effectiveness of the established models. If no piezoelectric actuator(PEA) is installed, the influence of the contact stiffness can be eliminated. Experimental results show that the estimation error on the output stiffness and first natural frequency can reach 2% and 1.7%, respectively. If PEAs are installed, the contact stiffness shows up in the models. As no effective method is currently available to measure or estimate the contact stiffness, it is impossible to precisely estimate the performance of the overall system. In this case, the established closed-form models can be utilized to calculate the bounds of the performance. The established closed-form models are widely applicable in the design and optimization of planar flexure-based mechanisms.

关键词： Flexure-based mechanism Statically indeterminate structure Dynamics Lever mechanism Piezoelectric actuator

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