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BGS Distribution Deformation in BOTDR Induced by Self-Phase Modulation

Photonic Sensors 2025年第1期15卷 11-25页

作者： Haoting WU Wencun GUO Zixuan ZHONG Guolu YIN Tao LIU Tao ZHU State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China The Key Laboratory of Optoelectronic Technology&Systems(Ministry of Education) Chongqing UniversityChongqing 400044China

We report the numerical and experimental studies of the two-dimensional Brillouin gain spectrum(BGS)distribution deformation induced by the self-phase modulation in the Brillouin optical time domain reflectometry(BOTDR)with a 20.6 km sensing *** BGS distribution deformation is investigated by analyzing the evolution of the point spread function along the fiber in the two-dimensional model of the *** the simulation and experimental results,the specific deformation degree of the BGS distribution induced by the self-phase modulation is related to the pump pulse profile,pump pulse peak power,BGS demodulation method,and detected scattered light *** comprehensively analyzing the evolution of the point spread function induced by the self-phase modulation and using the image deconvolution,a typical BOTDR sensor with a 25 ns pump pulse reaches the 20 cm spatial resolution over the 20.6 km sensing fiber.

关键词： Optical time domain reflectometry Brillouin scattering self-phase modulation deconvolution

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A Rhythmic Motion Control Method Inspired by Board Shoe Racing for a Weight-Bearing Exoskeleton

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Journal of Bionic Engineering 2022年第2期19卷 403-415页

作者： Tianshuo Wang Jie Zhao Dongbao Sui Sikai Zhao Yanhe Zhu State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

To ensure the flexible walking of the weight-bearing exoskeleton robot,most researchers control the exoskeleton to follow the wearer’s movements and provide force to maintain the current dynamic ***,due to the limitation of sensing information and computing power,it is difficult for the exoskeleton to provide the wearer reasonable and stable force only based on the dynamic model,especially in switching between swing phase and stance *** by China’s traditional sport named board shoe racing,a walking control method based on the cooperation of the human and the exoskeleton is proposed in this paper for a lower-limb exoskeleton named *** certain conditions,the exoskeleton itself can walk stably depending on the rhythm signals generated by the Central Pattern Generator(CPG).With certain initiative during walking,it can make proper adjustments according to the human *** the help of dynamic simulation software and Genetic Algorithm(GA),the optimized CPG parameters are *** control is introduced to increase the comfort of the *** impedance parameters as well as the CPG parameters are tuned in real time based on *** experiments were conducted with *** results demonstrate that PALExo can effectively assist the wearer walking with a 45-kg payload benefiting from the proposed method.

关键词： Exoskeleton robot Central pattern generator Walking control method

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Event-Triggered Robust Parallel Optimal Consensus Control for Multiagent systems

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 40-53页

作者： Qinglai Wei Shanshan Jiao Qi Dong Fei-Yue Wang IEEE the Institute of Systems Engineering Macau University of Science and Technology the State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of Automation Chinese Academy of Sciences the School of Artificial Intelligence University of Chinese Academy of Sciences China Academy of Electronics and Information Technology the State Key Laboratory of Multimodal Artificial Intelligence Systems the School of Artificial Intelligence University of Chinese Academy of Sciences

This paper highlights the utilization of parallel control and adaptive dynamic programming(ADP) for event-triggered robust parallel optimal consensus control(ETRPOC) of uncertain nonlinear continuous-time multiagent systems(MASs).First, the parallel control system, which consists of a virtual control variable and a specific auxiliary variable obtained from the coupled Hamiltonian, allows general systems to be transformed into affine systems. Of interest is the fact that the parallel control technique's introduction provides an unprecedented perspective on eliminating the negative effects of disturbance. Then, an eventtriggered mechanism is adopted to save communication resources while ensuring the system's stability. The coupled HamiltonJacobi(HJ) equation's solution is approximated using a critic neural network(NN), whose weights are updated in response to events. Furthermore, theoretical analysis reveals that the weight estimation error is uniformly ultimately bounded(UUB). Finally,numerical simulations demonstrate the effectiveness of the developed ETRPOC method.

关键词： Adaptive dynamic programming (ADP) critic neural network (NN) event-triggered control optimal consensus control robust control

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Real-Time Break-Through Detection in Craniotomy Using Long Short-Term Memory Networks

Real-Time Break-Through Detection in Craniotomy Using Long S...

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2024 IEEE International Conference on robotics and Biomimetics, ROBIO 2024

作者： Chen, Yunle Shen, Xingjian Meng, Xianghe Xie, Hui Harbin Institute of Technology State key Laboratory of Robotics and Systems 2 Yikuang Nangang District Harbin150080 China

ISBN: (纸本)9781665481090

An important step before the implantation of an invasive brain-computer interface (BCI) is craniotomy, which provides direct access to the brain. During the craniotomy, the precision of cranial drilling is critical, as any deviation or exces-sive penetration can pose significant risks, potentially leading to severe brain injury. Traditional methods of force signal analysis lack effective feedback in complex situations, leading to a risk of over-drilling and potential brain damage. Here, we proposes a Long Short-Term Memory (LSTM) neural network to detect the break-through of the drill bit in real-time. Thrust force data from five drilling experiments on a fancy rat skull specimen are collected. The force data are then split into 0.2-second intervals corresponding to different stages of the drilling process. An LSTM network is trained with these labeled datasets to detect changes in the drilling stage, thereby determining the break-through point. The trained classicfication network gets a accuracy of 96%. Practical drilling experiments on a fancy rat skull specimen validates the feasibility and accuracy of the break-through detection algorithm. The experimental results demonstrate that the method can achieve an over-penetration distance within 15 μm, which is safe for performing craniotomy in rats. Given that this method ensures safety for the stringent requirements of rat craniotomy, it can be expected to provide even greater safety for human craniotomy procedures. © 2024 IEEE.

关键词： Risk assessment

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Experimental and modeling study of surface topography generation considering tool-workpiece vibration in high-precision turning

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Chinese Journal of Aeronautics 2023年第7期36卷 194-212页

作者： Xingying ZHOU Henan LIU Tianyu YU Ruiyang GUO Guangzhou WANG Yazhou SUN Mingjun CHEN State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China

High-precision turning(HPT)is a main processing method for manufacturing rotary high-precision components,especially for metallic ***,the generated vibration between tool tip and workpiece during turning may seriously deteriorate the surface ***,exploring the effect of vibration on turning surface morphology and quality of copper parts using 3D surface topography regeneration model is crucial for predicting HPT *** developed model can update the machined surface topology in real *** this study,the effects of tool arc radius,feed rate,radial vibration,axial vibration and tangential vibration on the surface topography and surface roughness were *** results show that the effect of radial vibration on surface topography is greater than that of axial vibration and tangential *** radial vibration frequency is also *** vibration frequency changes,the surface topography profile presents three different types:the standard sinusoidal curve,the sinusoidal curve whose lowfrequency signal envelopes high-frequency signal,and the oscillation curve whose low-frequency signal superimposes high-frequency *** addition,HPT experiment was carried out to validate the developed *** surface roughness obtained in the experiment was Ra=53 nm,while the roughness obtained by the simulation was Ra=46 nm,achieving a prediction accuracy of 86.7%.Received 4 September 2022;revised 3 October 2022;accepted 17 October 2022.

关键词： High-precision turning Machining vibration Modeling Surface roughness Surface topography

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Recent progress in lanthanide ions doped inorganic metal halide perovskites

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Journal of Rare Earths 2024年第2期42卷 237-250,I0001页

作者： Yiyan Zhang Tianyu Zhao Guanying Chen MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringState Key Laboratory of Urban Water Resource and EnvironmentKey Laboratory of Micro-systems and Micro-structuresMinistry of EducationHarbin Institute of TechnologyHarbin150001China

Benefiting from their large molar extinction coefficient,high carrier mobility,narrow and tunable emissions,inorganic metal halide perovskites(IMHPs) demonstrate great potential in various optoelectrical devices including solar cells,light emitting diodes and photodetectors in the past few *** ions doping,well-known as a modification method of semiconductors,has been extensively applied in IMHPs as *** metal ions have been doped in IMHPs including alkali metals,alkali earth metals,transition metals and lanthanide metals,which either improve their optical performances or induce intriguing brand-new *** them,lanthanide metals feature plentiful energy levels and stable optical properties and are one of the most noteworthy *** we review recent progress in lanthanide ions doped *** summarize Yb,Eu or Er ions singly doping in detail,which was the most investigated species in *** lanthanide ions are also reviewed ***,we introduce lanthanide ions multi-doped IMHPs and at last we put forward several potential development *** the interests in lanthanide ions doped IMHPs rise,researchers have made some achievements in the *** though,there are more unexplored *** there are review articles focusing on metal ions doped IMHPs or lanthanide ions doped perovskites,this review aims to provide an overall introduction of lanthanide ions doped *** review may help researchers learn about lanthanide ions doped IMHPs and is to inspire researchers to make further promotion in this field.

关键词： Halide perovskite Lanthanide Doping Rare earths

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A novel method of water bath heating assisted small ball-end magnetorheological polishing for hemispherical shell resonators

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Chinese Journal of Aeronautics 2023年第12期36卷 451-460页

作者： Jinchuan TIAN Mingjun CHEN Jian CHENG Henan LIU State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001China

Hemispherical shell resonator(HSR)is the core component of hemispherical resonator *** is aφ-shaped small-bore complex component with minimum curvature radius less than 3 ***,traditional polishing methods are difficult to polish *** ball-end magnetorheological polishing method can polish the small components with complicated three-dimensional surface and obtain non-destructive ***,this method is suitable for polishing ***,the material removal rate of the ordinary small ball-end magnetorheological polishing is low,leading to long polishing time and low output of *** solve this problem,a water bath heating assisted small ball-end magnetorheological polishing method is proposed in this *** influence rule of processing parameters on the material removal rate is studied experimentally.A set of optimal processing parameters is obtained to maximize the material removal *** with the ordinary method,the material removal rate of the new method can be improved by 143%.Subsequently,an HSR is polished by the new *** results show that the polishing time can be reduced by 55%,and the polished surface roughness can reach 7.7 *** new method has the great potential to be used in actual production to improve the polishing efficiency of HSR.

关键词： Hemispherical shell resonator Magnetorheological fluid temperature Material removal rate Optimization Small ball-end magnetorheological polishing

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Effects of Environmental Factors on Corrosion Behavior of E690 Steel in Simulated Marine Environment

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 678-694页

作者： Jingjing Peng Jing Liu Shen Zhang Zhihui Wang Xian Zhang Kaiming Wu Collaborative Innovation Center for Advanced Steels Hubei Province Key Laboratory of Systems Science in Metallurgical ProcessThe State Key Laboratory of Refractories and MetallurgyWuhan University of Science and TechnologyWuhan430081China

The effects of hydrostatic pressure, dissolved oxygen, temperature and flow velocity, and their interaction on the corrosion rates of E690 high-strength steel (HSS) in simulated marine environments were studied using response surface methodology. The results show that the flow velocity exerts the most significant influence on the corrosion rate of E690 HSS. Consequently, the corrosion behavior of E690 HSS under varying flow velocities were analyzed profoundly from initial pitting corrosion to long-term corrosion properties. The results indicate that the flow state facilitates the mass transfer and enhances the adsorption tendency of Cl− by enhancing the electrochemical activity of the steel surface. These factors accelerate the electrochemical reactions, resulting in increased pitting density, depth and the long-term corrosion rates in dynamic seawater environments.

关键词： E690 steel Simulated marine environment Corrosion behavior Flow velocity Response surface methodology(RSM)

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A Humanoid Robot to Assess the Affective Imitative Expression Abilities of Children with Autism Spectrum Disorder

A Humanoid Robot to Assess the Affective Imitative Expressio...

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2023 International Conference on Machine Learning and Cybernetics, ICMLC 2023

作者： Ji, Hao-Yu Chen, Bo-Wen Wang, Zhi-Yong Ma, Han-Wei Lin, Rui-Han Sheng, Yi-Xuan Liu, Hong-Hai State Key Laboratory of Robotics and Systems Shenzhen518055 China

ISBN: (纸本)9798350303780

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by impairments in social interaction and communication, repetitive behaviors and restricted interests. Assessments and interventions targeting affective expression are crucial for supporting the development of children with ASD. However, existing approaches face challenges related to complex interventions, lack of unified metrics, and inadequate immersion and guidance in providing effective affective assessment. In this paper, an innovative humanoid robot is designed and evaluated to address specific challenges and assess the ability of children with ASD in affective imitative expression. The robot, with its meticulously designed mechanical and hardware structure, incorporates an assessment protocol for affective imitative expression and algorithms for assessing affective expression abilities. It utilizes several specially designed assessment metrics to generate a uniquely tailored assessment scale for affective imitative expression. A preliminary experiment involving ten neurotypical adults has been conducted to validate the feasibility and accuracy of the proposed system. The results demonstrate potential in supporting rehabilitation planning and research for ASD assessments. © 2023 IEEE.

关键词： Anthropomorphic robots

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Numerical simulation of the vacuum casting process of solid propellants 3

Numerical simulation of the vacuum casting process of solid ...

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2024 3rd International Conference on Acoustics, Fluid Mechanics and Engineering, AFME 2024

作者： Gao, Zhe Wei, Ming Li, Wensen Chen, Cunzhuang Li, Changle Zhao, Jie State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin150000 China Hubei Institute of Aerospace Chemical Technology Xiangyang441003 China

Solid propellant is one of the main components of rocket engines, and the casting of low-viscosity propellant slurry usually uses a vacuum casting process. During the vacuum casting process, the rheological properties of solid propellant slurry are complex, and the theoretical analytical method cannot intuitively and accurately analyze its flow characteristics. Therefore, this paper numerically simulates the casting process through simulation software, uses the Herschel-Bulkley model to characterize the changes in the flow characteristics of solid propellant slurry during the vacuum casting process, and studies the effects of different hopper angles and anti-break vacuum plug shapes on the slurry's rheological properties. By analyzing parameters such as slurry mass flow rate, velocity, residual amount in the hopper, and surface pressure of the plug, the appropriate hopper angle and the bottom edge angle of the anti-break vacuum plug are selected. Finally, the slurry leveling characteristics under suitable hopper and plug conditions are analyzed. The results indicate that a hopper angle of 140° and an anti-break vacuum plug bottom angle of 120° are optimal. The entire vacuum casting process takes approximately 42 seconds, and the overall slurry leveling is good. As the casting progresses, the slurry gradually compacts and levels out, and the bubbles at the bottom of both sides of the combustion chamber gradually disappear. © Published under licence by IOP Publishing Ltd.

关键词： Hoppers

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