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arXiv 2024年

作者： Meng, Lei He, Chen Ji, Wei Yen, Fei State Key Laboratory on Tunable Laser Technology Ministry of Industry and Information Technology Key Laboratory of Micro-Nano Optoelectronic Information System The School of Science Harbin Institute of Technology Shenzhen University Town Guangdong Shenzhen518055 China Education Center of Experiments and Innovations Harbin Institute of Technology Shenzhen University Town Guangdong Shenzhen518055 China

We observe sharp step-down discontinuities in the magnetic susceptibility of NH4H2PO4 and NH4H2PO4-d60 (60% deuterated) along the a and c-axes occurring exactly at their antiferroelectric transition temperatures. For the case of KH2PO4, less pronounced discontinuities occur at the ferroelectric transition temperature. To explain this, we treat the acid protons as individual oscillators that generate current elements which translate to magnetic forces in near resonance with each other. With decreasing temperature, the resonant forces become more commensurate which amplifies a disproportionate drop off of two types of magnetic forces to eventually trigger the structural phase transitions. For the case of NH4H2PO4, the associated internal magnetic field appears to aid the NH4+ to order at higher temperature. At 49 K, a shoulder-like anomaly in both NH4H2PO4 and KH2PO4 is attributed to a possible onset of macroscopic quantum tunneling of protons. Our findings bring forth a new category of intrinsic multiferroic systems. © 2024, CC BY-NC-ND.

关键词： Temperature

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Design and Verification of IE6 Ultra Efficiency Line-Start Permanent Magnet Assisted Synchronous Reluctance Motor

Design and Verification of IE6 Ultra Efficiency Line-Start P...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Yusheng Hu Yong Xiao Jinfei Shi Bin Chen Ying Li Liyi Li Guangdong Provincial Key Laboratory of High-speed and Energy Conservation Motor System China GREE ELECTRIC APPLIANCES INC. of ZHUHAI Zhuhai China Harbin Institute of technology Harbin China

ISBN: (数字)9784886864406

ISBN: (纸本)9798350379105

Line-start PM assisted synchronous reluctance machine (LS-PMaSynRM) combines the characteristics of an asynchronous motor and a permanent magnet assisted synchronous reluctance motor. It starts through asynchronous torque generated by squirrel cages (conductor bars) and runs synchronously through permanent magnet torque and reluctance torque. The basic principle of LS-PMaSynRM was introduced in this paper, and then the rotor structure was designed and optimized. The effects of the number of flux barrier (permanent magnet) layers, the thickness of PMs, the distribution of conductor bars, the amount of PMs in each layer, and the total amount of PMs on the efficiency were simulated, and the rotor structure was determined. Compared with line- start permanent magnet synchronous motor (LS-PMSM) with the same power, LS-PMaSynRM has obvious efficiency advantages at the same cost. Under the existing machine frame, the LS-PMaSynRM achieves IE6 ultra-high energy efficiency. Finally, the performance of the LS-PMaSynRM was verified through prototype testing.

关键词： Torque Costs Rotors Prototypes Conductors Permanent magnets Energy efficiency Reluctance motors Bars Testing

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A Novel Seesaw-Like Piezoelectric Energy Harvester for Low Frequency Vibration

SSRN

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SSRN 2022年

作者： Yu, Han Hou, Chengwei Shan, Xiaobiao Zhang, Xingxu Song, Henan Zhang, Xiaofan Xie, Tao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace Northwestern Polytechnical University Xi'An710072 China

This paper presents a novel seesaw-like piezoelectric energy harvester which has rotating motions to enhance the harvesting performance at low frequency vibrations. Firstly, the designing of the harvester with the specific structure was accomplished, and then the finite element analysis was conducted to simulate its dynamic characteristics. Finally, the prototype of the harvester was fabricated whose power generating behaviors were experimentally investigated. The influence of key structural parameters on the energy harvesting performance was evaluated by a combination of simulation and experiment. The results indicated that the energy harvester reached the second-order resonance at a low frequency due to the adoption of the rotating shaft. And the composite beam of the harvester was involved in a significant strain. The efficiency of the harvester is relevant to the system moment of inertia and the excitation acceleration. The second-order resonant frequency of the harvester is as low as 19.18 Hz. When the excitation acceleration is 2.94 m/s2, the maximum output voltage and power of the harvester are 49.15 V and 4.03 mW respectively, which demonstrate the superior harvesting performance of the structure. This work can provide a novel method for designing efficient ambient energy harvesters supplying for low-power electronic devices. © 2022, The Authors. All rights reserved.

关键词： Piezoelectricity

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Hydrogel-elastomer-based stretchable strain sensor fabricated by a simple projection lithography method

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International Journal of Smart and Nano Materials 2021年第3期12卷 256-268页

作者： Zhenqing Li Xiangnan He Jianxiang Cheng Honggeng Li Yuan-Fang Zhang Xiaojuan Shi Kai Yu Hui Ying Yang Qi Ge Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems Department of Mechanical and Energy EngineeringSouthern University of Science and TechnologyShenzhenChina Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities Southern University of Science and TechnologyShenzhenChina Digital Manufacturing and Design Centre Singapore University of Technology and DesignSingapore Department of Mechanical Engineering University of Colorado DenverDenverCOUSA National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbinP.R.China

Stretchable strain sensor detects a wide range of strain variation and is therefore a key component in various *** traditional ones made of elastomers doped with conductive components or fabricated with liquid conductors,ionically conductive hydrogel-based strain sensors remain conductive under large deformations and are ***,dehydration is a challenging issue for the *** have developed hydrogel-elastomer-based strain sensors where an elastomer matrix encapsulates a hydrogel circuit to prevent its ***,the reported multistep approaches are generally *** group recently reported a multimaterial 3D printing approach that enables fast fabrication of such sensors,yet requires a self-built digital-light-processing-based multimaterial 3D ***,we report a simple projection lithography method to fabricate hydrogel-elastomer-based stretchable strain sensors within 5 *** method only requires a UV projector/lamp with photomasks;the chemicals are commercially available;the protocols for preparing the polymer precursors are friendly to users without chemistry ***,the manufacturing flexibility allows users to readily pattern the sensor circuit and attach the sensor to a 3D printed soft pneumatic actuator to enable strain sensing on the *** proposed approach paves a simple and versatile way to fabricate hydrogel-elastomer-based stretchable strain sensors and flexible electronic devices.

关键词： Ionically conductive hydrogel stretchable strain sensor projection lithography

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Distributed Event-Triggered Consensus of Uncertain Multi-Agent systems Under a Directed Graph

Distributed Event-Triggered Consensus of Uncertain Multi-Age...

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American Control Conference (ACC)

作者： Yanhua Yang Jie Mei Guangfu Ma Guangdong Key Laboratory of Intelligent Morphing Mechanisms and Adaptive Robotics School of Mechanical Engineering and Automation Harbin Institute of Technology (Shenzhen) Shenzhen Guangdong China

ISBN: (数字)9798350382655

ISBN: (纸本)9798350382662

In this paper, the distributed event-triggered consensus control of uncertain multi-agent systems (MASs) under a directed graph is investigated, where the information transmission among agents is intermittent and asynchronous. Firstly, to eliminate the influence of the nonlinear uncertainties and reduce the communication burden among the agents, we employ the model reference adaptive consensus (MRACon) technique, where a reference model with the predicted relative state information initialized by intermittently collected state information of neighbors as input is introduced for each agent to track. An adaptive consensus algorithm is designed such that the uncertain MAS under a directed graph reaches consensus asymptotically. A novel graph-based Lyapunov functional is proposed to guarantee the correctness of theoretical analysis. Moreover, a lower bound of the minimum transmission interval is obtained for each agent, and thus the Zeno behavior is strictly ruled out. Finally, the effectiveness is verified by a simulation example.

关键词： Adaptation models Uncertainty Protocols Directed graphs Information processing Switches Predictive models

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Distributed Dual-Layer Adaptive Event-Triggered Formation Tracking for Quadrotor UAVs

Distributed Dual-Layer Adaptive Event-Triggered Formation Tr...

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American Control Conference (ACC)

作者： Tianxing Chen Hongwei Zhang Guangdong Provincial Key Laboratory of Intelligent Morphing Mechanisms and Adaptive Robotics School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen Guangdong China

ISBN: (数字)9798350382655

ISBN: (纸本)9798350382662

Achieving resource-efficient robust tracking is critical for micro aerial robotics subject to external disturbances. In this paper, a novel distributed dual-layer adaptive event-triggered controller is proposed for cooperative formation tracking under unknown disturbances. Two different triggering sequences are designed to determine the appropriate instants for communication and control updates, thus greatly reducing the update frequency of the controller and communication consumption. Moreover, adaptive event-triggered conditions with heterogeneous parameters are well-desigeed to cope with unknown disturbances, while improving the flexibility of parameter selection and excluding Zeno behavior. By employing Lyapunov theory, new sufficient conditions for ensuring the feasibility of the proposed algorithm are rigorously derived to eliminate the conservatism. The performance of the proposed algorithm is illustrated through numerical validations of co-operative formation tracking under cluttered nonlinear disturbances, and a detailed comparison with existing algorithms is made to fully demonstrate the robustness and advantage of the proposed algorithm.

关键词： Sufficient conditions Numerical simulation Stability analysis Robustness Frequency control Robots Numerical stability

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Development of a Spherical Wheel-legged Composite Mobile Robot with Multimodal Motion Capabilities

Development of a Spherical Wheel-legged Composite Mobile Rob...

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IEEE/RSJ International Conference on Intelligent Robots and systems (IROS)

作者： Yuyang Du Ruihua Ye Wenfu Xu School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen China Guangdong Key Laboratory of Intelligent Morphing Mechanisms and Adaptive Robotics Shenzhen China

ISBN: (数字)9798350377705

ISBN: (纸本)9798350377712

In this paper, we present a spherical wheel-legged mobile robot, aiming to meet the demands of adaptability to complex terrains and high maneuverability. It consists of a spherical main body and five-bar linkage parallel wheel-legged mechanisms. It can switch between legged and spherical modes by extending and retracting its legs according to the demands of the actual environment, thereby enhancing the overall mobility of the robot. By designing the Linear Quadratic Regulator (LQR) controller, we achieve the impact-resistant leg balancing motion and autonomous pitch adjustment for the robot on inclined surfaces in the legged configuration. For the rolling control in the spherical configuration, a hierarchical sliding mode control method and Proportional-Integral-Derivative controller (PID) are employed to control the rolling and turning of the robot. We verify the robustness of the robot in wheel-legged configuration against disturbances and the stability of its motion in spherical configuration.

关键词： Legged locomotion Torque Dynamics Switches Turning Mathematical models Stability analysis Steady-state Robots Sliding mode control

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Ultrathin SrTiO_(3)-based oxide memristor with both drift and diffusive dynamics as versatile synaptic emulators for neuromorphic computing

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Materials Futures 2023年第3期2卷 156-163页

作者： Fang Nie Jie Wang Hong Fang Shuanger Ma Feiyang Wu Wenbo Zhao Shizhan Wei Yuling Wang Le Zhao Shishen Yan Chen Ge Limei Zheng School of Physics State Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100People’s Republic of China School of Information and Automation Engineering Qilu University of Technology(Shandong Academy of Science)Jinan 250353People’s Republic of China Functional Materials and Acousto-Optic Instruments Institute School of Instrumentation Science and EngineeringHarbin Institute of TechnologyHarbin 150080People’s Republic of China Spintronics Institute School of Physics and TechnologyUniversity of JinanJinan 250022People’s Republic of China Heilongjiang Provincial Key Laboratory of Oilfield Applied Chemistry and Technology School of Mechatronic EngineeringDaqing Normal UniversityDaqing 163712People’s Republic of China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190People’s Republic of China

Artificial synapses are electronic devices that simulate important functions of biological synapses,and therefore are the basic components of artificial neural morphological networks for brain-like *** of the most important objectives for developing artificial synapses is to simulate the characteristics of biological synapses as much as possible,especially their self-adaptive ability to external ***,we have successfully developed an artificial synapse with multiple synaptic functions and highly adaptive characteristics based on a simple SrTiO_(3)/Nb:SrTiO_(3)heterojunction type *** functions of synaptic learning,such as short-term/long-term plasticity(STP/LTP),transition from STP to LTP,learning–forgetting–relearning behaviors,associative learning and dynamic filtering,are all bio-realistically implemented in a single *** remarkable synaptic performance is attributed to the fascinating inherent dynamics of oxygen vacancy drift and diffusion,which give rise to the coexistence of volatile-and nonvolatile-type resistive *** work reports a multi-functional synaptic emulator with advanced computing capability based on a simple heterostructure,showing great application potential for a compact and low-power neuromorphic computing system.

关键词： memristor artificial synapse synaptic plasticity associative learning learning-experience

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Single-Photon LiDAR Depth Estimation Based on Time Series Correlation

Single-Photon LiDAR Depth Estimation Based on Time Series Co...

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Academic International Symposium on Optoelectronics and Microelectronics technology (AISOMT)

作者： Lin Ruobin Sun Jianfeng Jiang Peng Ma Le Zhou Xin Ren Zhen Ding Ji National Key Laboratory of Laser Spatial Information Harbin Institute of Technology Harbin Heilongjiang China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou Henan China National Key Laboratory of Complex System Control and Intelligent Agent Cooperation Beijing China Tianjin Jinhang Technical Physics Institute Tianjin China Beijing Aerospace Automatic Control Institute Beijing China

ISBN: (数字)9798331542283

ISBN: (纸本)9798331542290

With advancements in science and technology, photon-counting LiDAR applications are growing due to long-range measurement, high-definition imaging, and accuracy. Geiger-mode avalanche photodiodes (Gm-APD) provide single-photon sensitivity and picosecond resolution, but noise in depth estimation affects imaging accuracy. This study introduces a novel depth estimation method using time series correlation to mitigate these noise issues, improving accuracy in LiDAR imaging. Utilizing a photon-counting LiDAR system and time-correlated single photon counting (TCSPC), this study capture target echo photon flight times to maintain depth information. The proposed denoising approach incorporates multiple time series windows and Bayesian estimation to enhance depth accuracy, alongside a pruning algorithm to optimize computational efficiency. Evaluation metrics show significant improvements: RSNR improved by 4% and MAE decreased by 43 % compared to traditional methods. The findings demonstrate the robustness of this method across various scenarios, enhancing depth estimation and noise mitigation in photon-counting LiDAR technology, thereby providing practical improvements for a range of applications.

关键词： Correlation Laser radar Accuracy Filtering Depth measurement Time series analysis Noise reduction Imaging Bayes methods Photonics

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Broadband high-efficiency dielectric metalenses based on quasi-continuous nanostrips

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Opto-Electronic Advances 2024年第5期7卷 43-51页

作者： Xiaohu Zhang Qinmiao Chen Dongliang Tang Kaifeng Liu Haimo Zhang Lintong Shi Mengyao He Yongcai Guo Shumin Xiao Key Laboratory of optoelectronic Technology and Systems of the Education Ministry of China Chongqing UniversityChongqing 400044China Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic SystemsHarbin Institute of TechnologyShenzhen 518055China Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China

Benefiting from the abrupt phase changes within subwavelength thicknesses,metasurfaces have been widely applied for lightweight and compact optical *** broadband and high-efficiency characteristics are highly attractive for the practical implementation of ***,current metasurface devices mostly adopt discrete micro/nano structures,which rarely realize both merits *** this paper,dielectric metasurfaces composed of quasi-continuous nanostrips are proposed to overcome this *** quasi-continuous nanostrips metasurface,a normal focusing metalens and a superoscillatory lens overcoming the diffraction limit are designed and experimentally *** quasi-continuous metadevices can operate in a broadband wavelength ranging from 450 nm to 1000nm and keep a high power *** average efficiency of the fabricated metalens reaches 54.24%,showing a significant improvement compared to the previously reported metalenses with the same *** proposed methodology can be easily extended to design other metadevices with the advantages of broadband and high-efficiency in practical optical systems.

关键词： broadband high-efficiency metalens sub-diffraction quasi-continuous

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