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Forming Circle Formations of Multi-agent systems Under Actuator Faults 5th

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Forming Circle Formations of Multi-agent Systems Under Actu...

5th Chinese Conference on Swarm Intelligence and Cooperative Control, CCSICC 2021

作者： Liu, Jiajun Ru, Xinfeng Xia, Weiguo Wang, Chen China National Aeronautical Radio Electronic Research Institute and National Key Laboratory of Science and Technology on Avionics System Integration Shanghai China Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education and School of Control Science and Engineering Dalian University of Technology Dalian China National Engineering Research Center of Software Engineering and the State Key Laboratory of Turbulence and Complex Systems Intelligent Biomimetic Design Lab College of Engineering Peking University Beijing China

ISBN: (纸本)9789811939976

A distributed fault-tolerant formation control law is designed in this paper for multi-agent systems under external disturbances and actuator faults including time-varying loss of effectiveness faults. The initial position of each agent is already on a circle and the control purpose is to form a desired formation on this circle. Based on this local information, a distributed adaptive formation control law is designed by employing the congelation of variables method to deal with time-varying actuator faults. Finally, a simulation example is given to verify the effectiveness of the adaptive fault-tolerant control design method. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Multi agent systems

Experimental Study on Surface Characteristics and Thermal Conductivity of New Zirconium Alloy with Oxide Layer

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SSRN 2022年

作者： Zhong, Lei Chen, Deqi Yu, Hongxing Liu, Haidong Chen, Mingjing Liu, Hanzhou Deng, Jian Ding, Shuhua Wu, Dan Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing University Ministry of Education Chongqing 400044 China

The surface properties and thermal conductivity of oxide layer formed on the new zirconium alloy due to high temperature steam oxidation are studied in this paper. The thickness of oxide layer, surface wettability and thermal conductivity are measured. The effects of oxidation temperature and time on the wettability and thermal conductivity of zirconium alloy are analyzed. The results show that zirconium on the surface is fully oxidized to ZrO2 , and the difference of surface wettability is caused by different surface morphology. The characteristics of oxide layer surface cracks will affect the surface wettability. At the same oxidation temperature, with increasing time duration, the size and number of oxide layer cracks increase. The change of thermal conductivity is the result of competition among factors such as the development of recrystallization process, the increase of oxide layer thickness and the influence of pores and cracks. © 2022, The Authors. All rights reserved.

关键词： Wetting

Study on Imc-Pid Control of Once Through Steam Generator for Small Lead Bismuth Fast reactor

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SSRN 2022年

作者： Sun, Aodi Zhang, Ru Xiao, Kai He, Zhengxi Sun, Peiwei Wei, Xinyu Key Laboratory of Advanced Nuclear Energy and Technology Shaanxi Engineering Research Center of Advanced Nuclear Energy Xi’an Jiaotong University Xi’an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

Due to the particularity of nuclear reactor, it is difficult to adjust the controller parameters by experiment. The simulation calculation inevitably simplifies the actual model. The controller parameters tuned by this model is likely to cause poor performance due to model mismatch. Therefore, the research on the adaptability of the controller to model mismatch has guiding significance for engineering application. In this paper, a once through steam generator(OTSG) for small lead bismuth fast reactor(SLBFR) is established and verified, and the presented model is simplified by three different methods. Internal model control(IMC) and IMC-PID controllers are designed based on the simplified models. With the increase of λ , IMC-PID controller becomes insensitive to model mismatch caused by model linearization, non-minimum phase characteristics, noise and time delay, and has high robustness to model mismatch. However, the robustness to model sacrifices the sensitivity of the system. In the study of rapid power reduction, it is found that large λ will lead to conservative control output, and then make the control performance worse. Through the research of this paper, Method 1 is recommended, and λ is selected between 5 and 10 to design feedwater IMC-PID controller for OTSG of SLBFR. © 2022, The Authors. All rights reserved.

关键词： Model predictive control

An Adaptive Bionic Sensor: Enhancing Ankle Joint Tracking with High Sensitivity and Superior Cushioning Performance

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SSRN 2024年

作者： Jin, Jianqiao Zhang, Chen Zhao, Jianyuan Yu, Minghan Lei, Ming Jin, Chun Yin, Rui Zhao, Weiwei Sauvage Laboratory for Smart Materials The School of Integrated Circuit Harbin Institute of Technology Shenzhen518055 China Shenzhen Key Laboratory of Flexible Printed Electronics Technology Harbin Institute of Technology Shenzhen518055 China State Key Laboratory of Advanced Welding & Joining Harbin Institute of Technology Harbin150001 China Human-Computer Interaction Design Lab School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China

Flexible sensors are renowned for their rapid responsiveness, high flexibility, and outstanding mechanical properties, making them ideal for applications in wearable devices, sports and health monitoring, and human-machine interfaces. To enhance the sensing performance of these flexible sensors, researchers have drawn inspiration from nature, creating various bionic microstructures. However, these structures often manifest in the macroscopic form of thin films, which do little to improve impact resistance and joint protection. In response, this work achieves a highly sensitive and impact-resistant pressure sensor by integrating bionic principles at both micro and macro levels. Specifically, at the micro level, a muscle-like hydrogel system consisting of MXene nanosheets incorporated into the double network of polyvinyl alcohol and sodium alginate matrix is selected. At the macro level, the bionic prototypes of mimosa leaves and durian spikes with good energy absorption structure, together with octopus’ sucker with good adsorption capacity are selected, and the synergistic construction of the three structures is realized through 3D printing methods. The obtained sensor has an appropriate response range, sensitivity and stability. More importantly, the displacement deformation of the hydrogel can be reduced by 91.22%, while its adhesion strength can be increased by 57.5% compared to the unstructured hydrogel. As a proof-of-concept, the proposed bionic flexible sensor can be used to monitor the motion status of the human ankle joint in real-time, thereby assisting users in making real-time judgments on gait health. © 2024, The Authors. All rights reserved.

关键词： Sodium alginate

Compression-based Privacy Preservation for Distributed Nash Equilibrium Seeking in Aggregative Games

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arXiv

arXiv 2024年

作者： Huo, Wei Chen, Xiaomeng Ding, Kemi Dey, Subhrakanti Shi, Ling The Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong The School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China The Department of Electrical Engineering Uppsala University Uppsala75103 Sweden

This paper explores distributed aggregative games in multi-agent systems. Current methods for finding distributed Nash equilibrium require players to send original messages to their neighbors, leading to communication burden and privacy issues. To jointly address these issues, we propose an algorithm that uses stochastic compression to save communication resources and conceal information through random errors induced by compression. Our theoretical analysis shows that the algorithm guarantees convergence accuracy, even with aggressive compression errors used to protect privacy. We prove that the algorithm achieves differential privacy through a stochastic quantization scheme. Simulation results for energy consumption games support the effectiveness of our approach. © 2024, CC BY.

关键词： Random errors

Charging Properties and Particle Dynamics of Chang’e-5 Lunar Sample in an External Electric Field

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Engineering 2024年第11期42卷 267-277页

作者： Junping Gu Xiaoyu Qian Yiwei Liu Qinggong Wang Yiyang Zhang Xuan Ruan Xiangjin Deng Yaowen Lu Jian Song Hui Zhang Yunning Dong Mengmeng Wei Wei Yao Shuiqing Li Weihua Wang Zhigang Zou Mengfei Yang Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Institute of Nuclear and New Energy TechnologyTsinghua UniversityBeijing 100084China Beijing Institute of Spacecraft System Engineering Beijing 100094China Beijing Orient Institute of Measurement and Test Beijing 100086China Institute of Physics Chinese Academy of SciencesBeijing 100190China College of Engineering and Applied Sciences Nanjing UniversityNanjing 210093China China Academy of Space Technology Beijing 100094China

Facing the challenges of in-situ utilization of lunar regolith resources,applying an external electric field to manipulate lunar particles has become a promising method for space particle control,which mainly depends on the particle charging properties in the applied electric *** the surficial lunar regolith samples brought back from the Moon by the Chang’e-5 mission(CE5 LS),this work successively studied their charging properties,particle dynamics,and their collision damages to aerospace materials under the action of an external electric field in high-vacuum *** results indicated that the charging pro-cess and electrostatic projection of lunar regolith particles under high-vacuum conditions were different from those under atmosphere *** particle diameter range of CE5 LS used in the experiment is 27.7-139.0 *** electric field strength of 3-12 kV·cm^(-1),the charge obtained by CE5 LS is 4.8×10^(-15)-4.7×10^(-13) C and the charge-to-mass ratio is 1.2×10^(-5)-6.8×10^(-4) C·kg^(-1).The CE5 LS is easier to be negatively charged in an external electric ***,significant damages were observed on the target impact surfaces,indicating severe influences of lunar regolith particles on aerospace *** work contributes to a more comprehensive understanding of physical mechanisms controlling the lunar regolith shielding and utilization,and will inspire broad efforts to develop the lunar in-situ engi-neering solutions.

关键词： Chang’e-5 lunar regolith sample Charging properties External electric field Particle dynamics Particle collision

Development of the Expanding Mandrel Test Facility for Investigation of Zircaloy Cladding Performance Under Loading Strain Rate Similar to Power Ramp

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SSRN 2022年

作者： He, Yanan Wu, Yingwei Qiu, Bowen Lei, Zhao He, Liang Jiao, Yongjun Chen, Ping Tian, Wenxi Su, Guanghui Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Shaanxi Engineering Research Center of Advanced Nuclear Energy Xi’an Jiaotong University Xi'An710049 China Nuclear Power Institute of China Science and Technology on Reactor System Design Technology Laboratory Chengdu China

The in-pile pellet-cladding interaction (PCI) is the one of challenging problems for conventional UO2-Zicaloy fuel systems, which can threaten the integrity of the fuel rod and lead to the release of fission product. Currently, several experiments and numerical studies have been devoted to PCI analysis. However, attributing the lacking of experimental data with high fidelity, the development, and validation of the PCI analysis model is not sufficient. In this study, an expanding mandrel test facility has been developed to investigate PCI behaviors, where the digital image correlation (DIC) measuring system was introduced to online monitor the displacements/strain of cladding outer surface with improved fidelity. In addition, the oxygen content measurement system was employed to identify the failure of cladding. Subsequently, the expanding mandrel test facility was leveraged to investigate the PCI performance of three types of cladding (e.g. N36 cladding, recrystallized Zircaloy4 cladding, and M5 cladding) under both with/without iodine corrosion and cladding real-time strain, failure time and failure strain were recorded. Then, performance comparisons among these claddings were completed and discussed. The results show that the established facility can be applied to expanding mandrel tests under varied theoretical loading strain rates (10~60%/h) and the working environment temperature can reach 350 . Meanwhile, there are three distinct stages for the deformed Zicaloy cladding during the expanding mandrel test. The comparison results suggest that recrystallized Zircaloy4 cladding shows the largest cladding failure strain with/without iodine corrosion under 20%/h theoretical loading strain, while M5 cladding and N36 cladding present considerable performance without iodine corrosion effect. In addition, N36 and recrystallized Zircaloy4 cladding seems more iodine corrosion resistant than that for M5 cladding, which can be beneficial for its in-pile performance. Besides,

关键词： Corrosion resistance

Thermal Management and Dynamic Performance of a Cooler design for the Supercritical CO2 Turbine Shaft Cooling

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FRONTIERS IN ENERGY RESEARCH 2022年 10卷

作者： Li, Jun Gurgenci, Hal Guan, Zhiqiang Li, Jishun Xue, Yujun Li, Lun School of Mechatronics Engineering Henan University of Science and Technology Henan Key Laboratory for Machinery Design and Transmission System Henan University of Science and Technology Luoyang China School of Mechanical and Mining Engineering University of Queensland Brisbane QLD Australia

This paper presents the results of a numerical study on a supercritical CO2 (SCO2) turboshaft cooling device by considering heat transfer and hydrodynamics. A micro-cooling device with a radius clearance of 50 micron and a nozzle diameter of 4 mm was designed and used to investigate the heat transfer characteristics of a micro-spacing impinging and gas film dynamics. Sixteen nozzles (N = 16) are equally spaced around the shaft in single or double rows. Investigations include journal speed- and eccentricity-dependent forward and cross-coupled force coefficients, and the effects of nozzle layouts and mass flow rate on the heat transfer efficiency. Analysis of the correlation coefficient shows that the gas density in the radial clearance is the dominant factor affecting the convective heat transfer performance, while the fluid velocity is a secondary factor. And the cooling efficiency (mass flow utilization rate) at low cooling pressure (p(s) < 0.7 MPa) is significantly greater than that at high cooling pressure (p(s) > 0.7 MP). In addition, considering the structure alone, a dual-row cooler exhibits a higher average Nusselt number, also registers a higher mass flow rate at the same pressure. Once the shaft is heated only one end, the difference in effectiveness between single- and dual-row cooling is not significant, so coolers with a single-row configuration should be preferred. Then, experimental values for the temperature of the heated rotor are provided under specific cooling airflow conditions. Dynamic analysis results show that the force coefficient of the single-row configuration is more dependent on the journal rotation speed and eccentricity ratio, and exhibits a negative direct stiffness coefficient at higher inlet pressure and journal rotation speed. Moreover, cross-coupled terms (stiffness coefficient) generally have a more explicit variation tendency than direct terms, and are more sensitive to changes in shaft speed and eccentricity. Small clearance cool

关键词： shaft cooling gas film stiffness heat transfer cooler jet impingement

On the Theory of Atomic Relaxation in Twisted Van Der Waals Bilayers with Out-of-Plane Deformation

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SSRN 2024年

作者： Zhang, Baidu Qiu, Wei Liao, Xiangbiao He, Linghui Ni, Yong CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Anhui Hefei230026 China Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing100081 China

The effects of out-of-plane deformation on atomic relaxation in twisted van der Waals bilayers are investigated by comprehensive multiscale modeling and simulations. The model integrates the DFT-informed generalized stacking-fault energy for interlayer interaction between layers and the Föppl–von Kármán plate theory for elastic energy in each layer with minimization of the total free energy for atomic relaxation governed by a gradient flow method. Our simulation results elucidate twist-angle dependent moiré pattern, strain field, tortional displacement field and stacking domain structures, in good agreement with recent experimental observations. In particular, we derive the strain soliton solution at a small twist angle and the elastic solution at a large twist angle for the reconstructed van der Waals bilayer with out-of-plane deformation. These results show that out-of-plane deformation not only narrows the strain soliton width but also induces substantial alterations in the strain field, local rotation, and stacking structures. Our findings reveal the pivotal role played by out-of-plane deformation in the atomic relaxation of twisted van der Waals bilayers, particularly at smaller twist angles. The intricate interplay between in-plane atomic relaxation and out-of-plane deformation provides opportunities for strain engineering in twisted van der Waals bilayers. © 2024, The Authors. All rights reserved.

关键词： Atoms