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SSRN 2023年

作者： Peng, Cheng Song, Youya Wu, Jiang Deng, Jian College of Energy and Mechanical Engineering Shanghai University of Electric Power Shanghai China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

The influence of deposited and suspended nanoparticles on pool boiling of Al2O3 nanofluids was examined through visualization approach in this paper. The deposited nanoparticles cause the wettability to progressively increase as the concentration of nanofluid increases. The findings in this study demonstrate that deposited and suspended nanoparticles increase the frequency of bubble detachment and the quantity of active nucleate sites in water at a mass concentration ranging from 0.001% to 0.005%. The bubble behavior prediction equation was then rectified based on the surface contact angle, and the error margin was found to be within ±12% by comparing the experimental data. Based on which, the predicted values of the bubble behavior parameters were substituted into a corrected equation for boiling heat transfer. By validating the experimental data, the error margin was found to be within ±25%. Additionally, it was discovered that the effect of deposited nanoparticles on boiling heat transfer is always dominant at the heat fluxes between 50 and 250 kW/m2. © 2023, The Authors. All rights reserved.

关键词： Nanoparticles

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Neural Network-Based Terminal Sliding Mode Controller design for Manipulator systems 1

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UNIfied Conference of International Workshop on Defence Applications of Multi-Agent systems, DAMAS 2023, International Conference on Maintenance Engineering, IncoME-V 2023, International conference on the Efficiency and Performance Engineering Network, TEPEN 2023

作者： Qu, Lufeng Fan, Qiming Kang, Yang Yang, Jun Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China School of Intelligent Manufacturing Tianjin Sino-German University of Applied Technology Tianjin300350 China School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9783031494130

ISBN: (纸本)9783031494123

In the context of nonlinear and uncertain manipulator systems, achieving fast and accurate desired trajectories for each joint of the manipulator is crucial. Our study aims to improve current control methods by combining sliding mode control and neural network techniques. Specifically, we leverage the neural networks’ approximation capabilities to estimate both the modeling error and external disturbance in our research. These estimates are then integrated into the synovial control as additional gains. This approach allows for the sliding mode controller’s switch gain to adapt to changing modeling error and external disturbance, thereby avoiding the vibration production typically associated with traditional sliding mode controllers. It can be observed from the simulation results that the combination of the proposed nonsingular terminal sliding mode controller and neural network achieves fast and precise tracking of desired trajectories. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Sliding mode control

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Distributed MQTT Brokers Infrastructure with Network Transparent Hardware Broker 11

Distributed MQTT Brokers Infrastructure with Network Transpa...

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11th International Symposium on Computing and Networking, CANDAR 2023

作者： Toyohara, Tokimasa Nishi, Hiroaki Keio University Graduate School of Science and Technology 3-14-1 Hiyoshi Kohoku Yokohama Kanagawa223-8522 Japan Keio University Department of System Design Faculty of Science and Technology 3-14-1 Hiyoshi Kohoku Yokohama Kanagawa223-8522 Japan

ISBN: (纸本)9798350306705

In recent years, the number of IoT devices has been rapidly increasing. Therefore, MQ Telemetry Transport (MQTT) has attracted attention as a lightweight protocol for IoT devices. MQTT employs a publish/subscribe model of communication via a broker, and since the performance of the MQTT broker directly affects the quality of service, various studies have been conducted to improve its performance. Among them, the hardware implementation of MQTT broker has higher performance than software implementations in terms of publish throughput and processing delay. However, there are some problems such as inflexibility and resource limitations. Therefore, we propose a distributed MQTT brokers infrastructure using the hardware broker. In this architecture, the software broker on the cloud and the hardware broker at the edge region work in cooperation to achieve low latency processing at the edge region and software flexibility. The hardware broker operates network transparently, so that end devices communicate with the software broker in the cloud and do not need to be aware of the presence of the hardware broker at the edge region. This enables resource and processing load distribution without affecting end devices. We implemented the network transparent hardware broker in a field-programmable gate array (FPGA) and evaluated it. © 2023 IEEE.

关键词： Edge computing

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High-Performance Torque Feedback Actuator for Humanoid Robots

High-Performance Torque Feedback Actuator for Humanoid Robot...

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IEEE International Conference on Robotics and Biomimetics

作者： Xiaoxiang Liu Zejun Hong Wei Zhang School of System Design and Intelligent Manufacturing (SDIM) Southern University of Science and Technology Shenzhen China

ISBN: (数字)9798331509644

ISBN: (纸本)9798331509651

Actuators are the most significant power sources for robot hardware platforms, and creating actuators suitable for humanoid robots remains a challenge. Humanoid robots demand more from their actuators, including higher massspecific torque, as well as both faster and more precise torque control. This paper presents the design of a novel actuator with torque feedback for humanoid robots that includes torque sensor, planetary gearbox, motor, drive, and encoder. The torque sensor is mounted at the output end of the actuator and forms a torque feedback loop from the torque source to the load. A hybrid controller for actuator torque control is also proposed in this paper. Finally, the performance of the actuator is experimentally evaluated.

关键词： Legged locomotion Actuators Motor drives Torque Torque control Humanoid robots Robot sensing systems Motors Magnetosphere Saturation magnetization

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Nanometer Scanning with Micrometer Sensing: Beating Quantization Constraints in Lissajous Trajectory Tracking 63

Nanometer Scanning with Micrometer Sensing: Beating Quantiza...

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63rd IEEE Conference on Decision and Control, CDC 2024

作者： Lohse, Matheus Castro, Rafael S. Salton, Aurelio T. Fu, Minyue Federal University of Rio Grade Do Sul School of Engineering Porto Alegre Brazil Pontifical Catholic University of Rio Grande Do Sul School of Technology RS Porto Alegre Brazil Southern University of Science and Technology School of System Design and Intelligent Manufacturing Shenzhen518055 China

ISBN: (纸本)9798350316339

This paper addresses the task of tracking Lissajous trajectories in the presence of quantized positioning sensors. To do so, theoretical results on tracking of continuous time periodic signals in the presence of output quantization are provided. With these results in hand, the application to Lissajous tracking is explored. The method proposed relies on the internal model principle and dispenses perfect knowledge of the system equations. Numerical results show that an arbitrary small scanning resolution is achievable despite large sensor quantization intervals. © 2024 IEEE.

关键词： Continuous time systems

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Safety-Aware Optimal Control of Nonlinear systems Using Off-Policy Reinforcement Learning∗

Safety-Aware Optimal Control of Nonlinear Systems Using Off-...

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2023 International Annual Conference on Complex systems and Intelligent science, CSIS-IAC 2023

作者： Lin, Mingduo Zhao, Bo Xia, Hongbing Liu, Derong School of Systems Science Beijing Normal University Beijing China School of Artificial Intelligence Anhui University Hefei China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

ISBN: (纸本)9798350309003

In this paper, we investigate the safety-aware optimal control (SAOC) problem, which attempts to minimize a predefined performance index function while ensuring the safety of nonlinear systems. First, the barrier function-based system transformation is utilized to design an optimal control policy which maintains the system states located in the safety region. To deal with the input constraints, a non-quadratic cost function is imposed to the control input. Then, the Hamilton-Jacobi-Bellman equation is established to provide the solution of the SAOC problem. Moreover, by utilizing the off-policy Bellman equation, a data-based off-policy reinforcement learning (OPRL) algorithm is developed to obtain the safety-aware optimal controller in a model-free manner. To implement this algorithm, a data collection process with the barrier transform is executed to generate the off-policy trajectory data, and an actor-critic neural network structure with the least-square updating law is employed in the off-policy learning phase. Finally, a simulation example is provided to verify the effectiveness of the developed control method. © 2023 IEEE.

关键词： Reinforcement learning

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Task-Based Quantizer design for Sensing With Random Signals

arXiv

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arXiv 2024年

作者： Ruan, Hang Liu, Fan School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China

In integrated sensing and communication (ISAC) systems, random signaling is used to convey useful information as well as sense the environment. Such randomness poses challenges in various components in sensing signal processing. In this paper, we investigate quantizer design for sensing in ISAC systems. Unlike quantizers for channel estimation in massive multiple-in-multiple-out (MIMO) communication systems, sensing in ISAC systems need to deal with random nonorthogonal transmitted signals rather than a fixed orthogonal pilot. Considering sensing performance and hardware implementation, we focus on task-based hardware-limited quantization with spatial analog combining. We propose two strategies of quantizer optimization, i.e., data-dependent (DD) and data-independent (DI). The former achieves optimized sensing performance with high implementation overhead. To reduce hardware complexity, the latter optimizes the quantizer with respect to the random signal from a stochastic perspective. We derive the optimal quantizers for both strategies and formulate an algorithm based on sample average approximation (SAA) to solve the optimization in the DI strategy. Numerical results show that the optimized quantizers outperform digital-only quantizers in terms of sensing performance. Additionally, the DI strategy, despite its lower computational complexity compared to the DD strategy, achieves near-optimal sensing performance. © 2024, CC BY.

关键词： Approximation algorithms

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Jigsaw-Based Benchmarking for Learning Robotic Manipulation 8

Jigsaw-Based Benchmarking for Learning Robotic Manipulation

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8th IEEE International Conference on Advanced Robotics and Mechatronics, ICARM 2023

作者： Liu, Xiaobo Wan, Fang Ge, Sheng Wang, Haokun Sun, Haoran Song, Chaoyang Southern University of Science and Technology Department of Mechanical and Energy Engineering Guangdong Shenzhen518055 China School of Design Southern University of Science and Technology Guangdong Shenzhen518055 China Hong Kong University of Science and Technology Robotics & Autonomous Systems Thrust System Hub Hong Kong Hong Kong The University of Hong Kong Department of Computer Science Hong Kong Hong Kong

ISBN: (纸本)9798350300178

Benchmarking provides experimental evidence of the scientific baseline to enhance the progression of fundamental research, which is also applicable to robotics. In this paper, we propose a method to benchmark metrics of robotic manipulation, which addresses the spatial-temporal reasoning skills for robot learning with the jigsaw game. In particular, our approach exploits a simple set of jigsaw pieces by designing a structured protocol, which can be highly customizable according to a wide range of task specifications. Researchers can selectively adopt the proposed protocol to benchmark their research outputs, on a comparable scale in the functional, task, and system-level of details. The purpose is to provide a potential look-up table for learning-based robot manipulation, commonly available in other engineering disciplines, to facilitate the adoption of robotics through calculated, empirical, and systematic experimental evidence. © 2023 IEEE.

关键词： Benchmarking

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Research on Fluctuation Attenuation and Optimization of Passive Residual Heat Removal system Based on Spring Vibrator

SSRN

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SSRN 2024年

作者： Kang, Zehang Wang, Sipeng Du, Peng Chen, Jin Su, Zhen Zhuang, Kun Department of Nuclear Science and Technology Nanjing University of Aeronautics and Astronautics JiangSu Nanjing211106 China Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautics Nanjing University of Aeronautics and Astronautics China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The potential for flow instability in passive residual heat removal systems (PRHRS) to result in equipment damage underscored the necessity for the development of effective mitigation strategies. In order to reduce the flow instabilities that occurs in the PRHRS, the idea of a fluctuation attenuation scheme based on a spring vibrator structure had been proposed. The structure was based on pressure pulsation attenuator in hydraulic systems and had been optimized. A model of a spring vibrator fluctuation attenuation pipe section was developed and its fluctuation attenuation effect was verified under specific parameters. Such as branch pipe length, cavity cross-sectional area, spring vibrator position, spring vibrator stiffness coefficient, and piston mass. The impact of these factors on fluctuation attenuation was investigated. The results demonstrated that, under identical inlet fluctuation conditions, the fluctuation peak at outlet of the pipe containing spring vibrator structure decreased. The optimization of the above parameters had been demonstrated to enhance the fluctuation removal effect of the spring vibrator structure. This study presented a novel approach to relieve flow instability in PRHRS. © 2024, The Authors. All rights reserved.

关键词： Vibrators

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Flash‑Induced High‑Throughput Porous Graphene via Synergistic Photo‑Effects for Electromagnetic Interference Shielding

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Nano-Micro Letters 2023年第11期15卷 1-18页

作者： Jin Soo Lee Jeong‑Wook Kim Jae Hee Lee Yong Koo Son Young Bin Kim Kyoohee Woo Chanhee Lee Il‑Doo Kim Jae Young Seok Jong Won Yu Jung Hwan Park Keon Jae Lee Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak‑roYuseong‑guDaejeon 34141Republic of Korea School of Electrical Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak‑roYuseong‑guDaejeon 34141Republic of Korea Department of Printed Electronics Nano‑Convergence Manufacturing Systems Research DivisionKorea Institute of Machinery and Materials(KIMM)156 Gajeongbuk‑RoYuseong‑GuDaejeon 34103Republic of Korea Department of Mechanical System Design Engineering Seoul National University of Science and Technology232 Gongneung‑roNowon‑guSeoul 01811Republic of Korea Department of Mechanical Engineering(Department of Aeronautics Mechanical and Electronic Convergence Engineering)Kumoh National Institute of Technology61 Daehak‑roGumiGyeongbuk 39177Republic of Korea

Porous 2D materials with high conductivity and large surface area have been proposed for potential electromagnetic interference(EMI)shielding materials in future mobility and wearable applications to prevent signal noise,transmission inaccuracy,system malfunction,and health ***,we report on the synthesis of lightweight and flexible flash-induced porous graphene(FPG)with excellent EMI shielding *** broad spectrum of pulsed flashlight induces photo-chemical and photo-thermal reactions in polyimide films,forming 5×10 cm^(2)-size porous graphene with a hollow pillar structure in a few *** resulting material demonstrated low density(0.0354 g cm^(−3))and outstanding absolute EMI shielding effectiveness of 1.12×10^(5) dB cm^(2) g^(−1).The FPG was characterized via thorough material analyses,and its mechanical durability and flexibility were confirmed by a bending cycle ***,the FPG was utilized in drone and wearable applications,showing effective EMI shielding performance for internal/external EMI in a drone radar system and reducing the specific absorption rate in the human body.

关键词： Porous graphene Flash lamp Photo-pyrolysis High-throughput Electromagnetic interference shielding

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