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2024 OES China Ocean Acoustics, COA 2024

作者： Lu, Xiaotian Gong, Zhixiong School of Ocean and Civil Engineering Shanghai Jiao Tong University State Key Laboratory of Ocean Engineering Shanghai China School of Ocean and Civil Engineering Key Laboratory of Marine Intelligent Equipment and System Shanghai Jiao Tong University State Key Laboratory of Ocean Engineering Shanghai China

ISBN: (纸本)9798350340297

It is challenging to predict the patterns of radiated acoustic field from a complex moving source while this topic is important in the field of ocean acoustics. A possible method is to decompose the complex field into the addition of fundamental sources such as monopolar and dipolar ones. In this study, we derive the analytical solution of radiated acoustic fields generated by a moving monopolar or dipolar source, and the combination of them based on the Lorentz transformation. The analytical expressions of the radiated sound pressure by a moving monopolar or dipolar source are given with no limit on the moving direction and excitation frequency. Numerical simulations are conducted to reveal the Doppler effect of the moving sources and the potential application of the combination of monopolar and dipolar sources to simulate complex fields. This work may help design acoustic models to predict the radiated sound field by complex sources in the field of ocean engineering. © 2024 IEEE.

关键词： Ocean engineering

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Combine Neural Radiance Fields in Different Reference Coordinates

Combine Neural Radiance Fields in Different Reference Coordi...

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2023 China Automation Congress, CAC 2023

作者： Zhang, Weili Li, Zhongheng Guo, Yu Wang, Fei Institute of Artificial Intelligence and Robotics Xi'An Jiaotong University Xi'an China Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing China

ISBN: (纸本)9798350303759

Neural Radiance Fields (NeRF) leverage deep learning networks to restore high-quality implicit representations of 3D scenes from 2D images, surpassing traditional texture mapping in rendering quality. Typically, reconstructed images by NeRF exist in a reference coordinate system, necessitating consideration of each surface's information in a single shot. Overlapping parts in adjacent images are addressed by obtaining the camera pose through sparse COLMAP reconstruction. However, occluded regions, caused by contact with support surfaces, pose challenges for complete reconstruction. To address this, we propose a scene fusion algorithm based on NeRF, facilitating the amalgamation of neural radiance fields under different reference coordinate systems. This reduces data requirements and shooting conditions, enhancing the implicit 3D reconstruction of real objects. By estimating the translation and rotation relationship between image capture angles and the NeRF model, we fuse neural radiance fields in distinct reference coordinate systems, completing object surface information. Evaluation is conducted on both NeRF synthetic dataset and real objects. © 2023 IEEE.

关键词： Cameras

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Flapping-Wing Robot Achieves Multi-Domain Locomotion Using Transformable Wheel Mechanism

Flapping-Wing Robot Achieves Multi-Domain Locomotion Using T...

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2024 IEEE International Conference on robotics and Biomimetics, ROBIO 2024

作者： Chai, Xiangxiao Wang, Shihua Pan, Erzhen Xu, Wenfu Shenzhen518055 China Key University Laboratory of Mechanism & Machine Theory and Intelligent Unmanned Systems of Guangdong Shenzhen518055 China Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin150001 China

ISBN: (纸本)9781665481090

The difficulty of moving from aquatic to aerial environment is one of the major challenges limiting the development of trans-medium multi-domain locomotion vehicles. In this paper, the concept of the transformable wheel, a feature commonly found in autonomous land vehicles (AL V s), is introduced into the design. Additionally, a flapping-wing robot equipped with multi-domain locomotion capability, which can not only realize aerial flight and surface navigation on water, but also ascend from water to land for subsequent takeoff is presented. The paper first introduces the system design of the robot and proposes the corresponding multi-domain locomotion strategy. Subsequently, the design of the transformable wheel mechanism is described in detail and the force analysis for the water-exit is conducted. The feasibility of the proposed strategy is experimentally validated, confirming the prototype's multi-domain locomotion performance finally. This research explores the feasibility of introducing the transformable wheel mechanism into trans-medium multi-domain vehicle platforms and provides a design example. © 2024 IEEE.

关键词： Machine design

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Secure Multi-way Join Query and Its Bench-Marking with Trusted Execution Environments 2nd

Secure Multi-way Join Query and Its Bench-Marking with Tru...

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2nd International Conference on Data Security and Privacy Protection, DSPP 2024

作者： Zhao, Yi Zhao, Sen Lv, Siyi School of Cyber Engineering Xidian University Xi’an China State Key Laboratory of Integrated Service Networks Xidian University Xi’an China Key Laboratory of Data and Intelligent System Security Ministry of Education Nankai University Tianjin China

ISBN: (纸本)9789819785452

Because of server-untrustable model in outsourcing encrypted database system, it’s fatal for data owners to keep their data confidential under complex query operations performed by database servers. Trusted Execution Environments (TEEs) provide a secure space for privacy computation via hardware-based methods to increase the efficiency of database system, and it ensures the availability of computing directly on sensitive data in untrusted outsourcing database servers. However, while various query schemes are designed under the combination of encrypted database and TEEs, designing an available and secure scheme for join queries on multiple data tables with TEEs remains an open problem. Besides, previous works also devote less to bench-marking multi-way joins on TEEs. In our work, we extend binary join query scheme into multi-way forms in encrypted database system based on TEEs. It combines various join algorithms based on hash functions (hash-based, radix-based, etc.) with parallelized optimizing mechanism. Besides, we do bench-marking with TEEBench framework on those multi-way join schemes in three-way forms using both cache-fit and cache-exceed datasets and do different evaluation on two TEEs hardware platforms (Intel SGX and AMD SEV) to show its availability. After that, we also propose a multi-way join scheme with access pattern protection through the combination between our previous scheme and oblivious I/O methods. With the evaluation of its efficiency and memory leakage, we can also verify the feasibility of our access-pattern-protected multi-way join scheme. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Outsourcing

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Monolithic Logic Units based on DCFL Structure on p-GaN platform for GaN ICs 15

Monolithic Logic Units based on DCFL Structure on p-GaN plat...

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15th IEEE International Conference on ASIC, ASICON 2023

作者： Pan, Maolin Wang, Luyu Wang, Qiang Zhang, Penghao Wang, Yuhang Xu, Min Fudan University Shanghai State Key Laboratory of ASIC and System Shanghai Institute of Intelligent Electronics & Systems School of Microelectronics China

ISBN: (纸本)9798350312980

GaN-based digital integrated circuits (ICs) are constructed on the commercially available GaN-on-Si p-GaN platform. The functions of inverter, NAND, AND, NOR, and OR logic circuits are successfully realized based on direct-coupled field-effect transistor logic (DCFL) structure. Under a drive voltage of 5V and a load ratio of 20, the low output (VOL) can reach as low as 0.1V. Additionally, a functional-oriented driver is constructed. All the transient tests at frequencies up to 100 kHz exhibit excellent performance characteristics. © 2023 IEEE.

关键词： GaN-ICs Inverter NAND-AND NOR-OR p-GaN HEMT

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Grid Strength Assessment Method for Evaluating Small-signal Synchronization Stability of Grid-following and Grid-forming Converters Integrated systems

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Journal of Modern Power systems and Clean Energy 2025年第1期13卷 55-65页

作者： Qianhong Shi Wei Dong Guanzhong Wang Junchao Ma Chenxu Wang Xianye Guo Vladimir Terzija Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education School of Electrical EngineeringShandong UniversityJinan 250061China Electric Power Research Institute State Grid Zhejiang Electric Power Co.Ltd.Hangzhou 310014China School of Engineering Newcastle UniversityNewcastle upon TyneUK

Oscillations caused by small-signal instability have been widely observed in AC grids with grid-following(GFL)and grid-forming(GFM)*** generalized short-circuit ratio is commonly used to assess the strength of GFL converters when integrated with weak AC systems at risk of *** paper provides the grid strength assessment method to evaluate the small-signal synchronization stability of GFL and GFM converters integrated ***,the admittance and impedance matrices of the GFL and GFM converters are analyzed to identify the frequency bands associated with negative damping in oscillation modes dominated by heterogeneous synchronization ***,based on the interaction rules between the short-circuit ratio and the different oscillation modes,an equivalent circuit is proposed to simplify the grid strength assessment through the topological transformation of the AC *** risk of sub-synchronization and low-frequency oscillations,influenced by GFL and GFM converters,is then reformulated as a semi-definite programming(SDP)model,incorporating the node admittance matrix and grid-connected device *** effectiveness of the proposed method is demonstrated through a case analysis.

关键词： Grid-following converter grid-forming converter grid strength assessment small-signal stability

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Driving Performance Analysis for Connected Vehicle Platoons: Velocity Perturbation and Fuel Consumption

Driving Performance Analysis for Connected Vehicle Platoons:...

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2023 IEEE International Conference on Unmanned systems, ICUS 2023

作者： Zhao, Yihan Duan, Xuting Zhou, Jianshan Zhang, Long School of Transportation Science and Engineering Beihang University Beijing China State Key Lab of Intelligent Transportation System Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems and Safety Control Beijing China State Key Lab of Intelligent Transportation System Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems and Safety Control Zhongguancun Laboratory Beijing China National Key Laboratory of Science and Technology on Information System Security Institute of Systems Engineering Beijing China

ISBN: (纸本)9798350316308

Vehicle platoon is one of the concrete manifestations of multi-vehicle cooperative control and intelligent transportation. However, the velocity perturbation in the driving process will bring about stability and safety problems. The connected autonomous vehicles (CAVs) can obtain the motion status of the lead vehicle in real time and respond to it in time, which is of far-reaching significance to platoon control. Based on this, this paper focuses on the longitudinal driving strategy of connected autonomous vehicle platoons. Specifically, we provide a discrete double-integral model controller for each vehicle in a generic scenario, and the controller performs acceleration and deceleration control at each timeslot according to the state of the vehicle in front and its own state. Simulation experiments are designed by varying the size of the platoon and the number of connected autonomous vehicles. The experimental results show that the introduction of connected autonomous vehicles can effectively suppress the platoon velocity perturbation, increase the stability of the platoon driving, and significantly reduce the fuel consumption at the same time. © 2023 IEEE.

关键词： Autonomous vehicles

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Mechanical Properties Inside Origami-Inspired Structures: An Overview

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Applied Mechanics Reviews 2025年第1期77卷 011001页

作者： Yan, Peng Huang, Hailin Meloni, Marco Li, Bing Cai, Jianguo Department of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen518052 China Harbin Institute of Technology Shenzhen518052 China Key Laboratory of C & PC Structures of Ministry of Education National Prestress Engineering Research Center Southeast University Nanjing211189 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Guangdong Provincial Key Laboratory of Intelligent Morphing Mechanisms and Adaptive Robotics Harbin Institute of Technology Shenzhen518052 China Key University Laboratory of Mechanism Machine Theory and Intelligent Unmanned Systems of Guangdong Habin Institute of Technology Shenzhen518052 China

In recent decades, origami has transitioned from a traditional art form into a systematic field of scientific inquiry, characterized by attributes such as high foldability, lightweight frameworks, diverse deformation modes, and limited degrees-of-freedom. Despite the abundant literature on smart materials, actuation methods, design principles, and manufacturing techniques, comprehensive reviews focusing on the mechanical properties of origami-inspired structures are relatively rare and unsystematic. This review aims to fill this void by analyzing and summarizing the significant studies conducted on the mechanical properties of origami-inspired structures from 2013 to 2023. We begin with an overview that includes essential definitions of origami, classical origami patterns, and their associated tessellated or stacked structures. Following this, we delve into the principal dynamic modeling method for origami and conduct an in-depth analysis of the key mechanical properties of origami-inspired structures. These properties include tunable stiffness, bistability and multistability, metamechanical properties demonstrated by origami-based metamaterials, and bio-inspired mechanical properties. Finally, we conclude with a comprehensive summary that discusses the current challenges and future directions in the field of origami-inspired structures. Our review provides a thorough synthesis of both the mechanical properties and practical applications of origami-inspired structures, aiming to serve as a reference and stimulate further research. © 2025 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Degrees of freedom (mechanics)

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A Hierarchical Control Scheme for Active Power-assist Lower-limb Exoskeletons

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Journal of Bionic Engineering 2024年第5期21卷 2184-2198页

作者： Jing Deng Wenzheng Jiang Haibo Gao Yapeng Shi Mantian Li State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001HeilongjiangChina Shenzhen Academy of Aerospace Technology Shenzhen518063China Faculty of Computing Harbin Institute of TechnologyHarbin150001HeilongjiangChina Institute of Intelligent Manufacturing Technology Shenzhen Polytechnic UniversityShenzhen518055China

Effectively controlling active power-assist lower-limb exoskeletons in a human-in-the-loop manner poses a substantial chal-lenge,demanding an approach that ensures wearer autonomy while seamlessly adapting to diverse wearer *** paper introduces a novel hierarchical control scheme comprising five integral components:intention recognition layer,dynamics feedforward layer,force distribution layer,feedback compensation layer,as well as sensors and *** intention rec-ognition layer predicts the wearer's movement and enables wearer-dominant movement through integrated force and position *** force distribution layer effectively resolves the statically indeterminate problem in the context of double-foot support,showcasing flexible control *** dynamics feedforward layer mitigates the effect of the exoskeleton itself on ***,the feedback compensation layer provides reliable closed-loop *** approach mitigates abrupt changes in joint torques during frequent transitions between swing and stance phases by decomposed *** this innovative hierarchical control scheme on a hydraulic exoskeleton platform through a series of experiments,the results demonstrate its capability to deliver assistance in various modes such as stepping,squatting,and jumping while adapting seamlessly to different terrains.

关键词： Hierarchical control Active power-assist Exoskeleton robots Dynamics feedforward Force distribution Feedback compensation

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A Comparative Study on Kinematic Calibration for a 3-DOF Parallel Manipulator Using the Complete-Minimal,Inverse-Kinematic and Geometric-Constraint Error Models

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Chinese Journal of Mechanical Engineering 2023年第5期36卷 206-230页

作者： Haiyu Wu Lingyu Kong Qinchuan Li Hao Wang Genliang Chen State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Intelligent Robot Research Center Zhejiang LabHangzhou 311100China School of Mechanical Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China

Kinematic calibration is a reliable way to improve the accuracy of parallel manipulators, while the error model dramatically afects the accuracy, reliability, and stability of identifcation results. In this paper, a comparison study on kinematic calibration for a 3-DOF parallel manipulator with three error models is presented to investigate the relative merits of diferent error modeling methods. The study takes into consideration the inverse-kinematic error model, which ignores all passive joint errors, the geometric-constraint error model, which is derived by special geometric constraints of the studied RPR-equivalent parallel manipulator, and the complete-minimal error model, which meets the complete, minimal, and continuous criteria. This comparison focuses on aspects such as modeling complexity, identifcation accuracy, the impact of noise uncertainty, and parameter identifability. To facilitate a more intuitive comparison, simulations are conducted to draw conclusions in certain aspects, including accuracy, the infuence of the S joint, identifcation with noises, and sensitivity indices. The simulations indicate that the complete-minimal error model exhibits the lowest residual values, and all error models demonstrate stability considering noises. Hereafter, an experiment is conducted on a prototype using a laser tracker, providing further insights into the diferences among the three error models. The results show that the residual errors of this machine tool are signifcantly improved according to the identifed parameters, and the complete-minimal error model can approach the measurements by nearly 90% compared to the inverse-kinematic error model. The fndings pertaining to the model process, complexity, and limitations are also instructive for other parallel manipulators.

关键词： Kinematic calibration Parallel manipulator Error modeling Product of exponential(POE)

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