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Direct conversion of CO_(2)to graphene via vapor–liquid reaction for magnesium matrix composites with structural and functional properties

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Journal of Magnesium and Alloys 2023年第4期11卷 1206-1212页

作者： Xuejian Li Xiaojun Wang Xiaoshi Hu Chao Xu Wenzhu Shao Kun Wu State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001PR China National Key Laboratory of Precision Hot Processing of Metal Harbin Institute of TechnologyHarbin 150001PR China

Converting CO_(2)to valuable materials is attractive in environmental protection and resource *** this study,a vapor-liquid interface reaction system for mass production of high-quality graphene is *** graphene obtained has high crystallinity and few defects during the reaction of CO_(2)and Mg *** growth mechanism of graphene is demonstrated in vapor-liquid interface area by combining the CO_(2)bubbles as a soft template to guide growth with the confinement effect of dense MgO *** quality of the graphene is verified by epoxy composites with high electromagnetic shielding ***,the V-L reaction method ingeniously solves the dispersion of graphene in metal,providing a preparation strategy of Mg matrix composites with structure and function integration.

关键词： Graphene Vapor-liquid interface Magnesiothermic reaction Dispersion Shielding effectiveness

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RGB-D Camera Based Map Building and Path Planning of Snake Robot 16th

RGB-D Camera Based Map Building and Path Planning of Snake R...

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16th International Conference on Intelligent robotics and Applications, ICIRA 2023

作者： Sun, Yongjun Wang, Qiang Xue, Zhao Liu, Rongqiang Liu, Hong State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China

ISBN: (纸本)9789819964826

Snake robot is a robot that can move freely in a small and complex space with super-redundant DOF and motion flexibility, and it has been proven to have a wide range of application prospects. RGB-D camera is a new type of visual sensor that can directly obtain color images and depth information. To enable the snake robot to work in some special task environments, we developed an orthogonal modular snake robot using RGB-D cameras, and conducted research on snake robot map building and path planning. An improved Batch Informed Tree (BIT*) algorithm is proposed. Finally, to verify the effectiveness of the proposed method, a corresponding experimental program is designed and related experimental analysis is carried out. The results show that our designed snake robot can complete the task of map building and path planning. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Motion planning

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Design and Implementation of Quasi-Direct-Drive Legs for a Frog-Like Jumping Robot 3

Design and Implementation of Quasi-Direct-Drive Legs for a F...

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3rd International Conference on Computer, Control and robotics, ICCCR 2023

作者： Zhihui, Dong Jizhuang, Fan Qilong, Du Jie, Zhao Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin150001 China

ISBN: (纸本)9781665492126

This study aims to design and optimize a motor-driven frog-like jumping robot leg for efficient vertical jumps and multiple consecutive horizontal jumps. We have conducted bionic research on frog legs' structure and motion characteristics and further explored their motion mechanism, providing new ideas and methods for designing and manufacturing robots with high mobility and adaptability. First, our research team designed a robot leg prototype based on the frog's body structure, optimized the robot using computer-Aided design software, and selected a suitable motor-driven actuator. Secondly, the weight reduction optimization of the robot body is carried out regarding material selection and topology optimization to improve the robot's maneuverability and jump height. Finally, after manufacturing the prototype of the robot legs, the robot is experimentally verified. The results show that the robot legs can achieve efficient vertical jumps (the maximum height is 1.40 meters, about 7.8 times the length of the leg link). It can also jump multiple times consecutively, which is significant for applying robots in dangerous environments, search and rescue, and other fields. © 2023 IEEE.

关键词： Machine design

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Structural Design and Experiment of a Small Wheel-legged Mobile Robot with Variable Configuration 20

Structural Design and Experiment of a Small Wheel-legged Mob...

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20th IEEE International Conference on Mechatronics and Automation, ICMA 2023

作者： Cui, Xiulong Fan, Jizhuang Dong, Zhihui Ou, Yue Zhao, Jie Harbin Institute of Technology The State Key Laboratory of Robotics and System Harbin150001 China

ISBN: (纸本)9798350320831

In this paper, we made an improved design on the traditional quadruped robot structure and developed a new small wheel-legged mobile robot structure. It has four legged configurations, which can be selected according to different situations, improving the mobility and operability of the robot. In wheeled mode, the robot can adjust its center of gravity according to actual needs. Including the rotational degree of freedom of the wheel, each leg has four degrees of freedom. Each leg adopts a series structure and moves the knee drive motor to the fuselage position using a parallel four-link mechanism and is symmetrically arranged with the hip drive motor. A wheel is installed at the end of the shank, and a DC brushless motor is built inside it, enabling the robot to have the function of wheeled motion. This article introduces the details of the wheel-legged robot, emphasizing the innovative design of the physical structure and the diversity of deformation. The forward kinematics was analyzed. Based on the full-elbow configuration (a type of legged configuration), a cycloidal motion optimization simulation was completed for the single leg structure. Simulation experiment has proven that the optimized robot's single leg motion is smoother. Finally, we conducted a typical experiment using an embedded controller to control single leg motion. The experimental results verify that the optimized cycloidal motion of the robot meets the desired motion effect. © 2023 IEEE.

关键词： Mobile robots

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Torque Ripple Suppression Under Open-Circuit Fault for DTPPMSM Considering Back EMF Harmonics

Torque Ripple Suppression Under Open-Circuit Fault for DTPPM...

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2023 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD 2023

作者： Liu, Chengsi Zou, Jibin Harbin Institute of Technology Hit State Key Laboratory of Robotics and System Harbin China

ISBN: (纸本)9798350301571

This paper analyzed the impact of phase back electromotive force (back EMF) harmonics on torque of dual three phase permanent magnet synchronous motor (DTPPMSM) from the view of electromagnetic power, and proposed a torque ripple suppression fault-tolerant method for open-circuit fault of DTPPMSM. The proposed method can consider the phase back EMF harmonics, thus achieveing both minimum torque ripple and maximum average torque. The proposed method is verified by both finite element analysis (FEA) and prototype experiment. © 2023 IEEE.

关键词： Dual three phase permanent magnet synchronous motor (DTPPMSM) fault-tolerant finite element analysis (FEA) open circuit

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Aerodynamic Analysis and Deployment Mechanism of A Foldable Mars Quadrotor 20

Aerodynamic Analysis and Deployment Mechanism of A Foldable ...

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20th IEEE International Conference on Mechatronics and Automation, ICMA 2023

作者： Zhu, Kaijie Tang, Dewei Quan, Qiquan Wang, Kaiyi Dong, Yachao Deng, Zongquan Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin150001 China

ISBN: (纸本)9798350320831

The Mars quadrotor is a vertical take-off and landing aerial platform developed to enhance the efficiency of Mars exploration. The four-blade rotor has a high thrust coefficient due to its high solidity, which enables the quadrotor to navigate the Martian atmospheric environment efficiently. This paper proposes a payload-carrying Mars quadrotor featuring four four-bladed rotors that can fold along the rotor arms. The computational fluid dynamics (CFD) method is employed to perform numerical hovering simulations, exploring the propulsion capability and aerodynamic efficiency of rotors with different diameters. The mass distribution and hovering time are estimated when the quadrotor consists of the rotors with the highest figure of merit. The results demonstrate that a larger rotor diameter of the quadrotor yields greater payload capacity and shorter hovering time. During the launch, the quadrotor is folded and constrained within an envelope to protect it from vibrations and shocks. A lifting mechanism with shape-constraint slides is utilized for quadrotor deployment. © 2023 IEEE.

关键词： Efficiency

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JADFER: Exploring Spatial-Contextual Interaction with Joint Attention Dropping for Facial Expression Recognition

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IEEE Transactions on Affective Computing 2024年第2期16卷 655-668页

作者： Gao, Yu Ren, Weihong Jiang, Weibo Dong, Qian Nie, Wei Wu, Wenhao Liu, Honghai Harbin Institute of Technology State Key Lab of Robotics and Systems School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen518055 China

Facial Expression Recognition (FER) aims to categorize emotional expressions depicted on a human face, and is a challenging task under unconstrained conditions, such as face occlusions and pose variations. Recent methods usually adopt self attention or cross attention to explore global or local relationships among different level features. However, these methods are inclined to focus on the redundant facial regions, causing model overfitting. To address this problem, we propose a new FER model named JADFER, which drops the joint attention in the weight matrix to adaptively enhance facial expression representations. Specifically, our JADFER model consists of three components: Spatial Branch (SB), Contextual Branch (CB), and Spatial-Contextual Interaction (SCI). Firstly, SB runs N paths in parallel, where a Variety loss is designed to guide the paths of SB to focus on different discriminative regions. Meanwhile, CB abstracts the contextual facial representations using self attention with Joint Attention Dropping (JAD). Then, the SCI adopts the spatial features from SB to query the contextual representations from CB through cross attention with JAD, which regulates the attention weights by dropping the similar activations to further enhance the facial embeddings. Experimental results demonstrate that the proposed model outperforms the state-of-the-art methods on several FER benchmarks. © 2010-2012 IEEE.

关键词： Face recognition

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A Study of Prototypical Network Techniques for Cross-Subject EEG Analysis 27

A Study of Prototypical Network Techniques for Cross-Subject...

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27th European Conference on Artificial Intelligence, ECAI 2024

作者： Liu, Wenchao Wang, Guagnyu He, Yuhong Bo, Hongjian Ma, Lin Li, Haifeng State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Faculty of Computing Harbin Institute of Technology Harbin China Shenzhen Academy of Aerospace Technology Shenzhen China

ISBN: (纸本)9781643685489

Electroencephalography (EEG), a technique that uses electrodes on the scalp to record changes in cerebral electrical potentials, plays a key role in various brain-computer interface applications. However, due to the large differences in EEG distribution across subjects, how to accurately classify cross-subject EEG is still a challenge. In practice, it is unavoidable to collect data for each subject to perform calibration, which is cumbersome and expensive. In this paper, we propose a Cross Subject EEG Prototypical Network (CS-EEGPNet) for accurate few-shot EEG classification. To the best of our knowledge, we are the first to eliminate inter-subject distribution shift in few-shot EEG classification through multiple feature layers computation. Specifically, to avoid the effect of individual differences, we propose a few-shot feature normalization (FSFN) method, which uses the mean and variance of the same subject’s support set features to normalize the query set features. Meanwhile, we design a prototypical module based on auxiliary factors. This module utilizes learnable vectors to store category-related information for assisting the construction of prototypes, thus mitigating the effects of EEG’s randomness and non-stationary characteristics on cross-subject few shot classification. To validate the effectiveness of the method, we selecte the motor imagery paradigm, which is relatively complex in brain-computer interfaces, and test our method on the BCIC IV 2a and HGD datasets. The results demonstrate that our method significantly enhances EEG classification performance, achieving the state-of-the-art accuracies. © 2024 The Authors.

关键词： Electroencephalography

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Development of a novel hand-eye calibration for intuitive control of minimally invasive surgical robot

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Frontiers of Mechanical Engineering 2022年第3期17卷 91-108页

作者： Yanwen SUN Bo PAN Yili FU State Key Laboratory of Robotics and Systems Harbin Institute of TechnologyHarbin150001China

Robotic-assisted surgical system has introduced a powerful platform through dexterous instrument and hand-eye coordination intuitive *** knowledge of laparoscopic vision is a crucial piece of information for robot-assisted minimally invasive surgery focusing on improved surgical *** the transformation with respect to the laparoscope and robot slave arm frames using hand-eye calibration is essential,which is a key component for developing intuitive control *** proposed a novel two-step modified dual quaternion for hand-eye calibration in this *** dual quaternion was exploited to solve the hand-eye calibration simultaneously and powered by an iteratively separate *** obtained hand-eye calibration result was applied to the intuitive control by using the hand-eye coordination *** simulations and experimental studies were conducted to evaluate the proposed method on our surgical robot *** extensively compared the proposed method with state-of-the-art *** demonstrate this method can improve the calibration *** effectiveness of the intuitive control algorithm was quantitatively evaluated,and an improved hand-eye calibration method was *** relationship between laparoscope and robot kinematics can be established for intuitive control.

关键词： minimally invasive surgery hand-eye calibration intuitive control surgical robot dual quaternion

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Experimental and numerical study of deposition mechanisms for cold spray additive manufacturing process

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Chinese Journal of Aeronautics 2022年第2期35卷 276-290页

作者： Tianyu YU Mingjun CHEN Zhuoru WU State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China Department of Mechanical Engineering Iowa State UniversityAmes 50011USA

Cold spray is an attractive and rapidly developing process for additive manufacturing with high efficiency and precision,repairing and coating,especially in aircraft and aerospace *** spray additive manufacturing deposits micro-particles with large plastic deformation below their melting point,eliminating heat effect zone which could deteriorate the quality of repairing *** particle deposition in cold spray is a complex process which involves high strain rate,high contact pressure and high *** we develop,utilize and validate a thermomechanical model to provide a definitive way to predict deposition mechanics and surface deformation evolution for particle deposition process in cold spray additive *** a single particle and dual particles models were developed to investigate the contact interaction between particle/substrate and particle/*** combinations of particle/substrate materials(Cu/Cu,Al/Al,steel/steel,and nickel/nickel)and process parameters were considered in this *** experimental study was conducted to validate simulation results,providing useful information for understanding the limitations and challenges associated with cold spray additive *** framework provides insights into improving the quality and precision of stress/strain formation,particle interactions and particle deposition in cold spray additive manufacturing process.

关键词： Additive manufacturing Cold spray Finite element analysis Residual stresses Surface morphology

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