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13th International Conference on Computer and Automation Engineering, ICCAE 2021

作者： Zhao, Xiaoyu Liu, Yang Xie, Zongwu Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin China

ISBN: (纸本)9780738132204

Visual servoing process is widely applied in robot control. In the visual servoing process, an interpolation of the robot end pose is necessary. In the interpolation, quaternion suffers a lot for the discontinuity in trajectory velocity and acceleration. In this paper, we propose an acceleration-level continuous interpolation method and apply it to visual servoing process. In the method, we make up use of the conversion between different rotation descriptors and achieve a smooth enough trajectory. Simulations and experiments are carried out to validate the method and the results show considerable performance. © 2021 IEEE.

关键词： Visual servoing

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Evaluation of surface integrity for ultra-precision machined fused silica surface based on atomic point-defect density

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Journal of Manufacturing Processes 2025年 149卷 917-930页

作者： Dinghuai Yang Linjie Zhao Jian Cheng Qi Liu Zixiao Zhang Hongqin Lei Zican Yang Henan Liu Jinghe Wang Yazhou Sun Mingjun Chen State Key Laboratory of Robotics and System School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China Centre for Precision Manufacturing DMEM University of Strathclyde Glasgow G1 1XJ UK Center for Precision Engineering School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China

The degree of plasticity and brittleness (DPB) of the material significantly affects the service performance of fused silica manufacturing surfaces in many frontier fields. However, there is still no effective method to quantitatively and non-destructively characterize their DPB, severely restricting the application of fused silica. Herein, atomic manufacturing-induced point defects on fused silica manufacturing surfaces were determined. Based on this, the evolution laws of various types of point defects with the DPB were discussed. Interestingly, it was found that the DPB is closely related to the densities of specific ODCII point defects, whose proportion ( k ) was chosen as the characteristic parameter to judge surface brittle fractures. Additionally, it was discovered that k sharply increased at the material brittle-plastic transition boundary, which was also verified based on the molecular dynamics simulation. Accordingly, whether k is >15 % was proposed as a criterion to judge whether the material has undergone brittle fractures during manufacturing processes. Furthermore, the significant increment of ODCII point defects was found to be the main cause of the obvious increment of k . Moreover, two causes of the significant increment of ODCII point defects were determined. Finally, the effectiveness of the judge criterion in six specific manufacturing cases was verified. Summarily, the study proposes a powerful nondestructive approach to judge the brittle fractures. It could quantitatively and non-destructively characterize the DPB during manufacturing processes. It is also applicable to the quantitative DPB characterization and the early warning detection of fracture breakdown for other brittle silicate materials.

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NNPP: A Learning-Based Heuristic Model for Accelerating Optimal Path Planning on Uneven Terrain

arXiv

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arXiv 2023年

作者： Ji, Yiming Liu, Yang Xie, Guanghu Ma, Boyu Xie, Zongwu Cao, Baoshi State Key Laboratory of Robotics and System Harbin Institute of Technology Heilongjiang Harbin150001 China

Intelligent autonomous path planning is essential for enhancing the exploration efficiency of mobile robots operating in uneven terrains like planetary surfaces and off-road environments. In this paper, we propose the NNPP model for computing the heuristic region, enabling foundation algorithms like A* to find the optimal path solely within this reduced search space, effectively decreasing the search time. The NNPP model learns semantic information about start and goal locations, as well as map representations, from numerous pre-annotated optimal path demonstrations, and produces a probabilistic distribution over each pixel representing the likelihood of it belonging to an optimal path on the map. More specifically, the paper computes the traversal cost for each grid cell from the slope, roughness and elevation difference obtained from the digital elevation model. Subsequently, the start and goal locations are encoded using a Gaussian distribution and different location encoding parameters are analyzed for their effect on model performance. After training, the NNPP model is able to accelerate path planning on novel maps. Experiments demonstrate that the heuristic region generated by the NNPP model achieves a 3×speedup for optimal path planning under identical hardware conditions. Moreover, the NNPP model’s advantage becomes more pronounced as the size of the map increases. Copyright © 2023, The Authors. All rights reserved.

关键词： Motion planning

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MECHANICAL CHARACTERISTICS ANALYSIS OF CORNER TENSIONED RECTANGULAR THIN MEMBRANES 1

MECHANICAL CHARACTERISTICS ANALYSIS OF CORNER TENSIONED RECT...

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1st International Conference on Mechanical system Dynamics, ICMSD 2022

作者： Li, Bingyan Peng, Tao Lin, Qiuhong Wang, Xiaoyu Cong, Qiang Tian, Xinqi Liu, Rongqiang Beijing Institute of Spacecraft Engineering Beijing100094 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China College of Mechanical and Electrical Engineering Harbin Engineering University Harbin150001 China

ISBN: (数字)9781839537837

ISBN: (纸本)9781839537837

This paper presents the calculation of the stress distribution of corner tensioned rectangular thin membrane based on the stress superposition method (SSM). By comparing with the results of finite element simulation, the theoretical results of stress distribution of tensioned membrane structure are verified. Based on SSM and free vibration calculation theory, the effects of tension boundary parameters on membrane stress distribution and models are investigated. The influence of corner tension on the mechanical characteristics is analyzed for the corner tensioned rectangular membranes with different aspect ratios. The formula for each order's fundamental frequency ratio of atmospheric to spatial environment is proposed. Conducting the dynamics experiment of a rectangular tensioned membrane, the theoretical analysis is verified by the experimental modal results. © 2022 IET Conference Proceedings. All rights reserved.

关键词： Stress concentration

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Influences of the ambient humidity and temperature on the material removal and wear behaviors on the soft-brittle KDP optics lithographed by the AFM probes

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Wear 2025年 571卷

作者： Chen, Guang Cheng, Jian Zhao, Linjie Chen, Mingjun Ding, Wenyu Lei, Hongqin Liu, Qi State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou450000 China Centre for Precision Manufacturing DMEM University of Strathclyde GlasgowG1 1XJ United Kingdom

KDP (K2HPO4) crystals possess excellent nonlinear electro-optical properties and are often employed as Pockels cells and frequency converters. Ink-free DPN (IF-DPN) provides a promising method to lithograph surface nano-patterns in KDP optics to improve their laser damage resistances. However, material removal and wear behaviors are greatly affected by humidity and temperature. In this work, theoretical analyses at atomic- and electronic-scales are performed based on molecular dynamics and ab initio to study lithography behaviors (indentation and scratching) for IF-DPN. Lithography experiments with different humidity and temperatures are also executed on KDP substrate, which align well with theoretical results. During indentation processes, surface materials are squeezed into substrate, leading to deep subsurface damages and significant material recoveries. While the scratching processes would cause intense surface material stripping, and sharp-edge of AFM probe facilitates this process. Numerous K-related chemical structure defects would emerge during the lithography processes, which is the predisposition of microstructure change inside KDP crystal. The binding processes of AFM probe, water, and KDP crystal are spontaneous exothermic reactions. Bonding reactions of Si-O, Si-H, and O-H covalent bonds would expedite the wear of AFM probe and KDP crystal. The humidity affects lithography behaviors mainly through chemical dissolution actions, reducing surface integrity and structural strength of KDP crystal and facilitating material stripping. The high humidity would intensify the hydroxylation reaction occurring on AFM probe and KDP crystal surfaces, enhancing their hydrophilicity. The high temperature would result in a reduction of the condensed water meniscus and adsorbed water film, weakening chemical actions of IF-DPN. But it is beneficial for the penetration of AFM probe into KDP crystal surface, material stripping, and minimization of subsurface damages. The hig

关键词： Molecular dynamics

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Force Distribution-Based Control Strategy of Landing Gear for the Unmanned Helicopter Landing on the Inclined Surface

Force Distribution-Based Control Strategy of Landing Gear fo...

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2022 IEEE International Conference on robotics and Biomimetics, ROBIO 2022

作者： Tian, Baolin Yu, Haitao Mao, Shihao Cui, Yuxin Yan, Zhen Gao, Haibo Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin China College of Electronic Information Engineering Beihang University and the Shanghai Academy of Spaceflight Technology Shanghai China

ISBN: (纸本)9781665481090

The unmanned helicopter plays an important role in the fields of cargo transportation and rescue missions. Due to the limitation of the traditional landing gear structure, the unmanned helicopter has more stringent requirements on the landing terrain. In order to improve the ability to land on the inclined surface for the unmanned helicopter, a novel control strategy of the landing gear based on contact force distribution algorithm is proposed. The overall of landing process includes the desired position tracking stage, the following stage and the attitude adjusting stage. By obtaining the desired acceleration according to the landing and attitude correcting curve of the fuselage, and calculating the desired force based on contact force distribution algorithm, the adaptive motion and trajectory tracking of the landing gear during the landing process has been realized. The simulation results have demonstrated the effectiveness of the strategy when the unmanned helicopter with the initial roll angle of -3 degrees and pitch angle of 3 degrees lands on the inclined surface of 7.07 degrees. In the future, the control strategy can provide a reference for the dynamic landing of the unmanned helicopter while at sea. © 2022 IEEE.

关键词： Acceleration

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Inverse Kinematics of a Reconfigurable Space Manipulator Based on the Closed-Loop Algorithm

Inverse Kinematics of a Reconfigurable Space Manipulator Bas...

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IEEE International Conference on Mechatronics and Automation

作者： Zhiyuan Zhao Xiaohang Yang Zichun Xu Yuntao Li Zhonglai Tian Jingdong Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang Province China

This paper investigates a reconfigurable space manipulator’s inverse kinematics (IK) with two lockable passive telescopic links (LPTLs). Depending on these LPTLs’ locking state, the manipulator includes free-space and reconfiguration operation modes. Firstly, we introduce a new ball joint-based solution for the reconfigurable operation mode. Then, we propose an IK simplified method capable of significantly reducing the computational load of the complex inverse differential kinematic (IDK) equations corresponding to the two operation modes. Next, to solve the resulting simplified IDK equations efficiently, we present an IK solution method based on the closed-loop algorithm. This method is developed to resolve the redundancy at the velocity level and can generate highly accurate and smooth trajectory IK solutions that satisfy the joint limit constraints. Finally, we design two typical case studies corresponding to working scenarios of the manipulator during two operation modes. Their simulation results validate the proposed methods’ effectiveness.

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TRUSTS: A novel treadmill-based multifunctional testing system for performance evaluation of wheeled planetary exploration rover

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robotics and Autonomous systems 2023年第1期164卷

作者： Yu, Haitao Chen, Jian Pan, Dong Gao, Haibo State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Beijing Institute of Spacecraft System Engineering Beijing100094 China

This paper presents a novel treadmill-based multifunctional testing system (TRUSTS) to execute ground testing for wheeled planetary exploration rover (WPER) in both regular and extreme physical conditions before launching. The TRUSTS with specially-made components featuring compact structure and multifunctional testing items comprises a traction loading subsystem (TLS) and a treadmill-based resistance torque loading subsystem (TRTLS). The former offers the working modes including traction loading, position holding, and range limiting. The latter offers working modes including resistance torque loading and leader–follower tracking. By appropriately allocating the working modes of two subsystems, the TRUSTS is capable of conducting diverse testing items. The customized controllers for the TLS and the TRTLS are proposed to guarantee the operation performance of the TRUSTS in all testing items. Extensive experimental results on a Mars rover prototype in both regular and extreme physical conditions demonstrate that the devised TRUSTS could effectively executing trafficability and maneuverability as well as adaptability tests with reliable scenarios and satisfactory precisions of motion tracking and traction/torque loading, which makes the TRUSTS a favorable choice for comprehensive performance assessment of rover in simulant extraterrestrial environment. © 2023 Elsevier B.V.

关键词： Sporting goods

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Design of Bionic Manta Ray Driven by SMA 7

Design of Bionic Manta Ray Driven by SMA

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7th International Conference on Control and robotics Engineering, ICCRE 2022

作者： Liu, Yiwei Chen, Zhiyuan Chen, Changjiang Wang, Tao Tian, Guoping Ji, Shihang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Shanghai Aerospace Equipment Manufacturing General Factory Co. Ltd Shanghai China

ISBN: (纸本)9781665468404

Taking manta ray as bionic object, a kind of bionic robot fish was designed, which was propelled by pectoral fin and driven by SMA (shape memory alloy) wire. Firstly, the model and driving structure were designed according to the appearance and motion mechanism of manta ray. Then, the mechanical model of the designed bionic pectoral fin was established, and the relationship between the pectoral fin swing angle and the current was obtained by combining with the thermodynamic model of SMA. Then, the motion law was determined by theoretical analysis, and the control system was designed. Finally, the prototype was made, and the experiments of pectoral fin swing and bionic manta ray swimming were carried out respectively. © 2022 IEEE.

关键词： Bionics

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Obstacle Identification Based on Deep Learning for Inspection Robot of FAST Wire Rope

Obstacle Identification Based on Deep Learning for Inspectio...

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Automation, robotics and Computer Engineering (ICARCE), International Conference on

作者： Chengxu Yang Xiangyu Sun Gangfeng Liu School of Mechatronics Engineering Harbin Institute of Technology Harbin China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

In this paper, for the requirements of image recognition and localization of the obstacles existing on the moving path in the inspection task of FAST cable inspection robot, the deep learning method is used to realize the recognition of multi-kind and multi-scale obstacles. The obstacles on FAST wire rope have not been identified before. By enhancing the data set and improving the network model, the recognition accuracy and speed are both improved, which meets the efficiency and accuracy requirements of obstacle detection on the wire rope, and provides help for the subsequent robot pace planning and overhaul tasks.

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