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IEEE International Conference on robotics and Automation (ICRA)

作者： Jingdong Zhao Zirui Wang Ziyi Liu Liangliang Zhao Qifan Duan Hong Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Chang Guang Satellite Technology Co. Ltd. Changchun China Beijing Honor Device Co. Ltd. Beijing China

ISBN: (数字)9798350384574

ISBN: (纸本)9798350384581

The construction of large-scale space facilities requires the use of on-orbit construction technology. However, several of its key components, such as standard interface design, compliant control methods, and path planning for multi-branch robots, still need improvement before practical application. This paper presents a comprehensive solution for on-orbit construction tasks, encompassing a novel standard interface, docking control method, and path planning method for space multi-branch robots. Firstly, a novel standard interface is introduced, which features multiple mating modes and a lightweight design. Additionally, a compliant docking method is provided to generate lower contact forces along the Z-direction. Furthermore, for four-armed space robots, a hierarchical planning method is proposed, which innovates in environment map construction and locomotion planning. Specifically, the closed-form Minkowski sum method is employed to solve the robot’s free space, and a concise locomotion method is elucidated based on transition support points. Finally, simulations and experiments are conducted.

关键词： Visualization Machine vision Prototypes Aerospace electronics Path planning Planning Task analysis

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Theoretical Modeling and Performance Analysis on the Linear Electromagnetic Actuator with High Nonlinear Dynamic Negative Stiffness

SSRN

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SSRN 2024年

作者： Wang, Chuchao Lu, Shizhou Liu, Xiaohan Mo, Wenyin Zhang, Bin Li, Kai Sun, Lining Mechanical Electrical & Information Engineering Shandong University Weihai264209 China School of Mechanical Engineering Dalian University of Technology Dalian116081 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China

Electromagnetic mechanisms are introduced to adjust the stiffness and improve the performance of mechanical systems, which have been widely researched. In this paper, the transient performance of a novel linear solenoid elastic actuator with higher nonlinear negative stiffness and speed by introducing the negative stiffness mechanism is analyzed and predicted. The actuator can achieve an initial theoretical stiffness of -20.96 N/m at 1 A current and a maximum stroke of 9 mm in 0.5 s. The performance indicators including peak time, overshoot, and steady-state displacement are obtained through electromagnetic-mechanical coupled modeling. The influence of system parameters including natural frequency, equivalent stiffness and damping coefficient on performance indicators is also studied. First, the approximate analytical model of the electromagnetic force is derived by constructing an innovative magnetic field distribution model. Second, the nonlinear vibration equation is solved theoretically to obtain the analytical results of the performance indicators and system parameters. Finally, the transient displacements and performance indicators obtained from the analytical model, the numerical model established in Simulink software and the simulation model obtained in Adams software are compared. The maximum errors of the peak time, overshoot and stable displacement through the analytical model and experiment are 2.56 ms, 9.37% and 0.32 mm, respectively. The theoretical and experimental results show the nonlinear effects of input currents on performance indicators and system parameters. The overshoot has a strong positive following feature on the damping coefficient, but the vibration frequency mainly depends on the equivalent stiffness of the system. This research provides a reference for the transient solution of nonlinear electromagnetic-dynamic coupling models and performance improvement of linear electromagnetic actuators. © 2024, The Authors. All rights reserved.

关键词： Stiffness

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Dynamical Modeling and Numerical Simulation of Water Discharge Process of Spherical Objects

Dynamical Modeling and Numerical Simulation of Water Dischar...

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IEEE International Conference on Mechatronics and Automation

作者： Lin Zhong Jiawei Dong Jiabin Liu Wei Wang Riyue Wu Shuqi Wang Tao Zhang State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment Guangdong University of Technology Guangzhou China School of Electromechanical Engineering Guangdong University of Technology Guangzhou China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

The process of an object leaping out of the water is very similar to the jumping process of an aquatic animal during prey or avoid predators. The study of the process of an object leaping out of the water is beneficial to the design of robots jumping out of water. In this work, the free jump of a sphere out of the water is successfully simulated based on the Computational Fluid Dynamics (CFD) software Fluent, with User-Defined Functions to control the motion of the sphere, the volume of Fluid model, dynamic meshing, and Detached Eddy Simulation. The velocity of the sphere at the water-air interface and the height of the sphere leaping out from the water surface obtained from the numerical simulation are compared with experimental results. The maximum error between the experimental and the simulated results is 2.28% in the water-discharge velocity and 2.65% in the leaping height from the water surface. In addition, this paper model the dynamics of the sphere during the water discharge process. The paper also analyses the free deformation of water surface, the water film rupture process on the surface of the sphere, the variation of fluid drag on the sphere, and the variation of the fluid velocity field during the free ascent of the sphere after acquiring an initial velocity of 2.81 m/s.

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A Collision Avoidance Path Planning Method for 7-DOF Space Manipulator*

A Collision Avoidance Path Planning Method for 7-DOF Space M...

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IEEE International Conference on robotics and Biomimetics

作者： Xu Han Guocai Yang Minghe Jin Qi Wang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilong Jiang China Department of the Aerospace Systems Department Military Representative Office of the Equipment Changchun China

This paper proposes a collision avoidance path planning approach for redundant robotic arms based on the RRT algorithm. The study focuses on a 7-DOF robotic arm with an SSRMS configuration. The method involves improved RRT-based path planning in configuration space (C-space) and collision detection in Cartesian space. The results of collision detection are employed to guide the path planning process. Emulating the SSRMS configuration robotic arm, a kinematic model is established. By enhancing the RRT algorithm with the following points: probabilistic sampling towards the target configuration, guided exploration near existing tree nodes, parent node reassignment for new nodes, and the adoption of a bidirectional searching tree, the randomness of sampling is reduced and the planning process is accelerated. By continuously mapping points on the surface of the arm to both the base coordinate system and the self-collision coordinate system, collision detection and self-collision detection are performed in the Cartesian space using a combination of surface equations and projection methods. Finally, a series of simulation experiments were conducted to analyze the impact of various parameters, different obstacles and different methods on the planning process. This validation confirmed the feasibility and effectiveness of the approach.

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R-SIEL: a physics-informed learning algorithm for discovering dynamics of serial manipulators

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Expert systems with Applications 2025年 287卷

作者： Omar, Mohamed Li, Ruifeng Wang, Ke Asker, Ahmed State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Production and Mechanical Design Engineering Department Faculty of Engineering Mansoura University Mansoura35516 Egypt Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou450000 China School of Engineering and Applied Sciences Nile University Giza12573 Egypt

Dynamic modeling is essential for serial manipulators’ design and control. Multi-body dynamics simulators, such as SIMULINK and Adams, can precisely replicate a robot's dynamic behavior but are incapable of determining its nonlinear dynamic model. This work aims to identify serial manipulators’ dynamics from simulation data, which extends the capability of using an algorithm that combines the Euler-Lagrange method and sparse identification of nonlinear dynamics (SINDy) with physics-based constraints and Akaike Information Criterion (AICc). The algorithm is called Recursive SINDy Euler-Lagrange (R-SIEL). The Euler-Lagrange method is used to construct a preliminary library of symbolic functions. The physics-informed constraints, which utilize the similarities between the symbolic coefficients of the dynamic equations, are employed to decrease the number of functions in the library to get a constrained library. SINDy is equipped with three kinds of constraints: the constrained library, the dataset, and similarities between links’ dynamic equations. The generation of the three distinct datasets—training, constraints, and testing data—uses simulated data from the MATLAB® SIMULINK environment. The algorithms of sequential threshold least-squares and L0-minimization are coded with the convex optimization package CVX to determine the best dynamic model. The resulting models are tested with the testing dataset, and based on the lowest AICc, the best model is chosen. The proposed algorithm is applied to different serial manipulators: 2DOF robot, Stanford, PRR robot, ABB SCARA, UR5, and KUKA KR4 AGILUS robots. The resulting model is validated with the dynamic model derived using the conventional Euler-Lagrange method. For the considered manipulators, the R-SIEL algorithm shows a high capability to identify the dynamic model compared to the one identified compared to the previous algorithm. © 2025 Elsevier Ltd

关键词： Lagrange multipliers

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Optical modulation of repaired damage site on fused silica produced by CO2 laser rapid ablation mitigation

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Chinese Physics B 2020年第5期29卷 288-296页

作者： Chao Tan Lin-Jie Zhao Ming-Jun Chen Jian Cheng Zhao-Yang Yin Qi Liu Hao Yang Wei Liao State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China Research Center of Laser Fusion China Academy of Engineering PhysicsMianyang 621900China

CO2 laser rapid ablation mitigation(RAM)of fused silica has been used in high-power laser systems owing to its advantages of high efficiency,and ease of implementing batch and automated *** order to study the effect of repaired morphology of RAM on laser modulation and to improve laser damage threshold of optics,an finite element method(FEM)mathematical model of 351 nm laser irradiating fused silica optics is developed based on Maxwell electromagnetic field equations,to explore the 3D near-field light intensity distribution inside optics with repaired site on its *** influences of the cone angle and the size of the repaired site on incident laser modulation are studied as *** results have shown that for the repaired site with a cone angle of 73.3°,the light intensity distribution has obvious three-dimensional *** relative light intensity on z-section has a circularly distribution,and the radius of the annular intensification zone increases with the decrease of *** the distribution of maximum relative light intensity on y-section is parabolical with the increase of *** the cone angle of the repaired site decreases,the effect of the repaired surface on light modulation becomes stronger,leading to a weak resistance to laser ***,the large size repaired site would also reduce the laser damage ***,a repaired site with a larger cone angle and smaller size is preferred in practical CO2 laser repairing of surface *** work will provide theoretical guidance for the design of repaired surface topography,as well as the improvement of RAM process.

关键词： fused silica laser repaired surface optical modulation finite element method(FEM)

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Exploring Supervised Contrastive Learning for Skeleton-Based Temporal Action Segmentation

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IEEE Transactions on Cognitive and Developmental systems 2025年

作者： Chen, Bowen Ji, Haoyu Ma, Hanwei Lin, Ruihan Nie, Wei Ren, Weihong Wang, Zhiyong Liu, Honghai Harbin Institute of Technology Shenzhen State Key Laboratory of Robotics and Systems Shenzhen518055 China University of Portsmouth School of Computing PortsmouthPO1 3HE United Kingdom

Skeleton-based temporal action segmentation (STAS) takes long human skeleton sequences as input and predicts action categories at the frame level. Current STAS methods primarily use frame-wise cross-entropy loss, which focuses only on the relationships among one-hot label logits and overlooks the importance of the quality of frame-wise representations. To this end, we propose a novel framework called Supervised Contrastive Skeleton-Based Temporal Action Segmentation (SCSAS) that optimizes representation learning. Specifically, our framework constructs a frame-level embedding space using a simple projection head and optimizes this space using three novel contrastive losses. These losses enhance the semantic relationships at the frame and segment levels by pulling together representations of the same activities and pushing apart those of different actions. Moreover, we introduce a confidence-based hard anchor sampling strategy to enhance the efficiency of contrastive learning. Finally, a boundary refinement module is also introduced to fully exploit the advantages of optimized representation. Our method seamlessly integrates with existing STAS methods and consistently enhances their performance across various datasets, without additional inference costs. With the incorporation of the boundary refinement branch, early STAS methods even achieve performance comparable to the state-of-the-art methods. © 2016 IEEE.

关键词： Contrastive Learning

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Least Squares Support Vector Machine Kalman Filter for Physiological Tremor Suppression in Minimally Invasive Surgical Robot

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Journal of harbin institute of technology(New Series) 2020年第5期27卷 22-28页

作者： Jiandong Dai Zhijiang Du Zhiyuan Yan Yunlei Liang State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

This paper studies the physiological tremor filtering in minimally invasive surgical *** surgeon􀆳s physiological tremor of the hand can cause the vibration of the tip of the surgical instrument,which may reduce operative accuracy and limit the application of surgical *** at the vibration caused by physiological tremor of hand,we propose a Least Squares Support Vector Machine Kalman Filter(LSSVMKF),which can filter the tremor by estimating and modeling the tremor signal by Kalman filter and then superimposing it reversely in the control *** estimating and modeling the tremor signal,the filter uses the Least Squares Support Vector Machine(LS⁃SVM)to build the regression model of the constant parameters(Process Noise Covariance and Measurement Noise Covariance)of the traditional Kalman filter,which can dynamically adjust these parameters during the operation and improve the accuracy of Kalman *** simulation results show that the LSSVMKF can effectively filter out the tremor signal,thereby improving the accuracy of surgery.

关键词： physiological tremor suppression minimally invasive surgical robot Kalman filter support vector machine

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Exploring Self- and Cross-Triplet Correlations for Human-Object Interaction Detection

arXiv

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arXiv 2024年

作者： Jiang, Weibo Ren, Weihong Tian, Jiandong Qu, Liangqiong Wang, Zhiyong Liu, Honghai State Key Laboratory of Robotics and System School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen China State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Science China Department of Statistics and Actuarial Science The University of Hong Kong Hong Kong

Human-Object Interaction (HOI) detection plays a vital role in scene understanding, which aims to predict the HOI triplet in the form of . Existing methods mainly extract multi-modal features (e.g., appearance, object semantics, human pose) and then fuse them together to directly predict HOI triplets. However, most of these methods focus on seeking for self-triplet aggregation, but ignore the potential cross-triplet dependencies, resulting in ambiguity of action prediction. In this work, we propose to explore Self- and Cross-Triplet Correlations (SCTC) for HOI detection. Specifically, we regard each triplet proposal as a graph where Human, Object represent nodes and Action indicates edge, to aggregate self-triplet correlation. Also, we try to explore cross-triplet dependencies by jointly considering instance-level, semantic-level, and layout-level relations. Besides, we leverage the CLIP model to assist our SCTC obtain interaction-aware feature by knowledge distillation, which provides useful action clues for HOI detection. Extensive experiments on HICO-DET and V-COCO datasets verify the effectiveness of our proposed SCTC. Copyright © 2024, The Authors. All rights reserved.

关键词： Distillation

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Material Removal Mechanism and Microstructure Fabrication in Micro-Milling of Glow Discharge Polymer (GDP)

SSRN

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SSRN 2022年

作者： Wang, Guangzhou Yu, Tianyu Zhou, Xingying Guo, Ruiyang Chen, Mingjun Sun, Yazhou School of Mechatronics Engineering Harbin Institute of Technology Heilongjiang Harbin150001 China State Key Laboratory of Robotics and System Harbin Institute of Technology Heilongjiang Harbin150001 China

Glow discharge polymer (GDP) is an essential material for target ball applied in inertial confinement fusion (ICF). The processing quality of GDP material directly affects its high energy performance. Machinability and material removal mechanism are critical to attain a high processing quality during micro cutting. In this work, a comprehensive study of the machinability and removal mechanism of GDP material is conducted. Mechanical properties of GDP, such as elastic modulus, hardness and elastic recovery rate, were investigated first using nanoindentation experiments. Micro milling experiments were performed using micro ball end milling. Chip modes, machined surface morphology and their formation mechanism are emphatically analyzed. An geometric model for calculating undeformed chip area removed by ball end mill was proposed for analyzing the specific cutting force. Additionally, the effects of minimum uncut chip thickness (MUCT) threshold and size effect on the machining quality of GDP material were also studied. By comprehensively analyzing chip morphology, cutting force, specific cutting force as well as surface integrity, the cutting mechanism of GDP material can be roughly divided into the ploughing dominated, the ploughing-shearing coexist and the shearing dominated Below normalized MUCT threshold of 0.339, the size effect is obvious. When the ratio of feed per tooth to cutting edge radius is up to 0.714, the size effect has little influence on the machining of GDP material. At the end, micro dimples were fabricated on the GDP surface by ball end milling. The surface quality of machined micro dimples indicates that the ploughing effect and size effect have significant impact on machining micro-dimpled structures in ploughing dominated mode. The parameters (e.g. step or pitch distance) of specific machining ways (e.g. layer milling or spiral milling) are the main factors affecting machining micro dimples in shearing dominated mode. © 2022, The Authors. All rig

关键词： Surface morphology

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