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Permanent Magnet Shape Optimization Method for PMSM Air Gap Flux Density Harmonics Reduction

CES Transactions on Electrical Machines and systems 2021年第4期5卷 284-290页

作者： Chengsi Liu Yongxiang Xu Jibin Zou Guodong Yu Liang Zhuo School of Electrical Engineering and Automation of HIT Department of Electrical Engineering Harbin Institute of Technology the State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Institute of Technology and National Engineering Research Center for Small and Special Precision Motors Guizhou Aerospace Linquan Motor Co.Ltd

This paper proposed a permanent magnet optimization method to suppress the air gap flux density harmonic of permanent magnet synchronous motor(PMSM).The method corrected the effective air gap length of the motor,calculated the magnetization length of the permanent in the case of parallel magnetization,and took the influence of the permanent magnet relative permeability into *** on these works,for a given sinusoidal air gap flux density waveform,the corresponding structural parameters can be calculated,so as to achieve the optimization of the permanent *** using this method to optimize the shape of the magnet,the fundamental wave of the air gap flux density can be retained to the greatest extent,so as to eliminate harmonics and maintain the output capacity at the same *** feasibility and accuracy of the method have been verified by finite element analysis(FEA)and prototype machine *** method is simple and time-saving,and has a satisfactory accuracy,which provides a reference method for permanent magnet optimization of PMSM.

关键词： Permanent magnet synchronous motor(PMSM) analytical method finite element analysis(FEA) magnet shape optimization.

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An Optimal Control Formulation of Tool Affordance Applied to Impact Tasks

arXiv

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arXiv 2024年

作者： Ti, Boyang Gao, Yongsheng Zhao, Jie Calinon, Sylvain The State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin150001 China Idiap Research Institute MartignyCH-1920 Switzerland Lausanne1015 Switzerland

Humans use tools to complete impact-aware tasks such as hammering a nail or playing tennis. The postures adopted to use these tools can significantly influence the performance of these tasks, where the force or velocity of the hand holding a tool plays a crucial role. The underlying motion planning challenge consists of grabbing the tool in preparation for the use of this tool with an optimal body posture. Directional manipulability describes the dexterity of force and velocity in a joint configuration along a specific direction. In order to take directional manipulability and tool affordances into account, we apply an optimal control method combining iterative linear quadratic regulator (iLQR) with the alternating direction method of multipliers (ADMM). Our approach considers the notion of tool affordances to solve motion planning problems, by introducing a cost based on directional velocity manipulability. The proposed approach is applied to impact tasks in simulation and on a real 7-axis robot, specifically in a nail-hammering task with the assistance of a pilot hole. Our comparison study demonstrates the importance of maximizing directional manipulability in impact-aware tasks. Copyright © 2024, The Authors. All rights reserved.

关键词： Motion planning

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PI2-CMA Based Trajectory Planning Method for the Tractor-Trailer Vehicle 6

PI2-CMA Based Trajectory Planning Method for the Tractor-Tra...

引用

6th IEEE International Conference on Pattern Recognition and Artificial Intelligence, PRAI 2023

作者： Wang, You Wang, Zehao Wang, Jingchuan Guo, Rui Xiao, Peng Shanghai Jiao Tong University Key Laboratory of System Control and Information Processing Ministry of Education Institute of Medical Robotics and Department of Automation Shanghai200240 China State Grid Intelligence Technology CO. LTD China

ISBN: (纸本)9798350325485

The motion primitive-based state lattice trajectory planning method has been widely used in the field of trajectory planning. However, due to the limitations of the search space and resolution of motion primitives, and the lack of consideration of scenario information during offline generation of motion primitives, the tractor-Trailer vehicles can easily fall into "jackknife phenomenon"when making large pose adjustments in narrow scenarios, which brings dilemma for trajectory planning. In this paper, a trajectory planning algorithm is proposed based on a general model of tractor-Trailer vehicle, which combines global planning and local optimization. The method first generates a series of motion primitives, including forward and backward driving conditions, and then an A based global state lattice planner is used to obtain a planning result, which is imported as the initial solution into the local trajectory optimizer based on PI2-CMA (Path Integral Policy Improvement with Covariance Matrix Adaptation) algorithm and dynamic potential method. Experiments show that this method significantly improves the performance in the obstacle avoidance, "jackknife phenomenon"avoidance and curvature compared to traditional motion primitive-based state lattice planning methods. © 2023 IEEE.

关键词： Trajectories

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Accelerating Visual Reinforcement Learning with Separate Primitive Policy for Peg-in-Hole Tasks

arXiv

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arXiv 2025年

作者： Xu, Zichun Wang, Zhaomin Li, Yuntao Zhuang, Lei Zhao, Zhiyuan Yang, Guocai Zhao, Jingdong State Key Laboratory of Robotics and Systems Harbin Institute of Technology Heilongjiang Province Harbin150001 China School of Mechanical Engineering Shandong University Jinan250061 China

For peg-in-hole tasks, humans rely on binocular visual perception to locate the peg above the hole surface and then proceed with insertion. This paper draws insights from this behavior to enable agents to learn efficient assembly strategies through visual reinforcement learning. Hence, we propose a Separate Primitive Policy (S2P) to simultaneously learn how to derive location and insertion actions. S2P is compatible with model-free reinforcement learning algorithms. Ten insertion tasks featuring different polygons are developed as benchmarks for evaluations. Simulation experiments show that S2P can boost the sample efficiency and success rate even with force constraints. Real-world experiments are also performed to verify the feasibility of S2P. Ablations are finally given to discuss the generalizability of S2P and some factors that affect its performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Reinforcement learning

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Model Design and Concept of Operations of Standard Interface for On-orbit Construction

Model Design and Concept of Operations of Standard Interface...

引用

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

引用

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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WSC-Trans: A CNN-Transformer Structure-Based 3D Multi-Structural Automatic Segmentation Model for Temporal Bone CT

WSC-Trans: A CNN-Transformer Structure-Based 3D Multi-Struct...

引用

IEEE International Conference on Bioinformatics and Biomedicine (BIBM)

作者： Xin Hua Jixin Ma Hongjian Yu Zhijiang Du Fanjun Zheng Chen Zhang Qiaohui Lu Hui Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Senior Department of Otolaryngology Head and Neck Surgery The 6th Medical Center of Chinese PLA General Hospital Beijing China

ISBN: (数字)9798350386226

ISBN: (纸本)9798350386233

Cochlear implantation is the most effective treatment for severe deafness, which requires accurate localization of temporal bone anatomy. Preoperative CT image segmentation is an essential technique to determine the location of relevant tissues in the temporal bone. However, manual segmentation is usually time-consuming and suffers from low accuracy due to the complex and small structures of these tissues in temporal bone CT. To address this issue, we proposed a CNN-Transformer structure-based 3D multi-structured model for the automatic segmentation of fine and complex tissues such as the cochlea, facial nerve, ossicles, vestibule and semicircular canal in the temporal bone CT. Our model adopts a new Transformer deformation structure, which effectively utilizes the spatial attention mechanism to capture feature dependencies, and uses the channel attention mechanism to fuse different channel semantic representations to improve segmentation accuracy. Extensive experiments on a private temporal bone CT dataset show that our model achieves higher DSS and JSS scores, and lower HD95 and ASSD scores for all targets compared with other existing segmentation methods, demonstrating its superior performance.

关键词： Image segmentation Solid modeling Irrigation Three-dimensional displays Accuracy Attention mechanisms Computed tomography Ear Bones Transformers

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MRI Super-Resolution via Hybrid Information Enhancement Network based on Multi-Attention and Adaptive Convolution

MRI Super-Resolution via Hybrid Information Enhancement Netw...

引用

IEEE International Conference on Bioinformatics and Biomedicine (BIBM)

作者： Jixin Ma Hongjian Yu Zhijiang Du Xin Hua Zibo Li Hui Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Senior Department of Otolaryngology Head and Neck Surgery The 6th Medical Center of Chinese PLA General Hospital Beijing China

ISBN: (数字)9798350386226

ISBN: (纸本)9798350386233

Deep learning-based super-resolution (SR) reconstruction is a critical approach which is used to generate high-resolution images from corresponding low-resolution images. However, the CNN-based methods are ineffective in capturing global information, whereas the Transformer-based methods have limited ability to model long-range dependencies caused by window self-attention. Besides, it is a challenging task to recover lost high-frequency information from downsampled images. In this paper, a Hybrid Information Enhanced Network (HIEN) is proposed for MRI super-resolution task. Specifically, we propose a Spatial-Channel Hybrid Attention (SCHA) to enhance specific semantics representation by combining spatial and channel self-attention together. To recover more high-frequency components, we propose a Dynamic High-Frequency Pass Filter (DHPF) to preserve high-frequency information adaptively in pixel-wise. The results of our extensive experiments indicate that HIEN outperforms other state-of-the-art methods.

关键词： Convolution Magnetic resonance imaging Magnetic separation Superresolution Semantics Magnetic resonance Transformers Information filters Image reconstruction Biomedical imaging

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

引用

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

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

引用

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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