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Mechatronics and robotics Engineering (ICMRE), International Conference on

作者： Xiangyu Sun Gangfeng Liu Xuehe Zhang Changle Li Jie Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

In this paper, a positioning system developed for cable inspection robot system which works on feed support cables of Five-hundred-meter Aperture Spherical radio Telescope (FAST) is introduced. The positioning system consists of wheeled odometers and a Real-tme kinematic (RTK) based Global Navigation Satellite system (GNSS). Firstly, the cable with fixed ends and free suspension in the middle is modeled, and the influence of wind on the cable in FAST site is analyzed. Then, the data of the four odometers on the robot are processed, and the odometer information is fused with GNSS information through Kalman filtering. Then the best position estimation of the cable inspection robot is determined. A simulation is finally established to verify the proposed robot positioning method. The result shows that the method can work pretty well under the real working situation.

关键词： Vibrations Global navigation satellite system Analytical models Solid modeling Inspection Mathematical models Feeds

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Aerodynamic Analysis and Deployment Mechanism of A Foldable Mars Quadrotor

Aerodynamic Analysis and Deployment Mechanism of A Foldable ...

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ieee International Conference on Mechatronics and Automation

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

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.

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

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

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Computer, Control and robotics (ICCCR), International Conference on

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

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.

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Optimizing Dataset Configuration for Improving Convolutional Neural Networks Performance in Chest X-ray Image Classification

Optimizing Dataset Configuration for Improving Convolutional...

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6th International Conference on Intelligent Computing and Signal Processing (ICSP)

作者： Zengmin He Yi Ren Honggang Wang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

Chest X-ray (CXR) is essential for physicians to diagnose lung diseases in clinical medicine. With the development of computer and deep learning techniques, creating CXR datasets to train convolutional neural networks (CNNs) has become a popular research topic. However, there are still challenges in creating datasets due to class imbalance and the ratio setting of datasets. This study investigated the impact of class imbalance and the ratio of training, validation, and test sets on CNNs classification performance by optimizing the dataset configuration. This was achieved by directly modifying the ratio, applying oversampling based on the adaptive contrast enhancement (ACE) algorithm, and random undersampling to balance the dataset classes, followed by modifying the ratio again. Therefore, seven datasets were obtained, which were utilized to individually train four CNNs based on transfer learning and fine-tuning techniques. Evaluation metrics based on the confusion matrix were utilized to demonstrate the enhanced classification performance of CNNs. The results indicated that at least 17% of the accuracy of CNNs trained by the dataset with modified ratios was improved as compared with the dataset with an unreasonable initial configuration. Additionally, the overall evaluation metrics of CNNs were further improved by balancing the dataset classes and modifying the ratios. ChexNet demonstrated the best classification performance among the four CNNs, as evidenced by the area under the receiver operating characteristic (ROC) curves (AUC). Furthermore, ChexNet was trained by a class balanced dataset with a ratio of 7:2:1, resulting in the best evaluation metrics, including F1 Score, balanced accuracy, accuracy, recall, specificity, and precision, which were 97.81%, 97.78%, 97.78%, 98.73%, 96.84%, and 96.89%, respectively. Therefore, optimizing dataset configuration can effectively improve the performance of CNNs, providing empirical guidance for researchers in creating dat

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

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

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ieee International Conference on Mechatronics and Automation

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

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.

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Design of Mixed Reality Assembly system Based on Improved ORB Algorithm 3

Design of Mixed Reality Assembly System Based on Improved OR...

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3rd International Conference on Computer Vision, Image and Deep Learning and International Conference on Computer Engineering and Applications, CVIDL and ICCEA 2022

作者： Lu, Na Xiao, YongFei Zhao, Jie Shandong Provincial Key Laboratory of Robot and Manufacturing Automation Technology ShanDong China Harbin Institute of Technology Institute of Automation Shandong State Key Laboratory of Robotics and System Harbin China

ISBN: (纸本)9781665459112

This paper studies the natural feature point detection algorithm in a virtual assembly system. To address the problems of unsatisfactory detection effect and poor matching accuracy of the ORB algorithm, a feature uniform distribution algorithm based on pyramidal grid division is proposed, and a strategy of retaining feature points according to Harris response values is formulated to solve the problem of feature point aggregation while ensuring extraction speed. Hamming distance and the RANSAC algorithm are used to constrain the matching results. The robot assembly system based on this algorithm overlays the 3D model of the spraying robot and virtual information in the mobile device to improve the assembly efficiency of the staff. The experimental results show that the mixed reality(MR) assembly system based on the algorithm of this paper performs well, and the real-time performance and alignment accuracy are improved. © 2022 ieee.

关键词： Assembly

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An Effective Rotor-Shape Optimization Method for IPM Motor with 1/2 Slot per Phase per Pole

An Effective Rotor-Shape Optimization Method for IPM Motor w...

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International Conference on Applied Superconductivity and Electromagnetic Devices, ASEMD

作者： Guodong Yu Shuqi Sun Junlong Li Lijun Xiao Yongxiang Xu Jibin Zou State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

Although IPM motor with 1/2 slot per phase per pole has a relatively less rotor loss in comparison with other fractional slot concentrated winding (FSCW), the problems of THD of back-EMF and cogging torque are worse, which limits its application in electric vehicles and other industry fields. This paper proposes an effective rotor-shape optimization method to suppress both THD of back-EMF and cogging torque for improving torque ripple problem. Different from the prevalent rotor optimization methods, the proposed rotor-shape optimization method associates both shape function optimization of rotor surface with PM shaping, which can effectively decrease optimization parameters, and enhance optimization efficiency. To clarify the optimization strategy, the back-EMF and cogging torque for this PM motor with 1/2 slot per phase per pole are analyzed firstly. Then, the proposed optimization method is presented in detail. Finally, the optimized IPM motor is prototyped and its experimental results verifies the effectiveness of the proposed optimization method.

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A Sequential Design Framework of Robot Leg for High Locomotion Performance*

A Sequential Design Framework of Robot Leg for High Locomoti...

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ieee International Conference on Cyborg and Bionic systems (CBS)

作者： Bin Qi Songyuan Zhang Yili Fu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

Leg length, joint maximum torque/speed, motor model and transmission ratio are the most concerning parameters in the leg mechanism design of the legged-robot. The first two parameters are related to the locomotion performance, and the last two determine the actuator’s performance. At the beginning of the design, it is difficult to intuitively grasp the relationship between the leg length, the maximum torque of the joint and the locomotion performance of the legged-robot. When selecting the motor and determining the transmission ratio, these factors impact the control bandwidth and the locomotion performance. Considering the above-mentioned practical problems in the design, this paper proposes a systematic and two-stage sequential leg design framework for the legged-robot, which provides the design guidance in the early stage and the selection of the actuator motor and the determination of the transmission ratio in the later stage. Furthermore, the analytic solution of nonlinear constraint’s gradient was derived. Finally, a case study shows the application of the proposed framework. This work shows that finding an optimal set of design parameters among multiple objectives is not always possible. During design process, it is necessary to weigh the relationship between multiple indexes in many aspects.

关键词： Legged locomotion Actuators Torque systematics Process control Indexes Task analysis

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Tool geometry design and microstructure fabrication by micro flat-end milling on soft-brittle LiF surface

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Journal of Manufacturing Processes 2025年 149卷 868-877页

作者： Lei, Hongqin Zhang, Zixiao Chen, Liang Guo, Yanqiu Cheng, Jian Zhao, Linjie Chen, Mingjun Yang, Dinghuai Chen, Guang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China

The LiF crystal with the three-layer step microstructure is vital in the laser-driven quasi-isentropic compression experiment. However, due to the high chemical activity and easy deliquescence of soft-brittle LiF crystals, brittle fracture can easily occur during the microstructure preparation achieved by the micro-milling technology. Therefore, it is essential to determine the optimal tool geometry and preferred processing parameters to achieve an ultra-smooth surface. A finite element (FE) model of the tool geometry optimization for LiF crystals is constructed based on dimensional analysis and the stress-strain curve obtained by nanoindentation tests. Micro-slot and microstructure preparation experiments are conducted to verify the cutting performance of the manufactured cutters with optimal geometry. It is found that the optimal negative rake/relief angles of side- and bottom edges are determined to be −35°/9° and − 25°/20° for tool I from the perspectives of the tensile stress, cutting force, and tool surface stress (σ1), respectively. For tool II, optimal negative rake/relief angles of the side- and bottom edges are −60°/15° and − 55°/20°, respectively. The σ1 of tool II is 110.3 MPa, which is 0.74 times and 0.95 times that of tool I (149 MPa) and the CBN tool (116.1 MPa), respectively, indicating that tool II has the most substantial wear resistance under the same processing parameters. Besides, compared with other tool structures, the cutting force and tensile stress are the smallest when using the tool II. The small stress can make the milling process stable, and the vibration and impact generated by the tool are smaller, which helps to make the micro-milled surface smooth. Therefore, the average surface roughness processed by tool II is 0.70 times and 0.47 times that of the CBN tool and tool I, respectively, further illustrating the best cutting performance of tool II. Furthermore, for tool II, the optimal spindle speed and feed per tooth are 40,000 r/min a

关键词： Cutting performance Flat-end milling LiF crystals Microstructure fabrication Tool geometry

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GCA-Net: A Global Context Aggregation Network for Effective Optical Flow

GCA-Net: A Global Context Aggregation Network for Effective ...

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Annual Conference of Industrial Electronics Society

作者： Tao Xie Jinghan Gao Ke Wang Ruifeng Li State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

Optical flow seeks to estimate the per-pixel 2D motion between two frames by identifying corresponding pixels. Current flow estimators typically involve per-pixel feature extraction, multi-scale 4D correlation volume construction, and iterative flow field updates through a Conv-GRU module. However, the locality of convolutional features in these methods renders the calculated correlations vulnerable to different noises. In addition, the Conv-GRU module of these methods is only executed with a convolution layer, which is incapable of exploiting context clues from larger window sizes even inside the image being queried itself, thus raising it more difficult for the model to process images with challenging regions, e.g., textureless areas. To this end, we introduce GCA-Net, a global context aggregation network for credible yet effective optical flow estimation. More specifically, we propose a highly efficient multi-scale transformer (MSFormer) layer which enables the per-pixel feature to aggregate long-range information from other features, hence building more accurate 4D correlation volumes. Besides, we develop an attention-enhanced Conv-GRU block (AttGRU) that can incorporate information alongside a larger context window even within itself empowering our network to estimate optical flow in even the most challenging regions. Experimentally, we demonstrate that GCA-Net outperforms previous state-of-the-art methods by large margins on Sintel (Final) and KITTI 2015 (background and foreground) benchmarks.

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