检索结果-内蒙古大学图书馆

Model heat source using actual distribution of laser power density for simulation of laser processing

Journal of Central South University 2022年第10期29卷 3277-3293页

作者： WANG Gen-wang DING Ye GUAN Yan-chao WANG Yang YANG Li-jun State Key Laboratory of Robotics and Systems Harbin Institute of TechnologyHarbin 150001China School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China

The model of heat source(MHS) which reflects the thermal interaction between materials and laser during processing determines the accuracy of simulation results. To acquire desirable simulations results, although various modifications of heat sources in the aspect of absorption process of laser by materials have been purposed, the distribution of laser power density(DLPD) in MHS is still modeled theoretically. However, in the actual situations of laser processing, the DLPD is definitely different from the ideal models. So, it is indispensable to build MHS using actual DLPD to improve the accuracy of simulation results. Besides, an automatic modeling method will be benefit to simplify the tedious pre-processing of simulations. This paper presents a modeling method and corresponding algorithm to model heat source using measured DLPD. This algorithm automatically processes original data to get modeling parameters and provides a step MHS combining with absorption models. Simulations and experiments of heat transfer in steel plates irradiated by laser prove the mothed and the step MHS. Moreover, the investigations of laser induced thermal-crack propagation in glass highlight the signification of modeling heat source based on actual DLPD and demonstrate the enormous application of this method in the simulation of laser processing.

关键词： heat source laser processing distribution of power density digital images processing heat transfer

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Automatic venous segmentation in venipuncture robot using deep learning

Automatic venous segmentation in venipuncture robot using de...

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2021 IEEE International Conference on Real-Time Computing and robotics, RCAR 2021

作者： He, Tianbao Guo, Chuangqiang Jiang, Li Liu, Hansong Harbin Institute of Technology State Key Laboratory of Robotics and System Heilongjiang Province Harbin China

ISBN: (纸本)9781665436786

Vein identification plays a pivotal role in realizing automatic venipuncture, and it has become a difficulty to segment the veins efficiently as well as accurately in the research of full-automatic venipuncture robots. Most studies in the field of vein segmentation have only focused on traditional image processing methods, the segmentation accuracy and generalization performance of which are poor. Therefore, we propose an automatic image segmentation algorithm using the U-Net model with the attention mechanism (Attention-UNet) which can suppress unnecessary features. Besides, the encoder-decoder and the skip-connection structure are applied for multi-scale feature recognition so that the segmentation accuracy can be improved. Meanwhile, on digital arm images for the vein segmentation data set (DAIVS data set), the newly-built human forearm veins data set, the effectiveness of the proposed method in vein segmentation is verified. Finally, we conduct experiments to acquire and process venous images with the Attention-UNet in real-time on the venipuncture robot. These results indicate that machine vision has better performance in complex visual tasks and can be translated into clinical application. © 2021 IEEE.

关键词： Robots

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Methane and nitrous oxide emissions from municipal wastewater treatment plants in China:A plant-level and technology-specific study

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Environmental Science and Ecotechnology 2024年第4期20卷 123-130页

作者： Haiyan Li Liangfang You He Du Bowen Yu Lu Lu Bo Zheng Qiang Zhang Kebin He Nanqi Ren School of Civil and Environmental Engineering Harbin Institute of TechnologyShenzhen518055China Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration Institute of Environment and EcologyTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing100084China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China

Wastewater treatment is an important source of greenhouse gases(GHGs).Yet large uncertainties remain in the quantification of GHG emissions from municipal wastewater treatment plants(MWWTPs)in China.A high-resolution and technology-specific emission inventory is still lacking to support mitigation strategies of *** we develop a plant-level and technology-based MWWTP emission inventory for China covering 8703 plants and 19 treatment technology categories by compiling and harmonizing the most up-to-date facility-level ***'s methane(CH_(4))and nitrous oxide(N_(2)O)emissions from MWWTPs in 2020 are estimated to be 150.6 Gg and 22.0 Gg,respectively,with the uncertainty range of-30%to 37%and-30%to 26%at 95%confidence *** find an emission inequality across cities,with the richest cities emitting two times more CH_(4)and N_(2)O per capita from municipal wastewater treatment than the poorest *** emitted CH_(4)and N_(2)O are dominated by Anaerobic/Anoxic/Oxic-,Sequencing Batch Reactor-,Oxidation Ditch-,and Anoxic/Oxic-based MWWTPs of less than 20 years *** the relatively young age structure of China's MWWTPs,the committed emissions highlight the importance of reducing on-site GHG emissions by optimization of operating conditions and innovation *** emission differences among our estimates,previous studies,and the Intergovernmental Panel on Climate Change guidelines are largely attributed to the uncertainties in emission factors,implying the urgent need for more plant-integrated measurements to improve the accuracy of emission accounting.

关键词： Methane Nitrous oxide Emissions Municipal wastewater treatment plants

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Design and Control for WLR-3P:A Hydraulic Wheel-Legged Robot

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Cyborg and Bionic systems 2023年第1期4卷 243-259页

作者： Xu Li Haoyang Yu Haibo Feng Songyuan Zhang Yili Fu State Key Laboratory of Robotics and System College of Mechatronics EngineeringHarbin Institute of TechnologyHarbin 150001China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China Intelligent Robot Research Center Zhejiang LaboratoryHangzhou 311100China

The robot used for disaster rescue or field exploration requires the ability of fast moving on flat road and adaptability on complex *** hybrid wheel-legged robot(WLR-3P,prototype of the third-generation hydraulic wheel-legged robot)has the characteristics of fast and efficient mobility on flat surfaces and high environmental adaptability on rough *** this paper,3 design requirements are proposed to improve the mobility and environmental adaptability of the *** meet these 3 requirements,2 design principles for each requirement are put ***,for light weight and low inertia with high stiffness,3-dimensional printing technology and lightweight material are ***,the integrated hydraulically driven unit is used for high power density and fast response ***,the microhydraulic power unit achieves power autonomy,adopting the hoseless design to strengthen the reliability of the hydraulic *** is more,the control system including hierarchical distributed electrical system and control strategy is *** mobility and adaptability of WLR-3P are demonstrated with a series of ***,the robot can achieve a speed of 13.6 km/h and a jumping height of 0.2 m.

关键词： robot Robot terrain

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Dynamic Object Removal of Static 3D Point-Cloud Map Building in Casualty Collection Point

Dynamic Object Removal of Static 3D Point-Cloud Map Building...

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International Conference on Control, Automation, robotics and Vision (ICARCV)

作者： Haidong Wang Wanlei Li Yijie Dai Xiaogang Xiong Yunjiang Lou State Key Laboratory of Robotics and System School of Mechanical Engineering and Automation Harbin Institute of Technology ShenZhen Shenzhen China

ISBN: (数字)9798331518493

ISBN: (纸本)9798331518509

Understanding the environment is crucial for the autonomous navigation of vehicles. Accurately identifying and removing dynamic objects that cause occlusions and noisy pose issues is crucial to the task. The casualty collection point (CCP) is a designated location for treating casualties during disasters. These sites are commonly located in open fields to ensure that the injured receive timely and appropriate care. Therefore, the construction of a 3D map in CCP may encounter additional challenges. In this paper, we introduces a novel algorithm that integrates a learning-based multi-object detection network with a Kalman Filter tracking framework to remove dynamic object traces from the 3D map building, particularly in CCP scenarios, and it redirects attention on the velocity attribute of dynamic objects at the object-level scale. Additionally, we contribute a new dataset specifically designed for the CCP scenario. Comparative experiments conducted on the SemanticKITTI dataset and CCP dataset show that our proposed method achieves the state-of-the-art performance in removing traces of dynamic objects on 3D Map. Dataset is available at https://***/haidongwang96/ccp_dataset.

关键词： Point cloud compression Three-dimensional displays Simultaneous localization and mapping Heuristic algorithms Buildings Object detection Kalman filters Object recognition Noise measurement Vehicle dynamics

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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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A ResNet-based approach for accurate radiographic diagnosis of knee osteoarthritis

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CAAI Transactions on Intelligence technology 2022年第3期7卷 512-521页

作者： Yu Wang Shibo Li Baoliang Zhao Jianwei Zhang Yuanyuan Yang Bing Li School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhenChina Shenzhen Key Laboratory of Minimally Invasive Surgical Robotics and System Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenChina TAMS Department of InformaticsUniversity of HamburgHamburgGermany

Currently X-ray images are clinically graded by experienced clinicians using the Kellgren and Lawrence(KL)scoring ***,individual scoring is subjective and error *** study proposes an approach for automated knee osteoarthritis classification based on deep neural *** knee X-ray images are first preprocessed with frequency-domain filtering and histogram normalisation,making the trabecular bone texture more obvious and benefiting the subsequent classification ***,a two-step classification strategy is proposed by extracting the joint centre based on the VGG network and classifying osteoarthritis grades based on the ResNet-50 *** addition,a rebalance operation is proposed to deal with the dataset unbalance problem,and a quick search technique is proposed to improve the iterative search efficiency for the joint *** all of these techniques,a classification accuracy of 81.41%is obtained,which is higher compared to the state-of-the-art approaches.

关键词： AMSGrad knee osteoarthritis recognition ResNet VGG

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Design and motion performance of new inspection robot for steam generator heat transfer tubes

Design and motion performance of new inspection robot for st...

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2021 IEEE International Conference on Real-Time Computing and robotics, RCAR 2021

作者： Xu, Biying Li, Ge Xing, Zhenming Cai, Hegao Zhao, Jie Fan, Jizhuang Harbin Institute of Technology State Key Laboratory of Robotics and System Heilongjiang Province Harbin China

ISBN: (纸本)9781665436786

The reliability of the Steam Generator is a key factor affecting the overall efficiency and safety of nuclear power plant reactors. Under the influence of nuclear radiation, remote control robots are currently used for Steam Generator heat transfer tubes inspection. In this paper, a new inspection robot is designed with better structure and higher working efficiency. Structural modeling and kinematic analysis are carried out. A modular control system is designed and applied for system integration. To verify the practicality of the robot, tube sheet motion experiments and performance analysis are undertaken. It results that the proposed inspection robot efficiently moves on the tube sheet and has excellent motion performance. © 2021 IEEE.

关键词： Steam generators

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Versatile Jumping of Humanoid Robots via Curriculum-Assisted Reinforcement Learning

Versatile Jumping of Humanoid Robots via Curriculum-Assisted...

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Chinese Automation Congress (CAC)

作者： Ruiyu Tan Xueai Li Fenglei Ni Dong Zhou Yi Ji Xiangyu Shao Key Laboratory of Autonomous Intelligent Unmanned Systems Harbin Institute of Technology Harbin China State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin China

ISBN: (数字)9798350368604

ISBN: (纸本)9798350368611

Versatile jumping is crucial for agile and adaptive behavior of humanoid robots in complex environments. However, humanoid robots have to manage impact forces while maintaining balance and stability throughout the take-off, flight, and landing phases, which imposes significant challenges for motion planning and controller design. This paper proposes a curriculum-assisted reinforcement learning framework for the humanoid robot to achieve various jumping tasks. The curriculum learning divides the jump training process into multi-stages and design different episodes in each stage to guarantee the training feasibility and generalize learned skills. Simulations on a 28 DOFs humanoid robot verify the excellent diverse jumping capability of the proposed policy. This exploration of different tasks also proves the policy's robustness, allowing the robot quickly recover from perturbations using a variety of learned maneuvers.

关键词： Training Automation Perturbation methods Humanoid robots Reinforcement learning Robustness Stability analysis Planning

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Robustness and Push Recovery of Humanoid Robots Using Predictive and Whole-Body Control

Robustness and Push Recovery of Humanoid Robots Using Predic...

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IEEE International Conference on Unmanned systems (ICUS)

作者： Shaojie Zhang Fenglei Ni Xueai Li Xu Li Yi Ji Xiangyu Shao State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin China Key Laboratory of Autonomous Intelligent Unmanned Systems Harbin Institute of Technology Harbin China

ISBN: (数字)9798350384185

ISBN: (纸本)9798350384192

Robustness walking and recovery ability in uneven terrains and unexpected collisions are crucial for the practical application of humanoid robots. However, existing methods struggle to effectively balance stability, motion safety and walking agility. This paper proposes a hybrid control strategy combing Nonlinear Model Predictive Control (NMPC) and Whole-Body Control (WBC) to improve the robot's walking stability and reaction safety in collisions situations. The NMPC generates long-term and macroscopic movements, with capture point theory being utilized for foot placements determination under external impacts. On this foundation, the WBC regulates the robot refinedly in real-time based on task priorities and weights. Simulations verify the effectiveness of the proposed method, involving uneven terrain walking and external impacts rejection.

关键词： Legged locomotion Resistance Humanoid robots Stability analysis Robustness Real-time systems Planning Collision avoidance Motion analysis Predictive control

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