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Simultaneous multi-material embedded printing for 3D heterogeneous structures

International Journal of Extreme Manufacturing 2023年第3期5卷 485-498页

作者： Ziqi Gao Jun Yin Peng Liu Qi Li Runan Zhang Huayong Yang Hongzhao Zhou State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310058People’s Republic of China School of Mechanical Engineering Zhejiang UniversityHangzhou 310058People’s Republic of China Department of Mechanical Engineering Centre for Power Transmission and Motion ControlUniversity of BathBath BA27AYUnited Kingdom

In order to mimic the natural heterogeneity of native tissue and provide a better microenvironment for cell culturing,multi-material bioprinting has become a common solution to construct tissue models in *** the embedded printing method,complex 3D structure can be printed using soft biomaterials with reasonable shape ***,the current sequential multi-material embedded printing method faces a major challenge,which is the inevitable trade-off between the printed structural integrity and printing ***,we propose a simultaneous multi-material embedded printing *** this method,we can easily print firmly attached and high-precision multilayer *** multiple individually controlled nozzles,different biomaterials can be precisely deposited into a single crevasse,minimizing uncontrolled squeezing and guarantees no contamination of embedding medium within the *** analyse the dynamics of the extruded bioink in the embedding medium both analytically and experimentally,and quantitatively evaluate the effects of printing parameters including printing speed and rheology of embedding medium,on the 3D morphology of the printed *** demonstrate the printing of double-layer thin-walled structures,each layer less than 200μm,as well as intestine and liver models with 5%gelatin methacryloyl that are crosslinked and extracted from the embedding medium without significant impairment or *** peeling test further proves that the proposed method offers better structural integrity than conventional sequential printing *** proposed simultaneous multi-material embedded printing method can serve as a powerful tool to support the complex heterogeneous structure fabrication and open unique prospects for personalized medicine.

关键词： embedded printing multi-material printing printability soft materials heterogeneous structures

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Multiagent Consensus over Time-Invariant and Time-Varying Signed Digraphs via Eventual Positivity

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IEEE Transactions on Automatic control 2023年第9期68卷 5429-5444页

作者： Fontan, Angela Wang, Lingfei Hong, Yiguang Shi, Guodong Altafini, Claudio Linköping University Division of Automatic Control Department of Electrical Engineering LinköpingSE-58183 Sweden KTH Royal Institute of Technology Division of Decision and Control Systems StockholmSE-10044 Sweden Chinese Academy of Sciences Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Beijing100190 China University of Chinese Academy of Sciences Beijing100190 China Tongji University Department of Control Science and Engineering Shanghai201804 China University of Sydney Australian Center for Field Robotics School of Aerospace Mechanical and Mechatronic Engineering SydneyNSW2008 Australia

Laplacian dynamics on signed digraphs have a richer behavior than those on nonnegative digraphs. In particular, for the so-called 'repelling' signed Laplacians, the marginal stability property (needed to achieve consensus) is not guaranteed a priori and, even when it holds, it does not automatically lead to consensus, as these signed Laplacians may lose rank even in strongly connected digraphs. Furthermore, in the time-varying case, instability can occur even when switching in a family of systems each of which corresponds to a marginally stable signed Laplacian with the correct corank. In this article, we present novel conditions for achieving consensus on signed digraphs based on the property of eventual positivity, a Perron-Frobenius (PF) type of property for signed matrices. The conditions we develop cover both time-invariant and time-varying cases. A particularly simple sufficient condition, valid in both cases, is that the Laplacians are normal matrices. Such condition can be relaxed in several ways. For instance, in the time-invariant case it is enough that the Laplacian has this PF property on the right side, but not on the left side (i.e., on the transpose). For the time-varying case, convergence to consensus can be guaranteed by the existence of a common Lyapunov function for all the signed Laplacians. All conditions can be easily extended to bipartite consensus. © 1963-2012 IEEE.

关键词： Lyapunov functions

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A Comprehensive Review of Humanoid Robots

SmartBot

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SmartBot 2025年第1期1卷 86-120页

作者： Qincheng Sheng Zhongxiang Zhou Jinhao Li Xiangyu Mi Pingyu Xiang Zhenghan Chen Haocheng Xu Shenhan Jia Xiyang Wu Yuxiang Cui Shuhao Ye Jiyu Yu Yuhan Du Shichao Zhai Kechun Xu Yifei Yang Zhichen Lou Zherui Song Zikang Yin Yu Sun Rong Xiong Jun Zou Huayong Yang State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhouChina State Key Laboratory of Industrial Control Technology School of Control Science and EngineeringZhejiang UniversityHangzhouChina

Humanoid robots,increasingly recognized for their potential to drive economic and social development,have garnered significant attention in recent *** paper aims to provide a comprehensive overview of the progress,challenges,and future directions in humanoid robotics,with a particular emphasis on essential system components and key technological *** a review of historical milestones,this paper explores critical aspects such as the design of the head and body,and examines state-of-the-art technologies in areas like locomotion control,perception,and intelligent *** presenting a thorough analysis of the field,this work aims to serve as a valuable resource for researchers and inspire future innovations that will drive the continued evolution of humanoid robots.

关键词： challenges and trends humanoid robot humanoid robot components key technologies

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Research on workflow recognition for liver rupture repair surgery

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Mathematical Biosciences and engineering 2024年第2期21卷 1844-1856页

作者： Men, Yutao Zhao, Zixian Chen, Wei Wu, Hang Zhang, Guang Luo, Feng Yu, Ming Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China Medical Support Technology Research Department Systems Engineering Institute Academy of Military Sciences People’s Liberation Army Tianjin300161 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China

Liver rupture repair surgery serves as one tool to treat liver rupture, especially beneficial for cases of mild liver rupture hemorrhage. Liver rupture can catalyze critical conditions such as hemorrhage and shock. Surgical workflow recognition in liver rupture repair surgery videos presents a significant task aimed at reducing surgical mistakes and enhancing the quality of surgeries conducted by surgeons. A liver rupture repair simulation surgical dataset is proposed in this paper which consists of 45 videos collaboratively completed by nine surgeons. Furthermore, an end-to-end SA-RLNet, a self attention-based recurrent convolutional neural network, is introduced in this paper. The self-attention mechanism is used to automatically identify the importance of input features in various instances and associate the relationships between input features. The accuracy of the surgical phase classification of the SA-RLNet approach is 90.6%. The present study demonstrates that the SA-RLNet approach shows strong generalization capabilities on the dataset. SA-RLNet has proved to be advantageous in capturing subtle variations between surgical phases. The application of surgical workflow recognition has promising feasibility in liver rupture repair surgery. ©2024 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons.

关键词： Image classification

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Micro-Newton scale variable thrust control technique and its noise problem for drag-free satellite platforms:a review

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2023年第10期24卷 841-858页

作者： Changyi XU Wenya LI Xuhui LIU Yong LI Chao ZHANG School of Control Science and Engineering Dalian University of TechnologyDalian 116024China Beijing Institute of Control Engineering Beijing 100190China State Key Laboratory of Fluid Power&Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310058China

High-precision detection in fundamental space physics,such as space gravitational wave detection,high-precision earth gravity field measurement,and reference frame drag effect measurement,is the key to achieving important breakthroughs in the scientific study of fundamental space *** high-precision measurements requires high-performance satellite platforms to achieve“drag-free control”in a near“pure gravity”flight *** critical technology for drag-free control is variable thrust control at the micro-Newton *** noise is the most important technical indicator for achieving drag-free ***,there is no literature about the current status and future prospects of variable thrust control based on thrust ***,the micro-Newton variable thrust control technology and the thrust noise of the drag-free satellite platform are reviewed in this ***,the research status of micro-Newton scale variable thrust control technology and its applications to drag-free satellite platforms are ***,the noise problem is analyzed in detail and its solution is theoretically investigated in three aspects:“cross-basin flow problem,”“control problem,”and“system instability and multiple-coupled problem.”Finally,a systematic overview is presented and the corresponding suggested directions of research are *** work provides detailed understanding and support for realizing low-noise variable thrust control in the next generation of drag-free satellites.

关键词： Space physics detection Satellite platforms Drag-free control Micro-Newton scale variable thrust Thrust noise

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Surgical Gesture Recognition in Open Surgery Based on 3DCNN and SlowFast 7

Surgical Gesture Recognition in Open Surgery Based on 3DCNN ...

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7th IEEE Information Technology, Networking, Electronic and Automation control Conference, ITNEC 2024

作者： Men, Yutao Luo, Jian Zhao, Zixian Wu, Hang Luo, Feng Zhang, Guang Yu, Ming Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China Tianjin300384 China Systems Engineering Institute Academy of Military Sciences People's Liberation Army Tianjin300161 China

ISBN: (纸本)9798350370782

In the field of computer-aided medicine, automated surgical gesture recognition is an important research direction. Its main applications include automated skills assessment, intraoperative guidance, and education and training systems. Current research has focused on robotic surgery, and there is less research on surgical gestures for open surgery. Therefore, in this study, a new simulated open surgery dataset was developed, and a series of surgical gestures for open surgery were defined for closure the abdomen surgery with the cooperation of professional doctors. In addition, this paper uses the classical algorithm 3DCNN and SlowFast model in the field of action recognition to perform offline recognition of surgical gestures for open surgery on the dataset. 3DCNN uses R3D and R(2+1)D models. The experimental results show that on the self-built open surgical dataset, the R3D model has the best surgical gesture recognition results, with an accuracy rate of 90.4%, a precision rate of 90.5%, and a recall rate of 90.0%. © 2024 IEEE.

关键词： Gesture recognition

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Research on Robust Measurement Method of Heart Rate Using Remote Photoplethysmography Based on Adversarial Learning Network with High and Low Frequency Features

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IEEE Transactions on Circuits and systems for Video Technology 2025年第6期35卷 5208-5222页

作者： Zhai, Dezhao Chen, Wei Ding, Yinghao Yu, Ming Li, Qinwei Wu, Hang Tianjin University of Technology Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China People's Liberation Army Systems Engineering Institute Academy of Military Sciences Tianjin300161 China Civil Aviation University of China Tianjin Key Laboratory for Advanced Signal Processing Tianjin300300 China Nankai University School of Artificial Intelligence Tianjin300381 China

Remote Photoplethysmography (rPPG) is a non-contact method for measuring heart rate (HR) through facial video, breaking the constraints of contact measurements and offering broad application prospects. However, in real monitoring scenarios, the distance of subjects and facial illumination often vary. This leads to degradation of rPPG signals due to changes in facial resolution and light intensity. This paper presents the High and Low Frequency Feature Adversarial Learning Network (HLFF-AL), which utilizes feature space interpolation and composite feature capture to perform multi-band global and local signal extraction. By adopting an adversarial learning strategy, it enhances the capability to capture semantic information of rPPG under varying resolutions and lighting, bridging the differences in rPPG signal generation due to resolution changes. While maintaining accuracy in HR measuring, the robustness of the network is improved to achieve robust measurement of HR via rPPG. Even under high-resolution conditions, the Mean Absolute Error (MAE) for the three public datasets - unchanging lighting (COHFACE, UBFC-rPPG) and varying lighting (BUAA-MIHR) - reached 1.10 bpm, 1.64 bpm, and 4.41 bpm, respectively, with a mere 0.29 bpm difference in MAE between high and low resolutions on the BUAA-MIHR dataset. This demonstrates that HLFF-AL can predict more robust rPPG signals in various resolutions and lighting scenarios, achieving competitive results compared to state-of-the-art methods. © 1991-2012 IEEE.

关键词： Heart

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Thermal Analysis of Stator Iron-Core-Less PMBLDC Motors Considering Both Winding Eddy and Circulating Current Losses 9

Thermal Analysis of Stator Iron-Core-Less PMBLDC Motors Cons...

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9th International Conference on Fluid Power and mechatronics, FPM 2023

作者： Yang, Liu Gao, Tianxiong Fu, Wenqi Wang, Rongren Ai, Chao Kong, Xiangdong School of Mechanical Engineering Yanshan University Qinhuangdao China Zhejiang University State Key Laboratory of Fluid Power and Mechatronic Systems Hangzhou China Beijing Institute of Aerospace Control Devices Motor Power Division Beijing China

ISBN: (纸本)9798350304947

Thermal analysis of three stator iron-core-less PMBLDC motors considering winding eddy and circulating current losses is investigated. First, the effects of strand diameter, permanent magnet (PM) magnetization and rotating speed on the above mentioned two winding losses and thermal characteristics are investigated by 3D finite element method (FEM). It is found that both strand diameter and rotating speed have great impacts on the temperature rise, Additionally, the temperature rise results for parallel and radial magnetizations are almost identical. Then, influence of eddy and circulating current losses on the thermal characteristics of the three PMBLDC motors are further studied separately. Furthermore, comprehensive study of the two winding losses on the thermal characteristics is carried out. Results show that thermal analysis considering both winding eddy and circulating current losses in parallel thin strands is vital during motor primary design process considering the limited insulation level of wires and PMs. Finally, three prototypes with different combinations of strand diameters and parallel numbers are selected for the temperature rise experiment. Experimental results demonstrate the effectiveness of the developed 3D FEM models and validate the obtained simulation results. © 2023 IEEE.

关键词： Thermoanalysis

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The use of machine learning to predict the effects of cryoprotective agents on the GelMA-based bioinks used in extrusion cryobioprinting

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Bio-Design and Manufacturing 2023年第4期6卷 464-477页

作者： Qian Qiao Xiang Zhang Zhenhao Yan Chuanyu Hou Juanli Zhang Yong He Na Zhao Shujie Yan Youping Gong Qian Li School of Mechanics and Safety Engineering Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China NMPA Key Laboratory for Quality Control of In Vitro Diagnostics Henan Institute of Medical Device InspectionsZhengzhou 450003China School of Mechanical Engineering Hangzhou Dianzi UniversityHangzhou 310018China National Center for International Joint Research of Micro-Nano Molding Technology Zhengzhou UniversityZhengzhou 450001China Key Laboratory for Micro Molding Technology of Henan Province Zhengzhou UniversityZhengzhou 450001China

Cryobioprinting has tremendous potential to solve problems to do with lack of shelf availability in traditional bioprinting by combining extrusion bioprinting and *** order to ensure the viability of cells in the frozen state and avoid the possible toxicity of dimethyl sulfoxide(DMSO),DMSO-free bioink design is critical for achieving successful cryobioprinting.A nontoxic gelatin methacryloyl-based bioink used in cryobioprinting is composed of cryoprotective agents(CPAs)and a buffer *** selection and ratio of CPAs in the bioink directly affect the survival of cells in the frozen ***,the development of universal and efficient cryoprotective bioinks requires extensive *** first compared two commonly used CPA formulations via experiments in this *** show that the effect of using ethylene glycol as the permeable CPA was 6.07%better than that of *** datasets were obtained and four machinelearning models were established to predict experimental *** predictive powers of multiple linear regression(MLR),decision tree(DT),random forest(RF),and artificial neural network(ANN)approaches were compared,suggesting an order of ANN>RF>DT>*** final selected ANN model was then applied to another *** reveal that this machine-learning method can accurately predict the effects of cryoprotective bioinks composed of different *** also suggest that the formulations presented here have *** findings are likely to greatly accelerate research and development on the use of bioinks for cryobioprinting.

关键词： Cryobioprinting Cryoprotective bioink 3D bioprinting Machine learning Artificial intelligence Prediction model

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LCA-based Multi-scenario Study on Steel or Aluminum Wheel Hub for Passenger Vehicles 30

LCA-based Multi-scenario Study on Steel or Aluminum Wheel Hu...

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30th CIRP Life Cycle engineering Conference, LCE 2023

作者： Gao, Lu Wang, Zhihui Wang, Yanan Peng, Tao Liu, Weipeng Tang, Renzhong State Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou310058 China Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province Zhejiang University Hangzhou310058 China State Key Laboratory of Industrial Control Technology College of Control Science and Engineering Zhejiang University Hangzhou310058 China School of Engineering Zhejiang University City College Hangzhou310015 China

Lightweighting is one of the enabling techniques for energy saving and carbon reduction in the automotive industry. However, the life cycle performance of lightweight components remains unclear. Wheel hub is an important component, and its trend of replacing steel with aluminum is happening. Based on life cycle assessment and using ReCiPe model, this paper reports a cradle-to-grave study on the environmental impact of steel and aluminum wheel hub in passenger vehicles. Considering multi-scenario in the Chinese market, it is found that when the service life of passenger vehicle is less than 5.6 years, steel wheel hub is more environmental-friendly, and when the service life is less than 8.6 years, steel wheel hub also has more economic advantages. Combining different lightweight methods and different types of vehicles, it is found that structural optimization reduces the environmental impact of per unit weight mostly, process optimization reduces the life cycle environmental impact of wheel hub, and using lightweight steel wheel hub in electric vehicles has more potential in environmental benefits. some suggestions are, 1) to choose wheel hub that matches your actual usage to enjoy more environmental-economic advantages;2) to prioritize structural-process integrated optimization for lightweight wheel hub;and 3) to use more lightweight components in electric vehicles. © 2023 The Authors. Published by Elsevier B.V.

关键词： Environmental impact

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