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15th IEEE International Conference on Mechatronics and Automation, ICMA 2018

作者： Wang, Zhigang Yun, Zerong Wang, Lingling Wang, Jinghui Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin China Tianjin University of Technology Tianjin China Natinal Institute of Metrology China Beijing China

ISBN: (纸本)9781538660720

Blackbody radiation source is used as a standard device for infrared thermometer, it plays increasingly important roles in the field of calibration. Through experiment discoveries that it is a typical nonlinear system and has a large transport delay when the blackbody is rise temperature or cooling in order to reach set temperature points. Based on the temperature control of blackbody is a kind of typical multi-variable, strong coupling and time-varying nonlinear control system. The paper proposes applying the theory of active disturbance rejection controller (ADRC) to suppress various disturbances and improve the dynamic performance of blackbody radiation source. First of all, describing the working principle of blackbody radiation source and building its mathematical model. Secondly, introducing the control method of ADRC, which is applied to the temperature control system of blackbody radiation source. Finally, through MATLAB/SIMULINK platform to simulate and compare the temperature control performances of blackbody among ADRC, PID and Smith predictor(SP) control strategies. The simulation results show that proposed ADRC algorithm improves the abilities of anti-interference of system and it is without overshoot. In addition, the results also indicated that the control method of ADRC shortens plant stable time and has a strong prospect for practical applications. © 2018 IEEE.

关键词： Temperature control

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Study on Vibration and Crack Propagation Control of Cracked Asymmetric Rotor Based on Three-Dimensional Finite Element Model

Study on Vibration and Crack Propagation Control of Cracked ...

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IEEE International Conference on Mechatronics and Automation

作者： Rong Hu Jun Liu Jianen Chen Xiaofeng Wang Weimin Ge School of Mechanical Engineering Tianjin University of Technology Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechanical System Tianjin China

In order to solve the vibration problems of a cracked asymmetric rotor, the three-dimensional finite element model of the rotor is established combined with a nonlinear contact approach. The free interface modal synthesis method is applied to shorten the computation time by reducing the order of the model. The vibration characteristics of the asymmetric rotor and the cracked asymmetric rotor in different crack locations are analyzed by the simulation. The results of numerical simulation show the appearance of crack will affect the resonance frequency and the range of unstable area on the major critical speed. At the same time, the active control of the rotor is realized by the electromagnetic actuator controlled by neural network PID. Secondly, based on the theory of rotor dynamics, the effects of rotational speed and unbalance on the breathing behavior of the cracked rotor are discussed. In this paper, it proposes a novel method delaying the crack extension effectively. In the process of operation, the electromagnetic actuator (EMA) can effectively control the vibration and can delay the crack propagation.

关键词： Rotors Finite element analysis Mathematical model Solid modeling Computational modeling Vibrations Analytical models

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Detection of Weld Defects Based on Incremental Two-Dimensional Principal Component Analysis

Detection of Weld Defects Based on Incremental Two-Dimension...

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IEEE International Conference on Mechatronics and Automation

作者： Yaohua Shen Weimin Ge Xiaofeng Wang School of Mechanical Engineering Tianjin University of Technology Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechanical System Tianjin China

Aiming at the requirements of the real-time detection of weld defects in the industry, the candid covariance-free incremental PCA (CCIPCA) algorithm was introduced into the Two-Dimensional Principal Component Analysis (2PCA) algorithm, therefore an incremental 2DPCA algorithm (I2DPCA) is proposed. Firstly, the images captured by camera are preprocessed to improve the quality of the images because the captured images might be affected in the process of image acquisition. Then the 12DPCA algorithm is used to achieve feature extraction, and the dimension of the images is reduced. Finally, the recognition of weld defects is implemented using the k-nearest neighbor algorithm (KNN). Compared with the methods of traditional recognition by extracting the sizes of several geometric defects, the proposed algorithm has the advantage of the small memory spaces, the high recognition rate and the strong real-time recognition. The experimental results show that the proposed algorithm has higher recognition rate and is more practical than the 2DPCA, and the recognition rate reaches 94%, which can meet the requirements of the real-time detection.

关键词： Welding Feature extraction Covariance matrices Principal component analysis Histograms Image recognition Low pass filters

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Dynamic Modeling and Simulation of Flexible Load System Operated by Reconfigurable Manipulators Under Different Constraints

Dynamic Modeling and Simulation of Flexible Load System Oper...

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IEEE International Conference on Mechatronics and Automation

作者： Huidong Ma Jinjin Guo Weimin Ge Xiaofeng Wang School of Mechanical Engineering Tianjin University of Technology Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin China

This paper aims at solving the problems that the manipulator will be constrained by the flexible load, and the caused constraint force is difficult to control. Based on the deflection screw theory, the dynamic model of the manipulator system is established by using the Lagrange equation. Firstly, according to the interaction of the end effector, the flexible load and the environmental constraints of the manipulator, the equation of motion of the entire system is built. Secondly, the dynamic model of the manipulator system is set up, that the system including the flexible load and the manipulator. Finally, Under the certain known environmental constraints, the dynamic modeling of a manipulator is performed. The effectiveness of the proposed method is verified by the simulation of a flexible beam operated by a 3-DOF manipulator.

关键词： Manipulator dynamics Force Mathematical model Load modeling Dynamics Torque

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Research on homoclinic orbits and homoclinic bifurcation motion in a typical triple-well potential vibration system 25

Research on homoclinic orbits and homoclinic bifurcation mot...

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25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018

作者： Feng, Jingjing Zhang, Wei Lui, Haiying Hu, Wenhua Beijing University of Technology College of Mechanical Engineering Beijing Key Laboratory on Nonlinear Vibrations and Strength of Mechanical Structures Beijing China Tianjin University of Technology School of Mechanical Engineering Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin China Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin China

ISBN: (纸本)9781510868458

The pull-in phenomenon is an important sign of instable movement for electrostatic micro-resonators. In present paper, the problems of homoclinic orbits and homoclinic bifurcation motion in a typical triple-well potential system with non-Z2 symmetric and higher-order nonlinear terms are studied, which is used to describe corresponding nonlinear dynamical behaviors of pull-in and complex vibration phenomena in typical micro-resonator. For the complexity between the equilibrium points and the phase space curves in triple-well potential system, the non-Z2 symmetric homoclinic orbits that are corresponding to the pull-in phenomenon are discussed under a certain energy input condition. Because the fact of the air damping in the actual micro-resonator cannot be ignored, the autonomous system containing the damping terms is studied directly. The further improved Padé approximation method can be applied to directly obtain analytical expressions of special homoclinic orbits with completely non-Z2 symmetry in corresponding conservative system, which contain not only the conventional Z2 symmetric nonlinear terms, but also the non-Z2 symmetric and higher-order nonlinear terms. In addition, the phase diagrams and bifurcation parameter curves of homoclinic orbit in corresponding autonomous system are obtained when the homoclinic bifurcation occurs. The present method is valid by comparing with the phase diagrams of homoclinic orbits from numerical method. Copyright © (2018) by International Institute of Acoustics & *** rights reserved.

关键词： Numerical methods

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Primary resonance analysis and optimal design of microbeam resonator with variable cross section under electrostatic actuator 25

Primary resonance analysis and optimal design of microbeam r...

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25th International Congress on Sound and Vibration 2018: Hiroshima Calling, ICSV 2018

作者： Liu, Cheng Hao, Shuying Zhang, Kunpeng Feng, Jingjing Zhang, Wei Tianjin University of Technology School of Mechanical Engineering Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin China Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin China Beijing University of Technology College of Mechanical Engineering Beijing Key Laboratory on Nonlinear Vibrations and Strength of Mechanical Structures Beijing China

ISBN: (纸本)9781510868458

In this paper, the doubly clamped microbeam-based resonator which actuated by two electrodes is investigated. A section parameter is proposed to describe the microbeam variables in the upper and under section. The differential equation is derived by considering the influence of neutral surface tension and the nonlinearity of electrostatic force. The Galerkin and Newton Cotes methods are used to obtain reduced-order model. The nonlinear vibration behaviors of system at equilibrium point are analysed. First, the frequency response is obtained by the method of multi-scale (MMS). The relationship between section parameter and mechanical property of the microresonator is studied. Then, the system is optimized by considering the relationship between section parameter and the actual physical parameters. Finally, the finite element method through COM-SOL software is used to verify the theoretical results, and the two results are very close to each other in the stable region. The research results provide a good reference for the design of microresonator. © 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. All rights reserved.

关键词： Resonators

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Mapping global lake dynamics reveals the emerging roles of small lakes (October, 10.1038/s41467-022-33239-3, 2022)

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NATURE COMMUNICATIONS 2022年第1期13卷 1-12页

作者： Pi, Xuehui Luo, Qiuqi Feng, Lian Xu, Yang Tang, Jing Liang, Xiuyu Ma, Enze Cheng, Ran Fensholt, Rasmus Brandt, Martin Cai, Xiaobin Gibson, Luke Liu, Junguo Zheng, Chunmiao Li, Weifeng Bryan, Brett A. Southern University of Science and Technology School of Environmental Science and Engineering Shenzhen China (GRID:grid.263817.9) (ISNI:0000 0004 1773 1790) The University of Hong Kong Department of Urban Planning and Design Hong Kong SAR China (GRID:grid.194645.b) (ISNI:***) The University of Hong Kong Urban Systems Institute Hong Kong SAR China (GRID:grid.194645.b) (ISNI:***) Southern University of Science and Technology School of Environmental Science and Engineering Shenzhen China (GRID:grid.263817.9) (ISNI:0000 0004 1773 1790) Southern University of Science and Technology School of Environmental Science and Engineering Shenzhen China (GRID:grid.263817.9) (ISNI:0000 0004 1773 1790) University of Copenhagen Department of Geosciences and Natural Resource Management Copenhagen Denmark (GRID:grid.5254.6) (ISNI:0000 0001 0674 042X) University of Copenhagen Department of Biology Copenhagen Denmark (GRID:grid.5254.6) (ISNI:0000 0001 0674 042X) Lund University Department of Physical Geography and Ecosystem Science Lund Sweden (GRID:grid.4514.4) (ISNI:0000 0001 0930 2361) Southern University of Science and Technology Guangdong Provincial Key Laboratory of Brain-inspired Intelligent Computation Department of Computer Science and Engineering Shenzhen China (GRID:grid.263817.9) (ISNI:0000 0004 1773 1790) University of Copenhagen Department of Geosciences and Natural Resource Management Copenhagen Denmark (GRID:grid.5254.6) (ISNI:0000 0001 0674 042X) Chinese Academy of Sciences Institute of Geodesy and Geophysics Wuhan China (GRID:grid.9227.e) (ISNI:***) Southern University of Science and Technology School of Environmental Science and Engineering Shenzhen China (GRID:grid.263817.9) (ISNI:0000 0004 1773 1790) North China University of Water Resources and Electric Power School of Water Conservancy Zhengzhou China (GRID:grid.412224.3) (ISNI:0000 0004 1759 6955) Southern University of Science and Technology School of Environmental Science and Engineering Shenzhen China (GRID:grid.263

Lakes are important natural resources and carbon gas emitters and are undergoing rapid changes worldwide in response to climate change and human activities. A detailed global characterization of lakes and their long-term dynamics does not exist, which is however crucial for evaluating the associated impacts on water availability and carbon emissions. Here, we map 3.4 million lakes on a global scale, including their explicit maximum extents and probability-weighted area changes over the past four decades. From the beginning period (1984–1999) to the end (2010–2019), the lake area increased across all six continents analyzed, with a net change of +46,278 km2, and 56% of the expansion was attributed to reservoirs. Interestingly, although small lakes (<1 km2) accounted for just 15% of the global lake area, they dominated the variability in total lake size in half of the global inland lake regions. The identified lake area increase over time led to higher lacustrine carbon emissions, mostly attributed to small lakes. Our findings illustrate the emerging roles of small lakes in regulating not only local inland water variability, but also the global trends of surface water extent and carbon *** are essential components of the hydrological and biogeochemical cycles. Here, Pi et al develop a global lake dataset called GLAKES via high-resolution satellite images and deep learning to examine global lake changes over four decades.

关键词： Hydrology Limnology

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Visual synchronization of two 3-variable Lotka-Volterra oscillators based on DNA strand displacement

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RSC advances 2018年第37期8卷 20941-20951页

作者： Chengye Zou Xiaopeng Wei Qiang Zhang School of Computer Science and Engineering Dalian University of Technology Dalian 116024 China zhangq@***. Key Laboratory of Advanced and Intelligent Computing Dalian University Ministry of Education Dalian 116622 China.

DNA strand displacement as a theoretic foundation is helpful in constructing reaction networks and DNA circuits. Research on chemical kinetics is significant to exploit the inherent potential property of biomolecular systems. In this study, we investigated two typical reactions and designed DNA strands with a fluorophore and dark quencher for reaction networks using a 3-variable Lotka-Volterra oscillator system as an example to show the convenience of and superiority for observation of dynamic trajectory using our design, and took advantage of the synchronization reaction module to synchronize two 3-variable Lotka-Volterra oscillators. The classical theory of chemical reaction networks can be used to represent biological processes for mathematical modeling. We used this method to simulate the nonlinear kinetics of a 3-variable Lotka-Volterra oscillator system.

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The soft sensor of the molten steel temperature using the modified maximum entropy based pruned bootstrap feature subsets ensemble method

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Chemical Engineering Science 2018年 189卷 401-412页

作者： Xiao-Jun Wang Xiao-Yan Wang Qiang Zhang Zhi-Zhong Mao Key Laboratory of Advanced Design and Intelligent Computing Ministry of Education Dalian University Dalian 116622 China School of Business Administration Dongbei University of Finance and Economics Dalian 116025 China Institute of Automatization College of Information Science and Engineering Northeastern University Shenyang 110004 China

The molten steel temperature in ladle furnace is a significant variable, but it is hard to be measured by real-time detection, which has some bad effects on productions. Soft sensors are alternative and effective techniques to solve this issue. In this paper, the soft sensor of the molten steel temperature established by the Modified Maximum Entropy based Pruned Bootstrap Feature Subsets Ensemble (MMEP-BFSE) method is proposed. Although the Bootstrap Feature Subsets Ensemble (BFSE) temperature model is prominent in the precision and the forecasting speed on the large-scale and noisy data, its main drawback is too many sub-models required to combine, which is not always feasible for applications. To alleviate this drawback, the Modified Maximum Entropy based Pruning (MMEP) approach is presented, in which a subset of sub-models that better approximates the complete ensemble is find based on the maximum Rényi entropy and the trade-off parameter between the precision and the diversity of sub-models. Then, the soft sensor of the temperature based on the MMEP-BFSE is established on the practical data. Experiments show that the proposed soft sensor outperforms the others in the precision, and meets the precision requirements. Sub-models of the BFSE temperature model are substantially pruned with improved generalization by the MMEP approach.

关键词： Chemical process Quality variables Soft sensor Data-driven model Machine learning Ensemble pruning

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Systematic Resource Allocation in Cloud RAN with Caching as a Service under Two Timescales

Systematic Resource Allocation in Cloud RAN with Caching as ...

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作者： Tang, Jianhua Quek, Tony Q. S. Chang, Tsung-Hui Shim, Byonghyo Hunan Provincial Key Laboratory of Intelligent Computing and Language Information Processing College of Information Science and Engineering Hunan Normal University Changsha410081 China Institute of New Media and Communications Department of Electrical and Computer Engineering Seoul National University Seoul08826 Korea Republic of Information Systems Technology and Design Pillar Singapore University of Technology and Design Singapore487372 Singapore Department of Electronic Engineering Kyung Hee University Yongin17104 Korea Republic of School of Science and Engineering Chinese University of Hong Kong Shenzhen518172 China Shenzhen Research Institute of Big Data Shenzhen518172 China Department of Electrical and Computer Engineering Institute of New Media and Communications Seoul National University Seoul08826 Korea Republic of

Recently, cloud radio access network (C-RAN) with caching as a service (CaaS) was proposed to merge the functionalities of communication, computing, and caching (CCC) together. In this paper, we dissect the interactions of CCC in C-RAN with CaaS from two dimensions: physical resource dimension and time dimension. In the physical resource dimension, we identify how to segment the baseband unit (BBU) pool resources (i.e., computation and storage) into different types of virtual machines (VMs). In the time dimension, we address how the long-term resource segmentation in the BBU pool impacts on the short-term transmit beamforming at the remote radio heads. We formulate the problem as a stochastic mixed-integer nonlinear programming (SMINLP) to minimize the system cost, including the server cost, VM cost and wireless transmission cost. After a series of approximation, including sample average approximation, successive convex approximation, and semidefinite relaxation, the SMINLP is approximated as a global consensus problem. The alternating direction method of multipliers (ADMM) is utilized to obtain the solution in a parallel fashion. Simulation results verify the convergence of our proposed algorithm, and also confirm that the proposed scheme is more cost-saving than that without considering the integration of CCC. © 1972-2012 IEEE.

关键词： Integer programming

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