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Propulsion modeling and Analysis of a Biomimetic Swimmer

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Journal of Bionic Engineering 2010年第3期7卷 259-266页

作者： Ngoc San Ha Nam Seo Goo Smart Microsystem Research lab. Department of Advanced Technology FusionKonkuk University

We have studied a biomimetic swimmer based on the motion of bacteria such as Escherichia coli (E. coli) theoretically andexperimentally. The swimmer has an ellipsoidal cell body propelled by a helical filament. The performance of this swimmer wasestimated by modeling the dynamics of a swimmer in viscous fluid. We applied the Resistive Force Theory (RFT) on this modelto calculate the linear swimming speed and the efficiency of the model. A parametric study on linear velocity and efficiency tooptimize the design of this swimmer was demonstrated. In order to validate the theoretical results, a biomimetic swimmer wasfabricated and an experiment setup was prepared to measure the swimming speed and thrust force in silicone oil. The experimentalresults agree well with the theoretical values predicted by RFT. In addition, we studied the flow patterns surrounding thefilament with a finite element simulation with different Reynolds number (Re) to understand the mechanism of propulsion. Thesimulation results provide information on the nature of flow patterns generated by swimming filament. Furthermore, the thrustforces from the simulation were compared with the thrust forces from theory. The simulation results are in good agreement withthe theoretical results.

关键词： biomimetic microrobots swimming microrobots propulsion of flagella flow visualization medical application

Numerical simulation of an extreme haze pollution event over the North China Plain based on initial and boundary condition ensembles

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Atmospheric and Oceanic Science Letters 2019年第6期12卷 434-443页

作者： LI Xiaobin LIU Hongbo ZHANG Ziyin LIU Juanjuan State Key laboratory of Numerical modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijingChina Institute of Urban Meteorology China Meteorological AdministrationBeijingChina

The North China Plain often su ers heavy haze pollution events in the cold season due to the rapid industrial development and urbanization in recent *** the winter of 2015,the megacity cluster of Beijing Tianjin Hebei experienced a seven-day extreme haze pollution episode with peak PM2.5(particulate matter(PM)with an aerodynamic diameter≤2.5μm)concentration of 727μg m *** the in uence of meteorological conditions on pollu-tant evolution,the e ects of varying initial conditions and lateral boundary conditions(LBCs)of the WRF-Chem model on PM2.5 concentration variation were investigated through ensemble methods.A control run(CTRL)and three groups of ensemble experiments(INDE,BDDE,INBDDE)were carried out based on difierent initial conditions and LBCs derived from ERA5 reanalysis data and its 10 ensemble *** CTRL run reproduced the meteorological conditions and the overall life cycle of the haze event reasonably well,but failed to capture the intense oscillation of the instantaneous PM2.5 ***,the ensemble forecasting showed a considerable advantage to some *** with the CTRL run,the root-mean-square error(RMSE)of PM2.5 concentration decreased by 4.33%,6.91%,and 8.44%in INDE,BDDE and INBDDE,respectively,and the RMSE decreases of wind direction(5.19%,8.89%and 9.61%)were the dominant reason for the improvement of PM2.5 concentration in the three ensemble *** on this case,the ensemble scheme seems an e ective method to improve the prediction skill of wind direction and PM2.5 concentration by using the WRF-Chem model.

关键词： Haze pollution PM 2.5 WRF Chem initial and lateral boundary conditions ensemble forecasting

珠三角大气观测项目与重点城市群污染控制项目(英文)

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珠三角大气观测项目与重点城市群污染控制项目(英文)

Kinematic and Dynamic Analysis of 3-DOF Rotary Table Manipulator

北京论坛（2008）文明的和谐与共同繁荣——文明的普遍价值和发展趋向

作者：张远航 State joint key lab of Environmental simulation and pollution control College of Environmental Sciences Peking University

Pearl River Delta(PRD) is one of the three areas in China which have experienced extremely fast economic *** in PRD is characterized by city clusters with two mega-cities(Guangzhou and Hong Kong) and many medium-small cities linked by dense *** in this region has expanded with breathtaking speed for three *** a result,industrial emissions and traffic exhausts together contribute to high levels of ozone(O) and fine particulate matter(PM) pollution problems ranging from urban to regional *** concurrent high concentrations of O and PM in PRD as well as in other China city clusters have led to rather unique pollution characteristics due to interactions between primary emissions and photochemical processes,between gaseous compounds and aerosol phase species,and between local and regional scale ***,investigations on air pollution problems in China are fragmented and limited in scope and depth due to lack of proper instrumentation and *** Program of Regional Integrated Experiments on Air Quality over Pearl River Delta of China(PRIDE-PRD),sponsored by the National Basic Research Program(2002CB410801 and 2002CB211605) from the Ministry of Science and Technology(MOST),China,is developed to investigate in depth the air pollution problem and to improve the understanding of the chemical and radiative processes in PRD.

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Kinematic and Dynamic Analysis of 3-DOF Rotary Table Manipul...

Flow Ripple of Axial Piston Pump with Computational Fluid Dynamic simulation Using Compressible Hydraulic Oil

2009中国控制与决策会议

作者： Masoud Dorosti Jafar Heyrani Nobari Digital and Nonlinear Control systems lab Electrical Engineering DepartmentK.N.Toosi University of TechnologyTehranIran

＜正＞3-DOF Rotary Table manipulator is a robotic mechanism which brings about spatial rotational movements. This mechanism helps to make a movement scenario in order to test Guidance and Navigation systems of moving *** has complicated dynamic equations which are crucial for control *** this paper,we study applicable kinematics of this ***,we choose the best kinematics and try to get the dynamic equations by applying the Newton’s Second Law for *** use the Newton’s Second Law instead of using common methods in robotic modeling such as Denavit-Hartenberg and Newton-Euler *** have extracted full dynamic equations that contain all designing parameters such as Moment of Inertia factor in all round and even the unbalanced and wobble *** we have verified obtained equations by simulation.

关键词： 3-DOF Rotary Table Manipulator Gimbal Unit under Test Dynamic Equations

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Chinese Journal of Mechanical Engineering 2010年第1期23卷 45-52页

作者： MA Ji＇en XU Bing ZHANG Bin YANG Huayong The State Key lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

The flow ripple, which is the source of noise in an axial piston pump, is widely studied today with the computational fluid dynamic（CFD） technology development. In the traditional CFD modeling, the fluid compressibility, which strongly influences the accuracy of the flow ripple simulation results, is often neglected. So a compressible sub-model was added with user defined function（UDF） in the CFD model to predict the flow ripple. At the same time, a test rig of flow ripple was built to study the validity of simulation. The flow ripple of pump was tested with different working parameters, including the rotation speed and the working pressure. The comparisons with experimental results show that the validity of the CFD model with compressible hydraulic oil is acceptable in analyzing the flow tipple characteristics. In this paper, the improved CFD model increases the accuracy of flow ripple rate to about one-magnitude order. Therefore, the compressible model of hydraulic oil is necessary in the flow ripple investigation of CFD simulation. The compressibility of hydraulic oil has significant effect on flow ripple, and the compression ripple takes about 88% of the total flow ripple of pump. Leakage ripple has the lowest proportion of about 4%, and geometrical ripple leakage ripple takes the remnant 8%. Besides, the influence of working parameters was investigated through the CFD simulations and experimental measurements. Comparison results show that the amplitude of flow ripple grows with the increasing of rotation speed and working pressure, and the flow ripple rate is independent of the rotation speed. However, flow ripple rate of piston pump grows with the increasing of working pressure, because the leakage ripple will increase with the pressure growing. The investigation on flow ripple of an axial piston pump using compressible hydraulic oil provides a more validity simulation model for the CFD analyzing and is beneficial to further understanding of the flow ripple ch

关键词： axial piston pump flow ripple computational fluid dynamics

simulation and Experiment Research on the Proportional Pressure Control of Water-assisted Injection Molding

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Chinese Journal of Mechanical Engineering 2012年第3期25卷 430-438页

作者： ZHOU Hua CHEN Yinglong ZHANG Zengmeng YANG Huayong The State Key lab of Fluid Power Transmission and Control Zhejiang UniversityHangzhou 310027China

Water-assisted injection molding（WAIM）,a newly developed fluid-assisted injection molding technology has drawn more and more attentions for the energy saving,short cooling circle time and high quality of *** research for the process of WAIM has shown that the pressure control of the injecting water is mostly important for the ***,the proportional pressure control for the WAIM system is quite complex due to the existence of nonlinearities in the water hydraulic *** order to achieve better pressure control performance of the injecting water to meet the requirements of the WAIM,the proportional pressure control of the WAIM system is investigated both numerically and experimentally.A newly designed water hydraulic system for WAIM is first modeled in AMEsim environment,the load characteristics and the nonlinearities of water hydraulic system are both considered,then the main factors affecting the injecting pressure and load flow rate are extensively ***,an open-loop model-based compensation control strategy is employed to regulate the water injection pressure and a feedback proportional integrator controller is further adopted to achieve better control *** order to verify the AMEsim simulation results WAIM experiment for particular Acrylonitrile Butadiene Styrene（ABS） parts is implemented and the measured experimental data including injecting pressure and flow rate results are compared with the *** good coincidence between experiment and simulation shows that the AMEsim model is accurate,and the tracking performance of the load pressure indicates that the proposed control strategy is effective for the proportional pressure control of the nonlinear WAIM *** proposed proportional pressure control strategy and the conclusions drawn from simulation and experiment contribute to the application of water hydraulic proportional control and WAIM technology.

关键词： water-assisted injection molding nonlinear modeling proportional pressure control AMEsim simulation

Study of Robinson instabilities with a higher-harmonic cavity for the HLS phase Ⅱ project

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Chinese Physics C 2012年第11期36卷 1136-1139页

作者：赵宇宁李为民吴丛凤王琳 National Synchrotron Radiation lab. University of Science and Technology of China

In the Phase Ⅱ Project at the Hefei Light Source, a fourth-harmonic ＂Landau＂ cavity will be operated in order to suppress the coupled-bunch instabilities and increase the beam lifetime of the Hefei storage ring. Instabilities limit the utility of the higher-harmonic cavity when the storage ring is operated with a small momentum compaction. Analytical modeling and simulations show that the instabilities result from Robinson mode coupling. In the analytic modeling, we operate an algorithm to consider the Robinson instabilities. To study the evolution of unstable behavior, simulations have been performed in which macroparticles are distributed among the buckets. Both the analytic modeling and simulations agree for passive operation of the harmonic cavity.

关键词： Robinson instability higher-harmonic cavity analytic modeling Landau damping rate simulation energy spread

Procedural generation and real-time rendering of a marine ecosystem

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第7期15卷 514-524页

作者： Rong LI Xin DING Jun-hao YU Tian-yi GAO Wen-ting ZHENG Rui WANG Hu-jun BAO State Key lab of CAD & CG Zhejiang University PLA Unit 61741

Underwater scene is one of the most marvelous environments in the world. In this study, we present an efficient procedural modeling and rendering system to generate marine ecosystems for swim-through graphic applications. To produce realistic and natural underwater scenes, several techniques and algorithms have been presented and introduced. First, to distribute sealife naturally on a seabed, we employ an ecosystem simulation that considers the influence of the underwater environment. Second, we propose a two-level procedural modeling system to generate sealife with unique biological features. At the base level, a series of grammars are designed to roughly represent underwater sealife on a central processing unit(CPU). Then at the fine level, additional details of the sealife are created and rendered using graphic processing units(GPUs). Such a hybrid CPU-GPU framework best adopts sequential and parallel computation in modeling a marine ecosystem, and achieves a high level of ***, the proposed system integrates dynamic simulations in the proposed procedural modeling process to support dynamic interactions between sealife and the underwater environment, where interactions and physical factors of the environment are formulated into parameters and control the geometric generation at the fine level. Results demonstrate that this system is capable of generating and rendering scenes with massive corals and sealife in real time.

关键词： Procedural generation Marine ecosystem Biological feature Graphic processing unit acceleration

Fault Detection and Identification Using Deep Learning Algorithms in Induction Motors

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Computer modeling in Engineering & Sciences 2022年第11期133卷 435-470页

作者： Majid Hussain Tayab Din Memon Imtiaz Hussain Zubair Ahmed Memon Dileep Kumar Department of Electronic Engineering Quaid-e-Awam University of Engineering Science and TechnologyNawabshah67480Pakistan NCRA Condition Monitoring systems lab Mehran University of Engineering and TechnologyJamshoro76062Pakistan Department of Electronic Engineering Mehran University of Engineering and TechnologyJamshoro76062Pakistan Design and Creative Technology Torrens University AustraliaMelbourneAustralia Department of Electronics and Power Engineering Pakistan Navy Engineering College NUSTKarachi75350Pakistan

Owing to the 4.0 industrial revolution condition monitoring maintenance is widely accepted as a useful approach to avoiding plant disturbances and ***,Motor Current Signature Analysis(MCSA)is widely reported as a condition monitoring technique in the detection and identification of individual andmultiple Induction Motor(IM)***,checking the fault detection and classification with deep learning models and its comparison among them selves or conventional approaches is rarely reported in the ***,in this work,wepresent the detection and identification of induction motor faults with MCSA and three Deep Learning(DL)models namely MLP,LSTM,and ***,we have developed the model of Squirrel Cage induction motor in MATlab and simulated it for single phasing and stator winding faults(SWF)using Fast Fourier Transform(FFT),Short Time Fourier Transform(STFT),and Continuous Wavelet Transform(CWT)to detect and identify the healthy and unhealthy conditions with phase to ground,single phasing and in multiple fault conditions using Motor Current Signature *** faults impact on stator current is presented in the time and frequency domain(i.e.,power spectrum).The simulation results show that the scalogram has shown good results in time-frequency analysis for fault and showing its impact on the energy of current during individual fault and multiple fault *** is further investigated with three deep learning models(i.e.,MLP,LSTM,and 1D-CNN)for checking the fault detection and identification(i.e.,classification)improvement in a three-phase induction *** simulating the three-phase induction motor in various healthy and unhealthy conditions in MATlab,we have collected current signature data in the time domain,labeled them accordingly and created the 50 thousand samples dataset for DL *** the DL models are trained and validated with a suitable number of architecture *** simulation,the multiclass confusion

关键词： Condition monitoring motor fault diagnosis stator winding faults deep learning signal processing