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Vibration Suppression for Active Magnetic Bearings Using Adaptive Filter with Iterative Search Algorithm

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 61-71页

作者： Jin-Hui Ye Dan Shi Yue-Sheng Qi Jin-Hui Gao Jian-Xin Shen IEEE Department of Electrical Engineering Zhejiang UniversityHangzhou 310027China CES and IEEE

Active Magnetic Bearing(AMB) is a kind of electromagnetic support that makes the rotor movement frictionless and can suppress rotor vibration by controlling the magnetic force. The most common approach to restrain the rotor vibration in AMBs is to adopt a notch filter or adaptive filter in the AMB controller. However, these methods cannot obtain the precise amplitude and phase of the compensation current. Thus, they are not so effective in terms of suppressing the vibrations of the fundamental and other harmonic orders over the whole speed range. To improve the vibration suppression performance of AMBs,an adaptive filter based on Least Mean Square(LMS) is applied to extract the vibration signals from the rotor displacement signal. An Iterative Search Algorithm(ISA) is proposed in this paper to obtain the corresponding relationship between the compensation current and vibration signals. The ISA is responsible for searching the compensating amplitude and shifting phase online for the LMS filter, enabling the AMB controller to generate the corresponding compensation force for vibration suppression. The results of ISA are recorded to suppress vibration using the Look-Up Table(LUT) in variable speed range. Comprehensive simulations and experimental validations are carried out in fixed and variable speed range, and the results demonstrate that by employing the ISA, vibrations of the fundamental and other harmonic orders are suppressed effectively.

关键词： Active Magnetic Bearing(AMB) Adaptive filter Iterative search algorithm Least mean square(LMS) Vibration suppression

Tuning mechanical behaviors of highly entangled hydrogels with the random distribution of mobile entanglements

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 277-294页

作者： Jinlong LIU Di LU Bin CHEN Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China Beijing System Design Institute of Electro-Mechanic Engineering Beijing 100854China Intelligent Robotic Research Center Zhejiang LaboratoryHangzhou 310027China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Hangzhou 311100China

Highly entangled hydrogels exhibit excellent mechanical properties,including high toughness,high stretchability,and low hysteresis.By considering the evolution of randomly distributed entanglements within the polymer network upon mechanical stretches,we develop a constitutive theory to describe the large stretch behaviors of these hydrogels.In the theory,we utilize a representative volume element(RVE)in the shape of a cube,within which there exists an averaged chain segment along each edge and a mobile entanglement at each corner.By employing an explicit method,we decouple the elasticity of the hydrogels from the sliding motion of their entanglements,and derive the stress-stretch relations for these hydrogels.The present theoretical analysis is in agreement with experiment,and highlights the significant influence of the entanglement distribution within the hydrogels on their elasticity.We also implement the present developed constitutive theory into a commercial finite element software,and the subsequent simulations demonstrate that the exact distribution of entanglements strongly affects the mechanical behaviors of the structures of these hydrogels.Overall,the present theory provides valuable insights into the deformation mechanism of highly entangled hydrogels,and can aid in the design of these hydrogels with enhanced performance.

关键词： highly entangled hydrogel constitutive theory entanglement gamma distribution

Multistage guidance on the diffusion model inspired by human artists’ creative thinking

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Frontiers of Information Technology & Electronic Engineering 2024年第1期25卷 170-178页

作者： Wang QI Huanghuang DENG Taihao LI AI Research Institute Zhejiang LabHangzhou 311121China Department of Computer Science and Technology Zhejiang UniversityHangzhou 310027China

Current research on text-conditional image generation shows parallel performance with ordinary painters but still has much room for improvement when compared to that of artist-ability paintings,which usually represent multilevel semantics by gathering features ofmultiple objects into one object.In a preliminary experiment,we confirm this and then seek the opinions of three groups of individuals with varying levels of art appreciation ability to determine the distinctions that exist between painters and artists.We then use these opinions to improve an artificial intelligence(AI)painting system from painter-level image generation toward artistic-level image generation.

关键词： gathering ordinary artist

Multi-Objective Optimization of VBHF in Deep Drawing Based on the Improved QO-Jaya Algorithm

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 189-202页

作者： Xiangyu Jiang Zhaoxi Hong Yixiong Feng Jianrong Tan State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province Zhejiang UniversityHangzhou 310027China Ningbo Innovation Center Zhejiang UniversityNingbo 315100China

Blank holder force(BHF)is a crucial parameter in deep drawing,having close relation with the forming quality of sheet metal.However,there are different BHFs maintaining the best forming effect in different stages of deep drawing.The variable blank holder force(VBHF)varying with the drawing stage can overcome this problem at an extent.The optimization of VBHF is to determine the optimal BHF in every deep drawing stage.In this paper,a new heuristic optimization algorithm named Jaya is introduced to solve the optimization efficiently.An improved“Quasi-oppositional”strategy is added to Jaya algorithm for improving population diversity.Meanwhile,an innovated stop criterion is added for better convergence.Firstly,the quality evaluation criteria for wrinkling and tearing are built.Secondly,the Kriging models are developed to approximate and quantify the relation between VBHF and forming defects under random sampling.Finally,the optimization models are established and solved by the improved QO-Jaya algorithm.A VBHF optimization example of component with complicated shape and thin wall is studied to prove the effectiveness of the improved Jaya algorithm.The optimization results are compared with that obtained by other algorithms based on the TOPSIS method.

关键词： Variable blank holder force Multi-objective optimization QO-Jaya algorithm Algorithm stop criterion

Injection of a Self-propelled Polymer into a Small Circular Cavity

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Chinese Journal of Polymer Science 2024年第6期42卷 886-894页

作者： Chao Wang Yan-Li Zhou Xiao Yang Fan Wu Meng-Bo Luo Department of Physics Taizhou UniversityTaizhou318000China Department of Physics Zhejiang UniversityHangzhou310027China

The injection of a polymer chain into a small circular cavity under tangential self-propelled force is studied by using Langevin dynamics simulation.Results indicate that the injection dynamics of the active polymer shows strong correlation with the polymer conformation inside the cavity depending on the polymer rigidity(k_(b)).The injection timeτvaries nonmonotonously with increasing k_(b),and reaches its minimum at k_(b)^(*).When k_(b) is small(k_(b)≪k_(b)^(*)),the polymer is nearly random coil in the cavity,and spends a long time at the final stage of the injection process due to the large repulsion between monomers inside the cavity.When k_(b) is moderate(k_(b)∼k_(b)^(*)),the part of polymer inside the cavity forms spiral configuration under the tangential active force,and the whole polymer moves synchronously with a constant velocity during the injection process,leading to a small injection time.When k_(b) is large(k_(b)≫k_(b)^(*)),the polymer is nearly straight at the initial stage of the injection process,and takes a long time to bend itself,leading to a large injection time.

关键词： Active Polymer Injection Dynamics Simulation

PIV MEASUREMENT OF THE GAS-SOLID FLOW PATTERN IN A CFB RISER

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Journal of Hydrodynamics 2003年第6期15卷 39-44页

作者： ShiHui-xian WangQin-hui WangCan-xing LuoZhong-yang CenKe-fa CleanEnergyandEnvironmentEngineeringKeyLaboratoryofMinistryofEducation InstituteforThermalPowerEngineeringZhejiangUniversityHangzhou310027China DepartmentofMechanics ZhejiangUniversityHangzhou310027China

Particle Imaging Velocimetry (PIV) is a valuable measuring tool for studyingmultiphase flows, such as liquid-gas and gas-solid flow. It can be used to carry out manyhydrodynamic studies, in particular, to determine accurately the gas solid flow structure in CFB(Circulating Fluidized Beds). In this paper, the technique characteristics was described in applyingthe PIV to measure the gas-solid flow in circulating fluidized beds. A primary experiment wascomple-ted on a CFB unit with the PIV, yielding the velocity vector fields of high-density particlesfor different gas-solid superficial velocities and solid recycle rates. Velocities of thetransported particles were calculated with cross-correlation method. The major factors influencingthe successful measurement of particle velocity with the PIV technique were also described.

关键词： gas-solid flow particle imaging velocimetry (PIV) circulating fluidizedbeds (CFB)

CHEMOENZYMATIC SYNTHESIS OF BIODEGRADABLE POLY(1’-O-VINYLADIPOYL-SUCROSE)

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Chinese Journal of Polymer Science 2002年第6期20卷 579-584页

作者： De-shui Lu Qi Wu Xian-fu Lin Department of Chemistry Zhejiang University hangzhou 310027, China Department of Chemistry Zhejiang University Hangzhou 310027

A novel polymer containing the sucrose group was synthesized by radical polymerization from an enzymatically prepared monomer, 1'-O-vinyladipoyl-sucrose (VAS). Transesterification reaction of sucrose with divinyl adipate in anhydrous pyridine catalyzed by an alkaline protease from Bacillus subtilis at 60degreesC for 7 days gave VAS (yield 55%) without any blocking/deblocking steps. The vinyl sucrose ester could be polymerized with potassium persulfate and H2O2 as initiator to give poly(1'-O-vinyladipoyl-sucrose) with M-n = 33,000 and M-w = 53,200, M-w/M-n = 1.61. The polymer was biodegradable. After 6 days in aqueous buffer (pH 7), this alkaline protease could degrade poly(1'-O-vinyladipoyl-sucrose) to M. of ca. 1080, M-w/M-n = 3.30 (37degreesC), and M-n of ca. 5200, M-w/M-n = 2.44 (4degreesC). The polymer containing the sucrose branch would be a functional material in various application fields.

关键词： divinyladipate sucrose alkaline protease polymerization biodegradation

Multi-Material magnetic field-assisted additive manufacturing system for flexible actuators with programmable magnetic arrangements

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Frontiers of Mechanical Engineering 2024年第2期19卷 109-120页

作者： Yujie HUANG Haonan SUN Chengqian ZHANG Ruoxiang GAO Hongyao SHEN Peng ZHAO The State Key Laboratory of Fluid Power and Mechatronic Systems College of Mechanical EngineeringZhejiang UniversityHangzhou 310027China The Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province College of Mechanical EngineeringZhejiang UniversityHangzhou 310027China Center for X-Mechanics Department of Engineering MechanicsZhejiang UniversityHangzhou 310027China

Manufacturing flexible magnetic-driven actuators with complex structures and magnetic arrangements to achieve diverse functionalities is becoming a popular trend.Among various manufacturing technologies,magnetic-assisted digital light processing(DLP)stands out because it enables precise manufacturing of macro-scale structures and micro-scale distributions with the assistance of an external magnetic field.Current research on manufacturing magnetic flexible actuators mostly employs single materials,which limits the magnetic driving performance to some extent.Based on these characterizations,we propose a multi-material magnetic field-assisted DLP technology to produce flexible actuators with an accuracy of 200μm.The flexible actuators are printed using two materials with different mechanical and magnetic properties.Considering the interface connectivity of multi-material printing,the effect of interfaces on mechanical properties is also explored.Experimental results indicate good chemical affinity between the two materials we selected.The overlap or connection length of the interface moderately improves the tensile strength of multi-material structures.In addition,we investigate the influence of the volume fraction of the magnetic part on deformation.Simulation and experimental results indicate that increasing the volume ratio(20%to 50%)of the magnetic structure can enhance the responsiveness of the actuator(more than 50%).Finally,we successfully manufacture two multi-material flexible actuators with specific magnetic arrangements:a multi-legged crawling robot and a flexible gripper capable of crawling and grasping actions.These results confirm that this method will pave the way for further research on the precise fabrication of magnetic flexible actuators with diverse functionalities.

关键词： multi-material magnetic field-assisted manufacturing digital light processing flexible actuators magnetic arrangement

Utility and Application of a Versatile Analytical Method for MMF Calculation in AC Machines

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 22-31页

作者： Ze-Zheng Wu Robert Nilssen Jian-Xin Shen IEEE the College of Electrical Engineering Zhejiang UniversityHangzhou 310027China the Department of Electric Energy Norwegian University of Science and TechnologyTrondheimNorwayand also affiliated with the College of Electrical EngineeringZhejiang UniversityHangzhou 310027China

A versatile analytical method(VAM) for calculating the harmonic components of the magnetomotive force(MMF) generated by diverse armature windings in AC machines has been proposed, and the versatility of this method has been established in early literature. However, its practical applications and significance in advancing the analysis of AC machines need further elaboration. This paper aims to complement VAM by augmenting its theory, offering additional insights into its conclusions, as well as demonstrating its utility in assessing armature windings and its application of calculating torque for permanent magnet synchronous machines(PMSM). This work contributes to advancing the analysis of AC machines and underscores the potential for improved design and performance optimization.

关键词： AC machine Analytical method Harmonic analysis MMF Magnetic field Torque calculation