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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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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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A Facile Surface Passivation of Hematite Photoanodes with Molybdate Overlayers for Efficient PEC Water Oxidation

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Chinese Journal of Chemical Physics 2018年第6期31卷 833-842,734页

作者： Qi Zhang Quan-ping Wu Yue Zhang Ji-tong Yan Song Xue Hong-yan Wang Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechanical System School of Mechanical Engineering Tianjin University of Technology Tianjin 300384 China Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion School of Chemistry & Chemical Engineering Tianjin University of Technology Tianjin 300384 China

α-Fe2O3 thin films have been synthesized and used as photoanodes for photo-electrochemical (PEC) water oxidation. Molybdate was introduced to mediate hematite thin films via two synthesis routes (namely in situin situ mediation and ex situ modification). Through the in situ mediation process, the morphology and film thickness could be changed significantly due to the addition of MoO42-, while for the ex situ modification, the PEC performance of the hematite has been greatly improved without changing the nanorod morphology. Various characterizations such as UV-Vis absorption, transmission electronic microscopy, scanning electronic microscopy, Mott-Schottky, electrochemical impedance spectroscopy were conducted and the PEC performances were investigated.

关键词： Hematite film Molybdate Passivation Water splitting Photocurrent

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Kinematic Analysis of a Redundant Actuated Five Degrees of Freedom Parallel Mechanism

Kinematic Analysis of a Redundant Actuated Five Degrees of F...

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2018 IEEE International Conference on Robotics and Biomimetics, ROBIO 2018

作者： Xiaolong, Yin Bin, Li Xinhua, Zhao Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology China Fac. of Natl. Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China

ISBN: (纸本)9781728103761

A 5 degree of freedom parallel mechanism with 6 branched redundant actuators is proposed. The mechanism is composed of 4 -SPS and 2-RPS kinematic branches. The mechanism can achieve three rotational and two translational motion. The performance of the forward and inverse kinematics, singularity and workspace, is analyzed, firstly, using the vector algebra method and Newton iteration method, the forward and inverse kinematics model were obtained from numerical solution and analytic solution;on this basis, get the Jacobian matrix of mechanism, and on the basis of the three kinds of performance parameters of matrix the singularity of the mechanism was analyzed;finally with the help of Monte Carlo method, obtaining the workspace of the mechanism. The related kinematic analysis will lay a theoretical foundation for the future study of the dynamics. © 2018 IEEE.

关键词： Mechanisms

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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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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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Influence of Micro-texture Parameters on Bone Drilling Force and Torque: A Finite Element Model

Influence of Micro-texture Parameters on Bone Drilling Force...

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2018 4th International Conference on mechanical engineering and Automation Science(ICMEAS2018)

作者： Yahui Hu Xiangjun Li Chuncheng Chen Lili Su QingchunZheng Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of Technology

The micro-texture on the tool surface is an effective way to improve the quality of the drilling. While high-performance micro-texture plays an important role in improving the quality of working surface and prolonging the life of tool. In this study, a three-dimensional finite element model was established to study the relationship between drilling thrust, torque and microstructure parameters(micro-pit depth, micro-pit diameter and micro-pit spacing) during drilling of cortical bone. The model was validated by cortical bone drilling using a micro-structured tool. On basis of this, the thrust and torque prediction models of the micro-texture parameters were obtained. The results indicate that the thrust and torque increased with the increase of micro-pit diameter;while the increase of the micro-pit spacing caused the thrust and torque to decrease. When the depth of the micro-pit increased, the thrust and torque decreased first and then increased, and we found that the effect of micro-pit spacing and micro-pit depth on force and torque is insignificant.

关键词： Influence of Micro-texture Parameters on Bone Drilling Force and Torque A Finite Element Model

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Ionic liquid choline chloride-urea dissolving cattle bone extracted hydroxyapatite

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Journal of Bionanoscience 2018年第3期12卷 437-441页

作者： Song, Wei Yang, Yan Deng, Yu Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China Department of Osteo-Internal Medicine Tianjin Hospital Tianjin300211 China School of Materials Science and Chemical Engineering Tianjin University of Science and Technology Tianjin300457 China

The dissolving technique of ionic liquid (IL) was applied in extraction process of hydroxyapatite (HAp). Product HAp was extracted by IL choline chloride-urea (ChCl-Urea) dissolving cattle bone. The optimum conditions for regeneration process of cattle bone were determined by single factor, orthogonal and verification experiments. IR spectra of regenerated bone, undissolved bone and raw bone showed that the main groups of regenerated bone did not change. It was indicated that ionic liquid did not damage the bone collagen of raw bone, and the collagen was only dissolved by IL. IR spectrum of the product HAp revealed that its components were similar to those of the natural bone. SEM pattern showed that the crystal shape of the product HAp appeared rod-like shape mostly, and the crystal structure was relatively complete. XRD diffraction explained that there was no difference between product HAp and standard HAp for the crystalline form and compositions. Copyright © 2018 American Scientific Publishers All rights reserved.

关键词： Hydroxyapatite

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Cooling Performance for Cylindrical Film-Cooling Hole with Divided Downstream Crescent-Shaped Block

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IOP Conference Series: Earth and Environmental Science 2020年第1期461卷

作者： Pengfei Zhang Zhiting Tong Fei Wang Linchao Bai Chao Zhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin 300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin 300384 China

The cooling performances for the cylindrical film-cooling hole with divided downstream crescent-shaped blocks were numerically investigated in present study. Four configurations with divided crescent-shaped block, i.e. linear, 30° convergence, 30° expansion, and 30° curved expansion, were studied at typical flow conditions. The successive crescent-shaped block case and the no block case were also solved in comparison. The temperature profiles, the local and lateral averaged cooling effectiveness at blowing ratios of 0.5 to 1.5 were obtained. As compared with the successive block case, the lateral coolant coverage were widened by using the divided block, and thus the lateral averaged cooling effectiveness were improved, especially at higher blowing ratios. Comparatively, the cylindrical hole with 30° expansion crescent-shaped block exhibited highest cooling performance.

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