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IEEE International Conference on mechatronics and Automation

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

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.

关键词： Mathematical model Simulation Temperature measurement Cooling Heating systems Temperature sensors

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A compact terahertz CW HCN dual laser and its stability control 43

A compact terahertz CW HCN dual laser and its stability cont...

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43rd International Conference on Infrared Millimeter and Terahertz Waves, IRMMW-THz 2018

作者： Xie, J.X. Liu, H.Q. Shen, J.J. Wei, X.C. Jie, Y.X. School of Mechanical Engineering Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechanical System Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China Institute of Plasma Physics Chinese Academy of Sciences Hefei230031 China

ISBN: (纸本)9781538638095

A compact terahertz continuous wave (CW) discharge-pumped Hydrogen cyanide (HCN) dual laser has been developed for better signal to noise ratio and higher time resolution, with active power and intermediate frequency (IF) control. The output power of about 110 mW on the 0.89 THz line has been obtained with 1 m long and 50 mm inner diameter dual discharge-pumped wave-guides laser. An output-power and IF feedback control system is applied to the HCN dual laser for output power and IF stability. This feedback system consists of two stepping motors, a piezoelectric ceramics (PZT), a PLC, a supervisory computer and the corresponding control program. The whole feedback control system can successful in stabilizing the power of the laser around 110 mW and the IF at around 1MHz in several hours. © 2018 IEEE.

关键词： Signal to noise ratio

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Development of a New Fluid Shearing system for Cell Culture in Vitro

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IOP Conference Series: Materials Science and Engineering 2019年第1期626卷

作者： Pengfei Wu Xin Wang Lilan Gao Chunqiu Zhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin 300384 China

Cells in organisms are surrounded by fluid environment, and the fluid shear force produced by this fluid affects the morphology and behaviour of cells. The stimulation of cells in a bioreactor is a key area of research in tissue engineering and regenerative medicine. This paper introduces a fluid shear system for cell culture in vitro. The main component of system is a perfusion chamber, which consists of an inoculation room and a perfusion cap. The inoculation room is used for the common laboratory consumables of microorganism or cell culture, such as petri dish, six-well plate and so on. It can realize to six independent experiments of fluid shear; the new type of perfusion cap was designed to obtain a reasonable cavity by hydrodynamic simulation. The cap was produced by casting technology. It not only has the function of cap with nozzles, but also has the function of sealing. With peristaltic pumps, nozzles, liquid storage bottles and so on, the fluid shearing system which can provide uniform, controllable and up to 60 dyn/cm2 shear stress along the bottom surface is constructed, and is easy to operate and can be personalized.

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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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Study on design method for dynamics of machine tools based on advanced process system

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Paper Asia 2018年第4期COMPENDIUM VOL. 1卷 102-105页

作者： Zhu, Peihao Li, Xiang Lu, KaiJie Zheng, QingChun Liu, JingNa Ma, WenPeng Hu, YaHui Yu, YangBin Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China

Machining accuracy depends not only the manufacturing error, thermal deformation, elastic deformation and wear but also the vibration produced by it. Establishing the dynamics model provides the basis of dynamic analysis. The most common dynamic models of machine tool are finite element model, lumped parameter model, distributed mass model and parameters identification. Above methods are applied by using the methods of multi-body dynamics, finite element and the progress of technology. design is finite optimization based on dynamic analysis to get limited improvements for existing empirical design. It is not possible to design the machine tool as required to achieve the expected dynamic performance. In order to comply with precision machine tool’s development demand and the challenge of machine structure design, This paper presents physical and dynamic models considering Machine-Tool-Workpiece Process system to discusses the dynamic cutting process of the dynamic cutting load, driving and executing devices under the excitations of non-equilibrium inertial load. The dynamic of machine tool is mapped to the relative displacement of tool nose. © 2018, SHPMedia Sdn Bhd. All rights reserved.

关键词： Dynamic models

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design and kinematic analysis of a novel over constrained parallel manipulator

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Paper Asia 2018年第COMPENDIUM3期2018卷 87-93页

作者： Zhang, Chao Li, Bin Guo, Peng Zhao, Xinhua Yang, Yuwei Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education [Tianjin University of Technology United States

In this paper, a novel over constrained 2-RRU&RSR parallel manipulator is proposed and analysed. This mechanism is composed of a moving platform and a base, which connected by two identical RRU limbs and one RSR limb. Here, R stand for the revolute, U and S represent universal and spherical joints respectively. Three revolute joints, fixed on the base, are set to be actively actuated. The moving platform of the structure can realize two rotational and one translational freedoms. The design process and kinematic performances are studied in this paper. Firstly, the configuration design and structure characteristics of the mechanism are expounded. Secondly, the number and the properties of degrees of freedom (DOF) of the mechanism are analysed using screw theory. Thirdly, the kinematic problems, including the inverse analyses and the forward position analyses, are solved analytically. Then, the performance of the mechanism, such as reachable workspace, transmission capability, are analysed. Finally, some numerical examples and conclusions of the mechanism are pointed out, and the potential applications of the mechanism are suggested.

关键词： Degrees of freedom (mechanics)

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Flow Mechanism of Cooling Effectiveness Improvement for the Cylindrical Film Cooling Hole with Contoured Craters

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IOP Conference Series: Materials Science and Engineering 2019年第1期473卷

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

In this paper, a typical cylindrical hole with contoured craters is investigated in terms of the downstream flow field by numerical method at blowing ratios of 0.5, 1 and 1.5. The flow field and the cooling effectiveness are analyzed using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. In comparison to the cylindrical hole, the cratered hole shows a wider coolant coverage in lateral direction and a lower penetration into the mainstream flow due to the larger hole exit area. Moreover, the interaction between the coolant and the curved protrusion induces a new anti-kidney-shaped vortex pair, which can obviously improve the cooling coverage and thus the cooling effectiveness. The area-averaged cooling effectiveness for the cratered hole is always higher than that for the cylindrical hole at all three blowing ratios.

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Comparison on Thermodynamic Performances between Basic and Regenerative Sub-Critical Organic Rankine Cycles Coupled with Low Grade Heat Source

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IOP Conference Series: Materials Science and Engineering 2019年第1期473卷

作者： Pengfei Yuan Chao Zhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control 300384 Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) Tianjin 300384 China

The coupling effects of low grade heat source on thermodynamic performances of both the basic and regenerative sub-critical Organic Rankine cycle (ORC) systems are investigated and compared. Turbine inlet pressure and turbine inlet temperature are treated as independent variables. The system exergy efficiency is selected as the thermodynamic performance criterion. The waste hot water with temperature range of 373.15K to 423.15K is selected as the low grade heat source. Optimization studies are carried out by using eight common organic working fluids to recover heat energy, and relevant operating conditions are obtained respectively. The results indicate that both hot fluid inlet temperature and the allowable minimum hot fluid outlet temperature influence the optimal working fluid, relevant turbine inlet condition and system exergy efficiency. Optimal system exergy efficiency increases monotonously with increasing of hot fluid temperature for both ORC systems above. In comparison to the basic cycle configuration, optimal system exergy efficiency for the regenerative system using the same working fluid is not changed if relevant turbine inlet vapor is saturated, but is significantly improved if relevant turbine inlet vapor is overheating. Besides, the optimal working fluid is dependent on the heat source temperature and specific cycle configuration.

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