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Chinese Automation Congress (CAC)

作者： Shuo Jia Wei Chen Wenchang Zhang Hang Wu Weixiao Li Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin China Academy of Military Sciences of Chinese PLA Institute of Medical Support Technology Tianjin China Information Management and Information System Nanjing University of Posts and Telecommunications Nanjing China

Parallel mobile robots have recently attracted wide attention due to their strong load capacity, high running stability and rapid response speed. This paper conducts the kinematics research based on a pair of novel mobile legs that consist of a dual Stewart parallel mechanism. Firstly, we describe its motion mechanism and analyze the DOF of the mechanism in detail. Secondly, the forward and inverse kinematic solutions of the mechanism are computed and analyzed, and then the workspace is obtained by Matlab simulation. Thirdly, according to the principle of kinematics, we carry out dynamic performance optimization research to analyze and compare various motion control rules. Finally, the human-computer interface is designed for ease of analysis and displaying the kinematic rules of robot motion.

关键词： Legged locomotion Robot kinematics Mobile robots Motion control Stability

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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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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 an HCN dual laser for the interferometer on EAST

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Plasma Science and Technology 2017年第8期19卷 37-42页

作者：李根魏学朝刘海庆申俊杰揭银先连辉曾龙邹志勇张际波王守信 Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University of Technology Institute of Plasma Physics Chinese Academy of Sciences

A two-color continuous wave（CW） discharge-pumped far-infrared（FIR） hydrogen cyanide（HCN） laser was developed as the source of an interferometer for measuring the line-averaged electron density in the Experimental advanced Superconducting Tokamak（EAST）. The output power of the dual laser system was about 120 m W from each laser on the 337 μm（0.89 THz）line. The polarization of each output beam was fixed using thin tungsten filaments and oscillated in the EH11 mode. Different megahertz intermediate frequencies（IF） and a slight frequency offset（～1 MHz） were generated in this system to replace the traditional rotating grating with～10 k Hz IF, and this can improve the time resolution of the interferometer significantly. The experimental result showed that different IF signals were obtained by successfully adjusting the cavity length. In particular, the beat frequency was captured at ～1.3 MHz by a Schottky mixer when the length of the resonant cavities was changed by 5 μm by an automatic adjustment system. In order to study the character of IF, a long time record of the IF signal was carried out,and the IF signal could be stabilized for a few minutes in the range of 2 MHz to 3 MHz. A realtime IF stability control system was initially designed for long pulse discharge experiments on the EAST. The ～MHz frequency response and good phase sensitivity of the dual laser HCN interferometer will allow the system to track fast density profiles and resolve fast MHD events,such as tearing/neoclassical tearing, disruptions, etc.

关键词： EAST interferometer Schottky pumped mixer captured tungsten grating resonant rotating

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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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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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Optimization of the Circuit Parameter in Class-E Power Amplifier in the Two-coil Wireless Power Transfer system

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IOP Conference Series: Materials Science and Engineering 2020年第1期740卷

作者： Zhuang Sun Qing Liu Kun Li Bin Hu Haibo Zhao Yankai Shi Shijie Zhang Yang Liu Tianjin Key Laboratory of Film Electronic and Communication Device Tianjin University of Technology Tianjin China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) Tianjin China Tianjin Institute of Power Sources Tianjin China

In this paper, the circuit parameters of the Class-E power amplifier are investigated and optimized to achieve the maximum of output power and efficiency in a two-coil Wireless Power Transfer (WPT) system. The circuit is simulated with software named Saber. Working frequency, the value of capacitors and inductor, which has relationship with the output power and efficiency, are investigated during the simulation. With the simulation results, it is found that the frequency and the shunt capacitor need to be optimized for high performance of the wireless power transfer system.

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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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Gradient piezoelectric composites for ultrasonic transducer design and imaging applications

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Journal of Materiomics 2025年第6期11卷

作者： Chenxue Hou Zhaoxi Li Chunlong Fei Qibo Lin Xiaofei Luo Xiongwei Wei Yiheng Yang Qi Lu Yi Quan Guangzhi Dong Zeyu Chen Xiaozhou Lü Weimin Bao Yintang Yang Shaanxi Provincial Key Laboratory of Integrated Circuit and System Integration Faculty of Integrated Circuit Xidian University Xi'an 710071 China The State Key Laboratory of Analog and Mixed-Signal VLSl Institute of Microelectronics University of Macau Macao 999078 China School of Aerospace Science and Technology Xidian University Xi'an 710071 China State Key Laboratory of Precision Manufacturing for Extreme Service Performance College of Mechanical and Electrical Engineering Central South University Changsha 410083 China College of Automotive and Mechanical Engineering Changsha University of Science and Technology Changsha 410114 China Hunan Province University Key Laboratory of Intelligent Testing and Control Technology for Engineering Equipment Changsha 410114 China School of Advanced Materials and Nanotechnology Xidian University Xi'an 710126 China Furong Laboratory (Precision Medicine) Changsha 410008 China National Engineering Research Center of Personalized Diagnostic and Therapeutic Technology Xiangya Hospital Central South University Changsha 410008 China Hunan Engineering Research Center of Skin Health and Disease Xiangya Hospital Central South University Changsha 410008 China

Ultrasonic imaging technology has advanced rapidly, the escalating demand for imaging quality has driven the continuous development of ultrasonic transducers featuring high-performance. Among them, the crucial factors constraining the further enhancement of imaging quality are the frequency of the device and the intensity of the echo signal. Piezoelectric composites have become a hotspot for ultrasonic transducers and imaging applications due to their excellent properties. However, due to the limitations of the accuracy of the cutting process, the development of piezoelectric/polymer composites is often undermined by undesirable pseudo-vibrations, especially in high-frequency applications, which will significantly reduce energy conversion efficiency. In this study, a novel design method of 1–3 piezoelectric composites with gradient nanoparticle doped polymer is proposed to eliminate the undesired lateral vibrations. Based on the optimized composites, a high-performance composite ultrasonic transducer with a center frequency of 8.51 MHz is prepared. Compared with the traditional composite transducer, the optimized transducer improves the echo voltage amplitude significantly, reaching nearly 3 times. The above advantages are further verified in high-quality ultrasound and photoacoustic imaging. The optimization method has valuable guidance for the design of high-frequency composite transducers, which have great potential in ultrasonic and photoacoustic imaging applications.

关键词： Piezoelectric composites Ultrasonic transducer Imaging applications Lateral vibration Finite element analysis

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