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Weld pool boundary and weld bead shape reconstruction based on passive vision in P-GMAW

China Welding 2006年第2期15卷 20-24页

作者：闫志鸿张广军高洪明吴林 State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology

A passive visual sensing system is established in this research, and clear weld pool images in pulsed gas metal arc welding （ P-GMA W） can be captured with this system. The three-dimensional weld pool geometry, especially the weld height, is not only a crucial factor in determining workpiece mechanical properties, but also an important parameter for reflecting the penetration. A new three-dimensional （3D） model is established to describe the weld pool geometry in P-GMAW. Then, a series of algorithms are developed to extract the model geometrical parameters from the weld pool images. Furthermore, the method to reconstruct the 3 D shape of weld pool boundary and weld bead from the two-dimensional images is investigated.

关键词： weld pool visual sensing geometrical model image processing 3D reconstruction

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Investigation on Human-Simulation Intelligent Control of the Touch Force in Remote Welding Teleteaching

Investigation on Human-Simulation Intelligent Control of the...

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International Conference on Innovative Computing, Information and Control (ICICIC)

作者： L.J. Liu H.M. Gao G.G. Zhang L. Wu State Key Laboratory of Advanced Welding Harbin Institute of Technology Harbin China

In remote welding teleteaching process (RWTP), some factors, such as the high-frequency interference, the vibration of the robot arm, the change of the actual gravity center of welding tracing probe produced by the change of robot space posture, and the roughness of the welding groove, etc. This may strongly interfere with the force signal, reduce the reliability of touch force signal transmission, distort the force telepresence of welding operator, and consequently influence remote welding teleteaching quality. The paper, by analyzing force error target track on the foundation of the PID control model, brings forward human-simulation intelligent control (HSIC) strategy based on the force guiding. Its characteristic algorithm is established, including the characteristic model, characteristic identification, characteristic memory, multi-model control and multi-target decision-making. The experimental results show that the force error between fact phase track and idea phase track is lessened, the oscillating scope of touch force obviously reduced, the stability time of RWTP shortened, the efficiency and playback precision of the RWTP improved by comparing HSIC with PID control

关键词： Intelligent control Welding Orbital robotics Error correction Three-term control Force control Interference Gravity Probes Distortion

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Comparison of Bond Interface Reaction in Al-Ni and Al-Au systems Formed by Ultrasonic Wedge Bonding

Comparison of Bond Interface Reaction in Al-Ni and Al-Au Sys...

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International Symposium on Electronic Materials and Packaging

作者： Mingyu Li Hongjun Ji Chunqing Wang Harbin Institute of Technology Shenzhen Graduate School HIT Campus Shenzhen University Shenzhen China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin China

Considering two kinds of the most widely used wire bonding pads of the COB and BGA packaging styles, the characters of the bond interfaces in Al-Ni and Al-Au systems were compared after high temperature storage test through SEM observation. It was found that, according to the appearance, the Al-Au bond aged at 250degC in air for more than 40 days was expanded badly, and surface cracks were severe, but the Al-Ni bond changed little. At bond interface, AuAl 2 IMC was formed in Al-Au system, furthermore, many inner cracks initial the boundary of the wire and the IMC connected with the cracks in the wire, however, there was no such thick IMC formed in Al-Ni system. The causation was analyzed based on the metallurgical theory. Experimentally, the Al-Ni system was more reliable than the Al-Au system.

关键词： Bonding Wire Gold Temperature Nickel Copper Packaging system testing Aging Substrates

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Numerical study of laser-induced collision process in Eu-Sr in strong field

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Science China(Physics,Mechanics & Astronomy) 2005年第1期48卷 78-88页

作者： ZHANG Hongying XlAYuanqin CHEN Deying XIAO Pan FAN Rongwei MA Zuguang State Key Laboratory of Tunable Laser Technology Institute of Opto-ElectronicsHarbin Institute of TechnologyHarbin 150001China

Theoretically based on the four-level model,one LICET process in Eu-Sr system in both weak and strong fields was calculated by immediate numerical *** results in weak field are in fair to good agreement with analytical *** results in strong field show that:(a)the peak of the LICET profiles moves to the violet side and the tuning range of the profiles obviously becomes narrower when the laser field intensity increases;and(b)numerical results in strong field differ a lot from analytical ones,which indicates that in strong field,the analytical expressions are not applicable any longer.

关键词： laser-induced collisional energy transfer(LICET) tuning range cross section strong field effect.

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Effect of strengthening start-up on nitrifying performance of biofilm in internal-circulation bio-fluidised bed

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Zhongguo Huanjing Kexue/China Environmental Science 2006年第3期26卷 298-302页

作者： Wen, Qin-Xue Shi, Han-Chang Chen, Zhi-Qiang Zhou, Yan-Jun Guo, Yu-Feng State Key Joint Laboratory of Environment Simulation and Pollution Control Department of Environmental Science and Engineering Tsinghua University Beijing 100084 China School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China School of Chemistry and Environment China University of Mining and Technology Beijing 100083 China

Through changing the start-up water quality of internal-circulation bio-fluidized bed, the N/C composition was enhanced to strengthen the nitrifying action of fluidized bed of late period. After the strengthening start-up (high N/C and low COD) treating living waste water with the HRT 2h, a high simultaneous removal efficiency of COD and ammonia nitrogen could be realized;the average ammonia nitrogen removal rate was 74%. The test of oxygen consumption rate showed that after the strengthening start-up, the activity of hetertrophic bacteria in the biofim of fluidized bed decreased greatly, the activity of ammonia oxidize bacteria enhanced obviously, the activity of nitrifying bacteria did not change greatly. The track analysis results of bacterial quinone of the system showed that after the strengthening start-up of ammonia removal, the number of nitrifying bacteria in the biofilm increased obviously;the distribution even change of the microbial community was small with the gram-negative bacteria being the dominant. The observation of scanning electric microscope showed that the biofilm under low N/C start-up condition was thick and dense, the heterotrophic bacteria had high proportion;high N/C start-up condition was favorable to the growth of nitrifying bacteria, the biofilm was thin relatively.

关键词： Bacterial quinone Biofilm Internal-circulation bio-fluidized bed Nitrifying action Oxygen consumption rate

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Neural Network Modeling and system Simulating for the Dynamic Process of Varied Gap Pulsed GTAW with Wire Filler

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Journal of Materials Science & technology 2005年第4期21卷 515-520页

作者： Guangjun ZHANG Shanben CHEN Lin WU State Key Laboratory of AWPT Harbin Institute of Technology Harbin 150001 China Institute of Welding Technology Shanghai Jiao Tong University Shanghai 200030 China

As the base of the research work on the weld shape control during pulsed gas tungsten arc welding （GTAW） with wire filler, this paper addressed the modeling of the dynamic welding process. Topside length Lt, maximum width Wt and half-length ratio Rh1 were selected to depict topside weld pool shape, and were measured on-line by vision sensing. A dynamic neural network model was constructed to predict the usually unmeasured backside width and topside height of the weld through topside shape parameters and welding parameters. The inputs of the model were the welding parameters （peak current, pulse duty ratio, welding speed, filler rate）, the joint gap, the topside pool shape parameters （Lt, Wt, and Rh1）, and their history values at two former pulse, a total of 24 numbers. The validating experiment results proved that the artificial neural network （ANN） model had high precision and could be used in process control. At last, with the developed dynamic model, steady and dynamic behavior was analyzed by simulation experiments, which discovered the variation rules of weld pool shape parameters under different welding parameters, and further knew well the characteristic of the welding process.

关键词： Modeling Neural network Dynamic welding process Pulsed GTAW

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Self-learning fuzzy neural network control for backside width of weld pool in pulsed GTAW with wire filler

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中国有色金属学会会刊：英文版 2005年第S2期15卷 47-50页

作者：张广军陈善本吴林 State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Institute of Welding Technology Shanghai Jiaotong University Shanghai 200030 China

The weld pool shape control by intelligent strategy was studied. In order to improve the ability of self-learning and self-adaptation of the ordinary fuzzy control, a self-learning fuzzy neural network controller (FNNC) for backside width of weld pool in pulsed gas tungsten arc welding (GTAW) with wire filler was designed. In FNNC, the fuzzy system was expressed by an equivalence neural network, the membership functions and inference rulers were decided through the learning of the neural network. Then, the FNNC control arithmetic was analyzed, simulating experiment was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were implemented. The maximum error between the real value and the given one was 0.39mm, the mean error was 0.014mm, and the root-mean-square was 0.14mm. The real backside width was maintained around the given value. The results show that the self-learning fuzzy neural network control strategy can achieve a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model.

关键词： fuzzy neural network control backside width pulsed GTAW wire filler intelligent control

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The effect of vacuum thermal cycling on LF6 aluminium alloy welded joints

The effect of vacuum thermal cycling on LF6 aluminium alloy ...

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作者： Niu, Jitai Guo, Wei Guo, Yongliang Meng, Qingchang State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin China

The investigation aimed at the invalidation mechanism analysis and reliability evaluation of aluminum alloy welded joint under space environment will provide spaceflight designing epartments and manufactures with important technology gist and data so as to greatly reduce paceflights manufactured cost and improve spaceflight working reliability, hi this paper, the tensile properties and microstructures of LF6 aluminum alloy welded joint under vacuum thermal cycling have been studied by means of vacuum thermal cycling system. The influence of vacuum thermal cycling on the tensile properties of the welded joint has investigated. Results show that the strength and the enlongation reach their maximum values at about 75 times cycling. The changes of the tensile properties are regarded as resulted from the changes of grain and the motion of dislocation.

关键词： Joints (structural components)

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Self-learning fuzzy neural network control for backside width of weld pool in pulsed GTAW with wire filler

Self-learning fuzzy neural network control for backside widt...

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作者： Zhang, Guang-Jun Chen, Shan-Ben Wu, Lin State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Institute of Welding Technology Shanghai Jiaotong University Shanghai 200030 China

The weld pool shape control by intelligent strategy was studied. In order to improve the ability of self- learning and self-adaptation of the ordinary fuzzy control, a self-learning fuzzy neural network controller (FNNC) for backside width of weld pool in pulsed gas tungsten arc welding (GTAW) with wire filler was designed. In FNNC, the fuzzy system was expressed by an equivalence neural network, the membership functions and inference rulers were decided through the learning of the neural network. Then, the FNNC control arithmetic was analyzed, simulating experiment was done, and the validating experiments on varied heat sink workpiece and varied gap work- piece were implemented. The maximum error between the real value and the given one was 0. 39 mm, the mean error was 0.014 mm, and the root-mean-square was 0. 14 mm. The real backside width was maintained around the given value. The results show that the self-learning fuzzy neural network control strategy can achieve a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model.

关键词： Wire

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A new approach for early detection of internet worms based on connection degree

A new approach for early detection of internet worms based o...

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International Conference on Machine Learning and Cybernetics, ICMLC 2005

作者： Bo, Chen Bin-Xingfang Yun, Xiao-Chun National Computer Information Content Security Key Laboratory Harbin Institute of Technology Harbin 150001 China National Computer Network and Information System Security Administration Center Beijing 100031 China

ISBN: (纸本)078039092X

In recent years, internet-scale worm incidents occurred many times. People wonder at the speediness of the worm spread and the severe damage to the internet. So people began to find methods to detect worms as quickly as possible. The paper first describes a worm behavior and propagation model. And then based on it, a new approach for early detection of internet worms is proposed. This approach determines whether a worm incident has occurred by the change of the computers' connection degree. The approach is proved to be effective on early detection of unknown worms by experiments © 2005 IEEE.

关键词： Computer worms

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