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March 30,2014
Volume 7,Issue 6
Pages -
Subject Area:Industrial Robot Technology,Electric Power System and Automation,Engineering Thermophysics

Title: CAN based phase synchronic control system for twin-wire pulsed MIG welding

Authors: WU Kaiyuan, CHENG Jia, ZHANG Tao, HUANG Xi
PP: 615-620
Abstract: To overcome the alternation type phase output of two pulsed waveform for master and salve power supply of twin-wire pulsed metal inert-gas (MIG) welding, a communication net between master and salve power supply was presented, which was established based on controller area network (CAN), and the alternation type phase output of two pulsed waveform with the same frequency and the 180 discrepancy of phase was realized, it could reduce the interaction of twin arc, enhance the stability of twin arc and improve travel speed effectively. The results of the experiment demonstrated that the developed CAN based phase synchronic control system for twin-wire pulsed MIG welding met the design requirements, and the merits of the twin-wire high speed welding were stable welding process and perfect weld seam formation.
Keywords: technology and equipment of jointing; twin-wire pulsed metal inert-gas welding; controller area network; phase synchronic control

Title: Study on surface crack detection of aluminum using planar array coils

Authors: ZENG Weiqin, ZHANG Weimin, YANG Xiujiang, CHEN Zhiyao
PP: 610-614
Abstract: This paper developed a planar array coil sensor and designed the corresponding test device. The feasibility of crack detection of aluminum plate using the array coils was proved through the simulation analysis. Based on the detection experiments of the pre-cracks on the aluminum plate, multiple sets of experimental data were collected. The variety of methods such as gradient analysis and wavelet transform were used to process the data . The experimental results showed that the method could meet the actual needs of detection and it had high sensitivity to the cracks.
Keywords: sensor technology; planar array coil; aluminum specimen; surface crack; amplitude discriminator circuit; gradient

Title: Research on operating environment visual reconstruction based on Power Crust algorithm for telerobotic

Authors: NI Tao, CAI Mingjun, ZHENG Huanfei, ZHAO Kemeng, MIAO Shuhui
PP: 597-609
Abstract: It becomes urgent for solving the problem to keep the consistence between the virtual environment and reality, and also impossible to update virtual environment in time of the 3-D reconstruction of the remote environment objects. The paper takes binocular vision technology to reconstruct the three dimensional model with Power Crust method on the basis of image characteristics extraction and stereo matching calculation. It elaborates the binocular camera calibration, stereo matching of the images and improvement of Power Crust method. Finally, the efficiency and accuracy of the method is verified by the experiment.
Keywords: robot technology; binocular stereo vision; Power Crust algorithm; 3-D reconstruction

Title: Multi-dimension system modeling related to the complex energy consumption characteristics of machine tools

Authors: HU Linming, LI Yufeng, HE Yan
PP: 592-596
Abstract: To efficiently exploit the characteristics contained in electrical power data, a systematic modeling approach for the complex energy consumption characteristics of machine tools was proposed in this work. Firstly, the complex energy consumption characteristics of machine tools was analyzed. Based on it, with the system modeling theory, the multi-dimension model related to the complex energy consumption characteristics of machine tools in term of three dimensions of machine tools including state model, mathematical and information model was created. The case study of the processing of workpiece mixed in numerical conrtol lathe showed that the information model of multi-dimension model could be used to identify workpiece in machining.
Keywords: mechanical manufacturing and automation; energy consumption characteristic; system modeling; electrical power data

Title: Stability anticipation of milling system with variable spindle speed

Authors: SONG Qinghua, AI Xing
PP: 585-591
Abstract: Equation of motion for milling process with periodic spindle speed modulation is a delay-differential equation with varying time delay. The varying time delay is accurately approximated by the Taylor series expansion around constant time delay. Semi-discretization technique is employed to construct the stability charts of the milling system. The research results show that improvement in the efficiency of machining can increase the frequency of the high modulation, especially for low spindle speed domain. The results, which are the more precise than former ones, are verified by variable spindle speed milling tests.
Keywords: mechanical manufacturing and automation; chatter; variable spindle speed milling; time-dependent delay

Title: Research on the effect of bell mouth structure on the performance of centrifugal fan

Authors: CHEN Zhenhua, CHEN Ke, YIN Lei
PP: 578-584
Abstract: The effects of six types of fan bell mouth on the performance of centrifugal fan were investigated by using the commercial computational fluid dynamics (CFD) method. By analyzing the total pressure and velocity distribution of two feature sections of centrifugal fans with different bell mouth forms, it was turned out that the cone arc bell mouth was the best in matching with fans, while the cylindrical and conical ones were the worst. The conclusion provided the gist for well design and reasonable choose for improving the performance of centrifugal fan.
Keywords: mechanical manufacturing and automation; centrifugal fan；bell mouth；simulation；computational fluid dynamics

Title: Study on the rollover stability of articulated steering off-road vehicle

Authors: LI Xuefei, LIU Huikai, WANG Guoqiang, LI Kai
PP: 569-577
Abstract: Articulated steering off-road vehicle (ASOV) is more likely to lose stability because of their own structural changes and poor working conditions. To solve this problem, a 6-degree of freedom (6-DOF) nonlinear dynamics model of the ASOV was established. By applying this model, the ASOV’s rollover mechanism was analyzed in different working conditions, such as turning on the level ground, moving through obstacles, and turning on the uneven road. The results showed that the main parameters which influenced the stability of the ASOV were the lateral acceleration and the roll rate. This research provides a reference for the ASOV’s instability warning and anti-rollover control.
Keywords: mechanical design; articulated steering; off-road vehicle; lateral stability

Title: Analysis of the impact on double circular arc gear caused by axial deviation and meshing stiffness

Authors: LI Yang, WU Baolin, ZHU Linlin
PP: 562-568
Abstract: The effect of axial deviation and meshing stiffness on double circular arc gear were analysed in the paper. According to the mechanical dynamics and dynamics of gear system, the gear meshing impact dynamic model was firstly built only considering tooth error and concave tooth as active tooth in the model. The reverse method and the graphing method were used to determine the starting positions of impact and build impact radius coordinate formulas. The effect of meshing stiffness on the impact was analysized and the method of decreasing impact caused by meshing stiffness was also proposed in the paper.
Keywords: mechanics; double circular arc gear; meshing impact; axial deviation; meshing stiffness; impact radius

Title: Study on the performance of ultra low temperature refrigerator

Authors: ZHAO Zhigui, SUN Zhigao, WANG Gongliang, JIAO Lijun
PP: 558-561
Abstract: The performances of refrigerants used in cascade refrigeration system was analysized and compared in this work. R404A/R508B was chosen as the refrigerant of ultra low temperature refrigeratore based on the above comparing work. An experimental apparatus of cascade refrigeration system was set up. The experimental results showed that the temperature of ultra low temperature refrigerator using R404A/R508B as refrigerant could drop to -82℃ within 6 hours. The system ran well and stably, which could meet the requirements of refrigeration of ultra low temperature refrigerator.
Keywords: refrigeration and cryogenic engineering; refrigerant; cascade refrigeration system; low temperature refrigerator; performance

Title: Vibration performance research of shape memory alloy damping interval

Authors: GAN Fenglin, YI Yawei, MEN Lili, ZUO Shi
PP: 551-557
Abstract: A new kind of damping interval was designed and made by use of the energy consumption and automatic reset ability of superelastic shape memory alloy wire. The finite element models of large span six split conductor of general interval and shape memory alloy (SMA) damping interval were installed respectively by using finite element software ANSYS. Response analysis was made on it after applying pulsating wind load. According to the best performance parameters of SMA damping interval got previously, dancing experiments was guided and proceeded. Experiment environment was simulated to re-establish finite element model. On the basis of experimental data, the accuracy of the finite element modeling was verified, and the best performance parameters of the SMA damping interval were found. Results showed that wave amplitude of the conductor installed with SMA damping interval was smaller than that installed with ordinary interval, which illustrated that the installation of SMA damping interval to the conductor could better inhibit conductor dancing and reduce the wave amplitude of the conductor dancing.
Keywords: power transmission and distribution engineering; shape memory alloy wire; interval; dance; amplitude

Title: Numerical research on heat transfer and flow loss in a rectangular channel with high-performance V-shaped ribs

Authors: XU Liang, ZHANG Shuai, CHEN Qiang, GAO Jianmin
PP: 544-550
Abstract: On the basis of experimental study on steam forced heat transfer in the ribbed channels, the SSG Reynolds stress turbulent model was adopted to solve the three dimensional steady Reynold-averaged Navier-Stokes (N-S) equations. The numerical simulation was carried out to a rectangular channel with three different angled V-shaped ribs (30 45 60 . To compare the cooling performance of steam and that of the traditional compressor air, steam and air were chosen as the coolants in this paper. We studied the influence of Reynolds number (Re) on flow and heat transfer characteristics and analyzed comparatively the cooling effects of two coolants on the ribbed surface. The results showed that the thermal performance of the 45 V-shaped ribbed channel was the same as that of the 60 V-shaped ribbed channel, while that of 30 V-shaped ribbed channel was poorer. A comparative study of thermal performances of steam convective cooling and air cooling demonstrated that using steam as a coolant had a better cooling effectiveness than using air as a coolant. The thermal performance coefficients of steam cooling in the 30 45 60癡-shaped ribbed channel steam was about 42.0%, 55.0%, 48.6% higher respectively than those of air cooling at the same flow conditions.
Keywords: power machinery engineering; convection heat and mass transfer; gas turbine; steam cooling; V-shaped rib; numercal simulation

Title: Research of CPU-GPU based transient stability heterogeneous parallel computing

Authors: DU Hao, YAN Zheng, ZHOU Tinghui
PP: 536-543
Abstract: For modern multi-core CPU and GPU features, a research is made on power system transient stability analysis and its parallel computing. Considering the sparse feature of power network grid and compute unified device architecture (CUDA) technology, a method of power system transient stability heterogeneous parallel computing based on CPU network grid partition and calculation dispatch, together with GPU fine-grained parallelism is proposed. This study tests the solution with a series of cases. Test results show that programs can gain a favorable speed-up ratio with the GPU and the CUDA technology, and there is a huge room for improvement.
Keywords: electric power system and automation; transient stability; heterogeneous parallel computing; compute unified device architecture

Title: A relieving distribution-line overload strategy based on the stimulus demand response

Authors: PAN Benren, DENG Caibo, FAN Ruixiang, XIN Jianbo
PP: 528-535
Abstract: The present study proposes the use of a new method for relieving distribution-line overload considering the demand response (DR). By using a response strategy based on stimulus demand, this strategy regards the minimum economic loss from overload as the target function for interruptible load (IL) cutoff. Furthcrmore, the influence of different load-interrupt schemes on the degree of relief is discussed. Finally, the study employs data from a specific domestic demonstration area to verify the feasibility of the proposed method. The results reveal that by maximally reducing the line overload risk via DR means, the safe operation of distribution lines is ensured.
Keywords: electric power system and automation; distribution-line overload; stimulus; demand response; interruptible load

Title: Research of full-order sliding mode observer for position sensorlesss IPMSM

Authors: WANG Gaolin, ZHANG Guoqiang, LI Zhuomin, ZHAN Hanlin, XU Dianguo
PP: 521-527
Abstract: In order to improve the rotor position estimation performance of position sensorless interior permanent magnet synchronous motor (IPMSM) control system in the dynamic situation, a high-order sliding mode observer (SMO), of which the state variables were current and extended electromotive force (EEMF), was analyzed in this paper. Then, based on the EEMF model of IPMSM, a full-order state equation in the stationary reference frame was established. On the basis of Lyapunov analysis, a simplified method of designing the feedback gain matrix for SMO was presented. The relationship between the parameters of the feedback-gain matrix and the dynamic response performance was studied specially. The experimental results demonstrated the feasibility of the position SMO with a position sensorless IPMSM control system.
Keywords: power electronics; interior permanent magnet synchronous motor; extended electromotive force model; full-order sliding mode observer; dynamic estimation performance; feedback gain matrix

Title: Summary of research on working fluids for organic Rankine cycle

Authors: ZHANG Ke, MENG Xianyang, WU Jiangtao
PP: 512-520
Abstract: Selection of working fluids is one of the key issues in organic Rankine cycle (ORC). In this paper, the research status of working fluids for ORC in domestic and foreign was reviewed. Working fluids for commercial ORC were illustrated with existing problems summarized. Pure fluids at low-middle temperature and high temperature were presented and compared respectively. At last, current research of fluid mixtures for ORC was introduced. The overview of working fluids in this paper revealed that ORC needed a demand of further exploration or the appearance of new invented fluid. Although it was available as an ideal fluid at certain operating conditions, however, no exact fluid had been proved perfectly suitable at high temperature.
Keywords: engineering thermophysics; organic Rankine cycle; review; working fluids

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