ENGINEERING NEWS IN BRIEF

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                  ENGINEERING NEWS IN BRIEF
                        E-Mail Newsletter

                               No.70
             Issued by the Asian TOP Panel, October 2007

           The Chinese Mechanical Engineering Society (CMES)
           The Institution of Engineers, Indonesia (PII)
           The Japan Society of Mechanical Engineers (JSME)
           The Korean Society of Mechanical Engineers (KSME)

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    According to the agreement made in the 2nd Asian TOP Panel Meeting,
the ENGINEERING NEWS IN BRIEF (E-mail newsletter) has now been edited
by the CMES for the year 2007.

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[Contents]

(1) Novel Gasbag Polishing Technique for Free-form Mold (Source: CMES)
(2) Elastomeric Imprint Lithography Process Based On Distortion Reduction By
     Precure Press Releasing (Source: CMES)
(3) Four Wheel Driving Hybrid System Based on Dual-Rotor Electric Motor
     (Source: CMES)
(4) Robotics in Medicine and Human Assist (Source: JSME)
(5) Incremental Forming Process - Die-Less and CNC Flexible Forming
     Technology (Source: JSME)
(6) MEMS-based Direct Methanol Fuel Cells and Their Stacks for the Reduction of      Cell-to-Cell Deviation and Interconnection Voltage Drop (Source: KSME)
(7) Real-time Measurement and Analysis for Micro Circular Path of Two-Axes Stage      Using Machine Vision (Source: KSME)
(8) Drying Performance Simulation for the Basic Design of a Heat Pump Dryer
     (Source: KSME)

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(1)Novel Gasbag Polishing Technique for Free-form Mold

    JI Shiming JIN Mingsheng ZHANG Xian Zhejiang University of Technology

A novel gasbag polishing technique based on flexible polishing principle is proposed for obtaining high polishing efficiency and well-proportioned surface quality of free-form mold. The information about gasbag polishing technique is discussed, such as automated robotic polishing system, spinning-inflated-gasbag polishing tool, various influence factors of surface roughness, etc. Also, in polishing process, the control of position and pose of the gasbag polishing tool and the characteristics of contact area when the rubber gasbag is pressed against the work-piece in a certain downward depth and obliquity are studied and analyzed. Regression orthogonal experiment research and theoretical analysis are based on the established automated robotic polishing system. The optimal parameters combination of different influence factors of surface roughness after the regression orthogonal experiment is given and the best average value of surface roughness 0.007 μm is obtained. Through a mass of experiment research, it is proved that gasbag polishing technique can enhance the stability, efficiency and quality of polishing effectively for the advantages of large flexible contact area between the polishing tool and work-piece, controllable pressure of the rubber gasbag, reliable movement accuracy of the automated robotic polishing system, tiny wiped off process of the mould surface, and so on.

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(2)Elastomeric Imprint Lithography Process Based on Distortion Reduction by Precure     Press Releasing

    LIU Hongzhong DING Yucheng LU Bingheng Xi'an Jiaotong University

Due to the conflict between the imprint area and the parallelity of mould and wafer, the elastometric imprint lithography is described. The loading process and the key technology of this process are analyzed and the error factors during pattern transferring process are also mined. Through comparing among the loading process factors, the conflict between the pattern transferring accuracy and residual resist thickness is indicated. By adjusting the elastic restore step before the UV-cure step, a novel imprint process-DRPPR, distortion reduction by precure press releasing is established and the inner conflict can be eliminated, and the imprint area can be lifted from 2 cm2 to 8 cm2. Based on the novel imprint lithography process, a low cost and simple structure prototype machine of step imprint lithography is designed and fabricated, and a series of imprint experiments show that the new imprint process can meet the needs for different pressing areas, feature sizes and repetitious imprints.

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(3)Four Wheel Driving Hybrid System Based on Dual-Rotor Electric Motor

    LUO Yutao ZHOU Sijia DENG Zhijun
    College of Automotive Engineering, South China University of Technology

The existing hybrid driving systems are studied. One kind of hybrid four wheel driving system is brought forward that is based on dual-rotor electric motor. This system is composed of mechanical transaxle and electric transaxle. By synthetically controlling of the two transaxles, the vehicle can be driven by either one or both of the two transaxles. The electric transaxle is composed of one dual-rotor electric motor and reducer and rotation direction exchange devices. It has the ability of driving, differencing and energy feedback. On the basis of performance theory of the dual-rotor electric motor, the mathematic model is established. Furthermore, the simulations of load mutation and swerve are carried out. Taking some sport utility vehicle as an example, the comparison simulation between prototype and novel type vehicle is done on the Matlab/Simulation calculating platform. The simulating results show that the driving performance of the novel vehicle is also the same as the prototype vehicle and the fuel economy is better than the prototype vehicle. The fuel consumption of the novel vehicle is 10.58% and 21.87% less than the prototype vehicle per 100 km based on the highway and city running cycle.

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(4)Robotics in Medicine and Human Assist

    Kazuo KIGUCHI, Saga University

In the field of medical robotics, surgery robots are expected to realize minimally invasive surgery, tele-surgery, precise surgery, and so on. The robots for endoscopic surgery and for total hip arthroplasty are already on the market and clinically applied. In the field of human assist robotics, many kinds of robots such as robotic mobile chairs, eating assist robots, or power assist robots are expected to be realized. The power assist robots, which magnify human force, are used for nursing person's assist, physically weak person's assist, and rehabilitation. In this article, the surgery robots for laparoscopic surgery and the power assist robots for physically weak person's assist are introduced.
In the laparoscopic robot surgery, robotic manipulators tele-operated by a surgeon are used as active forceps in the patient's abdomen. Applying the laparoscopic surgery robot, surgeon's wrist motion can be generated in the patient's abdomen.
A power-assist exoskeleton robot is directly attached to a user's body and assists the motion. It is important that the power-assist robot for physically weak persons automatically assists the user's motion according to the user's motion intension. Electromyogram (EMG) of the user's muscles can be applied as signals reflecting the user's motion intension for the power-assist robot.

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(5)Incremental Forming Process - Die-Less and CNC Flexible Forming Technology

    Shigekazu TANAKA, Shizuoka University

Incremental forming process is a new forming technology proposed in Japan in the 1990's. The forming process is die-less and intelligent.Various forming principles have been proposed and can be applied to the micro parts and large-scale parts for the aircraft.
In a typical process, the outer side of a blank is fixed and a moving stylus indents the blank by a given pitch and travels along a closed contour line. After traveling all contour lines, the sheet metal fits on the tool envelope surface The advantage of this process is a surpassing forming limit. In addition, multi pass process enables a vertical wall and thickness control.
This process is currently applied to manufacturing car body panels for trial purposes and the repair parts of classic cars.
Another important application is medical treatment or dental prosthesis. Recently, researches on next generation technology collaborated with the other new processes started in order to improve the accuracy.

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(6)MEMS-based Direct Methanol Fuel Cells and Their Stacks for the Reduction of     Cell-to-Cell Deviation and Interconnection Voltage Drop

    Young Ho Seo, Young-Ho Cho Gangwon National University

This paper presents a MEMS-based portable Direct Methanol Fuel Cell (micro-DFMC), featured by a platinum sputtered microcolumn electrode and a built-in fuel chamber containing a limited amount of methanol fuel. Also presented is a micro-DMFC stack structure having a common electrolyte sandwiched by the microcolumn electrodes. The single cells with ME16 and PE16 electrodes show the maximum power densities of 31.04±0.29μW/cm2 and 9.75±0.29μW/? respectively; thus indicating the microcolumn electrode (ME16) generates the power density (3.2 times) higher than the planar electrode (PE16). The single cell tests of ME16 and ME4 electrodes (Fig.8) show the maximum power of 31.04±0.29μW/? and 25.23±2.7μW/? respectively; thus demonstrating the increased window frame reduces the normalized standard power deviation (standard deviation over the average power). The normalized deviation of 0.11 in ME4 cell has been reduced to 0.01 in ME16 cell due to the increased window frames. The maximum power density of 4-cell stack is 15.7 times higher than that of the single cell. 4-cell stack produces the power capacity of 20.3mWh/g during 980min operation at the voltage of 450mV with the load resistance of 800?.

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(7)Real-time Measurement and Analysis for Micro Circular Path of Two-Axes Stage     Using Machine Vision

   Ju-Kyung Kim, Jong-Jin Park, Eung-Suk Lee Chungbuk National University

To verify the 2D or 3D positioning accuracy of a multi-axes stage is not easy, particularly, in the case the moving path of the stage is not linear. This paper is a study on a measuring method for the curved path accurately. A machine vision technique is used to trace the moving path of two-axes stage. To improve the accuracy of machine vision, a zoom lens is used for the 2D micro moving path. The accuracy of this method depends of the CCD resolution and array align accuracy with the zoom lens system. Also, a further study for software algorithm is required to increase the tracing speed. This technique will be useful to trace a small object in the 2D micro path in real-time accurately.

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(8) Drying Performance Simulation for the Basic Design of a Heat Pump Dryer

     Kong Hoon Lee, Ook Joong Kim Korea Institute of Machinery and Materials

Heat pump drying has a great potential for energy saving due to its high energy efficiency in comparison with conventional air drying. In the present study, the performance simulation for the basic design of a heat pump dryer has been carried out. The simulation includes one-stage heat pump cycle, simple drying process using the drying efficiency. As an example, the heat pump cycle with Refrigerant 134a has been investigated. For the operating conditions such as the average temperature of the condenser, the heat rate released in the condenser, the flow rate of drying air, and drying efficiency, the simulation has been carried out to figure out the performance of the dryer. The parameters considered in the design of the dryer are COP, MER, SMER, the rate of dehumidification, the temperature and humidity of drying air and those parameters are compared for different conditions after carrying out the simulation.

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Editor : Tian Ruizhu
           The Dept. of Internationa Affairs
           Chinese Mechanical Engineering Society