Mar 2006, Volume 1 Issue 1

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  • YANG Shu-zi, WU Bo, LI Bin
    This paper is a supplement to Trends in the Development of Advanced Manufacturing Technology  (Yang and Wu in Chin. J. Mech. Eng., 39: 73, 2003) but delves deeper into it. It first points out the strategic status of manufacturing industry in state development. Then, a detailed analysis is given on the features and trends in the development of advanced manufacturing technology in a total of 12 points from three aspects: precision,  extreme,  and culture  from the aspect of the product itself; green,  rapidness,  saving,  and efficiency  during the manufacturing process; and digit,  auto,  integration,  networking,  and intelligence  in view of the manufacturing method. In addition, it emphasizes that all the above aspects should be based on two base points: manufacture  and machinery.  Finally, it puts forth the guiding ideologies for the development of advanced manufacturing technology and the aspects China should give priority to in development, while stressing on the principles of independence, innovation and human orientation.
  • LU Bing-heng, LIU Hong-zhong, DING Yu-cheng, WANG Li, QIU Zhi-hui
    In this paper, the motion mode and nanopositioning accuracy in the step imprinting lithography process are presented, and the positioning errors different from the traditional errors, such as the gap error existing in the hinges of the stage structure and the random error produced during the process of the stage position adjustment, are analyzed. To avoid and eliminate these nonlinearity errors, radial basis function proportional integral derivative and position control algorithms are introduced into the macroand microdriving processes, respectively. The innovation of this driving method is that the motion locus is monotone, nonoscillatory, and a multistep approaching target, which eliminates the root of the random error by single direction driving mode and avoids the backlash error through preloading function. Driving experiments of different motion ranges prove that this nonlinearity compensation is very effective and the positioning accuracy during the step imprinting process can be improved up to 10 nm.
  • GUO Kong-hui, ZHUANG Ye, CHEN Shih-ken, WILLLAM Lin
    A newly developed tire rubber friction test machine is introduced. Friction test method of tire rubber is provided. Test data of tire rubber friction on concrete and icy road surfaces are obtained and analyzed. The effect of different road surface, ambient temperature, contact pressure, and slip velocity on friction coefficient is apprehended. The dynamic friction is introduced to tire semi-empirical modeling, and the accuracy of the model is improved. A way of forecasting tire property on high-rolling speed using data from low-rolling speed tire test is illustrated.
  • SHEN Jing-feng, YAO Fu-sheng
    To design various optimum parameters and simulate the working process of CP single-screw compressor, the Computer-Aided Design (CAD) system for the CP single-screw compressor has been established. A new method based on computer graphics technology, database technology, object-oriented programming technology, and visual simulation technology has been adopted in this CAD system. The system has integrated solid modeling function with parameterization design function and animator simulation function based on analyzing the working principle of the CP single-screw compressor. The experimental results show that the CAD system for the CP single-screw compressor is practical and feasible.
  • HU Guo-liang, XU Bing, YANG Hua-yong, ZHANG Yi-ding
    A new pipe rupture valve for hydraulic elevator is designed. Mathematical models established for the hydraulic elevator system are used in numerical simulations on the Simulink environment of Matlab kits. The effects of different viscous damping diameters, inlet pressures of pipe rupture valve, and elevator loads on the hydraulic elevator system s dynamic performance are analyzed. Experimental research is also carried out using a hydraulic elevator experiment rig. The numerical simulations accord with experimental results in general. Dynamic performance indexes are assessed by the EN81-2 standard. The results show that the newly designed pipe rupture valve meets the designing requirement for hydraulic elevators.
  • ZHANG Wen-zeng, CHEN Qiang, SUN Zhen-guo, XU Lei
    A novel underactuated finger mechanism was designed. Finger mechanism was incorporated into a humanoid robot hand to obtain more degrees of freedom with less actuators and good grasping functions with shape adaptation, therefore decreasing the requirements for the control system. A novel superunderactuated multifingered hand (TH-2 Hand) for a humanoid robot was designed based on a previous underactuated finger mechanism. The TH-2 Hand was attached to a humanoid robot because of its high personification, superunderactuation, compactness, easy real-time control, small volume, light weight, and strong grasping function.
  • DING Zhi-ping, LIU Yi-lun, YIN Ze-yong, YANG Zhi-guo, CHENG Xiao-ming
    Taking into account the effects that the components of tension stresses couple with components of torsion stresses when off-axis loads are applied to orthotropic materials, Hill s yield criterion for plastically orthotropic solids is modified by adding an invariant that is composed of the product item of quadratic components of the deviatoric stress tensor, and a new yield criterion is put forward in terms of the characteristics of the face-centered cubic (FCC) single-crystal material. The correlation of prediction and experiments is very good, and the new criterion is used to predict the yield stresses of an internal single-crystal, Nickel-based superalloy, DD3, which is more accurate than that of Hill s at 760?C. Equivalent stress and strain that adapt to the new criterion are defined. Thinking of the yield function as a plastic potential function from the associated flow rule, the elastic plastic constitutive model for the FCC single-crystal material is constructed, and the corresponding elastic plastic matrix is educed. The new yield criterion and its equivalent stress and strain will be reduced to Von Mises  yield criterion and corresponding equivalent stress and strain for isotropic materials.
  • YE Zhi-gang, ZOU Hui-jun, GUO Wei-zhong, HU Song, TIAN Yong-li, XU Yong
    Based on an analysis of mechanism combination methods of a current mechanism system kinematic scheme, input/output kinematic behavior and their constraint relations were proposed to represent the kinematic behavior knowledge of a mechanism system. Furthermore, a tree structure of a kinematic behavior decomposition process for a mechanism system was provided. Considering multiple outputs for a mechanism system, the matching algorithm and the attributes propagation method of kinematic behavior were used to generate a mechanism combination scheme. Its intermediate design solution and the constraint relations between input and output are generated to fill the common blackboard. Moreover, using information in the blackboard as input motion, the behavior attributes of other process actions are transmitted to attribute items of the blackboard, which finally enables a computer-aided automatic design process of a mechanism system kinematic scheme. To avoid the problem of schemes combination explosion caused by unbounded depth in the search process, bounded depth-first search was used to control the number of expanded hierarchies for a design tree. Finally, an example was given to show its feasibility and solution efficiency.
  • CHENG Guang-ming, SHEN Chuan-liang, YANG Zhi-gang
    A piezoelectric actuated prestage driver of hydraulic servo valves for the low-frequency response of electrohydraulic servo valve electromagnetic prestage driver was presented. The new driver was driven by piezoelectric multilayer actuators. The displacement of a piezoelectric multilayer actuator was amplified by a flexure-hinged amplifier based on the principles of triangle amplification. Static and dynamic characteristics were tested on the model machine. The characteristics of good linearity, high resolution, and high-frequency response were approved. The natural frequency reached 1.201 kHz using finite element analysis, and the practice measurement result was 1 kHz.
  • YANG Zhi-yong, WU Jiang, HUANG Tian, NI Yan-bing
    Aiming at a parallel mechanism with three degrees of freedom, a method for dynamic model building and the parameter identification of its servosystem is presented. First, the reverse solution models of position, velocity, and acceleration of parallelogram branch structure are deduced, and then, its dynamic model of a rigid body is set up by using the virtual work principle. Based on the above model, a method to identify the servo parameter of the parallel mechanism is put up. In this method, the triangle-shaped input with variable frequency is adopted to offset the disadvantages of pseudorandom number sequence in parameter identification, such as dramatically changing the vibration amplitude of the motor, easily impacting the motor that results in its velocity loop to easily open, and so on. Moreover, the rotary inertia can also be identified by the additive mass. The abovementioned data will lay a solid foundation for the optimum performance of the system in the whole workspace.
  • CHANG Jian-feng, ZHONG Yue-xian, HAN Zan-dong
    This paper analyzes the capacitated lot-sizing problem considering an individual machine s production capacity using a two-layer hierarchical method to minimize the sum of the dynamic inventory cost and the overtime penalty cost. The genetic algorithm, the parameter linear programming method, and a heuristic method were used in the developed method. The method uses the genetic operator to define the lot-sizing matrix (the first layer), linear programming to determine eachmachine' s schedule (the second layer) according to the lot-sizing matrix, and the heuristic method to verify the feasibility of the solutions by adjusting them to meet the constraint requirements. The scheduling of machines in a press shop demonstrates the effectiveness of the algorithm. The result shows that the algorithm is convergent.
  • WU Yi-jie, LENG Hong-bin
    By analyzing the structure characteristics of arbitrary n-polygon noncircular sections, mathematical formulas among the characteristic parameters were set up, and a theorem for designing this kind of sections was deduced by mathematical induction method. Based on the mechanistic transmission principle, the control theorems for the numerical control (NC) grinding of arbitrary n-polygon noncircular sections and the control model for the multicoordinate motion were built. A feed rate selfadjusting method was proposed to uniform the grinding speed with the changes of sectional curvature. Then, an NC machine tool for grinding n-polygon noncircular sections was developed. The test results of the grinded parts showed that the section profiles accorded with the design demands: the roughness was less than 0.32 ?m and the dimensional accuracy was within 8 ?m. The results prove that the proposed theorems and method can effectively direct the design and manufacture of the polygonal noncircular connection.
  • CHEN Xin-bo, YU Zhen
    The design of intermittent-motion linkages using traditional methods is usually complicated. In this paper, (1) a new method for realizing intermittent motion, using linkages with a slight difference in length between links, is studied; (2) some new types of intermittent-motion linkages and their software for visual analysis and design are developed; and (3) influences of some design parameters on intermittent-motion characteristics are clarified. Results confirmed that the theory and the software are useful, making the synthesis of intermittent-motion linkages clear and easy.
  • LU Xiao-chun, GUO Sheng, RUAN Feng
    A comprehensive evaluation system of die quality, a multiplayer hierarchical amendment index system according to the characteristics of cold stamping die production, an evaluation standard referring to the technique and design rules of dies, and a scientific evaluation by using the multiplayer hierarchical and the fuzzy comprehensive evaluation methods are presented in this paper. The applications show that the system can be used to evaluate the die quality objectively, fairly, and reasonably.
  • A novel fuzzy clustering method based on chaos immune evolutionary algorithm (CIEFCM) is presented to solve fuzzy edge detection problems in image processing. In CIEFCM, a tiny disturbance is added to a filial generation group using a chaos variable and the disturbance amplitude is adjusted step by step, which greatly improves the colony diversity of the immune evolution algorithm (IEA). The experimental results show that the method not only can correctly detect the fuzzy edge and exiguous edge but can evidently improve the searching efficiency of fuzzy clustering algorithm based on IEA.
  • SUN Yue-hai, DUAN Lu-qian, WANG Shu-ren, ZHANG Ce
    To exactly describe the contact state and contact area of tooth surface of toroidal involute (TI) worm gearing, the authors introduced boundary condition into contact line analysis.With helix angle chosen as parameter, the criterion for the existence of meshing boundary line on the surface of TI worm gearing is derived. Results show that there can be four situations for meshing boundary line on the tooth surface of gear, namely, inexistence of meshing boundary line, a unique line, two lines, and two coincident lines. If the helix angle is equal to or slightly smaller than the bigger angle, which makes two meshing boundary lines superpose, a preferable meshing performance is obtained. Computer simulation proves the validity of the above conclusion.
  • XU Hua, ZHU Jun
    In this paper, to consider the effects of mechanical seals, a lumped-mass model and the transfer matrix method are used to establish the equations for the dynamics performance of rotor bearing system. The general inverted iteration method is also used to solve the eigenvalue problem of these equations. To check the response of the rotor bearing system under unbalance motivation, the Gauss method is used to calculate the dynamic response of the constrained vibration. The results, based on the dynamic properties calculation of a typical mechanical spiral seal, such as stiffness coefficients and damping coefficients, exert the influence of the mechanical seal on the rotor bearing system of the high-speed machinery. Meanwhile, some structure parameters that may affect the dynamic performance and forced vibration under unbalance motivation of the rotor bearing system considering mechanical seals are analyzed in the paper. The analysis results show that the mechanical seal more or less has effects on the rotor bearing system. The mechanical seal has much more effects on the flexible rotor bearing system than on the rigid one. For instance, in a certain case, if the effects of the mechanical seal were taken into account, the system s critical speed may increase by 70 80%.
  • CAO Yan-long, MAO Jian, YANG Jiang-xin, WU Zhao-tong, WU Li-qun
    The traditional tolerance design model ignores the impact of noise factor, so that the design may be infeasible due to variations in design constraints. Based on the analysis of fuzzy factors in tolerance design and the limitations of the traditional Taguchi squared quality loss function, a fuzzy quality loss function model utilizing fuzzy theory was introduced. Concepts on fuzzy quality loss and fuzzy quality loss cost were proposed in the model. The characteristics of the new model and the advantages over the traditional Taguchi quality loss function were analyzed. A robust tolerance design model using a fuzzy quality loss function was proposed. An example was given to illustrate the proposed model. Results and comparisons show that the method is suitable and reliable, and makes the conclusions more objective and reasonable.
  • ZHOU Bin, GAO Zhong-yu, CHEN Huai, ZHANG Rong, CHEN Zhi-yong
    A new digital readout system for micromachined gyroscope has been proposed to implement flexible parameter adjustment, improve the control performance of gyroscope, and make error compensation. By digitalizing the output of the gyroscope, this system uses a floating-type digital signal processor (DSP) to process the signal demodulation and achieve the feedback control of the gyroscope. Therefore, the small change of capacitance in the micromachined gyroscope can be detected. A new demodulation algorithm of least mean square demodulation (LMSD) has been developed inside DSP. Simulation and measurement results show that LMSD can improve 29% of the noise performance compared with the typical multiplication method. In air pressure, a kind of vibration-wheel micromachined gyroscope has achieved a noise level of 0.0073 deg s-1z(z-1/2 over the 100-Hz bandwidth by using this digital readout technology.
  • LI De-sheng, LIU Ben-dong
    A new microelectromagnetic relay is presented and fabricated based on micromachining technology, aiming at the miniaturization and high manufacturing efficiency of electromagnetic relays. This microrelay is composed of a lower magnetic circuit, a planar exciting coil, and an upper magnetic armature. A complete magnetic circuit is composed, and the ON  and OFF  states are controlled by the current of the exciting coil. The dimension of this microrelay is 5 mm ? 5 mm ? 0.4 mm. The fabrication process mainly includes lithography, sputtering, electroplating, etching, sacrifice-layer technology, etc. Electromagnetic force is calculated theoretically. The calculation results are used for the optimization design of the armature and the number of turns of the exciting coil. A microelectromagnetic relay is fabricated and the initial test results are given. The resistance of the exciting coil is about 300 Ω. The switch-on state resistance is about 1.7 Ω at an exciting current of about 50 mA.
  • WANG Yan, HANG Lu-bin, YANG Ting-li
    This study presents a solution for the inverse kinematics problem in serial 6R manipulator. Using only seven equations composed of Duffy s four kinematical equations containing three angles and three corresponding angles  identical equations instead of the traditional 14 equations, the authors reduced the inverse kinematics problem in the general 6R manipulator to a univariate polynomial with a minimum degree based on the Groebner Base method. From that, they concluded that the maximum number of the solutions is 16, generally. Also, the mathematics mechanization method can be extended to solve other mechanism problems involving nonlinear equations symbolically.