Loading...

Table of Content

    25 October 2009, Volume 20 Issue 20
    A Novel Wearable Robot of Hand Repetitive Therapy
    Xing Kexin;Xu Qi;Huang Jian;Wang Yongji;Wu Jun
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (2522KB) ( )  
    Related Articles | Metrics

    A novel wearable robot of hand repetitive therapy was developed for stroke and traumatic brain rehabilitation.The robot
    driven by pneumatic muscles can help patients to complete repetitive training task for
    motion function rehabilitation of their fingers’ joints. The robot had three degrees of freedom,which was equipped with three angle sensors and two force sensors to acquire the state of the human-robot hybrid system.At the same time, virtual reality technology
    was used to build a virtual rehabilitation environment in the system in order to enhance the patient’s interest and optimize the effect of rehabilitation.Finally,a conventional PID controller was implemented and the cubic spline function trajectory tracking control for joint’s angles was realized.Experiments were performed to confirm
    the effectiveness of the proposed device and methods.

    A Prediction Model and Experimental Study of Surface Roughness in Micro-milling Based on RSM
    Shi Wentian,;Wang Xibin;Liu Yude;Liu Zhibing
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (1518KB) ( )  
    Related Articles | Metrics

    The influence of parameters used in micro-milling process on roughness of aluminum surface machined by a micro turn-milling NC machine developed
    by authors was analyzed based on RSM.The cutting parameters included cutting speed,
    feed per tooth,and depth of cut in the orthogonal design experiments central composite.
    A predictive model for surface roughness in micro-milling was established
    by RSM and the significances of the regression equation and regression factor coefficients were proved
    herein. It appears that the cutting speed has a significant effect on surface roughness and the next one is feed per tooth, the depth of cut has a little effect under the current experimental conditions. Analysis of variance was performed to evaluate the significance of regression. The fitting degree of the model is high.
    The parameters used in micro-milling can be selected to improve the quality of the surface based on the model of the paper.

    Detection and Compensation for Oil Film Thickness in Cold Tandem Rolling Mill
    Chen Gang;Wang Yiqun;Fang Yiming;Liu Tao  
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (1057KB) ( )  
    Related Articles | Metrics

    In order to reduce the impact of change of oil film
    thickness on strip export thickness in hydrodynamic oil film bearing of backup roller and
    improve the AGC precision,the ways of detecting oil film thickness were deduced based on deformation formula of Reynolds. A data collection on a 1450 tandem cold mill was
    taken as an example, an analytical expression for relative oil film thickness of tandem cold mill was derived by estimating nonlinear model parameters based on Levenberg-Marquardt(L-M) method.Finally oil film thickness compensation to the HGC of operating side and driving side was carried out simultaneously and remarkable effect is made.

    Research on Scroll Compressor’s Flank Sealing Structure Based on Labyrinth Effect
    Liu Xingwang,;Liu Zhenquan;Qi Xueyi
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (687KB) ( )  
    Related Articles | Metrics

    The difficulties of scroll compressor’s flank sealing were analyzed, and a new flank sealing structure was advanced based on the labyrinth effect.
    Geometrical model of clearance between two scrolls was established, a method
    for determining effect sealing length was advanced,the velocity of gas in clearance was
    determined as subsonic state,an algorithm for the leakage volume of gas through the new flank sealing structure was advanced.The calculation and experimental results show that the new flank sealing structure has good sealing ability.

    Research on the Convergence of Hydraulic Automatic Levelling System for High-voltage Cleaning Robot
    Tang Junmao;Weng Xinhua;Yang Ruqing
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (817KB) ( )  
    Related Articles | Metrics

    High-voltage cleaning robot needs a horizontal platform, but it is hard to ensure the convergence of a hydraulic automatic levelling system. Thus,this paper analysed the three key problems: platform modelling, movement coupling, characteristics of the leg’s velocity. And then, this paper designed a control algorithm to solve the convergence problem. According to the results of experiments, the algorithm can ensure the convergence and keep the high precision and speed. 

    Free Vibration Characterization Analysis of Encased Differential Herringbone Gear Train
    Bu Zhonghong;Liu Geng;Wu Liyan;Ma Shangjun
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (1122KB) ( )  
    Related Articles | Metrics

    A rotational and translational vibration model including the coupling between two stage trains was established to predict the natural modes of encased differential herringbone gear train. Vibration modes of this gear train were classified into rotational mode, translational mode of differential stage, translational mode of encased stage, planet mode of differential stage and planet mode encased stage. The natural frequencies were calculated by considering the Carioles inertial force and centrifugal force and the influence of rotating speed on natural frequencies was evaluated. The results show that the frequencies of translational mode in encased stage bifurcate while the rotating speed increases. 

    Active Vibration Control Design and Experimentation of Flexible Plate via μ-Synthesis
    Li Dongwei
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (2296KB) ( )  
    Related Articles | Metrics

    A new kind of μ-synthesis controller design method of mixed uncertainty model was presented and proved from test results based on a flexible plate which was bonded with piezoelectric actuators and sensors. Firstly, the MIMO(multi input multi output) transfer function model and the state space model of the vibration system were identified by the multivariable frequency-domain identification theory and the ERA(eigen realization algorithm) method. On the basis of two models, the canonical uncertainty block diagonal matrix extraction method of modal parameter perturbation was designed by means of eigenvalue decomposition of the test model system matrix and linear fraction transformation, at the same time the residual modal was expressed by the high band filter, then the μ-synthesis controller solution procedure was established, which considered the mixed uncertainty of the test model. The active vibration control tests of the plate with three additive masses indicate,comparing with the open-loop system, the attenuation time of initial disturbance is shortened 40s,the noise caused by random disturbance is reduced nearly 4dB.

    Passivation Model of Diamond Wheel for Constant-force Grinding Si3N4 Ceramics
    Wu Zhiyuan;Tian Xinli;Lin Yunsen;Yang Junfei
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (1087KB) ( )  
    Related Articles | Metrics

    Taking grinding efficiency as evaluation indicator, the passivation curve of grinding wheel was established during full passivation period under the constant-force grinding condition.The curve was divided into three stages according to passivation speeds and passivation patters, i.e. early passivation stage, stable passivation stage and sharp passivation stage. Of which, the passivation speed is the slowest but with the highest grinding efficiency in early passivation stage. The change of passivation curve with the time is a process from concave to convex, which is totally different from the wearing process of grinding wheel in this stage. Furthermore an exponential function y=abx
    was adopted to make fitting for passivation curve which was based on the scatter
    plots of stable passivation stage and regression equation was derived through the fitting
    results of origin,thus to testify the correctness of the inference.Based on the equation,the paper discussed a method to evaluate the effect of grinding fluid by means of passivation ratio k.

    Calculation of Transmission Error of Modification Double Helical Gears and Experimental Investigation
    Wang Cheng;Fang Zongde;Jia Haitao;Ji Qiang
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (1937KB) ( )  
    Related Articles | Metrics

    Firstly, a method of three segment modifications for pinion
    profile was presented. New cutter surface equation was deduced after the shape of cutter-edge being changed and lines being substituted with three segment parabolas. Secondly, the mathematic programming model for tooth contact of double helical gears was built with non-linear programming method,which was based on finite element flexibility matrix, and the particular restriction conditions of double helical gears were imported. Loaded transmission error in a meshing period was obtained by solving the mathematic programming in a modification of the simplex method. Finally, an example that compared the effects
    of experiment with calculation was provided.

    An Ontology-based Approach to Fault Diagnosis Service Discovery in Grid Environment
    Guo Jianwen;Yu Dejie;Liu Jian;Zeng Wei
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (2403KB) ( )  
    Related Articles | Metrics

    To improve quality of services discovery in grid-based fault diagnosis environment, a service discovery approach based on ontology was proposed. The approach utilized ontology to describe the function characteristics of fault diagnosis, and extended ontology Web language for service(OWL-S) to realize semantic representation of grid service, and then adopted functional characteristics of fault diagnosis as matching criterion to establish semantic matching mechanism. A semantic information service component of fault diagnosis according to the approach had been successfully applied to the grid-based fault diagnosis system.

    Analytical and Experimental Study of Grinding Temperature Field on Heavy-duty Cam 
    Chen Ronglian;Cheng Weiming;He Yaolong;Hu Zhihong
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (2416KB) ( )  
    Related Articles | Metrics

    In order to study the grinding mechanism and to improve the grinding quality of non-circular cams a mathematical heat transfer model for cam grinding was set up based on the heat transfer theory with reasonable assumptions and simplifications on a heavy duty cam grinding.Internal distributions of temperature of the cam were achieved from the cam grinding simulation by ANSYS together with the calculation and analysis on instantaneous thermal transfer.The results show that the simulation truly reflects the heat distribution in the cam grinding,and the temperature fields from ANSYS
    are matched basically by what from on line infra red cameras, with an average relative difference about 3%.This offers help in solving the problem of cam surface thermal damage and deformation and others during cam grinding.

    String-based CAD Models Similarity Assessment Algorithm
    Zhang Xin ;Mo Rong;Shi Yuan;Chang Zhiyong
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (1831KB) ( )  
    Related Articles | Metrics

    Ministry of Education,Northwestern Polytechnical University,Xi’an,710072
    This paper presented an algorithm based on string comparison to assess the similarity of CAD models.Boundary representation(B-rep) model was represented by AAG. Permutation function was defined to put the vertexes in AAG in certain order according to attributes of vertexes. Given the relationship between vertexes, the permuted AAG can be mapped into a string. Edit distance was then used to calculate the distance between the two strings and the distance suggested the shape similarity of the two CAD models.The experimental results show that the proposed algorithm can give the degree of similarity of the two CAD models accurately
    and efficiently.

    Research on Optimization of General Airfoil Profiles for Wind Turbines Based on Adaptive Genetic Algorithm
    Chen Jin;Lu Qunfeng;Wang Xudong;Cheng Jiangtao
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (959KB) ( )  
    Related Articles | Metrics

    Airfoil profiles for wind turbines are mostly chosen
    from aviatic ones,but design requirements between the two types are different in many aspect.So optimization methods from ordinary aviatic airfoil profiles to profiles used in wind turbines become very important.The general and integral equation of airfoil profiles based on Trajkovski transform and genetic algorithm were integrated to construct a universal
    optimization method of general airfoil profiles for wind turbines, which could attain specific airfoil profiles for wind turbines by optimizing ordinary aviatic ones. The method constructed adaptive crossover and mutation operators and adopted optimal individual preservation strategy in order to solve immature convergence.Airfoil flow field analysis was made with Reynolds-averaged Navier-Stokes equations,and resulted lift and drag coefficients were taken as objective function in optimizing GA program. It is concluded from results, the optimized airfoil profiles maintaine basic characteristics of ordinary aviatic airfoil profiles and acquire better aerodynamic performance,and they are more beneficial in wind turbines.

    Research on Rough Theory-based Knowledge Push in Product Collaborative Design
    Yang Jie,;Yang Yu;Wang Weili;Zhao Chuan
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (842KB) ( )  
    Related Articles | Metrics

    Aiming at the difficulties in searching knowledge, a knowledge matching technology based on rough theory in product collaborative design was proposed.Firstly,the architecture of product collaborative design knowledge match was constructed, and the knowledge match flow was analyzed. Secondly,rough sets theory was used to
    calculate the importance of the functional,and the sequence of matching knowledge was determined.Thirdly, the knowledge with product restrained condition was matched and pushed through text similarity computation. Finally, this method was applied to an engineering case. The results of application prove the feasibility and availability of this method.

    A New Access Control Model for Cooperative Product Development
    Zou Linghao;Guo Dongming;Gao Hang;Sun Changle
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (1209KB) ( )  
    Related Articles | Metrics

    The existing access control models can not completely meet the requirements of cooperative products development nowadays.Based on the task and role access control model and analyzing requirements of access control for cooperative
    product development,the paper refered to and expanded the mandatory access control strategy, a new mixed access control model was proposed, which faced the cooperative product development and gave the definition of the model and basic rules. The application on the access control of cooperative product development system for model aircraft design and manufacture shows the effectiveness of proposed method.

    Aiming at Frontier,Selecting Area,Standardizing Proposal and Advancing Level 

    ——Analyses of the Proposals by Mechanical Engineering Division,NSFC,in 2009
    Wang Guobiao;Peng Fangyu;Lai Yinan
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (1171KB) ( )  
    Related Articles | Metrics

    According to the analysis and statistics of proposals for general program submitted to the Mechanical Engineering Division at the National Natural Science Foundation of China(NSFC) in 2009,the applicable catalogs including 12 second level codes and 44 third level codes in mechanical engineering were discussed.The research
    areas of every third level code were described, as well as the application situations in 2009. 

    Constitutive Model of 2Cr13 for Finite Element Analysis of Chip Formation Process
    Li Lin;Xie Lijing;Wang Xibin;Zhang Zhijing
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (945KB) ( )  
    Related Articles | Metrics

    The prediction accuracy of cutting process simulation is related with the description of nonlinear behavior of material at extremely high strain, strain rate and temperature in machining.An integral Johnson-Cook model was presented herein to characterize the mechanical behavior of work materials in machining, and the parameters in the model were determined by fitting the data from both quasi-static compression and cutting tests. Then the material equation of 2Cr13 stainless steel was derived with this method and used in the finite element model of orthogonal cutting with carbide tools. At last, the simulation results were verified with experimental data.

    Analysis of Sharp Resonance Synchronization Stability for the Dual Motor Exciting Nonlinear System
    Li Xiaohao;Liu Jie;Liu Jintao;Yao Zhao
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (953KB) ( )  
    Related Articles | Metrics

    According to the synchronous driving problem of dual exciting motors in vibrating screen which was used in agricultures and industries, to establish the dynamic model of single-mass nonlinear system which was driven by dual exciting motors,
    the vibration synchronization and synchronous stability of dual exciting motors which
    were rotated in opposite directions had been researched by theoretical method, under system sharp resonance conditions (resonant frequency ratio z=0.95~1.05).And the necessary conditions of vibration synchronization stability were deduced while the dual exciting motors moving at
    the balance singular point. Using the numerical simulation, the influence factors of vibration synchronization for dual exciting motors were discussed under different initial conditions, and the validation of synchronous stability theory was investigated. This research provides the theoretical fundamental and test basis for further exploitation of efficient and energy-saving sharp resonance shaker.

    科学基金
    Research on Surface Roughness for Multi-axis NC Grinding of Spiral Bevel Gear
    Ming Xingzu,;Yan Hongzhi;Chen Shuhan
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (927KB) ( )  
    Related Articles | Metrics
    数控磨削;螺旋锥齿轮;表面粗糙度;残留面积高度;模型
    Design for System of Intelligent Robot Detecting Liquid Pharmaceutical Foreign Bodies #br#
    Zhang Hui;Wang Yaonan;Ge Ji;Zhou Bowen
    2009, 20(20):  0-2519. 
    Asbtract ( )  
    Related Articles | Metrics
    The paper developed a kind of automatic detection system for
    high-speed pharmaceutical injections visible foreign bodies online detection named intelligent robot system of pharmaceutical detecting and sorting(IRPDS).The system adopted
    multi-type foreign substance dynamic image acquisition principle, multi-frames image sequences detection methods and high precision servo control and other advanced technologies, which could detect small foreign body in liquid injection by the high sensitivity.
    Firstly, the system’s structure and composition of the working principle were introduced. Secondly,the mechanical system, electrical control structure, high speed rotation image acquisition and detection algorithm, etc. were illustrated. Finally, some experiments
    were done, and the experimental results indicate that IRPDS can detect the foreign substance
    in the liquid injection effectively, and detection resolution is greater than 50μm, false reject rate is less than 5%, which satisfies the enterprise requests.
    Solving the Kinematics Parameters of a Parallel Robot Based on CAD Geometry
    Xu Jiayin;Lu Yi
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (832KB) ( )  
    Related Articles | Metrics

    A CAD variation geometry approach was proposed for accurately solving the position-orientation, linear velocity/acceleration, and Euler angular velocity/angular acceleration of the parallel robot with six degrees of freedom. Based on the finite-difference method as the foundations, using the computer aided geometry constraints and dimension driving technique, a simulation mechanism of the parallel robot with Euler angles was created, and the position-orientation could be obtained.Then the linear velocity/acceleration simulation mechanisms and Euler angular velocity/angular acceleration
    ones were created. When modifying the driving dimension of the six driving limbs, the configurations of the simulation mechanisms were varied correspondingly, and all of the kinematical parameters were solved automatically. The results show that the CAD variation geometry is fairly quick and straightforward, and is also advantageous from viewpoint of accuracy and repeatability.

    Multi Feature Parameters Health State Evaluation of Mechanical Equipment Based on Fuzzy-AHP Methodology
    Bin Guangfu,;Zhou Yuan;Balbir S. Dhillon 
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (701KB) ( )  
    Related Articles | Metrics

    This paper is aimed at the system evaluation
    problem of mechanical equipment caused by factors, such as the multiplicity
    of structure, close relevancy, and complex operating environment, from the
    viewpoint of functional hierarchy, a quantitative evaluation method of mechanical equipment multi feature parameters health state was developed on the basis of theory of fuzzy set synthesis evaluation and AHP.Considering the concept of human health and the equipment running parameters(including reliability, maintenance, technical performance,etc.), the mechanical equipment health state and its evaluation hierarchy model were analyzed.The health value was employed to quantitatively describe the
    running state degree.The weight vectors of all evaluation hierarchies were discussed by using the AHP method with the experiences of experts.Applied the fuzzy set evaluation theory, a type of subjection function of positive and negative indicators was presented, and the evaluation matrix was discussed as well as fuzzy transformation algorithm operators. The valuation model for mechanical equipment’s multi feature parameters health state based on fuzzy-AHP was built. The health value of subsystems can be obtained by means
    of “from bottom to top”,then the database of health values of whole mechanical equipment will be established. Based on the database, the health state of mechanical equipment is clear, which provides theoretical guide for seeking further optimization maintenance strategy. Finally,a health state evaluation of rotary kiln used in cement industry was taken as an example to verify the effectiveness and feasibility of the proposed method.

    Reliability Modeling of Components Based on Life Measured by the Times of Load Application
    Wang Zheng;Kang Rui;Xie Liyang
    2009, 20(20):  0-2398. 
    Asbtract ( )   PDF (499KB) ( )  
    Related Articles | Metrics
    The reliability modeling method of components was developed
    when the life was measured by the times of load application. The models for reliability and failure rate of components under random repeated loads without strength degeneration and those with strength degeneration were respectively derived, and the relationship between the reliability and the times of load application, and that between the failure rate and the times of load application were discussed in different cases. The results show that even though strength does not degenerate, both reliability and failure rate of components decrease as the times of load application increases, and the failure rate curve has partial characteristics of bathtub curve with early failure period and random failure period. When strength degenerates with the times of load application, the reliability of components decreases more obviously as the times of load application increases, and the failure rate of components decreases first and then increases as the times of load application increases, with the whole shape of the bathtub curve.
    Analysis of Factors Affecting Instantaneous Speed Ratio between Workpiece and
    Roller of CWR
    He Tao;Wang Baoyu;Hu Zhenghuan
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (2862KB) ( )  
    Related Articles | Metrics

    In the rolling procedure of cross wedge rolling, the
    technological parameters and instantaneous rotational speed ratio of workpiece and roller have intimate and complicated relationship.Through simulation test model concerning parameters of instantaneous rotational speed ratio of workpiece and roller by FEM, a result has been obtained,which proves that calculation mill parameters of instantaneous rotational speed ratio by FEM has favorable reliability and versatility. Based on these researches,
    the influence mechanism of effecting parameters on instantaneous rotational
    speed ratio is completely and systematically clarified. The researches are benefit to understand the movement relations among workpiece,rollers and the equation of the roller’s profile.

    Load Distribution Optimization in Tandem Cold Rolling Based on Adaptive Genetic Algorithm
    Wei Lixin;Li Xingqiang;Liu Ze;Yang Jingming
    2009, 20(20):  0-2402. 
    Asbtract ( )   PDF (611KB) ( )  
    Related Articles | Metrics

    In view of imperfection of the rolling force model in tandem cold
    rolling,the paper use BP neural network to predict the deformation resistance and friction coefficient then combining with the mathematical model in order to improve the precision of the model. A load distribution method was designed with improving adaptive genetic algorithm in which rolling pressure relative balance was the optimized objective function.
    The load distribution method was compared with the existing method on five-stand tandem cold rolling mills. Experiments results demonstrate that the improved adaptive genetic optimization algorithm have the advantages of better convergence and higher precision. It provides an effective method in the intelligent optimization for tandem cold milling.

    Study on the Friction Behavior and Mechanism of Zr-based Bulk Metallic Glass Superplastic Forming in the Supercooled Liquid Region
    Zheng Zhizhen;Cheng Jiao;Wang Xinyun;Li Jianjun
    2009, 20(20):  0-2519. 
    Asbtract ( )   PDF (1440KB) ( )  
    Related Articles | Metrics

    The friction behavior of Zr55Al10Ni5Cu30 bulk metallic glass in the supercooled liquid region was investigated. The influence of forming temperature and velocity on friction factor was established by double cup extrusion test. The calibration curves of friction factor were evaluated by FE simulation
    and Kawamura’s constitutive equation was adopted. Constant parameters in the constitutive equation were acquired by fitting the data from compression test. The results indicate that the friction factor of bulk metallic glass forming in the supercooled liquid region is between 0.2 and 0.7. With the temperature rising, the friction factor decreases in general under a low forming velocity. However, the friction factor increases slightly and then decreases abruptly under a high forming velocity. In low temperature area of supercooled liquid region, the friction factor increases abruptly with increasing of the forming velocity. While in high temperature area of supercooled liquid region, the friction factor decreases
    slightly with increasing of the forming velocity. The friction mechanism of bulk metallic glass forming in supercooled liquid region was analyzed by modern tribology theory. Adhesion is the dominant factor contributing to the friction of bulk metallic glass.

    Investigation on Influence of Processing Parameters on Replication Capability of Plastic Parts in Rapid Heat Cycle Molding 
    Liu Donglei;Xin Yong;Wu Xiaoyu;Ding Lei
    2009, 20(20):  0-2402. 
    Asbtract ( )   PDF (1428KB) ( )  
    Related Articles | Metrics

    By integrating the high-gloss surface mold for front panel of mobile key and auxiliary device for controlling mold temperature, which had been developed and manufactured independently, the influence law of process parameters in rapid heat cycle molding on replication capability of part was investigated. Results reveal that the replication capability of part will be increased remarkably, being different from conventional injection technology.When mold temperature is heated to the thermal deformation temperature of polymer, it changes hardly with the changing of mold temperature at lower or higher than the thermal deformation temperature. The other parameters has the same influence tendency between RHCM and conventional technology. The weight of runner system
    has the same influence tendency with the variation of parameters between RHCM and conventional technology. Especially, it is not sensitive to mold temperature. So it is feasible to increase the replication capability of part by improving mold temperature.