Table of Content

10 October 2007, Volume 18 Issue 19

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A Journal Eddy Current Damper for Rotor Systems

Zhu Changsheng

2007, 18(19):  2269-2272. 

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Based on the eddy current principle, a novel journal eddy current damper for rotor systems was presented. The basic structure and the dynamics model of the radial eddy current damper were analyzed. The frequency response functions of a flexible rotor system supported on the radial eddy current damper in the stationary, the rotor motion orbits at the steady state rotational speeds and the unbalance response curves in the slow acceleration operation were measured for different magnetic flux densities. It is shown that the dynamics behavior of the radial eddy current damper is easily controlled by the applied magnetic field, and the radial eddy current damper can significantly reduce the vibration of the rotor system.

Information Loss in Failure Probability Calculation and System-level Modeling Approach

Xie Liyang Wu Ningxiang Wang Zheng

2007, 18(19):  2277-2283. 

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hrough a thorough analysis to the essence of the method to calculate component failure probability via load-strength interference relationship, the phenomenon of system failure attribute related information loss was revealed, and the reason why it was impossible to establish s-dependent system failure probability model simply by means of component failure probabilities was interpreted. This paper also discussed the mechanism of common cause failure (CCF) for general system. Based on system-level load-strength interference analysis, the attribute of component failure probability was presented and the relationship between component failure probability attribute and load/strength distribution was described. The coupling mechanism for common cause failure was explained mathematically. A parametric model was developed to estimate system failure probability according to limited amount of failure event data available. Examples show that the proposed model has a good consistency with experimental results.

TP391.7NC Machining Algorithm for Right Angular Exact Index Cam

Li Xiaoqing Chen Xuedong Yan Sijie Zhou Yunfei

2007, 18(19):  2284-2287. 

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Based on the working rules of right angular exact index cam, a method for designing and machining a cam which indexes without impact was proposed. The positions of cam and dial were analyzed accompanied with their angular position, angular velocity and angular acceleration. An algorithm for design of right angular exact index cam was given. The tool trace of NC machining was calculated, thus the NC machining and programming algorithm for 4-axis NC machine tool was presented. With NC machine tools, a right angular exact index cam was made. The experimentation shows the machining efficiency is improved obviously. The indexing accuracy, stability of the cam are improved obviously in practice use, And the experimentation indicates the algorithm for designing and machining a cam is effective and efficient.

Configuration Parameter Compositive Design for the Feed Fine-tuning Platform in FAST

Pei Shaofang Wang Qiming Tang Xiaoqiang

2007, 18(19):  2273-2276. 

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Based on the characteristics during the feed source tracing in FAST（five-hundred-meter aperture spherical telescope）, this paper took a 6-SPT Stewart platform as the feed fine-tuning platform and made a configuration parameter compositive design research, where 3 restrictive factors were taken into account synchronically, including the workspace, dexterity and preventing components from intervening. Upon the above method, this paper attains a set of configuration parameters designed for the fine-tuning platform.

Detection for Interference in Numerical Control Machining of Impeller

Cai Yonglin, Sun Weiqing, Jiang Hong

2007, 18(19):  2313-2318. 

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The interference may be occurred in multi-axis Numerical Control (NC) machining of free-form centrifugal impeller, and a detection method for interference was presented herein. Firstly, the offset surface of blade of the impeller was calculated, and the offset distance was the radius of cutter. The equation of cutter axis can be obtained by the given cutter location data. Then calculations were completed to judge whether there was an intersection point between the offset surface and cutter axis, if there is an intersection point, then the interference does exist. Otherwise, the minimum distance between boundary of blade and cutter axis was calculaled, if this distance is greater than the cutter radius, there is no interference, otherwise interference exists. This method has small quantity of computation, and it can greatly decrease the calculation time of computer in interference detection for large numbers of cutter location data in NC programming of impeller machining.

Modelling, Identification and Experimental Validation of CVT  #br# Clamping Force Control System

Zhou Yunshan, Liu Jingang, Zou Naiwei, Cai Yuanchun

2007, 18(19):  2291-2294. 

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It is very hard to attain CVT (continuously variable transmission) clamping force control system appropriate mathematical model for control purposes by means of mathematical analysis. So the necessity of experimental modelling for CVT clamping force control system was presented in order to resolve this issue,and the related AR model was established based on time series analysis, the parametric values of the AR model were estimated with Burg algorithm, and how well the model can predict the system behavior was validated by experiments.The simulation result of the identified model basically agrees with the experimental one of the system in step response. It is proved that the research herein provides a new effective method of electronic control for CVT clamping force control system.

A New Method for Estimating the Number of Blind Sources

Li Ning, Shi Tielin

2007, 18(19):  2298-2302. 

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The convetional methods for estimating the number of sources require that the number of sensors must be more than or equal to the number of the sources, and this is very difficult to satisfy for "blind" sources. A new method for estimating the number of sources was presented according to the ratio of power spectral density (PSD) of the observation signals when the relation between the number of sensors and sources was unknown. The effectivity of the proposed method was verified by theoretical analysis, simulation and experimental data.

Establishment of Kinematics Models and Performance Analysis of Elliptic-gear & Crank-rocker Weft Insertion Mechanism

Chen Jianneng, Zhao Xiong, Xu Bin, Zhao Yun

2007, 18(19):  2294-2297. 

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In order to analyze the kinematics performance of elliptic-gear & crank-rocker weft insertion mechanism which had been proposed by the authors, kinematics mathematical models of the mechanism were established, and the corresponding analytic software was compiled. Influences of some important parameters on the kinematics characteristics of the mechanism were analyzed. A group of preferable parameters were obtained and its kinematics performance was analyzed. Comparisons of kinematics performance were done between the mechanism and the spatial four-linkage weft insertion mechanism of GTM rapier loom manufactured by PICANOL Corp. in Belgium. So the mechanism invented by the authors can meet the requirements of inserting wefts.

Service-Embedded Manufacturing:Advanced Manufacturing Paradigm in 21st Century

Sun Linyan, Li Gang, Jiang Zhibin, Zheng Li, He Zhe

2007, 18(19):  2307-2312. 

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The service-embedded manufacturing paradigm, which was a new advanced manufacturing paradigm, was proposed. In the 21st century, the merge and interaction of the manufacture and services trigger the emergence of the service-embedded manufacturing paradigm. This new paradigm is different from traditional manufacturing paradigms. It can integrate dispersed manufacturing and service resources more efficiently, create more value for enterprises and customers, and better innovative technology. Based on the analysis of main problems of China’s manufacturing industries, this paper proposed that the implementation of service-embedded manufacturing paradigm can enhance the competence for enterprises and manufacturing industries, foster the upgrade of manufacturing industries and facilitate the balanced development of different regions in China. Finally, research opportunities of service-embedded manufacturing paradigm were proposed.

ICM Method for Topological Optimization of Continuum Structure Based on Different Filter Functions

Long Kai, Zuo Zhengxing

2007, 18(19):  2303-2306. 

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Due to the independence of design variables in independent,continuous,mapping(ICM) method,a new mixed modeling method was presented.SIMP and RAMP interpolation schemes were used as filter functions of element and volume element stiffness matrix.Based on mutual combination of filter functions, four different topological optimization models were presented. Compared with each other, the only difference among four models is about expression and numerical value of derivatives, so the same algorithm for the new models is ensured.New topological optimization model was illustrated by the examples of topological optimization problems with different parameters. Results are shown to demonstrate the feasibility and efficiency of method and model proposed herein.

Grey Fuzzy Synthetically Evaluation Method for RMS Layout Planning

Wu Zhijun, Ning Ruxin, Wang Aimin

2007, 18(19):  2313-2318. 

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A grey fuzzy synthetically evaluation method was presented for the reconfigurable manufacturing system (RMS) layout planning decision making problem. Based on analyzing the factors which affected the performance of the RMS, a hierarchy synthetically evaluation indicator system was proposed firstly. Then, a simulation model was constructed by commercial simulation software eM-Plant, by which the data of quantitative indices was got; the data of qualitative indices was obtained from expert grade method. Based on those data, grey relational analysis method was used to calculate the weight of indicators. Finally, fuzzy synthetically evaluation method was introduced to evaluate the layout schemes for RMS. Taking a job-shop floor as an example, the experimental results indicate that the grey fuzzy synthetically evaluation method is a more effective method for RMS layout planning decision making problem.

Partitioning Assembly Cells for Aircraft Using Case-based Reasoning

Xue Peng, Li Yuan, Peng Peilin

2007, 18(19):  2318-2321. 

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This paper studied the partitioning assembly cells for aircraft using CBR. The case to organize the knowledge of the partitioning assembly cells was constructed, including the geometrical and physical information, and the similarity-based retrieving was adopted in case retrieval algorithm. The best matching case for the design requirements on the case-based is obtained using the similarity-based retrieving. The algorithm was validated in a certain kind of girder of the aircraft wing assembly.

esearch on Process Rapid Proliferative System

Yu Feng, Liao Wenhe, Guo Yu, Liu Jinshan

2007, 18(19):  2322-2325. 

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Based on the analysis of military manufacturing enterprises achieving rapid proliferative manufacturing in China, the architecture and function of process rapid proliferative as well as the proliferative flow based on B/S framework were studied. At the same time, through the integration of the military manufacturing enterprise’s process data, manufacture preparing time is shortened and the quality of proliferative tasks can be ensured, so that the needs of rapid response for military manufacturing enterprise can be satisfied.

Extraction Approach of Patent Information Based on Regular Expression

Qiu Qingying, Zheng Guomin, Feng Pei’en, Wu Jianwei

2007, 18(19):  2326-2329. 

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Since current patent documents are saved as image-based type such as .TIF, .PDF, and so on, they are difficult for full-text search and further analysis. The approach that adoped the optical character recognition (OCR) tool and the fault-tolerant regular expressions was proposed for patent digitization and information extraction according to the structural features of patent documents. The software system was developed to support the batch extraction of patent information, which provided the data resources for the following automatic patent analysis and knowledge mining.

Constitution of an Extended MBOM View and Its Deduction Mechanism

Zhao Yan, Mo Rong, Chang Zhiyong, Liu Hongjun

2007, 18(19):  2334-2339. 

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In order to meet the needs that the data information in manufacturing must be coherent,non-redundant and so on, an extended MBOM view, e-MBOM view, was proposed , by which the information used in processing department and manufacturing department was managed uniformly. The constitution of e-MBOM view was studied in three aspects: structure, associated information and attribute.The e-MBOM view was divided into manufacturing-preparation e-MBOM view and manufacturing-performance e-MBOM view based on the division of associated information. The mechanism of deduction from e-BOM view to e-MBOM view was studied in structure, associated information and attribute. An instance of application in a war-industry factory was offered finally.

Research and Application of Virtual Tool in Assembly Workplace Simulation

Cheng Huanchong, Yang Rundang, Fan Xiuming

2007, 18(19):  2329-2333. 

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According to virtual tools used in assembly, firstly, assembly tools were categorized as three types by operational type, then assembly tool library was built in virtual environment. Each tool was expressed by displaying model, collision model and logic model. Secondly, assembly process using the tool kinds in virtual environment was given, including position between virtual tool and operated object, as well as assembling between operated object and related object. Finally, an assembly example of a simulation process using virtual tools in workplace planning of automobile engine assembly line was given to validate the feasibility and the validity of the method.

Markov Chain Simulation for Fast Evaluation of Failure Probability

Yuan Xiukai, Lu Zhenzhou

2007, 18(19):  2355-2359. 

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Based on fast Markov chain simulation for the samples distributed in failure region, an evaluation method was presented for fast evaluation of the small Failure Probability (FP) with non-linear limit state equation (LSE). The small FP of non-linear LSE was transformed into a product of the FP of the linear LSE and a feature ratio factor, which was the basic concept of the presented method. The linear LSE was obtained by the samples distributed in the failure region of the non-linear LSE and generated by the fast Markov chain simulation. The linear LSE and the non-linear one have the same maximum likelihood points in the failure regions. The feature ratio factor was computed by means of multiplicative rule of probability； it exposed the relation between the FP of the non-linear LSE and that of the linear LSE. Since the FP of the linear LSE can be calculated analytically and accurately, and the feature ratio factor can fast be computed by the samples distributed in the failure regions of the non-linear LSE and of the linear LSE, the presented method possesses high precision and high efficiency. These advantages were demonstrated by the given examples.

Laser Soldering System Calibration Based on Computer Vision

Zou Xinjue, Xiong Zhenhua, Wang Yulin, Ding Han

2007, 18(19):  2340-2345. 

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We developed an integrated laser-soldering system which combined a computer vision. Based on the analysis of experimental data, it is found the len distortion and assembly angular errors of X-Y stage to play a distinct role in introducing positioning errors. For the sake of satisfying positioning accuracy of end-effector and precision specification of packaging technique, an algorithm based on straight line method was built to abate distortion of image, and a compensation algorithm based on computer vision for positioning calibration of the non-vertical X-Y positioning stage was also developed. Finally, experimental results and comparative data to evaluate the performance of these approaches were reported.

Research on Fourth-order Profile Planning Algorithm for High Accuracy Point-to-point Motion System

Mu Haihua, Zhou Yunfei, Yan Sijie, Han Aiguo

2007, 18(19):  2346-2350. 

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A novel algorithm of four-order profile planning for point-to-point motion and error compensation method were investigated. The characteristics for the applicability of profile planning algorithm and the requirements for time-optimality of the profile were firstly analyzed. Under the consideration of the profile as a whole, the preprocessing and algorithm with time-optimality for four-order profile planning were presented, based on the system dynamics constraints. Also, an approach of switching time roundness was proposed by reducing system dynamics constraints. This approach compensates effectively accuracy losses in the discrete time implementation. Experimental results show the effectiveness and reliability of proposed methods. Practically, these methods have been successfully applied in semiconductor manufacturing equipment.

Mathematical Model for Linear Symmetry Based on Tolerancing Principle

Mao Jian, Cao Yanlong, Yang Jiangxin, Xu Xusong

2007, 18(19):  2351-2354. 

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Small displacement torsor(SDT) was introduced in tolerance modeling. The constraint conditions of linear symmetry tolerance were developed systematically under IP(independence principle) and MMR(maximum material requirement). The corresponding mathematical models of linear symmetry of surface feature and central feature were deduced. By using this model, the semantics of tolerance was exactly represented and can be used by the following processing. An example was proposed to show the effectiveness of the tolerance model.

Dynamic Lapping Force Analysis of Spiral Bevel Gear Lapping System with Ultrasonic Excitation

Deng Xiaozhong, Yang Jianjun, Wei Bingyang, Fang Zongde

2007, 18(19):  2359-2361. 

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The rotational two-degree freedom dynamics model of gear-lapping system of a spiral bevel gear with single backlash was established by considering ultrasonic excitation and transmission error excitation. The formula of dynamic lapping force was established .By means of numerical simulation method, it is showed that ultrasonic excitation increases the dynamic lapping force between gear pairs. In the process of gear meshing，the phenomenon of tooth surface impact is appeared. When the ultrasonic excitation amplitude equals to 165Nm, gear-lapping system changes from periodic motion into chaotic state.

Study on Fractal Physical Meaning and Relation of Fractal Dimension and Glossiness of Granite Polished Surface

Wang Jianjun

2007, 18(19):  2362-2366. 

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Fractal and characteristics were studied on two typical different grain size kinds of granite polished surface. The relation between fractal dimension of polished surface and diamond grind grain size was analyzed. At the same time, the fractal dimension of primary component that made up of granite was analyzed too. The relation between glossiness and fractal dimension was studied. The physical meaning of granite polished surface has been put forward by studying mechanism of polishing granite surface.

Research on the Loading Characteristics of VC Roller

Li Weimin, Liu Zhubai

2007, 18(19):  2371-2374. 

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The shape control feature of VC (variable crown) roller system under the combined actions of control pressure and rolling load was analyzed. Based on the VC roller developed, the roll gap profile and the relationship among crown of roll gap, rolling load and the control pressure were studied, and the concept of critical maximum control rolling force was put forward. The research results indicate that the capacity of VC roller in controlling the strip shape is superior to the common solid rollers whose specifications are the same as those of the VC rollers if rolling load is lower than the critical maximum control rolling force. Under the conditions of lower rolling force and the higher control pressure, the state that the crown of loading roll gap is equal to or less than zero can be realized with VC rollers.

Research on Trimmed B-spline Surface Reconstruction

Tan Changbai, Zhou Laishui, Zhang Liyan, An Luling

2007, 18(19):  2366-2370. 

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An approach was proposed to reconstruct trimmed B-spline surface with irregular boundaries. A base plane was firstly rebuilt to parameterize the data points, and the over-determinant equations were derived taking the control points of B-spline surface as variables. A hole detection algorithm based on valid point identification was proposed to mark holes with no or less data points, and then the CNSP(control network shape preservation) constraints were selectively imposed on control points relevant to holes to guarantee the existence of equations’ least square solution. Finally, an error-controllable algorithm was utilized to reconstruct B-spline surface covering the data points, and then irregular boundaries of trimmed surface could be rebuilt via boundary curves extraction or surface intersection. The proposed approach accordant with design intent is characterized by good shape consistence around holes and high precision of resulted surfaces.

Fabrication of the Mold for PDMS Microfluidic Chip By Hot Embossing Technology

Ye Jiaming, Li Mingjia, Zhou Yongliang

2007, 18(19):  2379-2382. 

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A simple and rapid method for fabricating the mold for polydimethylsiloxane(PDMS)microfluidic chip was presented. Polymethylmethacrylate(PMMA) mould was performed quickly by hot embossing on glass substrate with groove structure fabricated by photolithography and wet etching, and PDMS microfluidic chips can be replicated from these PMMA moulds. The SEM and optical microscope images show the microstructure in the PMMA molds and PDMS chips has low relative standard deviation (RSD) values.

A New Strategy to Optimize Variable Blank Holder Forces towards Improving the Forming Limits of Aluminum Sheet Metal Forming

Wang Wurong, Chen Guannong, Lin Zhongqing

2007, 18(19):  2374-2378. 

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This paper proposed a new strategy to optimize the variable BHF. The optimization strategy was based on the analysis of BHF formability window and integrated into FEM code to obtain time or/and spatial optimal BHF that applied on binders. And then a stepped rectangular box of 60 mm drawing height with segmented binders was adopted to validate the optimization strategy. Firstly, constant BHF FEM simulations through careful experimental design were conducted to discover the drawing limit height under maximum constant BHF. Secondly, FEM simulation combining the new BHF optimization strategy was carried out and the optimal profile of variable BHF was determined for both step box and cylinder cup during the whole punch stroke. The result shows this stepped box can be formed successfully using 5754-0 aluminum alloy sheet, while the maximum drawing height under constant BHF is 45mm.

Review of Grinding Temperature Research for Engineering Ceramics

Guo Li, Li Bo, Sheng Xiaomin, Huang, Han

2007, 18(19):  2388-2393. 

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The state of the art of the grinding temperature for engineering ceramics was given,and some very important effects of grind temperature on grinding mechanism were given, and several grinding thermal theoretical calculation methods were described.Several models of grinding heat partition to workpiece were given, and several technologies and post treatments in grinding temperature measurement were discussed.The relations among grinding parameters and the grinding temperatures were also paid an attention to, and control methods of grinding heat ,such as use grinding fluid, were discussed. At last, the paper presented an outlook of the research of grinding temperature for engineering ceramics in high speed & efficiency grinding.

Research Situation and Trend of Mechanical Testing of Micro Structures

Chu Jinkui, Zhang Duanqin

2007, 18(19):  2383-2387. 

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This paper firstly presented the recent research situations in the micromechanics testing technique and the problems in characterization of mechanics properties. Then the techniques about actuators, micro displacement sensors, and micro force sensors were discussed and compared respectively as they were main parts in microscale mechanics testing.