Table of Content

25 January 2010, Volume 21 Issue 02

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Algorithm for 5-axis Numerical Control Flank Milling of Arbitrary Surfaces Fan Hongzhou;Xi Guang;Wang Shangjin

FAN Hong-Zhou, XI Guang, WANG Chang-Jin

2010, 21(02):  127-130. 

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For the milling of arbitrary surface impellers,

the segmentation method with flanking milling was proposed to improve the quality and efficiency.For rough milling,the arbitrary surface was replaced by just one fitted ruled surface,the flank milling was a good method to replace the point milling.For semi-finish milling, the primal surface was replaced by

several needed ruled surfaces,using step flank milling to gain the satisfaction in model’s nicety and machining efficiency.Model building,NC programming and machining of a real pump impeller were conducted to test the proposed method. 

Study on the Dynamic Modeling of a Complex Flexible Hydraulic Robot System Carried

by Vehicle

MA Zhen-Shu, MEI Chao

2010, 21(02):  131-136. 

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The CMS method was used in the elastic dynamics modeling of a vehicle flexible robot system.On the basis of dividing the whole system into nine substructures and establishing their dynamics models respectively,the whole dynamics equation of the system was derived according to the boundary constraints.The substructures were looked as several beams with different constraints.The method enjoys the advantages of simplicity and high efficiency, which is convenient to study the influences of the geometrical parameters on the low-order modes.The location of the hydraulic actuators were defined by the boundary coordinates,which would be convienience to get the control state equations.

Design of Displacement Loading for Aircraft Skin in NC Stretch Forming

HE De-Hua, LI Dong-Sheng, TUN Zhi-Min, LI Xiao-Jiang

2010, 21(02):  137-140. 

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To deal with the problem how to efficiently combine among

the process design,numerical simulation and NC stretch forming equipment in aircraft skin stretch forming,a displacement loading design method coupling sheet metal deformation with mechanism motion was proposed.First,the numerical model was established,based on VTL1000 NC stretch forming equipment.Then,the relation between sheet metal deformation and loading of mechanism motion was induced using geometrical analysis method.And the solution of the calculation equations of displacement loading was applied to numerical simulation as boundary conditions.Finally,a case study indicates this method has high precision and good engineering practicability.

Research on Technologies of Optimal Testability Concept for Materiel Systems

CHEN Xi-Xiang, QIU Jing, LIU Guan-Jun

2010, 21(02):  141-145. 

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According to actual requirements of testability concept in engineering applications,the connotation is expanded and perfected.Through building a generalized

information description model and describing the optimization process of testability concept from the view of whole system & whole life,the key technologies which are desiderated to breakthrough were further clarified.Then a research idea based on the model and

multi-objective tradeoffs was proposed,which will lay a foundation for constructing the testability concept applicable to total life cycle and different maintenance levels.

Design and Research of an Assembly Facility for Opticmechanical Module for Cleaness and Precision

LIU Xiao-Bei, XIE Zhi-Jiang, LIU Nan, LI Meng-Ai, ZHANG Lin

2010, 21(02):  146-150. 

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As the clean-precise installment of the down-load module was undertaked by the assembly facility filled with optical technology,mechanical technology,electrical technology and wireless communication technology,a design solution was put forward through the analysis of installment flow and function in a large-scale laser device on the basis of our equipment’s characteristics.The key parts such as the adjustment part and the alignment part based on patial six degree of freedom,and clean box were designed in order to resolve some key technical problems such as keeping module clean,installment precision,installment efficiency.After the prototype design, production, and debugging,the results state that the design solution is suitable for precise installment of modules and meets the installment demands,and can improve the installment efficiency and precision. 

Numerical Solution for Two-dimensional Steady-state Pressure Distribution on Spherical Port Plate of Axial Piston Machines

LI Xiao-Jin, YU Shi-Hua, HU Ji-Bin

2010, 21(02):  150-154. 

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Grid generation equations and Reynolds equation in spherical body-fitted coordinates were proposed and solved by using finite difference algorithm.An average approximation method was used to transform the implicit equation to the explicit equation during automatic grid generation,and the computation time is greatly reduced by contrast to that of the implicit equation.Pressure distribution on a spherical port plate of the hydraulic transformer is obtained and the computation results indicate that the pressure distribution between adjacent ports can not be neglected especially when the pressure of these ports has little difference.The pressure distribution on a plane port plate is obtained and the computation results are very closely to those of electrical analogy.

Reliability Optimization of Multi-state System in Presence of Common Cause Failures

LI Chun-Xiang, CHEN Xun, YI Xiao-Shan

2010, 21(02):  155-159. 

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An optimal model of multi-state system reliability in the presence of common cause failures was built and solved. The redundancy allocation problem was

 formulated with the objective of minimizing the cost in order to provide a desired level of

reliability.The components were chosen from a list of products available in the market,

which were characterized in terms of their nominal performance level,reliability and cost.

The universal generating function was adapted to analyze the reliability of multi-state system,and the optimal model was solved using genetic algorithm.The results of redundancy allocation problem considering common cause failures were compared with ones of traditional redundancy allocation problem.The results show that the reliability of components is more important than redundancy for the redundancy allocation problem of multi-state systems subjected to common cause failures.

Flow Analysis for Installing and Calibrating System of Laser Device Based on Extended Design Structure Matrix

LI Meng-Ai, XIE Zhi-Jiang, LI Dong-Yang, LIN Zheng, ZHANG Lin

2010, 21(02):  159-163. 

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Based on DSM method which can meet feedback and iterate,an extended DSM was proposed to carry out flow analysis for installing and calibration system. Extended DSM included square DSM and long DSM. To analyze the relationship between the same elements with the square DSM, and to describe the relationship between different elements with the long-matrix, a general sequence of flow analysis with extended DSM was established. Case study of film-box to flow analysis of installing and calibrating system with the method verifies the availability.

Decision-making of Quality Control for Mechanical Assembly Activities

WANG Bei, XIAO Jing-

2010, 21(02):  164-168,174. 

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A “synthesis assembly index” (SAI) based on the “assembly quality entropy” concept was put forward to solve the objective and exact prediction of

 influence for the assembly activities according to the integrated measurement of key

grades of assembly activity and potential quality loss for assembly activity in the phase of production preparation.The decision-making methods of quality control tactics based on

the SAI were presented after the algorithm of assembly quality entropy was brought forward that was important for the SAI calculation.Furthermore,a decision-making case for quality control tactics of an assembly process of a plunger injection pump was studied,and proves the SAI reasonable and the decision-making methods feasible.

Prognosis System for Roll Eccentricity with MFFT Based on the Difference Evolution Algorithm

WANG Zhe-Yang, WANG Ge, SUN Xin-Wei-

2010, 21(02):  169-174. 

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As for the problem of roll eccentricity signals analyzed by FFT,

a MFFT based on the difference evolution was proposed.The basic algorithm,realization process and pertinent programming step were established.The simulation results show that the MFFT method by difference evolution can effectively analyze first-harmonic and harmonic components of eccentricity force signals under conditions that sampling duration

 were unequal to the integral multiple of the signal fundamental periodicity.The validation results demonstrate that the eccentricity influence of 1st stand is more serious and that

of 5th mill is second in 5 stand tandem cold rolling mill,further more the effects of skid marks before hot rolling is the primary factor to cyclical force deviations.The prognosis method provides credible the verification on the qualitative analysis and on–line control and compensation of the roll eccentricity.

Point Cloud Registration Using Surface Three-pyramid Volume Measure 

ZHANG Mei, WEN Jing-Hua, ZHANG Jie-Xun, ZHANG Jian-Qing

2010, 21(02):  175-178,211. 

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An improved ICP(iterative closest points) algorithm was researched,

which was based on discrete corresponding characteristics and error estimation of mean volume of three pyramid shaped by point and corresponding triangle between two surfaces, and it was used to align multi-view laser point cloud. Namely the registration of laser point cloud was instructed by searching effective point and corresponding triangle pair between two point cloud area and taking the spatial three-pyramid volume shaped by these point and corresponding triangle as error measure; then the new spatial position translation relation was estimated by using the point and the centroid of corresponding triangle as corresponding point pairs. The experimental results indicate the align accuracy of the improved algorithm is higher and its speed is faster than that of traditional ICP registration algorithm.

Stability of Fluid-conveying Pipes Lying on Two-parameter Foundation

LIANG Feng, JIN Ji-Duo, YANG Xiao-Dong, WEN Bang-Chun

2010, 21(02):  179-183. 

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Static stability for constant inner flow and dynamic stability for pulsating inner flow of pinned-pinned pipes lying on two-parameter foundation were investigated.Applying a complex mode method,the critical flow velocity was calculated.For the case of pulsating inner flow, regions of principal parametric resonances for first two modes

were obtained using the averaging method.The contributions of the linear, sheer foundation rigidities and some pipe parameters on the critical velocity and parametric resonance

regions were discussed.The results demonstrate that variation of the two foundation rigidities can both influence the static and dynamic stabilities of the system,however the effect of the sheer rigidity is much greater than the linear rigidity and can not be neglected;the axial

tension force,mass ratio,viscoelastic coefficient and mean flow velocity have some

effects on the stabilities of the system.

Analysis and Topology Optimization of Deployable Mechanism Based on Pantograph

YANG Yi, DING Xi-Lun

2010, 21(02):  184-189. 

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The 5 DOF element stiffness was derived and applied to analyze one kind of cylindrical deployable structure.The SIMP method was introduced to the deployable structure optimization.Aimed to the two objective functions which were of compliance minimization and structure efficiency maximization,the topology optimization for the cylindrical deployable structure was calculated.The mass of optimized structure is lower and the efficiency is higher.At last,the dynamics of structure was discussed preliminarily herein.The

results are helpful for the lightweight design of deployable structure.

Adaptive Piecewise NURBS Curve Interpolator Algorithm for Entireness Process S-curve ACC/DEC Control 

BO Hai-Hong, YANG Wei, CHEN Lin, TAN Hua-Qing, SUN Gong-Chao

2010, 21(02):  190-195. 

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Adaptive Piecewise NURBS Curve Interpolator Algorithm for Entireness Process S-curve ACC/DEC Control 

An adaptive piecewise NURBS curve interpolation algorithm based on 7-segment S-curve ACC/DEC control along the entire curve was present to meet the requirements of the modern CNC high-speed and high-precision machining.The algorithm adaptively divided a NURBS curve into small segments according to the information of the

curve geometry, and calculated the value of the parameters of the curve segments.This algorithm adaptively adjusted the ACC/DEC time of the velocity curve,which was corresponding with the 17 kind of types of the S-curve ACC/DEC conditions.At a fixed interpolation cycle, compared the proposed algorithm with alone adaptive algorithm and 5-segment S-curve ACC/DEC control method, the simulation and analysis results show that the interpolation precision of the proposed algorithm is higher than that of the alone adaptive interpolation method, and is approximate to the 5- segment S-curve ACC/DEC control method under the limitations of acceleration and jerk and the maximum chord height error being less than 0.5μm. Furthermore, the average feed rate along the full curve of the proposed algorithm is increased by 21.7%,compared with that of the 5-segment S-curve ACC/DEC control method,and which can reach 594mm/s.

Optimization of Hydrogenation Process and Hydrogenation Concentration in Improving Titanium Alloy Machinability

WEI Wei-Hua, XU Jiu-Hua, FU Yu-Can, HOU Gong-Liang, LI Zhi-Jiang

2010, 21(02):  196-201. 

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The titanium alloy is a kind of typical difficult-to-cut material.Before machining,the titanium alloys were processed at 650℃,750℃ and 800℃ by thermohydrogen treatment technology respectively in order to improve the machinability.The measurement experiments about cutting force and cutting temperature were carried out in dry cutting.The results show that, when the hydrogenation process is identical, thermoelectromotive force coefficient increases with the increase of hydrogen concentration.When the Ti-6Al-4V alloy was hydrogenated at 650℃,750℃ and 800℃ respectively,the main cutting force falls 2%,0% and 8% respectively.Moreover,the cutting temperature firstly rapidly reduces,secondly flatly changes,thirdly rapidly increses with the increase of hydrogen concentration, and the cutting temperature reduces 50℃,76℃ and 80℃ respectively under the three hydrogenation temperature.The preferred hydrogenation process of Ti-6Al-4V is as follows,the process is concluded at 800℃ for 6 hours,then cooled in the furnace, and the optimum hydrogen concentration ranges from 0.21% to 0.37%.

Calculation of Complex Surface Profile Errors Based on Hybrid Particle Swarm Optimization Algorithm

LIAO Beng

2010, 21(02):  201-205. 

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This paper established a math model of complex surface

profile errors,proposed subdivision approach algorithm for calculating the minimum distance between point and NURBS surface,and established the method for calculating

complex surface profile errors based on particle swarm optimization algorithm and subdivision approach algorithm.This method can obtain precise results to calculate complex surface profile errors,can be realized easily using computer and applied to three coordinate measuring machines.

Adaptive Fuzzy Sliding-mode Control for PM Synchronous Motor

ZHANG Xi-Zheng, WANG Yao-Na, YUAN Xiao-Fang

2010, 21(02):  206-211. 

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An AFSMC(adaptive fuzzy sliding-mode control) controller for PMSM system with parameters variation and load disturbances was designed based on this fuzzy model.

The AFSMC scheme can drive the dynamics of PMSM into a designated sliding surface in finite time,and guarantee the property of asymptotical stability.

It is also shown that the information of upper bound of modeling errors as well as perturbations will not be required when using the AFSMC controller.The performance of the proposed controller was verified by experimental results on PMSM system.

Research on Improved DSM Algorithm for Coupling Task Order Programming

LI Xiao-Bei, DIAO Liang, HU Zheng-Rong

2010, 21(02):  212-217. 

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Taking an industrial manipulator design as an example to illustrate the method how to express the coupling information in DSM,an improved DSM

algorithm was demonstrated,then the manipulator design task order programming was

finished.After that,applying an rational formula to evaluate the compact level of the original DSM and programmed DSM,then it is demonstrated that:compact level reduces in considerable extent and programming makes the coupling task more controllable,clear process and clear coupling relationship,achieves the purpose of programming. 

Analyses and Validation of Stability in Low Radial Immersion Milling

LIANG Rui-Jun, XIE Wen-Hua, HUANG Xiang

2010, 21(02):  218-221. 

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The fitting conditions for the dynamics model and the stability prediction model in the intermittent machining were presented by simulation analysis. The effects of the radial depth and the added Lobe on the stability in low radial immersion milling were analyzed, and the underlying causes of these effect phenomena were also analyzed. The model prediction results were validated by using the time-domain signal and the frequency spectrum of cutting vibration acquired from the low immersion milling experiments and using the periodic bifurcation instability theories for the high-speed and intermittent cutting. Simulation and experimental results show that the milling stability increases with the decrease of immersion and that the speed ranges of stable milling manifold in the low radial immersion.

Study on Micro-forming Process of Zr-based Bulk Metallic Glass with Silicon Mold

WANG Dong, LIAO An-Lan, BO,JIE,BANG Beng, LIU Lin, SHI Tie-Lin

2010, 21(02):  222-225. 

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Micro-forming hot embossing process with silicon mold was studied, and superplastic micro-forming of Zr65Cu17.5Al10Ni7.5 bulk metallic glass micro-parts was analyzed. Mechanical grinding was put forward to accurately remove the flashes of bulk metallic glass micro-parts.The micro-parts with silicon mold were then dipped into potassium hydroxide solution at 80℃ to dissolve the mold and obtain the others.The process is utilizd and a good dimensional accuracy for an amorphous micro-spur gear with 0.1 module,20 teeth and 300 micrometers in thickness is obtained.It follows from the results that the technology is promising for manufacturing high-performance complex micro amorphous components especially for those with complex structure in the core.

Effect of Arc Ultrasonic on Welding Heat Transfer Process

HE Long-Biao, LI Lu-Meng, TUN Min-Sheng

2010, 21(02):  225-228. 

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As the acoustic characteristics of high frequency modulating arc,

the arc ultrasonic influences the heat transfer process of welding. Ultrasonic was absorbed by

fused metal due to its high viscosity.Thermocouple was used to measure the cooling curve of structure in overheating zone with and without the effect of arc ultrasonic.The results show that the mechanical effects of arc ultrasonic improve the heat transfer process,

increase the cooling velocity of overheated zone,which is benefit to gain refinement structure and fine performance of welding joints. 

Fatigue Life Research of Composite Flexbeam Based on VCCT

LU Guo-Fu, LIU Yong, ZHANG Cheng-Lin

2010, 21(02):  229-233. 

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The paper built a 2D finite element model of helicopter

 composite flexbeam,and calculated the flexbeam strain-stress field under combination load of centrifugal force and flapping moment.The calculated strains are identical with experimental values,which proves the finite element model is right.At the same time, for the delamination of flexbeam because of inner ply-drop,the paper introduced VCCT;for the effect of varied element length in the delamination tip and large rotation,the strain energy release rate calculation formulae were modified.Based on VCCT,the strain energy release rate was calculated during the simulation of the delamination.The maximum of the strain energy release rate was used to calculate fatigue life of flexbeam,and a good agreement is found between the predictions and the experimental values.

Research on Strategy and Simulation for Dynamic Coordinative Control of PHEV

YAN Yun-Bing, YA Fu-Wu, DU Chang-Qing

2010, 21(02):  234-239. 

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It is necessary for PHEV to distribute energy between engine and motor and to control state-switch during work.Aimed at keeping the total torque unchanging under state-switch,a dynamic control algorithm was put forward,which can be expressed as motor torque compensation for engine after torque pre-distribution,engine speed regulation and dynamic engine torque estimation.

Taking MATLAB as the platform,a vehicle control simulation model was built, based on which the fundamental control algorithm was verified by simulation testing with fixed state-switch conditions and consecutive state-switch conditions.The results demonstrate that the dynamic control algorithm can effectively dampen torque fluctuations and ensure power transfer smoothly under various state-switches.

Study on Tire Pressure Monitoring and Alarming System of Automobile Based on the Comparison among Standard Pulse Numbers

HAN Zong-Ai, LIU Quan-Wei, WANG Li-Jiang, ZHANG Zhong-Xiao, JU Hua-Kun

2010, 21(02):  240-244,251. 

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The pulse numbers from wheel speed sensors of vehicle’s ABS have close relationship with tire pressure of the wheels.Recording and analyzing the pulse numbers in a certain distance,the tire pressure can be inspected indirectly.On the basis of test data on road about tire pressure,the authors of this paper brought forward firstly

the concepts about original numbers and standard numbers from wheel speed sensors.

And the authors gave a kind of new method to inspect the tire pressure indirectly in taking use of the standard numbers.The new method consisted of: how to demarcate different wheels and to correct the original pulse numbers,how to compare the standard pulse numbers of 4 wheels,how to calculate the limited relative errors,and how to judge a tire’s pressure abnormal using the small sample statistic method,and so on.Many real vehicle tests on road to trial-products were made using the method.And the test results prove

that the trial-samples work well and have favorable effect.This paper has important references to people who wants to develop the tire pressure monitoring and alarming system to take use of the pulses from ABS’s wheel speed sensors. 

Research on the Hardware-in-the-loop Test System for Heavy Vehicle with AMT

DENG Chao, SUN Dong-Shu, QIN Da-Tong, LIU Zhen-Jun, HU Jian-Jun

2010, 21(02):  245-251. 

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Taking heavy vehicle with AMT prototype development as application background,a HILS test system for heavy vehicle with AMT was developed, based on MATLAB/Simulink/Stateflow/RTW and dSPACE hardware and software system. By using the HILS system, the integrated two-parameter shift schedule was tested in real-time

and proved, and then AMT sample vehicle road test of starting on level road,starting on ramp and continuously upshifting and downshifting were carried out. The results show that the HILS test system can verify AMT shift schedule quickly and effectively,appraise overall performance correctly,and also provides a good system test and simulation platform for the development of control unit for heavy vehicle.