Table of Content

25 July 2013, Volume 24 Issue 14

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Rock Breakage Mechanism Analysis for Cutter Head of TBM Based on Digital Mockup

CHENG Jun, GONG E-Dong, LI Wei, LIU Ru-Meng

2013, 24(14):  1847-1853. 

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The rock-broken mechanism during the operation of the cutter head of TBM was analyzed to study the layout of cutters.A model of the cutters under the action of forces during TBM's working was therefore developed, thus a scheme was proposed to improve the rock breakability of TBM's cutter head on which the cutters were laid out.Then,a nonlinear multi-objective mathematical model with complex constraints was developed,and an optimization program was provided via an intelligent algorithm for the layout design of cutters on the tunnel shield/cutter head of a TBM.Focus on EPB 6.28m fullface TBM,a rock breakage finite element mode was founded. Single disc cutter rock breakage simulation and adjacent disc cutter rock breakage simulation were calculated with setting of real working conditions.Penetration rate, granite stress distribution results under different normal forces and optimal cutter distances were obtained,providing significant results for disc cutter and cutter head's parameter design and layout optimization.

Type Synthesis and Kinematics of a Novel High Frequency Compliant Parallel Vibration Actuators

YANG Qi-Zhi, CAO Dian-Feng, MA Lv-Zhong, CHEN,LONG,SHU Xiao-Bing, PENG Jia-Ai

2013, 24(14):  1854-1858. 

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The performances of a parallel mechanism are the basic of  a high frequency compliant parallel vibration actuator.Based on the screw theory,
a novel 3-PPRR parallel mechanism with 3 translational displacements was designed,
which was used in a compliant parallel vibration actuator.Then the degree of freedom
and actuating pairs and kinematics of the novel mechanism were analyzed.The models of the mechanism were established by MATLAB and Pro/E software.The  degree  of  freedom
and kinematics were analyzed by MATLAB software and simulated by ADAMS software.

Research and Verification of  Bending Effect for a Cantilever Piezoelectric Beam

GAO Chang-Yin-1, TUN Xiao-Ling-2

2013, 24(14):  1858-1861. 

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By means of anisotropic elasticity and Maxwell electromagnetic theory,the bending stress and polarization charge density were calculated.The distribution of the electric field in the piezoelectric beam was simulated by the finite element
method.Based on the theoretical analysis of the
 bound charge distribution,using the partitioned electrode method the measuring
electrodes were disposed effectively on the surfaces of the piezoelectric quartz beam.
A specially designed experiment was performed to validate that the polarization charge is
linear with the external force,and the experimental results are agreement with the
theoretical ones.Undoubtedly,the research will provide the theoretical and experimental
foundation for designing a new type of quartz resonator or actuator.

#br# Comparison and Analysis for Measurement and Determination Methods of NC Lathe Position Accuracy

WANG Qing-1, 2, LIU Hong-Zhao-1

2013, 24(14):  1862-1868. 

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In order to get the best measurement and evaluation methods of NC lathe, firstly, this paper introduced tools and methods in the measurement of position accuracy for NC lathe and analyzed several measuring methods. The commonly used at home and abroad four evaluation standards were detailed. Secondly, the position error values for NC lathe were measured by using laser interferometer.Finally, specific indicators of position accuracy——position accuracy, repeatable positioning accuracy, reverse difference，systematic deviation were calculated by using the four evaluation standard. The calculation results were analyzed and compared. This study clarifies various concrete situations when the four methods were applied to guide position accuracy measurement of production，checking for NC lathes.

Mechanical Stiffness Identification for Feed System of  CNC Machine Tools under Closed-loop Conditions

CHEN Guang-Qing, LI Hao-Lin, LIN Xian-Kun

2013, 24(14):  1868-1872. 

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As mechanical stiffness is an important parameter and has a great influence on dynamic performance of high-speed & high-precision machine tools. This paper proposed a novel method that servo mechanical stiffness can be identified under closed-loop conditions for machine tools in which popular commercial computer numerical control (CNC) system was employed. Based on 2 order control system for feeding mechanical system of worktable,an identification model for mechanical stiffness was obtained, and continuous and effective stimulation was achieved by inputting programmed displacement commands which were described as a multi-segment quadratic curve to CNC system. To verify validity of the proposed method, the simulations and experiments were performed, results show that the method is convenient, effective and suitable for commercial CNC system even closed-architecture system under industrial conditions.

Study on Non-contact Mechanical Vibration Sensor with FBG

WEI Chi, ZHOU Jie-De, HUANG Dun, HE Yu-Miao

2013, 24(14):  1873-1876. 

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This paper presented a novel non-contact radial vibration displacement measurement method based on FBG sensing technology.The structure of FBG vibration sensor was designed and theoretical analysis and numerical simulation were carried out using finite element software ANSYS.The static displacement
calibration and dynamic test on the experimental device indentified the linear range of the sensor.The results indicate that the sensitivity of the sensor is as 1.14μm  within the linear range,the linearity reaches 0.996 and  the measurement method proposed herein can be applied to mechanical system structure damage and the distributed dynamic running state monitoring.

Manufacturing Method for Fixed Curvic Coupling

HUANG De-Gong-1, WANG Zhi-Yong-2, CENG,TAO 3

2013, 24(14):  1877-1880,1885. 

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In order to manufacture the curvic coupling on a homemade CNC spiral bevel gear cutting or grinding machine, the manufacturing method for fixed curvic coupling was investigated. The cutting principle and cutting method of fixed curvic coupling was analyzed. According to the calculation cards of fixed curvic coupling, the method for determining cutter radius, blade point width, pressure angle of cutter blade and cutter profile radius were put forward. Based on the cutting principle and the configuration of CNC spiral bevel gear grinding machine, a method for determining the machine setting parameters was built and the calculation formulae was provided. Software for calculating the geometrical parameters and machine setting parameters for fixed curvic coupling was developed. According to calculation results of the software, a fixed curvic coupling was machined on H350G CNC spiral bevel gear grinding machine. The method for calculating the machine setting parameters was validated by the inspection of practical contact pattern and geometrical parameters.

Research on Loading Characteristics of  Spatial Linkage Weft Insertion Mechanism in Rapier Loom

ZHOU Xiang-Qin, ZHANG Lei

2013, 24(14):  1881-1885. 

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In order to study changes of main shaft loading that comes from spatial linkage weft insertion mechanism in rapier loom,using the function of mechanism analysis in Pro/E software,aiming at
the different spatial linkage weft insertion mechanisms,taking main shaft as a equivalent component,some projects were analyzed,such as the distributions and changes of equivalent moment of inertia from each component in weft insertion mechanism on main shaft,the equivalent
loading on main shaft that comes from weft insertion mechanism etc.The results indicate
 that the proportion of equivalent moment of inertia from
gripper,rapier,rapier wheel and its driving shaft to whole weft insertion is much
high,and it is increased as the loom widening;
equivalent loading of  the weft insertion comes from its inertia load mainly.It is trending to
reduce the quality and moment of inertia that comes from the gripper,
rapier,rapier wheel and its driving shaft as development of high speed rapier loom.

Effect of C/SiC Composites Material Structure on Grinding Forces and Machined Surface Quality

DING Kai, FU Yu-Can, SU Hong-Hua, XU Jiu-Hua, GONG Xiao-Bei

2013, 24(14):  1886-1890. 

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Surface grinding test was conducted on C/SiC and SiC materials with resin bond diamond wheel.The grinding forces and ground surface quality of C/SiC composites and SiC ceramic
were analyzed comparatively and the relations between material structure and grinding performance were studied.The results show that both carbon fibers and SiC matrix are removed by mechanism of brittle fracture.Compared with the ground surface roughness of SiC ceramic(Ra=0.2~0.3μm)，
the worse surface roughness of C/SiC composites(Ra=0.8~1.0μm) results from  the laminated fracture mechanism,pull-out of carbon fiber and nonsynchronous material removing of carbon fiber and SiC matrix.Additionally,the grinding forces of C/SiC composites are as 35%~76% of SiC ceramic's with the same parameters.

Reliability Evaluation of  Products with Life Following Weibull Distribution under Type I Censoring  Test  Plan with Small Sample Size

CONG Wei-1, CHEN Xiao-Yang-1, WANG Zhi-Jian-1, GU Jia-Ming-2

2013, 24(14):  1891-1896. 

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For reliability evaluation of the life following Weibull distribution under Type I censoring test plan with small sample size,it is discovered on the basis of Monte Carlo simulations that the ratio of the median of the shape parameter moment  estimation and the true value of the shape parameter depends only on the sample size and the failure number while neither on the shape parameter nor the scale parameter,
under the assumption that the failure number is in accordance with the arbitrary time in
 the corresponding time interval.Based on this,a median unbiased moment
estimation method was proposed,and the values of the bias correcting factor for the sample sizes
of 2~12 were provided.Further,the proposed method was compared with moment
estimation method through numerical analysis,and the results show that the former
performs significantly better than the latter,taking median bias and RMSE
(root mean square error) as evaluation criteria.Finally,practicality,validity and superiority of the proposed method were verified by conducting two tests.

Study on Angular Stiffness of a Laminated Membrane Coupling

SHEN Tu-Liu-Fang-1, SUN Cheng-Long-2, GONG Zun-Guo-2

2013, 24(14):  1897-1901. 

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In order to explore the compensation capacity of angular misalignment for a system process of installation or operation, a new method for calculating the angular stiffness was developed according to the deformation principle of the flexible components. The calculation formulas for the angular stiffness of the laminated membrane coupling with joint bearing and the laminated membrane coupling without joint bearing were built based on the positions of the maximum deformation and the minimum deformation respectively, and the reasons why they were difference were analyzed. The numerical example concludes that the calculation formulas are validity and practicability. The results show that the compensation capacity of the laminated membrane coupling with joint bearing is greater than the laminated membrane coupling without joint bearing.

Research on Method of Two-dimensional Straightness Measurement for Long Axle

TU Xiao-Fen, WANG Feng, FEI Li-Meng, MENG Fan-Liang, LIU Yuan-Yuan

2013, 24(14):  1901-1905. 

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According to the characteristics of the long axle with large size as well as the mutual compensation mechanism of two-dimensional measuring head, a new method of two-dimensional straightness measurement was proposed based on time-domain three-point method.The straightness of long axle's horizontal and vertical axis
 were measured by two-dimensional measuring head,thus the translation errors
of guide rail were dispelled,and the errors caused by the diverge between
 the long axle's generatrix and the measuring head's motion trail which caused by slide carriage's deflection will be mutually compensated.The effectiveness of
this straightness measurement method was proofed by simulations and experiments.

Research on Test System for Whirlwind Tool Holder Performance

JI Hong-Yu, YANG Jin-Song

2013, 24(14):  1906-1909. 

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Fission hinged whirlwind tool holder is the key equipment of
heavy-duty NC crankshaft milling and turning combined machining center.The vibration performance of the work piece in the
cutting process and the precision of U-axis cutting feed were its key technical indicators.The objective of this paper was to finish the test of them by constructing a performance test system.The work piece's vibration performance was tested with Advantech USB-4711a data acquisition and
 KISTLER micro-accelerometer.The U-axis cutting feed precision was tested with
PIC16F877A mcu and HEIDENHAIN grating length-gauge.The test system software was developed using VC 6.0,and was responsible for controlling the data acquisition,receiving data and doing completing data processing.Finally,the testing experiments and data processing show the test scheme and the
test system validity and feasibility.

A Study of Key Technologies of Building Parametrization Part/Component Library Based on Automatic Assembly Technology

YANG Xian-Gang, HE Yu-Lin, JIN Xin, LI Cheng-Wu

2013, 24(14):  1910-1915,1987. 

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On the basis of describing features,tabular layout of article characteristic,design with feature and
parametrization design,the paper proposed an idea of how to parameterize
components on general CAD systems.The technologies of building parametrization
parts library were put up,which was based on ‘fx' tool of
inventor.In the case of the part named by key,the feasibility was verified.The methodology of representing the assembly relation of the
components  and building parametrization component library were put up,which
was based on automatic assembly technology.A  related prototype  system was developed.The case of the methodology demonstrates the feasibility of the methodology.

Train Scheduling Problem Model and Its Solution Based on Hybrid Particle Swarm Optimization Algorithm

ZHANG Ji-Liang-1, 2, CHEN Yong-Sheng-1

2013, 24(14):  1916-1922. 

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A model of hybrid flow shop problem with blocking for describing the solution space was built for the train scheduling problem on double-track line, and a hybrid particle swarm optimization (HPSO) algorithm was proposed to solve it. With the objective of minimizing makespan, release-backstepping (RB) algorithm was put forward to sequence the running trains and calculate the minimizing makespan, while an improved particle swarm optimization algorithm was employed to solve track assignment problem and implement global optimization. Besides, an iterative neighborhood search algorithm was introduced to improve the local search ability of the particle swarm optimization algorithm.The experimental results show that the train scheduling problem on double-track lines can be solved effectively with the proposed method.

A Finite Element Analysis of Blade-wheel's Strength on Torque Converters Based on Steady Operating Conditions

LIU Shu-Cheng-1, YAN Qing-Dong-1, WEI Wei-1, ZHOU Yi-2, XIANG Xue-Feng-2

2013, 24(14):  1922-1926. 

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In order to solve the blade-wheel's strength problem  under actual work conditions of a  hydrodynamic torque converters used on vehicles,a finite element model of blade-wheel's strength was established.
Considering the torque converter's work conditions,a match calculation between the torque converter and the engine was finished firstly,through which the steady working point in actual applications was obtained.A finite element analysis was executed after fluid load and centrifugal load were applied on the blade-wheel,by which the relationship among blade-wheel's stress distribution,deformation and work conditions was got.During the analysis the blade-wheel was regarded as a cyclic symmetric structure,
so the cyclic boundary connection was defined by a data constraint equation.With the help of the constraint equation,the whole blade-wheel's strength analysis was able to complete on a single basic cyclic sector.It is suggested by the result of this study that this research method is effective in the blade-wheel's strength analysis.

Compound Method of Rotor Speed Self-sensing for a Bearingless Permanent Magnet Synchronous Motor

HU Bei, SHU Huang-Qiu, JI Wei

2013, 24(14):  1927-1932. 

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Because one method cannot obtain precise estimation of rotor speed and position in full speed, a compound method using high frequency signal injection and SMFEKF was proposed to estimate the rotor speed and position for a BPMSM herein. When the motor worked at state of zero and ultra-low speed, high frequency signal injection was used, which was based on motor space-saliency effect; at the high speed of the drive, SMFEKF was used. SMFEKF has strong robustness of the model mismatch and unique strong tracking ability, which can improve the tracking performance effectively to steady-state and mutation status. By designing speed switch, smooth switching was achieved. The sensorless vector control system of BPMSM was set up based on this estimation approach. Simulation study demonstrates that the proposed method is capable of precisely estimating rotor speed and position in full speed, high robustness is achieved under the conditions of step response or load disturbance.

 

Modeling and Simulation Analysis for a L-shaped Wideband Piezoelectric Cantilever Beam

WANG Guang-Qiang, BAO Feng, LIU Ti-Meng

2013, 24(14):  1933-1938. 

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In order to improve the transfer efficiency of the traditional single-frequency piezoelectric cantilever beam used in the energy harvesting technologies (EHT),an L-shaped piezoelectric cantilever beam, which was composed by a horizontal beam and a vertical beam, was proposed to wideband the frequency performance. The frequency-band was expanded by optimizing the structure and material parameters to reduce the distance between the 1st modal frequency and the 2nd modal frequency. The frequency equation and the vibration equation were derived according to Lagrange function and modal assumed method. The effects of the structure and material parameters on the frequency characteristics and the vibration characteristics were studied by numerical simulations.

Chip Formation in High Speed Milling of Hardened Mold Steel

LONG Dun-Zhong-1, 2, XIN Zhi-Jie-1, CHEN Xin-Quan-1, MIAO Hong-Bin-1

2013, 24(14):  1939-1942,1950. 

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Using solid carbide straight end mills with TiAlN coating, P20 steel was machined in the cutting speed range of 200 to 942m/min. The chip formations at various speeds were investigated. The saw-tooth chips with adiabatic shear bands are observed at 754 to 942m/min with P20 steel of 41HRC, but for P20 steel of 32HRC, they are formed at 848 to 942m/min. Cutting speed and workpiece hardness are found to have significant influences on chip formation. Based on micro-measurement of the chips, a calculation model for saw-tooth chip formation during high speed end milling of hardened steel was proposed. The results show that the average shear strain and shear strain rate are within the shear bands, and the saw-tooth frequency increases rapidly by increasing cutting speed, and their maximums at 942m/min exceed 23, 107s－1 and 244kHz respectively.

Optimization Method of Technological Parameters of Softness Abrasive Flow Precision Machining

JI Shi-Ming, ZHOU Long-Bing, TAN Da-Feng

2013, 24(14):  1943-1950. 

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With the abrasive flow temperature increasing, the viscosity of fluid will decrease in a solid-liquid two phase softness abrasive flow precision machining, leading to the uneven distribution of the turbulent kinetic energy and the dynamic pressure. For this problem, the paper put forward a new machining method, through changing the flow velocity to compensate the influences of the temperature changing on turbulent kinetic energy and dynamic pressure. Based on studying the machining mechanism, the paper considered the turbulent kinetic energy and the dynamic pressure affected the machining texture and material removal rate of the machining surface respectively, then it confirmed a standard of appraising turbulent flow form. Contrasting the size distribution of turbulent kinetic energy and dynamic pressure in the same speed and different temperatures, the influences of temperature on turbulent kinetic energy and dynamic pressure were studied. Contrasting the size distribution of turbulent kinetic energy and dynamic pressure in the same temperature and different speeds, the influences of the speed on turbulent kinetic energy and dynamic pressure were also studied. Through a large number of simulations, it gives the optimal temperature from the nine different temperatures and t-v curve, it offers the reference for the design of turbulent regulation and automatic control system. The experimental results indicate the machining homogeneous degree of workpiece surface has obvious promotion after speed regulation.

Mechanical Properties of Cross-connected Microchannel Porous Mesh Plate(CCMPMP)

LI Da-Lei-1, HE Tie-Shu-1, SHANG Yong-2

2013, 24(14):  1951-1956. 

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In order to increase the mechaniacal strength of CCMPMP,mechanical properties of CCMPMP,such as tensile,compressive and bending properties,were investigated theoretically,and  the corresponding mechanical models were established.The stress of CCMPMP under the load of  tension,compression or bending was simulated respectively.Results show the largest stress of CCMPMP is larger than that of metal plate with the same dimension under the same load of tension, compression or bending, so the mechaniacal strength of CCMPMP is smaller than that of metal plate with the same dimension. And the mechaniacal strength of CCMPMP decreases with the increase of microchannel width and depth.No stress concentration occurs if CCMPMP sustains only forces,small stress concentration occurs if CCMPMP sustains only moments,and large stress concentration occurs if CCMPMP sustains forces and moments simultaneously.In addtion,stress concentration occurs easily when the microchannel width is small.

Analysis and Compensation of Positioning Errors of Workpiece in Thread Measurement

CHEN Cheng-1, DIAO Dong-Biao-1, LIU Yong-Hua-1, LIU,KAI 1, ZHANG Yong-Nian-2

2013, 24(14):  1956-1960. 

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The  positioning errors of workpiece on thread measuring instrument were investigated and analyzed by the homogeneous coordinate transformation method. A precise mathematical model of workpiece was established including the geometry of the probe. The measuring curve was fitted using least square fitting method. The model errors caused by simple fitting line were decreased. According to the features of mathematical model and the range of the parameters, an improved simplex-simulated annealing algorithm was applied to calculate the model errors. Validation experiments and measurement were made based on the thread measuring instrument which was developed independently. The measuring results demonstrate the mathematical model is suitable for the real situation which can reduce the fixing error effectively.

Car Headlight Shape Design Based on Cubic Q-Bézier Curves

GUO Lei-1, 2, JI Xiao-Min-1, HU Gang-1, CHU Jian-Jie-3

2013, 24(14):  1961-1964,1969. 

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A method for car headlight shape design based on cubic quasi-Bézier(cubic Q-Bézier) curves was proposed herein, which described the car headlight shape contours with one single cubic Q-Bézier curves. Firstly, a cubic Q-Bézier curve with contral points was created and adjusted in a plane; then the curve was projected  on the car's surface; finally, the car surface was trimmed and formed the final shape contours of the car headlight. This method, based on the principle of the cubic Q-Bézier curve generation and splicing, can modify the curve quickly by global or partial adjustment and obtain many design solutions.

Infuluence of Micropores and Crack's Hydrogen Induced Stress Coupling Effect on Crack Growth in Heavy Forging

DU Feng-Shan-1, 2, FAN Dun-Jie-1, HUANG Hua-Gui-1, LI Jie-1, LI Yuan-1

2013, 24(14):  1965-1969. 

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Based on hydrogen pressure theory in heavy forging,the mechanical criteria for crack coupling with other micropores was established from the fracture mechanics,and the impact of micropores' coupling effect on crack's fracture parameters under different conditions was analyzed by finite element method.The results indicate  that the  influence of micropore's hydrogen stress field on the crack's propagation is very obvious,and the effect and intensity of impact are connected with the size and position of micropores.In addition,the void-microspores have the greatest effect on crack propagation under the same micropore size.The analysis conclusion provides the foundation for the study of crack propagation in heavy forging.

Application of Elastic Deformation Machining Method to Generate Aspheric Surface Glass

LV Bing-Hai-1, RUAN De-Na-2, YUAN Ju-Long-1, TUN Zhe-2, DIAO Ping-1

2013, 24(14):  1970-1974. 

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Traditional aspherical surface machining technologies have disadvantages such as high dependency of
precision machining equipment and low efficiency in batch production. An elastic deformation machining method for thin aspherical components was studied herein,which can transfer the aspherical machining to planar machining.By theoretical calculation and ABAQUS finite element simulation,the elastical deformation profile of circular glass plate was determined when the plate was simply supported and bearing a uniform pressure,and the experiments  were  carried out.The RMS(root mean square) value and PV
(peak valley) value of the form error between machined surface and target profile is
as 1.66μm and 2.8μm respectively,which verify the validation of elastic deformation method for the machining of thin aspherical components.

Research on Compilation of Automotive Swing Arm Program Spectrum

CHEN Yong-Feng-1, 3, ZHENG Song-Lin-1, WANG Chi-Rui-1, MA Za-Gen-2, HU Wen-Wei-2

2013, 24(14):  1974-1978. 

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The load spectrum of target points was analyzed statistically through collection of road load spectrum of a car swing arm,a compilation method of program spectrum was proposed,which contained strengthening effect load by considering the structure of the characteristics of strengthening under low amplitude load and traditional load spectrum method.The method deleted a large number of invalid loads based on
 the characteristics of strengthening under low amplitude load, while retaining the load with strengthening effect.After the strengthening equivalent principle among different
 strengthening loads was researched,the strengthening load was converted  to the best strengthening load levels, the method reduces the test frequency,simulates the situation of automotive parts under actual load conditions more quickly and realistically and the test acceleration effect  is obvious.

Research on Adaptive CUSUM Control Chart of Body Quality Control Based on Variance Monitoring

LI Jing, LIU Jian, LI Rong

2013, 24(14):  1979-1983. 

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Considering the high workload and extremely simple data processing in body welding quality inspection,
an adaptive CUSUM control chart for variance monitoring was proposed herein for body welding quality control,whose principle was adaptively updated the reference values to monitor small variances infinitely in the process of body welding. Evaluation instance results show that, compared with traditional CUSUM control chart and exponential weighted moving average(EWMA) control charts, the adaptive CUSUM
control chart  based on variance monitoring is more sensitive to the small abnormal variation fluctuation.

Study on SHEV Generator Group Control Strategy Based on Fuzzy Theory

LIN Ju-An-1, GU Jie-1, TU Xiang-Dong-2

2013, 24(14):  1983-1987. 

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The fuel economy of SHEV was determined by the work state of
generator group.In order to enable SHEV to have good fuel economy when generator group working,a
fuzzy control strategy was proposed to control operating points of the generator
group herein.And a simulation model was built for this control system.Finally,the control strategy was transplanted into vehicle control
unit for a real vehicle testing.The simulation and test results show that,this control strategy can control
operating points of generator group to switch between some limited operating points which are very efficient following the vehicle demand power.This control strategy enables SHEV to have good fuel economy,so the control purpose is achieved.