Table of Content

10 February 2012, Volume 23 Issue 3

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Tooth Profile Design and Manufacture of Higher-order Elliptical Bevel Gears

LIN Chao-1, GONG Hai-1, HOU Yu-Jie-1, 2, NIE Ling-1

2012, 23(3):  253-258. 

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Based on the space engagement theory, the space position of cutter was analyzed when the tooth profile of a higher-order elliptical bevel gear was generated, a mathematical model of higher-order elliptical bevel gear's tooth profile was established; and then tooth surface equation of higher-order elliptical bevel gear was derived, pseudo-entity and assembly model of higher-order elliptical bevel gear were also acquired. Manufacturing methods by five-axis CNC of higher-order elliptical bevel gear were discussed, by the processing and mesh experimental research of a higher-order elliptical bevel gear pair, comparisons between experimental results and theoretical analysis was made to verify the mathematical model of higher-order elliptical bevel gear's tooth profile, and the feasibility of processing methods shows the processing methods can be used in the actual machining.

Analyses for Performance Indices of a Four-DOF Parallel Manipulator

JI Ye, LIU Hong-Zhao, YUAN Da-Ning, WANG Geng-Xiang

2012, 23(3):  258-263. 

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A spatial 4-DOF parallel manipulator was deduced in the event that the topology of parallel manipulator was changed. Based on the equation of position, the mapping analytic equation of velocity and acceleration was built by theoretical derivation, and simultaneously the first and second order influence coefficient matrixes were solved. Performance indexes of kinematics and dynamics were multianalyzed, and the factors that output perturbation affects the sensitivity of inputs perturbation were received. Taking different units into account, a matrix of Jacobian was detached, and then performance indexes of velocity, force, angular velocity and moment were analyzed in task workspace of the motion platform. A method of stratifiedly researching the matrix of Hessian was proposed in order to calculate perturbation of each limp differing in the degree in acceleration and inertial force performance indexes in task workspace of motion platform. The results provide theoretic proof for designing and optimizing the mechanism and choice of control strategy.

Study on One-class Classification with Multi Hyper-spheres Based on Maximal Tree Clustering and Its Applications

LIU Li-Juan, CHEN Guan

2012, 23(3):  264-269. 

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An one-class Classification with multi hyper-spheres based on maximal tree clustering algorithm was presented herein. The training samples were firstly clustered into several sub-classes by the maximal tree clustering algorithm, and then, the sub-classes data were trained separately using one-class SVM(OC-SVM) and the multi hyper-spheres classifying models were established. The new method was applied to the instances of the simulation data set, UCI data sets and the rotor faults diagnosis, and the results show the effectiveness of the new method.

Analysis and Comparison of Grinding Forces between Plunge Grinding and Traverse Grinding

LI Sha, LI Hao-Lin

2012, 23(3):  269-273. 

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Complex cylindrical grinding processes including both plunge grinding and traverse grinding were investigated. According to the traverse grinding characteristics, the grinding wheel was equivalent to a number of small wheels,a parabolic model for wheel wear was built based on the traditional steps model. The comparision formula of tangential grinding force was derived based on two tangential grinding forces of plunge grinding and traverse grinding the ratio of the tangential grinding force reflected tangential grinding varieties from the plunge grinding to the traverse grinding and was concerned with grinding coefficient, the wheel width and the traverse feed rate. The tangential grinding force was analyzed by the grinding wheel spindle power signals in experiments and the parabolic model is more realistic.Using force signals and power signals to monitor the complex grinding processes provides a reference method.

Development of an Experimental Platform for Linear Motors in CNC Machine Tools

HONG Mu-Lan-1, 2, ZHANG Chong-Wei-1, LIN Jian-2, BO Chao-3

2012, 23(3):  274-278. 

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On the basis of the dynamic characteristics analysis of linear servo systems,the advanced control strategies were put forward to restrain disturbance,improve static and dynamic performance,and achieve strong robustness. An integrated experimental platform for linear motor drive unit of CNC servo system was developed,including the corresponding debugging software. Finally,some notable technical problems were also cited in the use of linear motor in CNC machine tools.

An Experimental System of Constant Volume Combustion Bomb for Dual-fuel of Diesel/Methanol

TAO Chun-De-1, DAI Gan-1, 2, HU Han-Jun-1, YANG An-Feng-1

2012, 23(3):  278-281. 

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An experimental system of constant volume combustion bomb was designed and developed, which was carried out for the fundamental research of combustion characteristics of diesel in premixed air/methanol mixtures atmosphere. The distribution, function and characteristics of the sub-system of the experimental equipment were introduced. The experimental results show that the existence of methanol in the mixture can suppress ignition of diesel fuel. As the increase of the methanol concentration in the mixture, the flame of the combustion becomes dim and consequently the formation of soot are inhibited. Comparing with the combustion of diesel in the pure air atmosphere the ignition delay of diesel fuel is postponed and the lift-off length of diesel fuel flame is extended and the variation of lift-off length is strengthened in the premixed methanol ambient.

Permanent Calibration Method Based on B-spline in High Ratio Balancing Machine

DIAO Ding-Ding, CA Ping

2012, 23(3):  282-286. 

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An improved calibration method based on bicubic B spline interpolation was introduced, which can reduce errors as a result of ignoring rotor's inertia and system's damping and can achieve a permanent calibration both on hard bearing and soft bearing frame. Finally an experiment was setup to get calibration results and measurement results at several rotating speeds between 180~1423r/min on different rotors. After comparing measurement results from direct calibration results and interpolation calibration results, the effectiveness and veracity were proved.

System Design and Experimental Analysis for Hydraulic Power Unit with Permanent Magnet Synchronous Motor Drive

GU Yong-Feng-1, 2, GU Li-Chen-1

2012, 23(3):  286-290. 

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For the traditional hydraulic power system driven by the asynchronous motor(ASM) has some defects in practical applications such as low efficiency, slow response and instability at low-speed, this paper researched a new energy-saving hydraulic power system based on the permanent magnet synchronous motor(PMSM) which had good performance in energy-saving and speed regulation and the gear pump which had good performance in reliability.And an experimental system was designed under the guidance of energy-saving and frequency control theory. The experimental results prove the feasibility of such a power source, show some unique system performance and technical advantages,and show that the hydraulic power driven by the PMSM is better than the hydraulic power driven by the ASM in power matching of the load, response time and speed regulation precision,especially in the energy-saving of the low-speed and light load.

A Multi-objective Optimization Method for Forging Machine Based on Genetic Algorithm

SHEN Yuan, JIN Yi, CHU Biao, JIA Nian-Wu, DU Chang-An

2012, 23(3):  291-294. 

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This paper proposed a genetic algorithm-based design and optimization method for forging machines,and based on this method developed an integrated platform whose core was a multi-objective optimization system.It can direct the design,expedite the optimization and improve the optimization result by calculating the precise analysis results of 3D models and carrying through multi-objective optimization based on genetic algorithm.Finally,the reliability and validity of the platform was validated by optimizing a forging machine.

Fault Diagnosis Study of Ball Bearing Based on Wavelet Packet Transform

WANG Dong-Yun-1, 2, ZHANG Wen-Zhi-1

2012, 23(3):  295-298. 

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For the modulation and energy concentration feature of fault ball bearing vibration signals, a fault diagnosis study based on wavelet packet energy and Hilbert transform was put forward. The vibration signals of ball bearing were decomposed and reconstructed using wavelet packet transform. And energy of every frequency band was calculated, then the signals of the frequency band with maximal energy were analyzed by applying Hilbert transform. Finally, the characteristic frequency of fault signals was extracted. The computation of fault features was accomplished artificially. A new method which can select fault features automatically was presented herein. Through processing and analyzing the practical ball bearing experimental data, it is shown that the fault diagnosis study can diagnose different running states of ball bearings due to surface damage accurately and quickly.

Parametric Curve Look-ahead Interpolatin Algorithm with Flexible Acceleration and Deceleration Method

WANG Hai-Chao, DIAO Dong-Biao, LIU Yong-Hua, LIU Kai

2012, 23(3):  299-304. 

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A parametric curve look-ahead acceleration and deceleration was planed by the look-ahead algorithm with S shape method. Meanwile, at areas of the curvature radius changing frequently, the trigonometric function acceleration and deceleration method was used. By the fexible acceleration and deceleration method, the impact on the machine is greatly reduced and the computation is also reduced.At the curvature radius changing section, the look-ahead distance was self-decided according to curvature radius. The experimental results verify the feasibility and precision of the proposed interpolation algorithm.

Study on Robot Force Position Control Method for Arbitrarily Inclined Plane Tracking

LI Zheng-Xi, TANG Xiao-Qi, XIONG Luo, XIE Ba-Sheng

2012, 23(3):  304-309. 

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This paper introduced an adaptive impedance control of a robot for the arbitrarily inclined planel tracking, it overcomes the problem of force position tracking for the constraint surface with unknown normal direction and uncertainties of the environmental damping and stiffness. The proposed method used the recursive least square algorithm to estimate the environment damping and stiffness during the impact-contact, and achieved the expected attitude adjustment for the robot end-effector based on the difference between the actual and expected contact moment, During the robot end-effector sliding on the inclined plane, a rule self-adjusting fuzzy logic controller was developed to adjust the robot impedance control parameters on-line based on the robot end-effector position and force tracking errors to adapt to the variations of the environmental damping and stiffness.The designed robot force position control method is robust to the changes of the environmental parameters, but the implementation of the algorithm programming is simple. The experiments demonstrate the effectiveness of the approach.

Fuzzy Sliding Mode Positioning and Anti-swing Control for Gantry Crane

CHEN Zhi-Mei, MENG Wen-Dun

2012, 23(3):  310-314. 

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A new positioning and an anti-swing control scheme with fuzzy sliding mode were proposed herein. The gantry crane was simplified into three multi-input subsystems, four sliding mode surfaces were defined and a fuzzy sliding controller was designed. The crane trolley can be quickly and accurately reached to the anticipated position, and the swing of heavy body was restrained during the process of high-speed load hoisting and dropping, and then the varying length of lifting rope can be traced exactly, as thus the control objective was realized and the operating efficiency was improved. Meanwhile, the inherent chattering phenomena of sliding mode control can be eliminated and the performances of control system can be ameliorated. The simulation results show the correctness and validity of this method.

Speed Ratio Control of Continuously Variable Transmission Based on Active Coupling Control Strategy

HAO Yuan-Zhi-1, 2, SUN Dong-Shu-1, QIN Da-Tong-1, LIN Xin-You-1

2012, 23(3):  315-319. 

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Utilizing the coupling effect between clamping force and speed ratio, the shift speed is improved by conditioning the pressure of both primary and second pulleys' hydraulic cylinders. System pressure safety must be ensured to satisfy the clamping force which could meet the requirements of torque transmission. As a result, real ratio tracked the target more rapidly and shift speed range was enlarged. An active coupling control strategy was studied, which included shift speed, clamping force related transmission reliability, fuel economic, dynamic performance, hard condition adaptability, and shift speed related comfortableness. Simulation results show that by adopting active coupling control strategy, reliability, economic, and comfortableness are ensured while ratio tracking performance and power performance are improved. Particularly, ratio tracking error is reduced by 11%~53%, 30~60km/h overtaking acceleration time is shortened by 0.7s.

Hydraulic Design of Axial Turbine Blades with Ultra-low Specific Speed for Decreasing Capacity and Increasing Efficiency

LIU Wei-Tu-1, 2, HAN Jiang-2

2012, 23(3):  320-323. 

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To solve the problem that propeller turbines were unfit for working under small discharge conditions in dry seasons, after discussing the influencing factors, a rebuilding scheme for decreasing capacity and increasing efficiency was put forward. The distribution of the axial velocity and the velocity circulation at the inlet and the outlet were researched. Some key technologies in computer aided hydraulic design were solved herein, including unfolded drawing of aero foil converted to cylindrical surface and intelligent extension of curve. An example of a runner blade for a real turbine sets was successfully developed with the self-development CAD software. When the discharge is decreased from 4.5m3/s to 1.5m3/s, the efficiency of the hydraulic turbine increases from less than 30.1% to 82.7%, then the sets can work properly, and its cavitation performances are superior to the original one.

Dynamic Performance Study of MR Damping System Based on AR Model

CHEN Qiang-Tang-1, HUANG Yi-Jian-2

2012, 23(3):  324-329. 

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The paper used MRF properties for designing MR damping and testing system, a dynamic model for damping system was founded, based on the correspondence between transfer function of continuous system and time series AR model of the discrete system, the dynamic performance parameters,formulas for three-order system were illated.The damping performance and dynamic response of the system were analyzed,in order to find the suitable wording condition for the system.

Simulation and Analysis of a New Type Buffer's Design Based on Nose Landing Gear Extension Technology

WANG Tong, HU Feng, NIE Hong

2012, 23(3):  330-334,338. 

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Most carrier-based airplanes were catapult launched from carrier decks, and nose landing gear extended at the moment of separating. In this situation, the problem of an oleo-pneumatic buffer was studied to suit for catapult launch. Some different extension modes of buffer were discussed, and a new oleo-pneumatic buffer with two-stage chambers was studied for better take-off performance. The co-simulation models of nose landing gear were well established, subsequently, the catapult launch-extension simulation was carried out. The simulation results indicate that the combination of injecting high pressure gas and releasing potential energy is more effective; in addition, the improved buffer can actually extent more quickly.

Correction and Application of Numerical Model on Plate Roller Levelling

WANG Xiao-Gang, HUANG Qiang-Hua, HU Ying

2012, 23(3):  335-338. 

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A model of plate in level was studied herein using both numerical analysis and experimental verification.The results show that the relative accurate results can be obtained between measurement data and calculated results. It is obtained that the distribution of stresses and strains in the level init. The distribution of residual stress on the cross section is drawn at the same time, the results show that the maximum valve of residual stress locates at the transition part which transmit from elastic zone to plastic zone in 1~4 level unit, and locates at the plate surface in 5~9 level unit.

Research on Kinematics/Dynamics Simulation of Servo-Press Transmission Mechanism Based on MATLAB

FANG Ya-1, SUN You-Song-1, HU Jian-Guo-1, CHENG Yong-Ai-1, ZHANG Feng-1, RUAN Wei-Beng-2

2012, 23(3):  339-342. 

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Knuckle mechanisms have large force gain. The working properties of strait link-knuckle and triangle link-knuckle mechanisms were analyzed and their mathematic models were built up herein. Taking 4000kN servo press as example, the numerical simulations were conducted. The simulation results show that the triangle link-knuckle mechanism has better kinetic-dynamic characteristics. In comparison with common strait link-knuckle mechanism, the required torque reduces by 70.6% and the average velocity of the slide within the nominal pressure stroke reduces by 50% with the same nominal pressures.

Experimental Study on Characteristics of Drive and Anti-skid of ADBRM for Electric Vehicles

ZHOU Shi-Jia-1, LONG Jiang-Qi-1, CHU Jun-1, ZHANG Yin-Xian-2

2012, 23(3):  343-346. 

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Based on the study results of the new type ADBRM, a hardware in loop simulative test bed was constructed and a series of tests such as driving, differential driving and anti-skidding were carried out. The testing results show that the ADBRM possesses the same driving characteristics as the theoretical analysis. Furthermore, when the driving system worked suddenly on a low adhesive road, the simulation results indicate that the application of the wheel-speed following strategy onto the ADBRM is quite feasible.

A Novel Noncircular Planetary Differential for Off-road Vehicles

GU Ju-Min, GAO Bei

2012, 23(3):  346-348. 

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With three noncircular gear items integrated, a new noncircular planetary differential was put forward, which may deliver variable proportional torque onto its two output axes and help to improve passing capacity for off-road vehicles. The new differential has two uniform centre gears, meshing with three double planetary gears, the double planetary gears have the same features with an angular difference of 90°. The driving theory and the design method of pitch curves were presented, a case study of gears with involute tooth profile was illustrated, which shows the effectiveness of the new differential. 

Experimental Research on Rapid Control Prototyping and HILS for Control System of Forklift Automatic Transmission

ZHANG Bing-Li-1, DONG Pan-Wen-1, HU Fu-Jian-1, LIU Zong-Ji-1, 2

2012, 23(3):  349-353,361. 

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Based on the pump pressure,the forklift' working conditions can be divided into no-load,full load and half load.By calculating forklift's input features,output characteristics and traction features,shift schedule of three variable parameters(throttle position,speed and pressure of oil pump) were designed.The rapid control prototyping experiments based on dSPACE system were designed to verify the shift and actuator control strategy.On the basis of TCU and HILS system,the HILS experiments was carried on,which testified the effect of control strategy in real TCU.The test results show that TCU designed by using dSPACE can meet the performance requirements,improve development efficiency,providing a reference for the development of forklift automatic transmission control unit.

Development of Coating of Photoresist in Semiconductor Manufacturing

XIANG Dong-1, HE Lei-Meng-1, JI De-Gang-1, 2, MAO Feng-1, DUAN An-Hong-1

2012, 23(3):  354-361. 

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The quality of the coating of the photoresist impacts the quality of lithography directly. The spin coating and spray coating method and their development process were presented, as well as the electrodeposition(ED), vapor deposition methods. Advantage and disadvantages of the spin coating, spray coating and ED were outlined, and the applications of the different coating methods were summarized.

Progresses of Research on Hydraulic Vibration Technology

GENG Tong, ZUO Jiang, YANG Yong-Shuai, RUAN Jian

2012, 23(3):  362-367,377. 

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The hydraulic vibration technology was classified and its principles, applications, and respective pros and cons were discussed. A typical hydraulic vibration equipment was presented, involving their latest development, system structure and performance indices. In addition, the latest achievements of hydraulic vibration control technology were introduced briefly at home and abroad. The viewpoints are that multi-axis and high frequency vibration technology are the focus in current research, especially it is concluded the development of the 2D valve electro-hydraulic exciting method is an access to the high-frequency excitation of the hydraulic vibration.

Finite Element Mesh Generation and Decision Criteria of Mesh Quality

LI Hai-Feng-1, TUN Ji-Chuan-2, LIU Jian-Bei-1, LIANG Yu-Bing-1

2012, 23(3):  368-377. 

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Some general problems in mesh generation were discussed, the demands of mesh generation were expounded, the mesh generation methods were introduced, the mesh generation algorithms in last ten years were retrospected and their advantages and disadvantages were compared. Based on the requirements of practical engineering calculation,the authors brought up the mesh quality demands and decision index, explored the mesh quality optimization, introduced the preprocessors and their applications of the commercial softwares,then gave out several practical examples of the mesh generation. At last, the trends of mesh generation were also presented.