Table of Content

10 August 2013, Volume 24 Issue 15

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A Detection Algorithm of Motion Mutation during 3D Cutter Compensation in#br# Five Axis End Milling with a Flat-bottomed Tool

WANG Feng-1, 2, LIN Hu-2, LIU Feng-1, 2, ZHENG Liao-Mo-2, ZHENG Yi-Lin-1, 2

2013, 24(15):  1989-1995. 

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In the process of five-axis end milling with a  flat-bottomed tool,if the 3D cutter compensation function was adopted,the motion of linear axis control point would be unsteady because there would be singular solution during solving the radius
compensation vector.To provide the precondition for solving such problem,it was needed to detect positions where motion mutation will happen.The reason that the singular point generated during 3D cutter compensation was analyzed based on building the relationship between coordinates of the cutter contact point and the linear axis control  point.For the singular point,the adjacent points of the singular point and the boundary of the singular area, which were three positions where motion mutation would happen,a detected algorithm was advanced,which was based on calculating the angle between the tool axis vector and the normal vector and observing the symbol of the dominant angle of the tool axis posture.A simulation experiment was performed to verify the correctness and the effectiveness of this algorithm. 

Design and Experimental Study of Cylindrical Non-contact Piezoelectric Actuator

GU Bing, CHEN Chao, LI Fan, DIAO Chun-Sheng

2013, 24(15):  1996-2000. 

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Based on near-field acoustic levitation and driving, a novel
absolutely non-contact piezoelectric actuator was presented.The cylinder rotor
was levitated by a Langevin transducer,and driven by a cylinder type stator.
Applying voltages on the piezoelectric ceramic patches of transducer and stator,
the first order of flexural vibration was exerted on radiating surface of the transducer,
and two B(0,3) flexural standing waves at different phases  were generated and
lead to a traveling wave in the cylinder type stator,which applied driving force for the rotor
by the induced high intensity sound.The finite element models of the cylinder
type actuator,including Langevin transducer and stator,were built,and the dynamic
analysis,design,and experiments for scanning and fitting frequencies for
 the stator were conducted.At last,a prototype was manufactured and the test system for the actuator was built,and its levitation and driving characteristics were  measured.The rotation speed of the rotor can achieve 4261r/min.The experimental results confirm that the rotor successfully achieves absolutely non-contact rotation based on near film ultrasonic levitation and driving effect.

Research on SrTiO3 Ceramics Substrate Surface with Cluster Magnetorheological Effect Lapping

LIU Dun-Long, YAN Qiu-Sheng, LU Jia-Bin, BO Ji-Sheng

2013, 24(15):  2000-2004. 

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The plane lapping of SrTiO3 ceramics substrate by cluster MR-effect technology was researched.The factors that influenced the surface roughness and the integrality,such as the material of lapping disc,the kind of abrasive,the lapping pressure and the abrasive agglomeration,were analyzed.The results demonstrate that the local big scratches which ruin the integrality of the surface are mainly attributed to the big abrasives of SiC,Al2O3 and CeO2.The integrated surface whose roughness decreases from Ra1.7854μm to Ra0.6282μm  can be attained with the iron disc and SiO2 abrasive.The chemical and mechanical processes between SrTiO3 and SiO2
promote the improvement of  the surface quality.The grinding pressure of 1.875kPa is preferred.

Experimental Study of Variable Tumble Intake System in a Gasoline Direct Injection Engine

YIN Cong-Bo, ZHANG Zhen-Dong, YIN Hang, SUN Ti-Dong

2013, 24(15):  2005-2009. 

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An optical variable tumble intake port steady flow rig for 4-valve GDI engine was established, and a PIV system was used to study the change of in-cylinder airflow under different intake-valve lifts at two cases of opening and closing the tumble control valve(TCV). Results show that: in-cylinder swirl motion at both of two cases is mainly tumble motion which flows around the axis perpendicular to the cylinder axis. When TVC is open, two large scale tumbles, a counterclockwise and a clockwise, respectively emerge on the left and right sides in the cylinder. When TVC is closed, the airflow velocity under the intake valve side in the cylinder becomes weak, while the airflow under the exhaust valve side is greatly enhanced, a single clockwise tumble flow trends become apparent. When intake valve lift is smaller, the effect of tumble change with TCV is very weak.

Experimental Investigation of Migration Characteristics of Lubricants under Minimum Lubricant Supply Conditions

JIAN Shan-Hua-1, GUO Dan-2, LU Xin-Chun-2

2013, 24(15):  2010-2015. 

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The migration characteristics of lubricant around a point contact were discussed by investigation of the variation in an oil pool under minimum lubricant supply. On the friction pair between the ball and the glass disc, the lubricants of different supplies were injected into the point contact using a micro pipette with a fix scale. The variation of the oil pool was investigated with the fluorescence technique. The results show that the closed oil pool always occurs around the point contact region. As the speed is increased, the oil pool of the micro lubrication goes through the changes of the circular, flat circular, two valves, the meniscus in the inlet while the oil pool of the full lubrication only undergoes through the change of the circular and flat circular. The variation of the oil pool at the decreasing speed is non-symmetrical to that at the increasing speed. The critical speed of the valve information functions as a positive relation with the lubricant supply volume. The variation of the oil pool shows the migration characteristics of the lubricant around a point contact, and is related with the lubricant supply, the entrainment speed, the surface tension, and the centrifugal force and other factors.

Structure and Analysis of an Omni-directional Wheel with Circular Conical Rollers

WANG Ban, ZHOU Wei-Hua, GUO Ji-Feng, HUANG Chang-Jiang

2013, 24(15):  2015-2019. 

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This paper presented the structure and some design methods of a new omni-directional wheel with circular conical rollers. Several single row circular cone rollers which interpenetrate each other were placed in the wheel rim. It was a kind of single row continuous omni-directional wheel. Firstly, structure of several typical omni-directional wheels was analyzed and the surface parameter equation of rollers was established at the same time. According to its structural characteristics, formula of other structural parameters was established and the optimal number of cone rollers was studied from geometric relations and strength analysis of the wheel. 

Research on Load Characteristics of Picks on Auger Drill Miner's  Aiguille

FU Lin, DU Chang-Long, LIU Song-Yong, LUO Chen-Xu

2013, 24(15):  2020-2024. 

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In order to study the load characteristics of point-attack pick on auger drill miner's aiguille and provide reference for aiguille's design,a  finite element model of single pick drilling and cutting coal was built by nonlinear dynamics simulation software LS-DYNA,which was applied to study pick's load feature and the relation between pick's load characteristics and installation parameters.The research indicates that the pick on aiguille will bear very large feeding resistance because of semi-closed cutting conditions.The pick's cutting resistance will decrease in quadratic function form with cutting angle's increase and keep stable firstly and then sharply increase in exponential function form with inclination angle's increase. Pick's feeding resistance is the exponential function of cutting angle and the linear function of inclination.It decreases along with the increase of cutting angle or inclination angle.It is better to choose larger cutting angle in the condition of avoiding interference between pick-body and coal. Pick's inclination angle is the best to have no more than 30°to achieve good cutting and drilling performance.

Identification Process and Decomposition Method for Product Key Characteristics

ZHANG Chi-1, FENG Ding-Zhong-2, WANG Lin-Jun-3

2013, 24(15):  2025-2030. 

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For improving product quality,variation transmission chain of key
characteristics based on assembly oriented graph was studied,and the candidate
 lower key characteristics sets were established.The index in candidate key
characteristics set was analyzed quantitatively by using DEMATEL method based on
fuzzy theory.The quantified causal relationship among indexes and importance ranking were presented according to quantized results.The importance degree was used to identify key characteristics of this level.Finally,the proposed method was applied to thread trimmer mechanism,and the results suggest its feasibility and effectiveness.

#br# Research on Optimized Model of Development Cycle and R&D Team Communication Strategies and Its Application to Complex Product

GU Jun-1, 2, ZHANG Zhuo-1

2013, 24(15):  2030-2035. 

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The paper put forward a Markov chain model to compute R&D iteration time.And total development cycle,cost model and frequent information exchange model were constructed considering R&D team communication costs.Then,optimal product development cycle and communication strategies were analyzed.The cost of team communication was taken into account and product R&D process was described in the model.Finally,an example was given to verify the model.

Optimization Design of Mining Dump Truck Steering Mechanism Based on Orthogonal Test

JIANG Li-Biao, LIU Jian-Xiong, CHENG Cheng

2013, 24(15):  2036-2041. 

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In response to the defects of traditional design method of steering mechanism,multi-objective parameter optimization was conducted based on orthogonal test.The dynamics simulation model of a 220 ton mining bump truck was established and simulated with ADAMS,in which the sideslip under straight driven,wheel steer angle error under steering and the wheel angle under bouncing were taken into account.
A comprehensive objective function was accomplished based on the multi-objective optimization theory, and the influence of front wheel alignment parameters and the space location of steering mechanism were analyzed using orthogonal test.The optimization results show that:the comprehensive performance of steering mechanism can be improved significantly,which provides theoretical foundation for the optimization design of mining dump truck steering mechanism.

Histogram-based Stress-strength Interference Model and Approach to Reliability Calculation by Using UGF

GUO Hui-Cuan, DAI Juan, CHENG Li-Zhi, JIA Zun-Feng

2013, 24(15):  2041-2047. 

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Based on UGF approach and histograms of stress and strength,a method for approximately calculating the component reliability was proposed when the probability density functions of stress and strength can not be determined exactly. For finite experimental data about stress acted on a component and its strength,the histograms of stress and strength were obtained through statistical analysis.The conventional UGF was extended and an interval-valued UGF(IVUGF) was proposed to characterize the interval-valued discrete random variables.The stress and strength characterized by histograms were expressed by using IVUGF,and then a histogram-based stress-strength interference model was proposed.A combination operator of IVUGF was applied to component's limit state function(LSF) and the IVUGF of  the LSF was obtained.The weighting coefficient of probability mass was defined.The component reliability was obtained by calculating the weighted sum of all probability mass within the safety margin determined by LSF.Three typical examples were presented and it is showed that the proposed method can achieve satisfactory accuracy of reliability calculation and possesses practical value in engineering.

#br# Simulation Analysis and Experimental Research on Movements of Biomimetic Propulsion Unit Based on Basilisk Lizard

LV Jian-Gang, GAO Fei, BAI Xiang-Hua, LI Pan-Lu

2013, 24(15):  2048-2052,2059. 

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A bionic propulsion unit was developed herein by simulating the moving status of a basilisk lizard running on the water. Based on the theoretical analyses, we focused on the change rules of propulsive performance under different rotating speeds. Comparison and analysis of the results obtained by using a two-dimensional computational fluid dynamics method for propulsion unit model were presented and emphasized. At the same time, a water entry test was finished to verify the simulation analysis. The simulation and test results indicate that the advance of bionic propulsion unit increases considerably with the rise of the rotational speeds, for increasing speed there exists a rotating speed range of the propulsion unit; once the rotating speed out of the scope, increasing underwater depth of bionic propulsion is an efficient method to improve the speed.

Product  DSS Model Based on Cloud Service

FENG Jing, TU Duo-Fu, YANG Yan-Pu, SONG Gong, LIU Chang-De

2013, 24(15):  2053-2059. 

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To solve the decision service problems in the process of complex product design,cloud services,requirements-driven and service-oriented architecture were used to DSS.In the DSS,  through cloud service's virtualization and service-orientation to various types of hardware and software,also with its rich semantic web services,the decision support process modeling and dynamic mapping among the actual implementation of decision-making process service could be achieved.In addition, to improve the system's decision-making capacity,based on the system-level model the paper proposed the idea of decision-making task submission and a decomposition model;meanwhile,it discussed the module operation between each model and then developed cloud services platform prototype for DSS to verify the feasibility of this method.

Research on Web-oriented Virtual Assembly Technologies of Modular Fixture

JI Chang, WEI Wan-Wan, WANG Jun-Ze, DENG Jie

2013, 24(15):  2060-2065. 

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In order to realize virtual assembly of modular fixture in network environment, the five-layer hierarchical information models of modular fixture elements were created. The virtual assembly technologies were put forward, including collision detection based on hierarchical bounding box trees and interactive assembly constraint matching. The hierarchical bounding boxes by partitioning model with binary tree were constructed. And a collision detection algorithm based on network was developed to detect interference and to compute the puncture depth. The assembly features of fixture elements can be captured from their functional surfaces and be matched interactively to adjust the position and orientation. And then the precise location and virtual assembly simulation of fixture elements were implemented rapidly. A web-based interactive virtual assembly platform of modular fixture was developed and examples were given to verify the feasibility of the above-mentioned assembly technologies. The applications show that the technologies satisfy the requirements of the real-time and interactive Web-oriented virtual assembly, and they are the foundation of collaborative assembly design of modular fixture.

A Multipole Galerkin Boundary Element Method for Two Dimensional Half Space Acoustic Problems

WANG Yan-An, WEN Gui-Lin, CHEN Zhi-Fu, WANG Meng

2013, 24(15):  2066-2071. 

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In order to improve the computational efficiency for half space acoustic problems, a half space Green function was introduced in boundary integral equations, then the multipole Galerkin boundary element method (BEM) was used to solve the half space acoustic problems. During this process, the matrix-vector multiplication procedure was discussed, and the generalized minimal RESidual (GMRES) iterative solver pre-conditioned by approximate inverse method was employed to solve the system linear equations. The numerical results show that, the accuracy and efficiency of the multipole Galerkin BEM is validated by the half space monopole scattering problem. The approximate inverse pre-conditioner can accelerate the convergence rate of the GMRES solver, the iterative steps are reduced dramatically. Finally, the multipole Galerkin BEM was applied to solve the diffraction problem of two dimensional T shape noise barrier.

Adaptive Algorithms of Genetic Algorithm Parameters and Its Application to Hydraulic System Control

MA Yu, GU Li-Chen

2013, 24(15):  2071-2075. 

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Fixed parameters of genetic algorithm are easy to fall into premature convergence and local optimum situation．An improved genetic algorithm was proposed herein in order to improve the convergence speed and the ability to global solution. Fuzzy controller was established in order to achieve adaptive adjustment of the genetic algorithm parameters (Pc and Pm). Through the use of conventional optimization methods, simple genetic algorithms and improved optimization algorithms, complete the control of hydraulic flow driven by （PMSM）.The results show that: using fuzzy logic genetic algorithms a hydraulic system achieves good control performance and strong robustness under typical operating conditions.

Research on Gearshift Piecewise Control for AMT Based on a 2-DOF Electromagnetic Actuator

LIN Shu-Sen, CHANG Sai-Qi, LI Bei

2013, 24(15):  2076-2080,2087. 

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To improve the shifting quality and reduce the shift time of AMT, a new type of AMT gearshift system based on a 2-DOF electromagnetic actuator was developed. The structure and working principle of the actuator was described and the static, dynamic characteristics were investigated through experiments. The shift synchronization process was divided into four stages, and variable structure control strategies based on PID and fuzzy control were proposed and simulated. The test bench was developed and used to verify the gearshift system and the proposed variable structure gearshift control strategy. The results show that the proposed control strategy can improve the shift quality and reduce the impact and friction work per unit of the gearshift process.

Statics Analysis of a Spherical Parallel Mechanism UP+R with 2-DOF

ZHOU Yu-Lin-1, LI Bei-2, YANG Long-1, GAO Feng-3

2013, 24(15):  2081-2087. 

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By the dismantle-bar method, the statics equilibrium equations of the mechanism were set up, considering the elasticity of member and then utilizing the micro-deformation and superposition principle, the deformation equations of compatibility were derived and then the statics analysis of the spherical parallel mechanism UP+R with 2-DOF was fulfilled. As a numerical example, some figures which showed the relationship between input torque, each force on each member and the position and posture of the mechanism were drawn under three kinds of external loads, respectively. The results show that, under the external force only, the input torque of the mechanism is vanishing identically and the variation of forces acting on members with the position and orientation of the mechanism in whole space is gentler slope. Under the external torque only, the variations of the input torques and the forces with the position and orientation of the mechanism are associated with the characteristic of the mechanism. The two portions of force jointly produced by external force and external torque are independent and detachable. The research provides the theoretical basis of statics for structure design and application of the mechanism in engineering．

Application of High Order and Multi-level Autoregressive Distributed Lag Model to Thermal Error Compensation of Machine Tools

MIAO En-Ming, CHENG Tian-Ju, NIU Feng-Cheng, GONG E-Yun

2013, 24(15):  2088-2093. 

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Based on the synthesis of the fuzzy clustering and gray relational theory, the temperature sensors for monitoring CNC machine tools were optimized. According to the commonly used multiple regression model,this paper used ADL model to model the thermal error of CNC machine tools. On the basis of better accuracy, we expanded the ADL model and proposed a new high order and multi-level ADL modeling technique, also, analysed its modeling method and accuracy. It shows that the high order and multi-level ADL model has better accuracy in the thermal error compensation of CNC machine tools by the examples presented herein.

Fluid Resistance Analyses and Experimental Research of Disc Rotor

HAN Gong-Biao-1, GAO Shan-Qun-1, LI Ji-Shun-1, WANG Ji-Sheng-2, MA Wei-1

2013, 24(15):  2093-2096. 

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Fluid resistance of rotating disc rotor was analysed in turbulence fluid. Boundary layer theory was used in calculating the torque and the power of rotating disc rotor. A testing apparatus was designed to obtain the torque and power data of the rotor in fluid in different rotating speeds. The relation curve among the speed, torque and power was fitted with the method of least square. The results show that the torque has the first power and second power relation with rotating speed, and the power has the first power and second power and third power relation with rotating speed. Some of the factors such as the surface shape were ignored, so the result is smaller than the experimental data, but it can be used as a reference for choosing the motor. Furthermore, by revising the coefficient of frictional resistance, the calculation results are conformed to experimental data.

An Explicit Boundary Level Set Method for Optimization Design of Fluid Channel

JIAN Xiao-Hui-1, 2, DENG Yong-Bei-1, LIU Yong-Shun-1, 2, TUN Yi-Hui-1, LIU Shen-Yu-1

2013, 24(15):  2097-2100,2113. 

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This paper focused on solving mass distribution problem of fluid channel design with COMSOL script,based on explicit boundary level set method(EbLSM) for incompressible Navier-Stokes flow.The physical field was solved by using explicit no-slip boundary conditions. A method to construct explicit boundaries and optimization model for mass distribution problem was discussed,and the model's sensitivity was verified numerically.Finally,the numerical examples illustrate that,based on the EbLSM,the proposed numerical model can  solve mass distribution efficiently problem.At the same time,in the progress of optimization,the EbLSM possesses the capability to modify channel's topology.

Research on Generating Process of Product Innovation Projects  Based on QTF in Customer Collaborative Design

GENG Jing-Song-1, 2, YANG Yo-1, LIU Ai-Jun-1, TAO Hao-3

2013, 24(15):  2101-2109. 

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QFD,TRIZ and FDEA were integrated to construct the frame of the generating process of product innovation projects and the generating stages of product innovation projects in customer collaborative design were put forward.Then,aiming at the key points,the transform method of the multi-agent creativity based on Web ontology language for services,the solving method of innovation bottleneck based on TRIZ and the evolution method of innovation projects based on FDEA were proposed.Finally,the generating process of a certain refrigerator innovation projects certified  the feasibility and validity of the method.

Analysis of Microstructure Evolution of Extruded Cross Wedge Rolling for Small Remnant Rolling

SHU Hua-Dao, CHENG Chao, GONG Wen-Wei, BANG Wen-Fei, SUN Bao-Shou

2013, 24(15):  2109-2113. 

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For the remnants of cross wedge rolling technology were large at the present time, which lead to material utilization ratio decrease, an extruded cross wedge rolling technology was put forward to achieve small remnants rolling innovativly. First a dynamic recrystallization model of 42CrMo was set up in the DEFORM-3D finite software, then the dynamic recrystallization volume fraction of extruded cross wedge rolling and average austenitic grain size distribution were analyzed. At last, combining oil pump shaft experiment of extruded cross wedge rolling with metallographic analysis experiment, the feasibility of the extruded cross wedge rolling for small remnants rolling was verified. The study shows that material volume of the extruded cross wedge rolling decreases by about 75% and material utilization ratio can reach to 95%, at the same time the extruded cross wedge rolling can also refine grain and improve comprehensive mechanical properties.

Research on Rolling Pressure Model of Plate Steel Warm-rolling Based on Non-constant Deformation Resistance

LI Zhi-Jie-1, BANG,YAN 1, 2, LIU Hong-Min-1, 2, WANG Su-Fen-1, XIAO Li-Zi-3

2013, 24(15):  2114-2118. 

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For calculating deformation resistance in the warm rolling of plate steel, a new rolling force model was proposed based on non-constant value of deformation resistance. Contact arc of deformation zone was discretized into micro-segment unit, and the deformation resistance model of segmented micro cell about deformation and deformation rate was established, unit rolling pressure of segmentation unit was calculated that unit arc replaced by line based on Karlman balance differential equations. Deformation process of warm-rolling was simulated using ANSYS/LS-DYNA finite element. The comparison of the two calculation results indicates that the new model has high accuracy and is more conforming to actual production.

Study on Optimization for Automobile Safety and Lightweight Based on Variable Complexity Approximate Model

LIAO Dai-Hui, CHENG Ai-Guo, ZHONG Zhi-Hua

2013, 24(15):  2118-2121,2129. 

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Aiming at the complexity characteristics of automobile safety optimization considering the effects of stamping, a compensation response surface model was created by using optimal Latin square design through the small sample data spanning the traditional model and high accuracy model. And then a new Kriging response surface model was established on the basis of new test data which was created through the traditional model and compensation response surface model. A multi-objective particle swarm optimization algorithm was used to solve and optimize the response surface model.  The method was applied to vehicle frontal impact and lightweight multi-objective optimization design. The results show that this method can ensure the response surface precision, rapid convergence to the optimal solution.

Research on Fuzzy Compensating Slope Shift Strategy for DCT Vehicles

DIAO Chi-Guo, WANG Qi, DIAO Wei-Zhen, CHEN Hai-Jun

2013, 24(15):  2122-2129. 

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Based on the independently developed five-speed dry dual clutch transmission and its mounted prototype car, a fuzzy compensating slop shift schedule was developed. Firstly, the vehicle mass and slope were estimated in real time with the method of modified recursive least squares based on the vehicle longitudinal dynamics model. Then a BP neural network was established to calculate the estimated parameters. Secondly, a fuzzy compensating slop shift schedule was devised based on fuzzy logic. Finally, the effectiveness of fuzzy compensating slope shift schedule was verified by the simulation and HIL test platform. The results show that the fuzzy compensating slope shift schedule can solve the frequent shift and unexpected shift phenomenon caused by the slope effectively,and decrease the action frequency of DCT synchronizer and improve the driving comfort.