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RSS2015 Vol. 34, No. 7
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2015, 34(7): 985-988.
doi: 10.13433/j.cnki.1003-8728.2015.0701
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Abstract:
Aiming at enhance the positioning accuracy of a traditional piezoelectric ceramic device in a micro-displacement system, we propose the flexible hinge micro-displacement magnification mechanism. The motion characteristics of the mechanism is analyzed and simulated with the finite element method (FEM). The influence of the distance between two hinges and their key parameters are discussed. The analysis results show that the FEM simulation results agree well with the theoretical analysis results. The FEM simulation results can be used to determine the effect of the geometric parameters of the flexible hinge on the performance of the micro-displacement mechanism and can enhance the efficiency and accuracy of micro-displacement mechanism design. With the micro-displacement mechanism, the lack of simulation analysis support is avoided in carrying out structural design. The simulation results show that the micro-displacement mechanism we designed has a high precision in super-precision processing.
Aiming at enhance the positioning accuracy of a traditional piezoelectric ceramic device in a micro-displacement system, we propose the flexible hinge micro-displacement magnification mechanism. The motion characteristics of the mechanism is analyzed and simulated with the finite element method (FEM). The influence of the distance between two hinges and their key parameters are discussed. The analysis results show that the FEM simulation results agree well with the theoretical analysis results. The FEM simulation results can be used to determine the effect of the geometric parameters of the flexible hinge on the performance of the micro-displacement mechanism and can enhance the efficiency and accuracy of micro-displacement mechanism design. With the micro-displacement mechanism, the lack of simulation analysis support is avoided in carrying out structural design. The simulation results show that the micro-displacement mechanism we designed has a high precision in super-precision processing.
2015, 34(7): 989-992.
doi: 10.13433/j.cnki.1003-8728.2015.0702
Abstract:
The distribution of friction heat flow on meshing surface of asymmetrical involute helical surface was obtained based on the analysis of meshing face. The finite element model for temperature distribution of asymmetrical involute helical gear was established based on APDL. Considering the influence of temperature on the contact pressure, we carried out coupled analysis of heat and force for asymmetric involute helical gear. The results and their analysis preliminarily showed that the maximum bulk temperature of asymmetric gear is lower by about 18% than the symmetrical gear at reaching thermal equilibrium, which could effectively improve the tooth surface scuffing capacity. The contact stress of asymmetrical involute helical gear increased by about 16% due to the influence of temperature distribution.
The distribution of friction heat flow on meshing surface of asymmetrical involute helical surface was obtained based on the analysis of meshing face. The finite element model for temperature distribution of asymmetrical involute helical gear was established based on APDL. Considering the influence of temperature on the contact pressure, we carried out coupled analysis of heat and force for asymmetric involute helical gear. The results and their analysis preliminarily showed that the maximum bulk temperature of asymmetric gear is lower by about 18% than the symmetrical gear at reaching thermal equilibrium, which could effectively improve the tooth surface scuffing capacity. The contact stress of asymmetrical involute helical gear increased by about 16% due to the influence of temperature distribution.
2015, 34(7): 993-996.
doi: 10.13433/j.cnki.1003-8728.2015.0703
Abstract:
In order to reduce the hand hacking during tooth contact analysis based on Abaqus software and to improve the readability of the results, we proposed a pretreatment method for modeling, assembling and presetting conditions with input file, and a post treatment method for extracting the calculation results with script files of Abaqus software. The MATLAB software was used to program the input file and to process the extracted data. This method can avoid hand hacking in pretreatment, and extract the contact pattern and stress curve.
In order to reduce the hand hacking during tooth contact analysis based on Abaqus software and to improve the readability of the results, we proposed a pretreatment method for modeling, assembling and presetting conditions with input file, and a post treatment method for extracting the calculation results with script files of Abaqus software. The MATLAB software was used to program the input file and to process the extracted data. This method can avoid hand hacking in pretreatment, and extract the contact pattern and stress curve.
2015, 34(7): 997-1001.
doi: 10.13433/j.cnki.1003-8728.2015.0704
Abstract:
Aiming at the different original errors affecting on the pose errors and the large calculation in the exhaustion method to solve the parallel mechanism's accuracy synthesis problem in the whole workspace, we propose an approach combining the impact factor weighting method of geometry original errors with the orthogonal design method, and take the 2UPS-RPU parallel mechanism as an object to get the accuracy synthesis result and validated the final accuracy synthesis result. The verification result shows that it is easily to get the tolerance value of 22 geometry original errors in the present method, and in the whole workspace the probability of the pose error δy、δz、δα、δβ beyond the given accuracy range are 4.92%, 2.33%, 1.25%, 1.42% respectively and the feasibility and validity of the present method are verified.
Aiming at the different original errors affecting on the pose errors and the large calculation in the exhaustion method to solve the parallel mechanism's accuracy synthesis problem in the whole workspace, we propose an approach combining the impact factor weighting method of geometry original errors with the orthogonal design method, and take the 2UPS-RPU parallel mechanism as an object to get the accuracy synthesis result and validated the final accuracy synthesis result. The verification result shows that it is easily to get the tolerance value of 22 geometry original errors in the present method, and in the whole workspace the probability of the pose error δy、δz、δα、δβ beyond the given accuracy range are 4.92%, 2.33%, 1.25%, 1.42% respectively and the feasibility and validity of the present method are verified.
2015, 34(7): 1002-1005.
doi: 10.13433/j.cnki.1003-8728.2015.0705
Abstract:
An accurate and convenient edge tooth contact analysis methodology of Klingelnberg Cyclo-palloid hypoid gears is developed, by which the contact points on tooth edges and the long axis direction and length of contact ellipses could be determined. The main directions between two tooth surfaces and all the possible contact points were then obtained with MATLAB. A mathematical model for contact analysis(LTCA) considered edge loading is put forward. Finally, the loaded tooth edge contact problem is resolved successfully. The feasibility and reliability of the present method is verified with analyzing the existing examples, and a simulation example is given. The present edge tooth contact analysis methodology can used as a basis for developing a general technique of edge tooth contact analysis for hypoid gears, spiral bevel gears and other gear types.
An accurate and convenient edge tooth contact analysis methodology of Klingelnberg Cyclo-palloid hypoid gears is developed, by which the contact points on tooth edges and the long axis direction and length of contact ellipses could be determined. The main directions between two tooth surfaces and all the possible contact points were then obtained with MATLAB. A mathematical model for contact analysis(LTCA) considered edge loading is put forward. Finally, the loaded tooth edge contact problem is resolved successfully. The feasibility and reliability of the present method is verified with analyzing the existing examples, and a simulation example is given. The present edge tooth contact analysis methodology can used as a basis for developing a general technique of edge tooth contact analysis for hypoid gears, spiral bevel gears and other gear types.
2015, 34(7): 1006-1010.
doi: 10.13433/j.cnki.1003-8728.2015.0706
Abstract:
Based on the topology optimization design method,a 2-DOF full compliant planar mechanism is proposed in this paper. Continuous mapping between the 2-DOF full compliant planar mechanism and traditional parallel mechanism is established through Jacobi matrix. Solid isotropic material penalization (SIMP) model of the 2-DOF full compliant planar mechanism is established and solved by OC algorithm. The problems of Checkerboard and mesh-dependency are treated by Heaviside filter technique. With curve fitting method, three dimensional model of the 2-DOF full compliant planar mechanism is built. The static analysis for this structure is performed with the finite element analysis software. The differential motion characteristics of the 2-DOF full compliant planar mechanism is the same as those of the traditional parallel mechanism.
Based on the topology optimization design method,a 2-DOF full compliant planar mechanism is proposed in this paper. Continuous mapping between the 2-DOF full compliant planar mechanism and traditional parallel mechanism is established through Jacobi matrix. Solid isotropic material penalization (SIMP) model of the 2-DOF full compliant planar mechanism is established and solved by OC algorithm. The problems of Checkerboard and mesh-dependency are treated by Heaviside filter technique. With curve fitting method, three dimensional model of the 2-DOF full compliant planar mechanism is built. The static analysis for this structure is performed with the finite element analysis software. The differential motion characteristics of the 2-DOF full compliant planar mechanism is the same as those of the traditional parallel mechanism.
2015, 34(7): 1011-1015.
doi: 10.13433/j.cnki.1003-8728.2015.0707
Abstract:
Based on the gear system dynamics and dynamic theories of nonlinear systems, the nonlinear dynamic model of blade rolling mill transmission system was established with the consideration of backlash,time-varying stiffness and transmission error. Nonlinear differential equations with the backlash were solved with numerical integration method. The influence of backlash on rolling mill transmission system was studied. The results showed that the increasing of backlash causes the system vibration from harmonic motion to chaotic motion. The meshing state of transmission system changes from double-sided impact to single-sided impact, and the increasing of backlash has larger influence on meshing dynamic response of first-stage and second-stage pinion and rack drive of upper roller than that of the lower roller.
Based on the gear system dynamics and dynamic theories of nonlinear systems, the nonlinear dynamic model of blade rolling mill transmission system was established with the consideration of backlash,time-varying stiffness and transmission error. Nonlinear differential equations with the backlash were solved with numerical integration method. The influence of backlash on rolling mill transmission system was studied. The results showed that the increasing of backlash causes the system vibration from harmonic motion to chaotic motion. The meshing state of transmission system changes from double-sided impact to single-sided impact, and the increasing of backlash has larger influence on meshing dynamic response of first-stage and second-stage pinion and rack drive of upper roller than that of the lower roller.
2015, 34(7): 1016-1018.
doi: 10.13433/j.cnki.1003-8728.2015.0708
Abstract:
CuW70 electrodes applied for electrical discharge dressing of metal-bonded grinding wheel were adopted to study the effect of main electrical parameters on the electrode wear rate with orthogonal experiments. The wear at the edge and the bottom of electrode, the thickness and surface topography of the carbon layer were explored through the processing of different number of holes by optimized discharge parameters. Experimental results showed that large pulse duration and low current can reduce the electrode wear rate. Although carbon layer adhered to the bottom surface of electrode can be easily wiped out, wear rate of CuW70 electrode decreases with the increasing of the carbon layer on the bottom surface in the initial phase.
CuW70 electrodes applied for electrical discharge dressing of metal-bonded grinding wheel were adopted to study the effect of main electrical parameters on the electrode wear rate with orthogonal experiments. The wear at the edge and the bottom of electrode, the thickness and surface topography of the carbon layer were explored through the processing of different number of holes by optimized discharge parameters. Experimental results showed that large pulse duration and low current can reduce the electrode wear rate. Although carbon layer adhered to the bottom surface of electrode can be easily wiped out, wear rate of CuW70 electrode decreases with the increasing of the carbon layer on the bottom surface in the initial phase.
2015, 34(7): 1019-1023.
doi: 10.13433/j.cnki.1003-8728.2015.0709
Abstract:
The definitions of key geometric error and impact factor for NC machine tool were given, and then the mapping relation model of the machine tool geometric error and comprehensive error was built up with the multi-body system theory, and a new method of identifying the key geometric error was proposed with calculating and comparing the impact factor. Taking grinding machine as an example, we identified 15 key geometric errors which affected the accuracy of the machine tool finally with the method proposed above. The conclusions show that geometric error factors that have relatively significant influence on comprehensive spatial error of the machine tools can be identified effectively, thus an important theoretical basis is provided for improving precision of machine tools reasonably and economically.
The definitions of key geometric error and impact factor for NC machine tool were given, and then the mapping relation model of the machine tool geometric error and comprehensive error was built up with the multi-body system theory, and a new method of identifying the key geometric error was proposed with calculating and comparing the impact factor. Taking grinding machine as an example, we identified 15 key geometric errors which affected the accuracy of the machine tool finally with the method proposed above. The conclusions show that geometric error factors that have relatively significant influence on comprehensive spatial error of the machine tools can be identified effectively, thus an important theoretical basis is provided for improving precision of machine tools reasonably and economically.
2015, 34(7): 1024-1030.
doi: 10.13433/j.cnki.1003-8728.2015.0710
Abstract:
A 7-segment dissymmetrical S curve acceleration and deceleration control method was proposed and studied. According to the characteristics of trajectory, we particularly deduced and planned 8 kinds of acceleration curves that exist in practice applications. Accuracy losses will appear when this algorithm was implemented with discrete process in engineering applications. Thus, accuracy control strategies of rounding of interpolation time and internal integer calculation of interpolation parameters were proposed to achieve the requirement of high-precision control. The presented acceleration and deceleration method and accuracy control strategy were carried out on the digital signal processor (DSP) 67 series controller of floating-point double-precision type for verification. Experimental results indicate that the presented method and strategy can effectively plan 8 types curve for acceleration and deceleration, and the position calculation precision of trajectory getting according to the accuracy control strategies can reach 0.01μm.
A 7-segment dissymmetrical S curve acceleration and deceleration control method was proposed and studied. According to the characteristics of trajectory, we particularly deduced and planned 8 kinds of acceleration curves that exist in practice applications. Accuracy losses will appear when this algorithm was implemented with discrete process in engineering applications. Thus, accuracy control strategies of rounding of interpolation time and internal integer calculation of interpolation parameters were proposed to achieve the requirement of high-precision control. The presented acceleration and deceleration method and accuracy control strategy were carried out on the digital signal processor (DSP) 67 series controller of floating-point double-precision type for verification. Experimental results indicate that the presented method and strategy can effectively plan 8 types curve for acceleration and deceleration, and the position calculation precision of trajectory getting according to the accuracy control strategies can reach 0.01μm.
2015, 34(7): 1031-1034.
doi: 10.13433/j.cnki.1003-8728.2015.0711
Abstract:
With the integration of ITO (indium tin oxide) conductive glass into the laser electrochemical machining system established, the uniformities respectively of the electric field distribution and oxidation film were achieved; this contributed to the efficient combination of laser electrochemical machining. An aluminum alloy workpiece was etched by a compound processing in the NaNO3 electrolyte of 0.5 mol/L, and the influence of an predominant process parameters on the localization was investigated. The scanning electron microscopy and the optical microscope were used to analyze etching morphological characteristics of machining areas. The experimental results showed that the groove-width increased with increasing laser energy, frequency and machining current, while the groove-width decreased with increasing feed speed.
With the integration of ITO (indium tin oxide) conductive glass into the laser electrochemical machining system established, the uniformities respectively of the electric field distribution and oxidation film were achieved; this contributed to the efficient combination of laser electrochemical machining. An aluminum alloy workpiece was etched by a compound processing in the NaNO3 electrolyte of 0.5 mol/L, and the influence of an predominant process parameters on the localization was investigated. The scanning electron microscopy and the optical microscope were used to analyze etching morphological characteristics of machining areas. The experimental results showed that the groove-width increased with increasing laser energy, frequency and machining current, while the groove-width decreased with increasing feed speed.
2015, 34(7): 1035-1039.
doi: 10.13433/j.cnki.1003-8728.2015.0712
Abstract:
Using vector method as a research tool, aiming at the restriction of single profile, we gave the general scroll profiles equations based on functional expression with Taylor series and differential geometry theories. Through planar curve meshing theory and general scroll profiles equations, we proved the department vector size relationship between normal and tangent direction of scroll profile at its meshing point, also its normal vector size can be expressed by general scroll profiles equation. In creating of scroll profiles, this vector expression saves hassle of quadrature by coefficient changes. Derive the conjugation meshing condition with vector method is easy to create scroll profiles and conjugated profiles based on the MATLAB, since vector method is in line with the calculation ruled of MATLAB, which can speed up the calculations, contribute to research on the designing of profiles of the scroll compressors.
Using vector method as a research tool, aiming at the restriction of single profile, we gave the general scroll profiles equations based on functional expression with Taylor series and differential geometry theories. Through planar curve meshing theory and general scroll profiles equations, we proved the department vector size relationship between normal and tangent direction of scroll profile at its meshing point, also its normal vector size can be expressed by general scroll profiles equation. In creating of scroll profiles, this vector expression saves hassle of quadrature by coefficient changes. Derive the conjugation meshing condition with vector method is easy to create scroll profiles and conjugated profiles based on the MATLAB, since vector method is in line with the calculation ruled of MATLAB, which can speed up the calculations, contribute to research on the designing of profiles of the scroll compressors.
2015, 34(7): 1040-1043.
doi: 10.13433/j.cnki.1003-8728.2015.0713
Abstract:
The laser surface texturing technology forms a negative recast layer. This paper analyzed its formation process and characteristics based on the laser beam power distribution curve. The paper implemented the single pulse intervals method to suppress the recast layer generation and then determined the following post-processes: polishing with medium-soft oilstones in the removal stage, processing time is 15 s; with super-soft oilstones in the recovery stage, processing time is 20 s. Honing pressure is 1.5 MPa. The results show that the post-processing can remove the recast layer effectively and steadily, the micro-structure and the non-texturing surface are non-destructive as well.
The laser surface texturing technology forms a negative recast layer. This paper analyzed its formation process and characteristics based on the laser beam power distribution curve. The paper implemented the single pulse intervals method to suppress the recast layer generation and then determined the following post-processes: polishing with medium-soft oilstones in the removal stage, processing time is 15 s; with super-soft oilstones in the recovery stage, processing time is 20 s. Honing pressure is 1.5 MPa. The results show that the post-processing can remove the recast layer effectively and steadily, the micro-structure and the non-texturing surface are non-destructive as well.
2015, 34(7): 1044-1047.
doi: 10.13433/j.cnki.1003-8728.2015.0714
Abstract:
For forming the cone part with a forming angles of 45°, the theoretical analysis, the experimental investigation and the finite element simulation via ABAQUS/Explicit were respectively used to study the variation of forming force in the forming process. Based on the exactness of the finite element model, the forming forces in the axis direction and contour line direction were obtained, furthermore the magnitude of forming forces and its changing rules have also been studied. The results show that the axial force in the axis direction were much greater than that in the contour line direction, so the design of forming facilities and tool should take full consideration of forming force inn the axis direction.
For forming the cone part with a forming angles of 45°, the theoretical analysis, the experimental investigation and the finite element simulation via ABAQUS/Explicit were respectively used to study the variation of forming force in the forming process. Based on the exactness of the finite element model, the forming forces in the axis direction and contour line direction were obtained, furthermore the magnitude of forming forces and its changing rules have also been studied. The results show that the axial force in the axis direction were much greater than that in the contour line direction, so the design of forming facilities and tool should take full consideration of forming force inn the axis direction.
2015, 34(7): 1048-1053.
doi: 10.13433/j.cnki.1003-8728.2015.0715
Abstract:
A method of detecting axial vector, radius and the position of round holes on the curved surface of stamping is proposed for the stamping parts of automotive can't be assembled due to the holes position relation changes because of the spring-back. Firstly, the fitting plane by three dimensional points on the edge of hole on the curved surface with least square to obtain initial projection plane. Then, projecting the edge points to this plane, and converting the projection points into two dimensional points by coordinate conversion in order to calculate the circle radius with least square. When the radius does not meet the judgment condition, rotating the least square plane in space. Re-projecting and iterating until it meets the determined conditions. Now the normal vector of least square plane is axial vector of hole, and the least square circle radius of projection points is the hole radius. After obtaining the axial vector and radius of holes on the curved surface, the holes relation can be further detected. The experimental results show that the hole axial vector precision is of 0.093 1°, radius precision bof 0.002 775 mm, and the position relation of holes on the curved surface can be accurately detected.
A method of detecting axial vector, radius and the position of round holes on the curved surface of stamping is proposed for the stamping parts of automotive can't be assembled due to the holes position relation changes because of the spring-back. Firstly, the fitting plane by three dimensional points on the edge of hole on the curved surface with least square to obtain initial projection plane. Then, projecting the edge points to this plane, and converting the projection points into two dimensional points by coordinate conversion in order to calculate the circle radius with least square. When the radius does not meet the judgment condition, rotating the least square plane in space. Re-projecting and iterating until it meets the determined conditions. Now the normal vector of least square plane is axial vector of hole, and the least square circle radius of projection points is the hole radius. After obtaining the axial vector and radius of holes on the curved surface, the holes relation can be further detected. The experimental results show that the hole axial vector precision is of 0.093 1°, radius precision bof 0.002 775 mm, and the position relation of holes on the curved surface can be accurately detected.
2015, 34(7): 1054-1058.
doi: 10.13433/j.cnki.1003-8728.2015.0716
Abstract:
Combining with the Taguchi technique, we use finite element method to simulate the deep-drawing process of electroplating nickel coating sheet. Based on the predict of thickness distribution and thinning of the deep drawn circular cup the significance of the important process parameters namely, die radius, blank holder force and friction coefficient on the deep-drawing characteristics of electroplating nickel coating sheet is determined. At last, the influence of the process parameters on the quality characteristics (thickness variation) of the circular cup and their percentage contribution is calculated. In addition the finite element simulation results are compared with the experimental results for validation.
Combining with the Taguchi technique, we use finite element method to simulate the deep-drawing process of electroplating nickel coating sheet. Based on the predict of thickness distribution and thinning of the deep drawn circular cup the significance of the important process parameters namely, die radius, blank holder force and friction coefficient on the deep-drawing characteristics of electroplating nickel coating sheet is determined. At last, the influence of the process parameters on the quality characteristics (thickness variation) of the circular cup and their percentage contribution is calculated. In addition the finite element simulation results are compared with the experimental results for validation.
2015, 34(7): 1059-1062.
doi: 10.13433/j.cnki.1003-8728.2015.0717
Abstract:
In order to obtain the dynamic response of the spindle, a new displacement testing method using a new laser sensor is presented in this paper based on the equipment structure and the working condition. The new method is used to test the steady response of the high-speed winder spindle without filament yarn. The test results show that this new testing method is accurate and reliable for the dynamic response testing of the high-speed winder spindle without filament yarn.
In order to obtain the dynamic response of the spindle, a new displacement testing method using a new laser sensor is presented in this paper based on the equipment structure and the working condition. The new method is used to test the steady response of the high-speed winder spindle without filament yarn. The test results show that this new testing method is accurate and reliable for the dynamic response testing of the high-speed winder spindle without filament yarn.
2015, 34(7): 1063-1067.
doi: 10.13433/j.cnki.1003-8728.2015.0718
Abstract:
To exercise the dynamic positioning control of Giant Magneto-restrictive Actuator (GMA) for high precision, it is very crucial to compensate for the impact of strong perturbation derived from structurally inherent uncertainties and outside circumstances. In this paper, a model that considers the perturbation of GMA is established. A sliding mode controller with self-tuning shift gains based on fuzzy control is designed to realize the position tracking of GMA for high precision. The effectiveness of the GMA is verified, its tracking error being below 5%.
To exercise the dynamic positioning control of Giant Magneto-restrictive Actuator (GMA) for high precision, it is very crucial to compensate for the impact of strong perturbation derived from structurally inherent uncertainties and outside circumstances. In this paper, a model that considers the perturbation of GMA is established. A sliding mode controller with self-tuning shift gains based on fuzzy control is designed to realize the position tracking of GMA for high precision. The effectiveness of the GMA is verified, its tracking error being below 5%.
2015, 34(7): 1068-1071.
doi: 10.13433/j.cnki.1003-8728.2015.0719
Abstract:
This paper proposes the design of a continuously variable-speed transmission for grid-connected wind turbines with the influence of a frequency converter taken into consideration. The designed transmission consists of a variable-speed motor and a differential gear train. Through adjusting the motor's output speed, the transmission can provide the constant output rotational speed for the generator under different wind speeds. Then, the generator can output the power to the grid at the constant frequency without the large capacity frequency converter. The dynamic model of the designed transmission is built with the SIMULINK and the aerodynamic loading on rotors under turbulence wind profiles is obtained with simulating a 1.5 MW variable-speed turbine model with the FAST (fatigue, aerodynamics, structural and turbulence) software developed by the NREL (National Renewable Energy Laboratory). The designed motor's variable-speed transmission and its PID controller are verified through computer simulations.
This paper proposes the design of a continuously variable-speed transmission for grid-connected wind turbines with the influence of a frequency converter taken into consideration. The designed transmission consists of a variable-speed motor and a differential gear train. Through adjusting the motor's output speed, the transmission can provide the constant output rotational speed for the generator under different wind speeds. Then, the generator can output the power to the grid at the constant frequency without the large capacity frequency converter. The dynamic model of the designed transmission is built with the SIMULINK and the aerodynamic loading on rotors under turbulence wind profiles is obtained with simulating a 1.5 MW variable-speed turbine model with the FAST (fatigue, aerodynamics, structural and turbulence) software developed by the NREL (National Renewable Energy Laboratory). The designed motor's variable-speed transmission and its PID controller are verified through computer simulations.
2015, 34(7): 1072-1075.
doi: 10.13433/j.cnki.1003-8728.2015.0720
Abstract:
In order to solve the severe buffeting problems of path tracking for visual automated guided vehicle (AGV), an immune particle swarm optimization method is presented to optimize the parameters of sliding mode control law to satisfy achieve more accurate and stable control requirements. Firstly, this paper describes the basic particle swarm optimization and improves it with the introduction of immune mechanism. Then the kinematics model of the visual AGV is analyzed and discrete sliding mode control law is designed. Finally, the simulation of straight-line path and circular path is made with the MATLAB software. The simulation results show that the performance of optimized sliding mode controller is significantly improved.
In order to solve the severe buffeting problems of path tracking for visual automated guided vehicle (AGV), an immune particle swarm optimization method is presented to optimize the parameters of sliding mode control law to satisfy achieve more accurate and stable control requirements. Firstly, this paper describes the basic particle swarm optimization and improves it with the introduction of immune mechanism. Then the kinematics model of the visual AGV is analyzed and discrete sliding mode control law is designed. Finally, the simulation of straight-line path and circular path is made with the MATLAB software. The simulation results show that the performance of optimized sliding mode controller is significantly improved.
2015, 34(7): 1076-1079.
doi: 10.13433/j.cnki.1003-8728.2015.0721
Abstract:
After the balanced processing of GHM multi-wavelets, this paper restores the interfered reverse image signal of a vehicle's information bus with the constant modulus blind equalization algorithm based on balanced orthogonal multi-wavelet transform (MWTCMA). The (MWTCMA with the traditional algorithms such as Constant Modulus Blind Equalization Algorithm (CMA) and Wavelets Transform Constant Modulus Algorithm (WTCMA) are compared. The results show that the use of MWTCMA algorithm can enhance the convergence speed and effectively reduce calculation errors.
After the balanced processing of GHM multi-wavelets, this paper restores the interfered reverse image signal of a vehicle's information bus with the constant modulus blind equalization algorithm based on balanced orthogonal multi-wavelet transform (MWTCMA). The (MWTCMA with the traditional algorithms such as Constant Modulus Blind Equalization Algorithm (CMA) and Wavelets Transform Constant Modulus Algorithm (WTCMA) are compared. The results show that the use of MWTCMA algorithm can enhance the convergence speed and effectively reduce calculation errors.
2015, 34(7): 1080-1084.
doi: 10.13433/j.cnki.1003-8728.2015.0722
Abstract:
In the concept design phase of vehicle body development, based on actual joints, a simplified model of aluminum electric vehicle skeleton was built for lightweight design and stiffness optimization. The components with high sensitivity were selected through sensitivity analysis, and then their sectional thickness were optimized with hybrid and adaptive meta-modeling method (HAM). As a result, the optimization target of body weight has been reduced, while the mode and stiffness of the vehicle body were also improved. The electric vehicle body was produced with the obtained data.
In the concept design phase of vehicle body development, based on actual joints, a simplified model of aluminum electric vehicle skeleton was built for lightweight design and stiffness optimization. The components with high sensitivity were selected through sensitivity analysis, and then their sectional thickness were optimized with hybrid and adaptive meta-modeling method (HAM). As a result, the optimization target of body weight has been reduced, while the mode and stiffness of the vehicle body were also improved. The electric vehicle body was produced with the obtained data.
2015, 34(7): 1085-1088.
doi: 10.13433/j.cnki.1003-8728.2015.0723
Abstract:
The model for simulating the flow and heat transfer in the lubrication system of a heavy-duty automobile transmission was established with AMESim and AMESet and validated on the test bed designed for the automobile transmission. The flow and heat transfer in the lubrication system under different operation conditions were simulated, and the lubrication conditions at several typical nodes were analyzed and improved. The simulation results and their analysis show that all the validated bearings have good lubrication except the left bearing of the middle axle of the heavy-duty automobile transmission under the operation conditions of high speed and light load or low speed and heavy load. It is feasible to increase the oil channel diameter so that the node flow rate increases in order to improve the lubrication of the left bearing of the middle axle.
The model for simulating the flow and heat transfer in the lubrication system of a heavy-duty automobile transmission was established with AMESim and AMESet and validated on the test bed designed for the automobile transmission. The flow and heat transfer in the lubrication system under different operation conditions were simulated, and the lubrication conditions at several typical nodes were analyzed and improved. The simulation results and their analysis show that all the validated bearings have good lubrication except the left bearing of the middle axle of the heavy-duty automobile transmission under the operation conditions of high speed and light load or low speed and heavy load. It is feasible to increase the oil channel diameter so that the node flow rate increases in order to improve the lubrication of the left bearing of the middle axle.
2015, 34(7): 1089-1093.
doi: 10.13433/j.cnki.1003-8728.2015.0724
Abstract:
A simplified vehicle system model was built consisting of bogie and elastic car-body, and the influence of various suspension types of underframe equipments on the vibration of car-body was analyzed. The results show that the flexible suspension of equipment can reduce the vibration of car-body within a certain range of frequency compared to the rigid suspension significantly. The mathematical equation of optimal stiffness was obtained based on the transferring function theory. The equation illustrates that the optimal suspension frequency should be equal to the frequency of first bending mode for car-body. A rigid-flexible coupling model was built in FEM and SIMPACK, and a vibration test was conducted on the roller test rig. The experiments show a good agreement with the simulation results.
A simplified vehicle system model was built consisting of bogie and elastic car-body, and the influence of various suspension types of underframe equipments on the vibration of car-body was analyzed. The results show that the flexible suspension of equipment can reduce the vibration of car-body within a certain range of frequency compared to the rigid suspension significantly. The mathematical equation of optimal stiffness was obtained based on the transferring function theory. The equation illustrates that the optimal suspension frequency should be equal to the frequency of first bending mode for car-body. A rigid-flexible coupling model was built in FEM and SIMPACK, and a vibration test was conducted on the roller test rig. The experiments show a good agreement with the simulation results.
2015, 34(7): 1094-1098.
doi: 10.13433/j.cnki.1003-8728.2015.0725
Abstract:
3-Dimensional solid model and 2-Dimensional axisymmetric model, as well as two numerical simulation methods of calculating mechanical stress field, were introduced in this paper. The 2-Dimensional axisymmetric model was established with the Fourier expansion of mechanical force. Results of these two methods verified that.The stress distribution of wheel web plate under three typical conditions had been analyzed, and von-misses equivalent stress and radial stress variation during one cycle of wheel under three conditions had been obtained. The results of stress analysis show that: wheel hub fillets are weak areas.
3-Dimensional solid model and 2-Dimensional axisymmetric model, as well as two numerical simulation methods of calculating mechanical stress field, were introduced in this paper. The 2-Dimensional axisymmetric model was established with the Fourier expansion of mechanical force. Results of these two methods verified that.The stress distribution of wheel web plate under three typical conditions had been analyzed, and von-misses equivalent stress and radial stress variation during one cycle of wheel under three conditions had been obtained. The results of stress analysis show that: wheel hub fillets are weak areas.
2015, 34(7): 1099-1103.
doi: 10.13433/j.cnki.1003-8728.2015.0726
Abstract:
Through analyzing generated mechanism of steering wheel shimmy, an efficient solution combination of physical experiment and simulation is proposed. Firstly, steering wheel shimmy phenomenon is diagnosed through test, and then the major excitation source and transmission path can be identified. Secondly, the relevant parameters of tire balancing are controlled to reduce the tire incentives. Thirdly, finite element model (FEM) of the whole steering system from the knuckle to the steering wheel is conducted, and then frequency spectrum of acceleration which is obtained based on test is loaded at the knuckle to simulate steering wheel shimmy. Finally, the sequential quadratic programming is performed to optimize the steering system structure and improve the vibration isolation performance. The plate thickness and stiffness of bushing are set as discrete optimization variables, and the Y-direction acceleration of steering wheel at 12 o'clock is set as the objective function. Engineering examples demonstrate that the proposed method can effectively solve the problem of steering wheel shimmy.
Through analyzing generated mechanism of steering wheel shimmy, an efficient solution combination of physical experiment and simulation is proposed. Firstly, steering wheel shimmy phenomenon is diagnosed through test, and then the major excitation source and transmission path can be identified. Secondly, the relevant parameters of tire balancing are controlled to reduce the tire incentives. Thirdly, finite element model (FEM) of the whole steering system from the knuckle to the steering wheel is conducted, and then frequency spectrum of acceleration which is obtained based on test is loaded at the knuckle to simulate steering wheel shimmy. Finally, the sequential quadratic programming is performed to optimize the steering system structure and improve the vibration isolation performance. The plate thickness and stiffness of bushing are set as discrete optimization variables, and the Y-direction acceleration of steering wheel at 12 o'clock is set as the objective function. Engineering examples demonstrate that the proposed method can effectively solve the problem of steering wheel shimmy.
2015, 34(7): 1104-1108.
doi: 10.13433/j.cnki.1003-8728.2015.0727
Abstract:
The finite element model for the aluminum alloy door of an electric vehicle was established. The modal analysis for the door was carried out. The stiffness of the door under 4 harsh conditions was also analyzed. A comprehensive optimization method which was based on the topology optimization, the size optimization and simultaneous optimization for multi-working conditions was proposed. An optimization for the aluminum alloy door was completed to identify the effectiveness of the proposed method. The results show that the weak areas of the door can be found with the present comprehensive optimization method considering the multi-working conditions of Electric Vehicle Door. The stiffness of the door under the 4 working-conditions is increased to 67%~73%, while only little mass is increased for the door. That means that the aim of the light-weight for the door is achieved.
The finite element model for the aluminum alloy door of an electric vehicle was established. The modal analysis for the door was carried out. The stiffness of the door under 4 harsh conditions was also analyzed. A comprehensive optimization method which was based on the topology optimization, the size optimization and simultaneous optimization for multi-working conditions was proposed. An optimization for the aluminum alloy door was completed to identify the effectiveness of the proposed method. The results show that the weak areas of the door can be found with the present comprehensive optimization method considering the multi-working conditions of Electric Vehicle Door. The stiffness of the door under the 4 working-conditions is increased to 67%~73%, while only little mass is increased for the door. That means that the aim of the light-weight for the door is achieved.
2015, 34(7): 1109-1113.
doi: 10.13433/j.cnki.1003-8728.2015.0728
Abstract:
In order to meet the European pedestrian protection regulations for exportation and realize the vehicle lightweight design, the application of aluminum alloy hood is an effective approach to solve this problem. Taking the hood prototype of a sedan as an example, we conduct the lightweight design and analysis with light material substitution and structure dimension topology optimization. The test results show that the aluminum alloy hood with lightweight design satisfied the requirement of static stiffness and outer panel elastic deformation capacity, and the weight of the hood is reduced by 47%.
In order to meet the European pedestrian protection regulations for exportation and realize the vehicle lightweight design, the application of aluminum alloy hood is an effective approach to solve this problem. Taking the hood prototype of a sedan as an example, we conduct the lightweight design and analysis with light material substitution and structure dimension topology optimization. The test results show that the aluminum alloy hood with lightweight design satisfied the requirement of static stiffness and outer panel elastic deformation capacity, and the weight of the hood is reduced by 47%.
2015, 34(7): 1114-1116.
doi: 10.13433/j.cnki.1003-8728.2015.0729
Abstract:
HfO2 film and HfO2:Au film are deposited on ITO substrates with reactive sputtering, and the resistive switching properties of Cu/HfO2/ITO and Cu/HfO2:Au/ITO sandwich structures are investigated. Both devices exhibit bipolar resistive switching behavior. Enhanced performances are achieved in the Cu/HfO2:Au/ITO, including low set voltages and improved uniformity of switching parameters. The switching mechanism of the devices is space charge limited current according to the fitting of the double-log I-V curves. The performance improvement in Cu/HfO2:Au/ITO is clarified to defects and uniform oxygen vacancy conducting filaments induced by Au doping.
HfO2 film and HfO2:Au film are deposited on ITO substrates with reactive sputtering, and the resistive switching properties of Cu/HfO2/ITO and Cu/HfO2:Au/ITO sandwich structures are investigated. Both devices exhibit bipolar resistive switching behavior. Enhanced performances are achieved in the Cu/HfO2:Au/ITO, including low set voltages and improved uniformity of switching parameters. The switching mechanism of the devices is space charge limited current according to the fitting of the double-log I-V curves. The performance improvement in Cu/HfO2:Au/ITO is clarified to defects and uniform oxygen vacancy conducting filaments induced by Au doping.
Weibull Distribution Features and Application of Sample Standard Deviation for Normal Fatigue Matrix
2015, 34(7): 1117-1122.
doi: 10.13433/j.cnki.1003-8728.2015.0730
Abstract:
A computer simulation has been made to study the statistical distribution features of sample standard deviation in different sampling sizes under the normal distribution matrix. The results and their analysis show that the distribution of sample standard deviation appears a skewness which has the same characteristics as Weibull distribution in small scale samples. Then, a stochastic model based on three-parameter Weibull distribution is generalized to describe the distribution parameters. Furthermore, an interval estimating method with higher accuracy which is verified by experimental data, is proposed for the overall standard deviation of small scale samples in reliability analysis.
A computer simulation has been made to study the statistical distribution features of sample standard deviation in different sampling sizes under the normal distribution matrix. The results and their analysis show that the distribution of sample standard deviation appears a skewness which has the same characteristics as Weibull distribution in small scale samples. Then, a stochastic model based on three-parameter Weibull distribution is generalized to describe the distribution parameters. Furthermore, an interval estimating method with higher accuracy which is verified by experimental data, is proposed for the overall standard deviation of small scale samples in reliability analysis.
2015, 34(7): 1123-1126.
doi: 10.13433/j.cnki.1003-8728.2015.0731
Abstract:
Comprehensive experiments were carried out to study the drilling of T300 and T800 carbon fiber reinforced composites using a diamond coated drill. A dynamometer was used to test and observe the drilling force in the process of drilling. The exponential formula models of drilling force were established with the regression analysis method, and the drilling force of the T300 and T800 carbon fiber reinforced composites was obtained. The relationship between the feed and drilling speed was verified, the verification error value being less than 6%. The relationship between export tear factor and drilling force was also established. The axial force and tear factor of T800 carbon fiber reinforced composites have a negative linear relationship, while the axial force and tear factor of T300 carbon fiber reinforced composites have a positive linear relationship.
Comprehensive experiments were carried out to study the drilling of T300 and T800 carbon fiber reinforced composites using a diamond coated drill. A dynamometer was used to test and observe the drilling force in the process of drilling. The exponential formula models of drilling force were established with the regression analysis method, and the drilling force of the T300 and T800 carbon fiber reinforced composites was obtained. The relationship between the feed and drilling speed was verified, the verification error value being less than 6%. The relationship between export tear factor and drilling force was also established. The axial force and tear factor of T800 carbon fiber reinforced composites have a negative linear relationship, while the axial force and tear factor of T300 carbon fiber reinforced composites have a positive linear relationship.
2015, 34(7): 1127-1130.
doi: 10.13433/j.cnki.1003-8728.2015.0732
Abstract:
The existing deflection mechanisms' characteristics are analyzed, the requirements of the nose deflection mechanism is summarized, an efficient mechanism programs-a Screw-Spike nose deflecting mechanism is designed. The relationship between the deflecting angles of nose and the rotation of motors is deduced. Virtual prototype is established and coupled simulating the ADAMS-MATLAB/Simulink. The advantages of high precision, fast response, larger achievable deflection angles meets the requirements of deflectable nose control.
The existing deflection mechanisms' characteristics are analyzed, the requirements of the nose deflection mechanism is summarized, an efficient mechanism programs-a Screw-Spike nose deflecting mechanism is designed. The relationship between the deflecting angles of nose and the rotation of motors is deduced. Virtual prototype is established and coupled simulating the ADAMS-MATLAB/Simulink. The advantages of high precision, fast response, larger achievable deflection angles meets the requirements of deflectable nose control.
2015, 34(7): 1131-1134.
doi: 10.13433/j.cnki.1003-8728.2015.0733
Abstract:
In this paper, the docking accuracy of the low-impact mating system is studied. Referring to the anti-solving equations of the spatial parallel six degrees of freedom mechanism, we deduce the docking accuracy analysis model for the docking process of the low-impact mating system. Then the position and attitude error of the docking ring of low-impact mating system is analyzed with Matlab and the influence of the docking ring radius on the accuracy of the mating system is discussed. Taking the preliminary design simulation model of LIDS for example, we determine the maximum position and attitude error and its location in the working space, and verify the model meets the requirement of accuracy design.
In this paper, the docking accuracy of the low-impact mating system is studied. Referring to the anti-solving equations of the spatial parallel six degrees of freedom mechanism, we deduce the docking accuracy analysis model for the docking process of the low-impact mating system. Then the position and attitude error of the docking ring of low-impact mating system is analyzed with Matlab and the influence of the docking ring radius on the accuracy of the mating system is discussed. Taking the preliminary design simulation model of LIDS for example, we determine the maximum position and attitude error and its location in the working space, and verify the model meets the requirement of accuracy design.
2015, 34(7): 1135-1139.
doi: 10.13433/j.cnki.1003-8728.2015.0734
Abstract:
In this paper, the numerical model of oil droplet impacting and spreading on inclined solid wall is established with volume of fluid(VOF) method, and the spreading characteristics of oil droplet impacting on solid wall is analyzed. The influences of incident angle, impact velocity and diameter of oil droplet on spreading factors are discussed particularly. The results show that front spreading factor increases with decreasing incident angle, increasing impact velocity and diameter of oil droplet; the absolute value of back spreading factor decreases with decreasing incident angle and diameter of oil droplet, whereas it is not affected by impact velocity. Slip phenomenon of oil film is easily observed under the condition of smaller incident angle and diameter of droplet. The analysis results are close to the experimental results and that indicate the correctness of numerical simulation method.
In this paper, the numerical model of oil droplet impacting and spreading on inclined solid wall is established with volume of fluid(VOF) method, and the spreading characteristics of oil droplet impacting on solid wall is analyzed. The influences of incident angle, impact velocity and diameter of oil droplet on spreading factors are discussed particularly. The results show that front spreading factor increases with decreasing incident angle, increasing impact velocity and diameter of oil droplet; the absolute value of back spreading factor decreases with decreasing incident angle and diameter of oil droplet, whereas it is not affected by impact velocity. Slip phenomenon of oil film is easily observed under the condition of smaller incident angle and diameter of droplet. The analysis results are close to the experimental results and that indicate the correctness of numerical simulation method.
2015, 34(7): 1140-1143.
doi: 10.13433/j.cnki.1003-8728.2015.0735
Abstract:
CFRP honeycomb sandwich structures are applied to the design of rudder and elevator of A320 aircraft. Several design evolutions of A320 empennage trailing edge in service were presented. Meanwhile,numerical simulations were carried out by means of FEM and CFD techniques. Main characteristics of different design configurations were studied and the reasons of these design evolutions were analyzed.
CFRP honeycomb sandwich structures are applied to the design of rudder and elevator of A320 aircraft. Several design evolutions of A320 empennage trailing edge in service were presented. Meanwhile,numerical simulations were carried out by means of FEM and CFD techniques. Main characteristics of different design configurations were studied and the reasons of these design evolutions were analyzed.
2015, 34(7): 1144-1148.
doi: 10.13433/j.cnki.1003-8728.2015.0736
Abstract:
The work is focused on engineering design to determine the strength of fuselage structure with large opening under vertical load, lateral load and torsional load. The fuselage stress between the closed fuselage section and the fuselage section with large opening is calculated and compared. The influence of the side beam area ratio and the size of opening on the strength of opening sections are investigated. The present engineering method is validated by comparing with the testing results. It is illustrated that the present method is applicable in the large scale aero-transport fuselage design with large opening.
The work is focused on engineering design to determine the strength of fuselage structure with large opening under vertical load, lateral load and torsional load. The fuselage stress between the closed fuselage section and the fuselage section with large opening is calculated and compared. The influence of the side beam area ratio and the size of opening on the strength of opening sections are investigated. The present engineering method is validated by comparing with the testing results. It is illustrated that the present method is applicable in the large scale aero-transport fuselage design with large opening.
