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RSS2014 Vol. 33, No. 5
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2014, 33(5): 625-629.
doi: 10.13433/j.cnki.1003-8728.2014.0501
PDF 568KB
Abstract:
The Incremental Fuzzy Self-tuning PID Control(IFSPC) is proposed for active vibration control of flexible piezoelectric manipulator. The control system combines fuzzy logic control and incremental PID algorithm, and the main parameters of incremental PID are tuned by fuzzy logic algorithm. The vibration amplitude can be suppressed by IFSPC with a decrement of 80%. And its advanced performance of vibration suppression and stability can be proved by comparison with no-feedback control and the incremental PID control. Its adaptability can be verified by changing the concentrated mass at the end of the arm. The simulation results show that the proposed IFSPC can be used for real-time vibration control in flexible manipulator effectively.
The Incremental Fuzzy Self-tuning PID Control(IFSPC) is proposed for active vibration control of flexible piezoelectric manipulator. The control system combines fuzzy logic control and incremental PID algorithm, and the main parameters of incremental PID are tuned by fuzzy logic algorithm. The vibration amplitude can be suppressed by IFSPC with a decrement of 80%. And its advanced performance of vibration suppression and stability can be proved by comparison with no-feedback control and the incremental PID control. Its adaptability can be verified by changing the concentrated mass at the end of the arm. The simulation results show that the proposed IFSPC can be used for real-time vibration control in flexible manipulator effectively.
2014, 33(5): 630-634.
doi: 10.13433/j.cnki.1003-8728.2014.0502
Abstract:
The calculation of the forward-inclination stability of a complete hydraulic excavator shows that the ratio of normal and tangential digging resistance(marked as λ for short) has great influence on its stability. To enhance its stability and reduce its instability probability,we propose an excavator' s structural optimization method that considers the change in ratio of normal and tangential digging resistance during digging. The genetic algorithm was used to develop the Visual Basic software so as to carry out the multi-objective optimization and design of the counter-balanced parameters of the backhoe hydraulic excavator. The stability coefficient under working conditions is obtained while the ratio of normal and tangential digging resistance is changing. The optimization results meet the work requirements for the hydraulic excavator and prove that our optimization method is valid and feasible.
The calculation of the forward-inclination stability of a complete hydraulic excavator shows that the ratio of normal and tangential digging resistance(marked as λ for short) has great influence on its stability. To enhance its stability and reduce its instability probability,we propose an excavator' s structural optimization method that considers the change in ratio of normal and tangential digging resistance during digging. The genetic algorithm was used to develop the Visual Basic software so as to carry out the multi-objective optimization and design of the counter-balanced parameters of the backhoe hydraulic excavator. The stability coefficient under working conditions is obtained while the ratio of normal and tangential digging resistance is changing. The optimization results meet the work requirements for the hydraulic excavator and prove that our optimization method is valid and feasible.
2014, 33(5): 635-642.
doi: 10.13433/j.cnki.1003-8728.2014.0503
Abstract:
The cleaning robots is gradually becoming a new hot spot which integrated the characteristics of mobile robots and the cleaning technology to become a new high-tech products in service robots with good market prospects in recent years. The composition,classification and characteristics of the cleaning robot werer discussed and the research and development status of the cleaning robot at home and abroad were systemically summarized and the key technologies and the development trend of cleaning robot were presented.
The cleaning robots is gradually becoming a new hot spot which integrated the characteristics of mobile robots and the cleaning technology to become a new high-tech products in service robots with good market prospects in recent years. The composition,classification and characteristics of the cleaning robot werer discussed and the research and development status of the cleaning robot at home and abroad were systemically summarized and the key technologies and the development trend of cleaning robot were presented.
2014, 33(5): 643-646.
doi: 10.13433/j.cnki.1003-8728.2014.0504
Abstract:
The fluid-solid coupling of the river structure was analyzed utilizing the computational fluid module CFX and the Workbench platform in Ansys software. The coupling analysis method in this paper could simulate the modal accurately and effectively,and reduce the calculation error significantly compared with the previous theoretical formula methods. In this method,the fluid force was calculated through CFX; then Workbench delivered the fluid force to the structure by the interpolation method; finally the deformation and stress distributions of the structure were obtained through solid mechanics analysis. This paper also analyzed the size and distribution of the fluid force that acts on the pillar which has the high Reynolds number and free surface flow around cylinder. The result shows the fluid pressure increases approximately linear along the height of the pillar,and decreases firstly then increases along the cylindrical section.
The fluid-solid coupling of the river structure was analyzed utilizing the computational fluid module CFX and the Workbench platform in Ansys software. The coupling analysis method in this paper could simulate the modal accurately and effectively,and reduce the calculation error significantly compared with the previous theoretical formula methods. In this method,the fluid force was calculated through CFX; then Workbench delivered the fluid force to the structure by the interpolation method; finally the deformation and stress distributions of the structure were obtained through solid mechanics analysis. This paper also analyzed the size and distribution of the fluid force that acts on the pillar which has the high Reynolds number and free surface flow around cylinder. The result shows the fluid pressure increases approximately linear along the height of the pillar,and decreases firstly then increases along the cylindrical section.
2014, 33(5): 647-651.
doi: 10.13433/j.cnki.1003-8728.2014.0505
Abstract:
Based on the characteristics of the assembly sequence,the geometric feasibility,the number of assembly orientation changes,and the assembly stability are chosen to be the optimization objective. Subsequently,a modified iterative method of evolutionary direction operator(MEDO) algorithm is used to accelerate the convergence rate of discrete particle swarm optimization(DPSO) algorithm. Then,a new hybrid algorithm MEDODPSO is proposed. The present hybrid algorithm improved the global search ability,and reduced the average iteration algorithm efficiency. The present results show that the hybrid algorithm has excellent global convergence properties and a fast convergence rate. The hybrid algorithm based on IDPSO and MEDO is efficient for solving ASP problems.
Based on the characteristics of the assembly sequence,the geometric feasibility,the number of assembly orientation changes,and the assembly stability are chosen to be the optimization objective. Subsequently,a modified iterative method of evolutionary direction operator(MEDO) algorithm is used to accelerate the convergence rate of discrete particle swarm optimization(DPSO) algorithm. Then,a new hybrid algorithm MEDODPSO is proposed. The present hybrid algorithm improved the global search ability,and reduced the average iteration algorithm efficiency. The present results show that the hybrid algorithm has excellent global convergence properties and a fast convergence rate. The hybrid algorithm based on IDPSO and MEDO is efficient for solving ASP problems.
2014, 33(5): 652-656.
doi: 10.13433/j.cnki.1003-8728.2014.0506
Abstract:
The rubber alloy filtering gear reducer and the filtering gear reducer without rubber alloy layer are established by using the CAD software Solidworks and the mechanical system dynamics simulation software ADAMS,then the rigid-flexible model of the rubber alloy filtering gear reducer is established by using ADAMS. The methods and processes of model establishment is expounded,the dynamic property is analyzed by using ADAMS. The angular velocity,angular acceleration of their output internal gear,the engaging force between the output internal gear and duplicate gear are compared. The displacement of rubber alloy layer is analyzed. The results verified the advance of rubber alloy filtering reducer in smooth transmission.
The rubber alloy filtering gear reducer and the filtering gear reducer without rubber alloy layer are established by using the CAD software Solidworks and the mechanical system dynamics simulation software ADAMS,then the rigid-flexible model of the rubber alloy filtering gear reducer is established by using ADAMS. The methods and processes of model establishment is expounded,the dynamic property is analyzed by using ADAMS. The angular velocity,angular acceleration of their output internal gear,the engaging force between the output internal gear and duplicate gear are compared. The displacement of rubber alloy layer is analyzed. The results verified the advance of rubber alloy filtering reducer in smooth transmission.
2014, 33(5): 657-661.
doi: 10.13433/j.cnki.1003-8728.2014.0507
Abstract:
The grinding experiments are carried out by using the vitrified cubic boron nitride(CBN) wheels on the casted nickel-based superalloy K418. The grinding forces are measured on the various process parameters, including the wheel speed,workpiece speed and depth of cut,and the influencing law of process parameters on the grinding force,force ratio and specific energy are studied in details. The grinding force and force ratio increase with the increasing of workpiece speed,depth of cut and equivalent grinding chip thickness,and with the decreasing of wheel speed. The specific energy decreases with the increasing of equivalent grinding chip thickness. The experience formula of the grinding force with a vitrified CBN wheels is obtained and the relative error is less than 10%.
The grinding experiments are carried out by using the vitrified cubic boron nitride(CBN) wheels on the casted nickel-based superalloy K418. The grinding forces are measured on the various process parameters, including the wheel speed,workpiece speed and depth of cut,and the influencing law of process parameters on the grinding force,force ratio and specific energy are studied in details. The grinding force and force ratio increase with the increasing of workpiece speed,depth of cut and equivalent grinding chip thickness,and with the decreasing of wheel speed. The specific energy decreases with the increasing of equivalent grinding chip thickness. The experience formula of the grinding force with a vitrified CBN wheels is obtained and the relative error is less than 10%.
2014, 33(5): 662-666.
doi: 10.13433/j.cnki.1003-8728.2014.0508
Abstract:
In the process of helical surface form grinding,there are often systematic errors brought via the machining and installation process,and these errors are difficult to avoid and eliminate,which will directly affect the precision of form grinding. A new concept was proposed that the systematic errors was taken as a constant error and feedback to the algorithm of grinding wheel sectional shape,to eliminate the error by changing the theoretical equation of grinding wheel sectional shape. According to the theory of space meshing,the algorithm of grinding wheel sectional shape for helical surface form grinding based on the errors compensation was studied. Moreover,a set of versatility and simple to operate software system about the wheel dressing for helical surface form grinding was developed with VC + +. The experimental results show that the accuracy of gear grinding reaches level 6,the algorithm software is feasibility and practicability.
In the process of helical surface form grinding,there are often systematic errors brought via the machining and installation process,and these errors are difficult to avoid and eliminate,which will directly affect the precision of form grinding. A new concept was proposed that the systematic errors was taken as a constant error and feedback to the algorithm of grinding wheel sectional shape,to eliminate the error by changing the theoretical equation of grinding wheel sectional shape. According to the theory of space meshing,the algorithm of grinding wheel sectional shape for helical surface form grinding based on the errors compensation was studied. Moreover,a set of versatility and simple to operate software system about the wheel dressing for helical surface form grinding was developed with VC + +. The experimental results show that the accuracy of gear grinding reaches level 6,the algorithm software is feasibility and practicability.
2014, 33(5): 667-671.
doi: 10.13433/j.cnki.1003-8728.2014.0509
Abstract:
In order to narrow the product disassembly sequence screening range,to simplify disassembly sequence, and acquire the reasonable disassembly sequence ultimately,the skeleton conceptual models are introduced into the top-down process of product design in this paper. The basic functional-structural information and engineering semantic information which can support the disassembly analysis of products are included in the skeleton model. The product hierarchical relationship is represented by the undirected graph. Through the adjacency matrix which is transformed by undirected graph, disassemble semantic information and the skeleton model, the reasonable disassembly sequence can be acquired concurrently in the design phase of the conceptual design. Finally,this method is used in the bogie design of a high-speed train to verify its feasibility.
In order to narrow the product disassembly sequence screening range,to simplify disassembly sequence, and acquire the reasonable disassembly sequence ultimately,the skeleton conceptual models are introduced into the top-down process of product design in this paper. The basic functional-structural information and engineering semantic information which can support the disassembly analysis of products are included in the skeleton model. The product hierarchical relationship is represented by the undirected graph. Through the adjacency matrix which is transformed by undirected graph, disassemble semantic information and the skeleton model, the reasonable disassembly sequence can be acquired concurrently in the design phase of the conceptual design. Finally,this method is used in the bogie design of a high-speed train to verify its feasibility.
2014, 33(5): 672-676.
doi: 10.13433/j.cnki.1003-8728.2014.0510
Abstract:
Scroll Plate is the main component affecting the performance of the scroll machine. Based on the Reverse Engineering,this paper has obtained the scroll point cloud data via laser scanning and compared the advantages and disadvantages of the contact measurement with the non-contact measurement at the same time. After using the Image ware into the processing point cloud data,the scroll' s reconstruction and reverse based on the CATIA software platform have carried out. This paper has absorbed the advanced technology and promoted the achievements, progress and technical innovation. More importantly,this study has further validated the principle of work of the scroll machine. This paper provided the new technology and methods for the scroll machine' s product design and manufacturing,greatly improved the precision of product design and manufacturing and realized the paperless processing,and the product development cycle has been shortened.
Scroll Plate is the main component affecting the performance of the scroll machine. Based on the Reverse Engineering,this paper has obtained the scroll point cloud data via laser scanning and compared the advantages and disadvantages of the contact measurement with the non-contact measurement at the same time. After using the Image ware into the processing point cloud data,the scroll' s reconstruction and reverse based on the CATIA software platform have carried out. This paper has absorbed the advanced technology and promoted the achievements, progress and technical innovation. More importantly,this study has further validated the principle of work of the scroll machine. This paper provided the new technology and methods for the scroll machine' s product design and manufacturing,greatly improved the precision of product design and manufacturing and realized the paperless processing,and the product development cycle has been shortened.
2014, 33(5): 677-681.
doi: 10.13433/j.cnki.1003-8728.2014.0511
Abstract:
The propagation distance coefficient in the long and short distance Clapper-Yule model represents the probability of incident light propagating laterally along the short and middle distance in halftone prints. In previous works,it was considered as a constant. Based on the spectral reflectance of single ink halftone gradients measured and the actual dot area coverage calculated by using the density method,the relationship between the propagation distance coefficient and the wavelength was studied,the propagation distance coefficient as a function of the wavelength was demonstrated, the long and short distance Clapper-Yule model was improved by using the propagation distance function fitting,and the preliminary analysis on the interaction between the propagation distance function and the optical characteristics of inks and papers was provided. The results of experiments show that enhanced model can more accurately predict the spectral reflectance of single ink halftone print.
The propagation distance coefficient in the long and short distance Clapper-Yule model represents the probability of incident light propagating laterally along the short and middle distance in halftone prints. In previous works,it was considered as a constant. Based on the spectral reflectance of single ink halftone gradients measured and the actual dot area coverage calculated by using the density method,the relationship between the propagation distance coefficient and the wavelength was studied,the propagation distance coefficient as a function of the wavelength was demonstrated, the long and short distance Clapper-Yule model was improved by using the propagation distance function fitting,and the preliminary analysis on the interaction between the propagation distance function and the optical characteristics of inks and papers was provided. The results of experiments show that enhanced model can more accurately predict the spectral reflectance of single ink halftone print.
2014, 33(5): 682-687.
doi: 10.13433/j.cnki.1003-8728.2014.0512
Abstract:
The failure diagnosis technology is an important part of the equipments' normal running. Aiming at the problems in the fault diagnosis,a method combining the extension theory with grey system is proposed. It adopts the extension theory to build matter element modes of failure diagnosis and provides a formal description of the monitoring data. It also applys the principle of index data generation for geting the normalized data. The method covered the shortage of the insurmountable problems of small sample and poor information. a more precise analysis of the correlation degree by increasing the diagnostic information area can be gotten. In order to improve the accuracy of failure diagnosis,the formula of the correlation degree is corrected. The new method is used in the failure diagnosis of antifriction bearing to prove to be effective.
The failure diagnosis technology is an important part of the equipments' normal running. Aiming at the problems in the fault diagnosis,a method combining the extension theory with grey system is proposed. It adopts the extension theory to build matter element modes of failure diagnosis and provides a formal description of the monitoring data. It also applys the principle of index data generation for geting the normalized data. The method covered the shortage of the insurmountable problems of small sample and poor information. a more precise analysis of the correlation degree by increasing the diagnostic information area can be gotten. In order to improve the accuracy of failure diagnosis,the formula of the correlation degree is corrected. The new method is used in the failure diagnosis of antifriction bearing to prove to be effective.
2014, 33(5): 688-692.
doi: 10.13433/j.cnki.1003-8728.2014.0513
Abstract:
Mud pulse transmission is a kind of the most widely used method of wireless measurement while drilling. In order to improve the performance of mud positive pulse generator and to accelerate the generation rate of the pulse signal and its transmission distance in the Logging While Drilling(LWD) system,the stator and the rotor blade should be rationally designed. The equations of valve shape curve to generate desired pressure valve signal can be derived from orifice pressure-flow relationship. Based on the optimized equation,the design of the stator and rotor shape can be rectified. With the help of computational fluid dynamics(CFD) technique,the threedimensional flow fields simulation analysis has been conducted on the characteristics of the rotary valve coverage. Then the transmission characteristics of the rotary valve in LWD system are validated experimentally. The results show that the rotor blade profile can be designed as a polar coordinate curve,which can be used to get stable positive pressure wave signal of positive pulse; The hydraulic torque can be changed mildly using the curved orifice; The overflow valve and wear sleeve are designed to solve the problem of erosion.
Mud pulse transmission is a kind of the most widely used method of wireless measurement while drilling. In order to improve the performance of mud positive pulse generator and to accelerate the generation rate of the pulse signal and its transmission distance in the Logging While Drilling(LWD) system,the stator and the rotor blade should be rationally designed. The equations of valve shape curve to generate desired pressure valve signal can be derived from orifice pressure-flow relationship. Based on the optimized equation,the design of the stator and rotor shape can be rectified. With the help of computational fluid dynamics(CFD) technique,the threedimensional flow fields simulation analysis has been conducted on the characteristics of the rotary valve coverage. Then the transmission characteristics of the rotary valve in LWD system are validated experimentally. The results show that the rotor blade profile can be designed as a polar coordinate curve,which can be used to get stable positive pressure wave signal of positive pulse; The hydraulic torque can be changed mildly using the curved orifice; The overflow valve and wear sleeve are designed to solve the problem of erosion.
2014, 33(5): 693-696.
doi: 10.13433/j.cnki.1003-8728.2014.0514
Abstract:
To design the flow field in electrochemical turning(ECT),the numerical model was established based on the structure of the inner-spraying cathode and the physical model of the flow channel. The computational fluid dynamics(CFD) method was applied to solve the numerical model and the distributions of the velocity and pressure were obtained. The influences of the cathode internal structure on the flow field were analyzed according to the numerical simulation results. The better simulation results were obtained by means of the optimization of the cathode internal structure. Based on the experiment,the accuracy of numerical simulation results was verified. It is indicated that the CFD method can be applied to simulate the flow field and guide the optimization of the cathode internal structure.
To design the flow field in electrochemical turning(ECT),the numerical model was established based on the structure of the inner-spraying cathode and the physical model of the flow channel. The computational fluid dynamics(CFD) method was applied to solve the numerical model and the distributions of the velocity and pressure were obtained. The influences of the cathode internal structure on the flow field were analyzed according to the numerical simulation results. The better simulation results were obtained by means of the optimization of the cathode internal structure. Based on the experiment,the accuracy of numerical simulation results was verified. It is indicated that the CFD method can be applied to simulate the flow field and guide the optimization of the cathode internal structure.
2014, 33(5): 697-701.
doi: 10.13433/j.cnki.1003-8728.2014.0515
Abstract:
Based on the mechanical model of traditional multi-support rotor system,the effects of stiffness of the bearing load sensors and couplings,and the torque excitation on multi-support rotor were considered,and thus an improved mechanical model for traditional multi-support rotor system was set up. Taking the transient torque excitation as an example,the vibration responses of the multi-support rotor system with and without transient torque excitation were simulated and analyzed,which result was also verified by the experiment. The accuracy of the improved model is checked,laying foundation for the study of the vibration in multi-support rotor system.
Based on the mechanical model of traditional multi-support rotor system,the effects of stiffness of the bearing load sensors and couplings,and the torque excitation on multi-support rotor were considered,and thus an improved mechanical model for traditional multi-support rotor system was set up. Taking the transient torque excitation as an example,the vibration responses of the multi-support rotor system with and without transient torque excitation were simulated and analyzed,which result was also verified by the experiment. The accuracy of the improved model is checked,laying foundation for the study of the vibration in multi-support rotor system.
2014, 33(5): 702-705.
doi: 10.13433/j.cnki.1003-8728.2014.0516
Abstract:
The temperature filed in the multi-step cold forging of a camber bolt was predicted by using finite element method coupling heat. Firstly,the mechanical energy conversion rate was determined according to the practice data,and the temperature filed in the forging process of a camber bolt was analyzed. Furthermore,the effect of the punch speed on the temperature and the load was also studied. Finally,the experimental results was presented for the correctness of the present method. As a result,the present method was reliable and analyzed that the temperature was approximately linear increase within the given punch speed,while the load decrease and then nearly change little. It provides an important reference for productivity in industry.
The temperature filed in the multi-step cold forging of a camber bolt was predicted by using finite element method coupling heat. Firstly,the mechanical energy conversion rate was determined according to the practice data,and the temperature filed in the forging process of a camber bolt was analyzed. Furthermore,the effect of the punch speed on the temperature and the load was also studied. Finally,the experimental results was presented for the correctness of the present method. As a result,the present method was reliable and analyzed that the temperature was approximately linear increase within the given punch speed,while the load decrease and then nearly change little. It provides an important reference for productivity in industry.
2014, 33(5): 706-710.
doi: 10.13433/j.cnki.1003-8728.2014.0517
Abstract:
Considering the mode mixing in empirical mode decomposition,a novel method that combines singular value decomposition(SVD) with improved empirical mode decomposition(EMD) is proposed. The first step of this method is to reduce the random noise in fault signal by the SVD,and then the high frequency harmonic is added by the characteristic of original signal before EMD. The preprocessed signal is decomposed by EMD to restrain the mode mixing effectively. Finally,envelope demodulation is performed for the intrinsic mode function(IMF) of shock signal and as a result,the fault feature was extracted successfully. The implementation process was analyzed by simulated signal and this method has been successfully applied in inner race and outer race of rolling bearing fault diagnosis. The results show that this method can extract the fault information of rolling bearing effectively and realize the fault diagnosis.
Considering the mode mixing in empirical mode decomposition,a novel method that combines singular value decomposition(SVD) with improved empirical mode decomposition(EMD) is proposed. The first step of this method is to reduce the random noise in fault signal by the SVD,and then the high frequency harmonic is added by the characteristic of original signal before EMD. The preprocessed signal is decomposed by EMD to restrain the mode mixing effectively. Finally,envelope demodulation is performed for the intrinsic mode function(IMF) of shock signal and as a result,the fault feature was extracted successfully. The implementation process was analyzed by simulated signal and this method has been successfully applied in inner race and outer race of rolling bearing fault diagnosis. The results show that this method can extract the fault information of rolling bearing effectively and realize the fault diagnosis.
2014, 33(5): 711-715.
doi: 10.13433/j.cnki.1003-8728.2014.0518
Abstract:
The working conditions of open-pit's frontloader are very odious,and depends on the tradition man-made lubrication method in a long time. There are many problems,such as the inefficient,lubrication poor,high production costs and so on. Using quicklub solve the issue,the self-lubrication system has been designed,the working principle and mathematical model are studied. Gaining some the oil circuit of flow and pressure in different system working pressure or external load relys on AMESim. In addition,it use equipment to gather some the oil circuit of flow and pressure,and compared the scene with the research results. As a result,the scene is the same as the research results,this design is reasonable and effective,the self-lubrication system meets the Wheel loader lubrication requirements.
The working conditions of open-pit's frontloader are very odious,and depends on the tradition man-made lubrication method in a long time. There are many problems,such as the inefficient,lubrication poor,high production costs and so on. Using quicklub solve the issue,the self-lubrication system has been designed,the working principle and mathematical model are studied. Gaining some the oil circuit of flow and pressure in different system working pressure or external load relys on AMESim. In addition,it use equipment to gather some the oil circuit of flow and pressure,and compared the scene with the research results. As a result,the scene is the same as the research results,this design is reasonable and effective,the self-lubrication system meets the Wheel loader lubrication requirements.
2014, 33(5): 716-722.
doi: 10.13433/j.cnki.1003-8728.2014.0519
Abstract:
The torque stability of a permanent magnet(PM) synchronous motor spindle is affected by the torque ripple caused by cogging torque. The surface quality of work-piece is further affected. The engineering analytical method may lead to big errors between theory and reality because it is assumed that it does not consider magnetic saturation,magnetic flux leakage and complex structure. The finite element method is adopted to study the effects of stator slot width,skewing,pole-arc coefficient and PM offset on cogging torque and motor performance.The physical mechanism of cogging torque is revealed. The method for reducing cogging torque is proposed by optimizing the motor's parameters. The study results show that the method proposed in the paper can reduce cogging torque substantially and improve the dynamic performance.
The torque stability of a permanent magnet(PM) synchronous motor spindle is affected by the torque ripple caused by cogging torque. The surface quality of work-piece is further affected. The engineering analytical method may lead to big errors between theory and reality because it is assumed that it does not consider magnetic saturation,magnetic flux leakage and complex structure. The finite element method is adopted to study the effects of stator slot width,skewing,pole-arc coefficient and PM offset on cogging torque and motor performance.The physical mechanism of cogging torque is revealed. The method for reducing cogging torque is proposed by optimizing the motor's parameters. The study results show that the method proposed in the paper can reduce cogging torque substantially and improve the dynamic performance.
2014, 33(5): 723-729.
doi: 10.13433/j.cnki.1003-8728.2014.0520
Abstract:
Due to its non-smoothness and multi-value mapping,it is difficult to apply the conventional identification methods to identifying the hysteresis model. Moreover,if the hysteresis subsystem follows with a linear subsystem,it is more challenging to identify the Hammerstein model because the output of the hysteresis model cannot be measured directly. This paper proposes a two-stage method. Firstly,the degeneration input,which is a special exciting signal,is designed to degenerate the hysteresis into a static smooth curve with one-to-one mapping. Thus, the non-smoothness and multi-value mapping of hysteresis are avoided so that the parameters of the linear subsystem can be estimated by the recursive general identification algorithm(RGIA). Secondly,with the identified linear submodel,the hysteresis subsystem is modeled with the expanded input space method. Finally,a PID feedforward controller for controlling the motion of the PEA is proposed. The experimental results on the PEA are presented to show the effects of the identification and control method.
Due to its non-smoothness and multi-value mapping,it is difficult to apply the conventional identification methods to identifying the hysteresis model. Moreover,if the hysteresis subsystem follows with a linear subsystem,it is more challenging to identify the Hammerstein model because the output of the hysteresis model cannot be measured directly. This paper proposes a two-stage method. Firstly,the degeneration input,which is a special exciting signal,is designed to degenerate the hysteresis into a static smooth curve with one-to-one mapping. Thus, the non-smoothness and multi-value mapping of hysteresis are avoided so that the parameters of the linear subsystem can be estimated by the recursive general identification algorithm(RGIA). Secondly,with the identified linear submodel,the hysteresis subsystem is modeled with the expanded input space method. Finally,a PID feedforward controller for controlling the motion of the PEA is proposed. The experimental results on the PEA are presented to show the effects of the identification and control method.
2014, 33(5): 730-734.
doi: 10.13433/j.cnki.1003-8728.2014.0521
Abstract:
Wind turbine blade easily vibrate and deform as a slender elastomer at working,and the smooth running of wind turbine have been seriously affected. In this pape,the finite element numerical simulation is adopted for studying the vibration characteristics of the blade. The static frequency and dynamic frequency of the blade is studied by the modal analysis,the first six order vibration frequency and the corresponding vibration mode of blade are acquired,the waving and swing vibration for the main vibration mode are showed; then the prestressed vibration characteristics in a certain wind speeds and rotor speeds are analyzed,the effective rules of wind speeds and rotor speeds on the blade vibration frequency are received. On that basis,the vibration characteristics at the biggest wind pressure and rotor speed are analyzed through the harmonic response analysis,the change rules of displacementfrequency response of the blade which is under the action of forced load are acquired.
Wind turbine blade easily vibrate and deform as a slender elastomer at working,and the smooth running of wind turbine have been seriously affected. In this pape,the finite element numerical simulation is adopted for studying the vibration characteristics of the blade. The static frequency and dynamic frequency of the blade is studied by the modal analysis,the first six order vibration frequency and the corresponding vibration mode of blade are acquired,the waving and swing vibration for the main vibration mode are showed; then the prestressed vibration characteristics in a certain wind speeds and rotor speeds are analyzed,the effective rules of wind speeds and rotor speeds on the blade vibration frequency are received. On that basis,the vibration characteristics at the biggest wind pressure and rotor speed are analyzed through the harmonic response analysis,the change rules of displacementfrequency response of the blade which is under the action of forced load are acquired.
2014, 33(5): 735-740.
doi: 10.13433/j.cnki.1003-8728.2014.0522
Abstract:
The heat generated by the rotor of a high-speed and large-power motor is very big. If the heat is not effectively removed by the cooling system of the rotor,the temperature of its bearing will rise greatly. When the motor is operating,its reliability and safety may be reduced,too. It is difficult for the traditional method that separates the rotor and its cooling gas flow field to show the heat coupling between the rotor and its cooling gas flow field and achieve heat dissipation efficiency optimization. Therefore we propose the method of dynamic heat transfer characteristics of the rotor of the high-speed and large-power motor based on fluid-solid coupling. The fluid-solid coupling heat transfer model of the rotor is established. The method and the model are used to study the effects of rotational speed,entrance pressure and velocity of cooling air flow,aperture,distribution and axial distance of the cooling hole of the rotor on its temperature field and heat dissipation efficiency. The heat dissipation efficiency of the rotor is optimized. The simulation and experimental results show that the heat dissipation efficiency optimization method is effective.
The heat generated by the rotor of a high-speed and large-power motor is very big. If the heat is not effectively removed by the cooling system of the rotor,the temperature of its bearing will rise greatly. When the motor is operating,its reliability and safety may be reduced,too. It is difficult for the traditional method that separates the rotor and its cooling gas flow field to show the heat coupling between the rotor and its cooling gas flow field and achieve heat dissipation efficiency optimization. Therefore we propose the method of dynamic heat transfer characteristics of the rotor of the high-speed and large-power motor based on fluid-solid coupling. The fluid-solid coupling heat transfer model of the rotor is established. The method and the model are used to study the effects of rotational speed,entrance pressure and velocity of cooling air flow,aperture,distribution and axial distance of the cooling hole of the rotor on its temperature field and heat dissipation efficiency. The heat dissipation efficiency of the rotor is optimized. The simulation and experimental results show that the heat dissipation efficiency optimization method is effective.
2014, 33(5): 741-745.
doi: 10.13433/j.cnki.1003-8728.2014.0523
Abstract:
Due to the defects of low energy transfer efficiency and high residuary pressure in water-gas two phase jet pump,the concept of annular water-air self-excited oscillation jet has been put forward combining with the advantages of the annular jet and the self-excited oscillating jet. The conservation of momentum and continuity equations has been obtained based on the theory of annular jet. The flow field of the annular water-air self-excited oscillating jet has been simulated by using the Realizable k-ε turbulence model and the Euler multiphase model on the steady and unsteady simulations respectively. The performance parameters of the annular water-jet self-excited oscillation jet pump,such as the pressure ratio h、the efficiency η and the flow ratio q,have been calculated,and the basic performance curve has been obtained comparing with ordinary annular water-air jet pump. The average fluid speed at the down nozzle has been calculated via the unsteady simulation,and the frequency of instantaneous pressure pulse at the down nozzle has been obtained by analyzing the experiment data. The results showed that the entrainment capability can be enhanced by the annular water-air self-excited oscillation jet comparing with the ordinary annular water-gas jet,and the instantaneous speed of the mixed phase at the down nozzle has a significant pulse frequency.
Due to the defects of low energy transfer efficiency and high residuary pressure in water-gas two phase jet pump,the concept of annular water-air self-excited oscillation jet has been put forward combining with the advantages of the annular jet and the self-excited oscillating jet. The conservation of momentum and continuity equations has been obtained based on the theory of annular jet. The flow field of the annular water-air self-excited oscillating jet has been simulated by using the Realizable k-ε turbulence model and the Euler multiphase model on the steady and unsteady simulations respectively. The performance parameters of the annular water-jet self-excited oscillation jet pump,such as the pressure ratio h、the efficiency η and the flow ratio q,have been calculated,and the basic performance curve has been obtained comparing with ordinary annular water-air jet pump. The average fluid speed at the down nozzle has been calculated via the unsteady simulation,and the frequency of instantaneous pressure pulse at the down nozzle has been obtained by analyzing the experiment data. The results showed that the entrainment capability can be enhanced by the annular water-air self-excited oscillation jet comparing with the ordinary annular water-gas jet,and the instantaneous speed of the mixed phase at the down nozzle has a significant pulse frequency.
2014, 33(5): 746-750.
doi: 10.13433/j.cnki.1003-8728.2014.0524
Abstract:
This paper took a tractor frame as the research object,analyzed the frame with finite element method,and got the strength of the frame structure value. Because frame materials elasticity and density is uncertain. It is needed to consider these uncertainties to get the reliability. This paper used IRSM to construct the approximation model,then got the reliability. The objective function is the lightest quality which associated with variable frame components and the original thickness of reliability indexes as constraint. Using the IP-GA to solve this uncertain optimization model. Then compared with the probabilistic reliability optimization. The results show that the certainty and uncertainty optimization can be lightweight without reducing the original thickness of the reliability index; uncertain optimization is more than the deterministic optimization to reduce quality of 20 kg,so it has more advantages.
This paper took a tractor frame as the research object,analyzed the frame with finite element method,and got the strength of the frame structure value. Because frame materials elasticity and density is uncertain. It is needed to consider these uncertainties to get the reliability. This paper used IRSM to construct the approximation model,then got the reliability. The objective function is the lightest quality which associated with variable frame components and the original thickness of reliability indexes as constraint. Using the IP-GA to solve this uncertain optimization model. Then compared with the probabilistic reliability optimization. The results show that the certainty and uncertainty optimization can be lightweight without reducing the original thickness of the reliability index; uncertain optimization is more than the deterministic optimization to reduce quality of 20 kg,so it has more advantages.
2014, 33(5): 751-753.
doi: 10.13433/j.cnki.1003-8728.2014.0525
Abstract:
The finite element model for the cab of a heavy mine car is set up and the modal analysis is performed based on the model to get first ten order frequencies of the cab. Comparing the sensitivities of the first order torsion modal frequency to thickness and mass of main parts by the finite element method,the large absolute value of relative sensitive cab's panels are selected as design variables for structural optimization. The optimization results show that the first order modal frequency of the cab is changed from 35.3 Hz to 45.2 Hz while the cab's mass doesn't increase.
The finite element model for the cab of a heavy mine car is set up and the modal analysis is performed based on the model to get first ten order frequencies of the cab. Comparing the sensitivities of the first order torsion modal frequency to thickness and mass of main parts by the finite element method,the large absolute value of relative sensitive cab's panels are selected as design variables for structural optimization. The optimization results show that the first order modal frequency of the cab is changed from 35.3 Hz to 45.2 Hz while the cab's mass doesn't increase.
2014, 33(5): 754-757.
doi: 10.13433/j.cnki.1003-8728.2014.0526
Abstract:
Applying the theory of FEA(Finite Element Analysis) and Optistuct software,the paper analyzed the stiffness and frequency of the support base of a motorcycle seat to get the deformation distribution,stress distribution and lower modal frequencies. Based on the analyzing results,an optimization approach combining topological optimization and topography optimization is adopted to conduct structure optimization by taking flexibility and frequency as the optimization objective respectively; then aiming at the insufficiency in single objective optimization, a multi-objective optimization scheme is proposed with comprehensive consideration; a optimization model is acquired and compared with the original scheme and the single objective optimization scheme.The results indicate that the multi-objective optimization scheme not only reduces 10% of product weight and 60% of flexibility,saves the cost with 1 Yuan RMB,but also the comprehensive performances such as frequency are much more optimized than the original one and single objective one.
Applying the theory of FEA(Finite Element Analysis) and Optistuct software,the paper analyzed the stiffness and frequency of the support base of a motorcycle seat to get the deformation distribution,stress distribution and lower modal frequencies. Based on the analyzing results,an optimization approach combining topological optimization and topography optimization is adopted to conduct structure optimization by taking flexibility and frequency as the optimization objective respectively; then aiming at the insufficiency in single objective optimization, a multi-objective optimization scheme is proposed with comprehensive consideration; a optimization model is acquired and compared with the original scheme and the single objective optimization scheme.The results indicate that the multi-objective optimization scheme not only reduces 10% of product weight and 60% of flexibility,saves the cost with 1 Yuan RMB,but also the comprehensive performances such as frequency are much more optimized than the original one and single objective one.
2014, 33(5): 758-762.
doi: 10.13433/j.cnki.1003-8728.2014.0527
Abstract:
The mechanical model and the mathematical model were established according to the structure of magnetorheological(MR) engine mount,and the influence of dynamic characteristics under low frequency excitation was studied by using MATLAB / SIMULINK. The influences of current intensity,excitation amplitude,the equivalent area of rubber spring and the excitation frequency on the dynamic characteristics of MR mount have been analyzed. The results show that the MR mount can gain greater damping and stiffness than the hydraulic mount under the conditions of low frequency and large amplitude.
The mechanical model and the mathematical model were established according to the structure of magnetorheological(MR) engine mount,and the influence of dynamic characteristics under low frequency excitation was studied by using MATLAB / SIMULINK. The influences of current intensity,excitation amplitude,the equivalent area of rubber spring and the excitation frequency on the dynamic characteristics of MR mount have been analyzed. The results show that the MR mount can gain greater damping and stiffness than the hydraulic mount under the conditions of low frequency and large amplitude.
2014, 33(5): 763-768.
doi: 10.13433/j.cnki.1003-8728.2014.0528
Abstract:
In the view of the problem of cost,accuracy and reliability requirements of the high-speed train bearing, a minimum sample censored time test can only be performed in a short time during the reliability life test. In this case,the incomplete mixed Beta distribution is adopted as a prior distribution of the bearing cumulative failure probability to evaluate its reliability effectively. According to the hierarchical bayesian reliability assessment method,the reliability mathematical model is obtained for the high-speed train bearing in the condition of minimum sample and zero-failure. The calculating result is in line with the actual situation at the request of a given reliability index. And the assessment method considering the incomplete mixed Beta distribution is more reasonable than the traditional Bayesian method.
In the view of the problem of cost,accuracy and reliability requirements of the high-speed train bearing, a minimum sample censored time test can only be performed in a short time during the reliability life test. In this case,the incomplete mixed Beta distribution is adopted as a prior distribution of the bearing cumulative failure probability to evaluate its reliability effectively. According to the hierarchical bayesian reliability assessment method,the reliability mathematical model is obtained for the high-speed train bearing in the condition of minimum sample and zero-failure. The calculating result is in line with the actual situation at the request of a given reliability index. And the assessment method considering the incomplete mixed Beta distribution is more reasonable than the traditional Bayesian method.
2014, 33(5): 769-775.
doi: 10.13433/j.cnki.1003-8728.2014.0529
Abstract:
In order to improve the locomotive cab design,the driving interface layout design based on the locomotive driver's cognitive and behavioral characteristics was studied. The driver' s integrated cognition model and behavior dynamic model were established, and the driver' s eye tracking experiment was executed. Furthermore,the relationship between the behavioral levels and the cognitive hierarchies was analyzed,and the principles of the locomotive driving interface design were proposed taking the general features of driver's cognition and behavior as constraints. Based on the above-mentioned,the general design procedure of the locomotive driving interface was proposed,the visual information in the cab were grouped and integrated,and the layout design scheme of the locomotive driving interface was proposed.
In order to improve the locomotive cab design,the driving interface layout design based on the locomotive driver's cognitive and behavioral characteristics was studied. The driver' s integrated cognition model and behavior dynamic model were established, and the driver' s eye tracking experiment was executed. Furthermore,the relationship between the behavioral levels and the cognitive hierarchies was analyzed,and the principles of the locomotive driving interface design were proposed taking the general features of driver's cognition and behavior as constraints. Based on the above-mentioned,the general design procedure of the locomotive driving interface was proposed,the visual information in the cab were grouped and integrated,and the layout design scheme of the locomotive driving interface was proposed.
2014, 33(5): 776-780.
doi: 10.13433/j.cnki.1003-8728.2014.0530
Abstract:
In order to improve the damping performance of vehicle seat suspension,a three degree-of-freedom seat suspension model was established and an adaptive fuzzy proportion-integration-differentiation(PID) control method integrating the Fuzzy and PID control theories was presented. Selecting the seat vertical vibration velocity as the input variable,a PID controller was designed and its parameters were modified by the fuzzy controller with qualities of parameter self-regulating function,which used the velocity and acceleration of seat vertical vibration as the input sources. By using MATLAB / Simulink,the adaptive fuzzy-PID controller was validated under the input of the white noise stochastic road surface of C-grade. The simulation results show that the adaptive fuzzy-PID control method can effectively suppress the seat suspension's vibration and obviously reduce the acceleration of seat vertical vibration, compared with the control modes of seat passive suspension and active suspension only with the conventional PID controller.
In order to improve the damping performance of vehicle seat suspension,a three degree-of-freedom seat suspension model was established and an adaptive fuzzy proportion-integration-differentiation(PID) control method integrating the Fuzzy and PID control theories was presented. Selecting the seat vertical vibration velocity as the input variable,a PID controller was designed and its parameters were modified by the fuzzy controller with qualities of parameter self-regulating function,which used the velocity and acceleration of seat vertical vibration as the input sources. By using MATLAB / Simulink,the adaptive fuzzy-PID controller was validated under the input of the white noise stochastic road surface of C-grade. The simulation results show that the adaptive fuzzy-PID control method can effectively suppress the seat suspension's vibration and obviously reduce the acceleration of seat vertical vibration, compared with the control modes of seat passive suspension and active suspension only with the conventional PID controller.
2014, 33(5): 781-784.
doi: 10.13433/j.cnki.1003-8728.2014.0531
Abstract:
A new non-probabilistic model of structural fatigue reliability was proposed based on interval analysis theory to deal with the lack of exact probabilistic data of uncertain parameters in structural reliability analysis. The uncertain parameters of structures,such as initial crack size,crack tolerance and structural longevity were indicated by interval variables. An interfering model combining residual strength with service time was established using interval analysis method. Based on this model,a new calculation method of structural fatigue reliability was proposed,which can be used not only to analyze structural fatigue reliability conveniently but also requires less distribution information of uncertainties. Numerical example was presented to verify the validity of this proposed method.
A new non-probabilistic model of structural fatigue reliability was proposed based on interval analysis theory to deal with the lack of exact probabilistic data of uncertain parameters in structural reliability analysis. The uncertain parameters of structures,such as initial crack size,crack tolerance and structural longevity were indicated by interval variables. An interfering model combining residual strength with service time was established using interval analysis method. Based on this model,a new calculation method of structural fatigue reliability was proposed,which can be used not only to analyze structural fatigue reliability conveniently but also requires less distribution information of uncertainties. Numerical example was presented to verify the validity of this proposed method.
2014, 33(5): 785-788.
doi: 10.13433/j.cnki.1003-8728.2014.0532
Abstract:
For a more reasonable ergonomics evaluating method of airplane passenger cabin interior environment, the system of related evaluation indexes was analyzed,the hierarchies and the character of grey system were clarified,the index weights were established,and three design works were evaluated by the multi-hierarchy grey relation(MHGR) model practically and fed back with some constructive design suggestions. Fuzzy evaluation theory was applied to evaluation and comparison for the objects above,and the results were consistent. The practical experiments indicated that the MHGR model used in ergonomics evaluation can obtain scientific consequences and will be of greater value to program design optimization.
For a more reasonable ergonomics evaluating method of airplane passenger cabin interior environment, the system of related evaluation indexes was analyzed,the hierarchies and the character of grey system were clarified,the index weights were established,and three design works were evaluated by the multi-hierarchy grey relation(MHGR) model practically and fed back with some constructive design suggestions. Fuzzy evaluation theory was applied to evaluation and comparison for the objects above,and the results were consistent. The practical experiments indicated that the MHGR model used in ergonomics evaluation can obtain scientific consequences and will be of greater value to program design optimization.
