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RSS2012 Vol. 31, No. 10
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2012, 31(10): 1549-1553.
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Abstract:
To improve the grinding efficiency of a large nuclear-electric blade and the existing sand belt grinding tool path generation method,we propose a novel six-axis joint motion spiral grinding method for the blade with a compound surface.Its core consists of: 1) with the boundary curves and the surface form adjacent to the compound surface,we work out the formula for calculating the blade's sand belt spiral grinding and cutter contact points and the tool path;2) we develop the CNC programming module with our own CAD/CAM programming platform,thus generating the continuously smooth spiral grinding tool path for the blade.Compared with the previous horizontal and vertical sand belt grinding method,our method significantly reduces the processing time and production costs and improves the machining efficiency.
To improve the grinding efficiency of a large nuclear-electric blade and the existing sand belt grinding tool path generation method,we propose a novel six-axis joint motion spiral grinding method for the blade with a compound surface.Its core consists of: 1) with the boundary curves and the surface form adjacent to the compound surface,we work out the formula for calculating the blade's sand belt spiral grinding and cutter contact points and the tool path;2) we develop the CNC programming module with our own CAD/CAM programming platform,thus generating the continuously smooth spiral grinding tool path for the blade.Compared with the previous horizontal and vertical sand belt grinding method,our method significantly reduces the processing time and production costs and improves the machining efficiency.
2012, 31(10): 1554-1558.
Abstract:
In order to improve the positioning accuracy of the permanent magnet linear synchronous motors(PMLSM),a neural network is adopted to identify and compensate two types of disturbance force represented by thrust ripple and cutting force respectively in this paper.At first,the thrust ripple result from special structure of PMLSM was identified by sampling the no-load current of motor and modifying the phase difference;then,the model of thrust ripple was built and the parameters of neural network offline were optimized.Also,eliminate the error of model and compensate for the second type of disturbance force with the adaptability and nonlinear function of neural network.A complex controller with three loops and feed forward based on neural network is designed to conquer the disadvantage of pure model and makes full use of the predictable disturbance force.Simulation results verify that this controller can improve the positioning accuracy of PMLSM and its robustness is strong.
In order to improve the positioning accuracy of the permanent magnet linear synchronous motors(PMLSM),a neural network is adopted to identify and compensate two types of disturbance force represented by thrust ripple and cutting force respectively in this paper.At first,the thrust ripple result from special structure of PMLSM was identified by sampling the no-load current of motor and modifying the phase difference;then,the model of thrust ripple was built and the parameters of neural network offline were optimized.Also,eliminate the error of model and compensate for the second type of disturbance force with the adaptability and nonlinear function of neural network.A complex controller with three loops and feed forward based on neural network is designed to conquer the disadvantage of pure model and makes full use of the predictable disturbance force.Simulation results verify that this controller can improve the positioning accuracy of PMLSM and its robustness is strong.
2012, 31(10): 1559-1563.
Abstract:
It is a potential method of reseach on two-phase oil/gas flow lubrication in aeroengine bearing chamber based on flow pattern classification,in which the identification to oil/gas two-phase flow pattern in bearing chamber is an important work.Based on the relationships between the two-phase oil/gas flow pattern and the match of geometry and operating condition in bearing chamber relying on nondimensional parameters and mean splashing parameter,a new method was proposed to identify flow pattern of oil/gas two-phase flow.The results of two-phase oil/gas flow pattern identification by the present method agreed well with the former experimental results.The present work realized evaluation of two-phase flow pattern according to the geometry and operating condition in bearing chamber,and it is conducive to analyzing two-phase oil/gas flow lubrication and designing heat transfer.
It is a potential method of reseach on two-phase oil/gas flow lubrication in aeroengine bearing chamber based on flow pattern classification,in which the identification to oil/gas two-phase flow pattern in bearing chamber is an important work.Based on the relationships between the two-phase oil/gas flow pattern and the match of geometry and operating condition in bearing chamber relying on nondimensional parameters and mean splashing parameter,a new method was proposed to identify flow pattern of oil/gas two-phase flow.The results of two-phase oil/gas flow pattern identification by the present method agreed well with the former experimental results.The present work realized evaluation of two-phase flow pattern according to the geometry and operating condition in bearing chamber,and it is conducive to analyzing two-phase oil/gas flow lubrication and designing heat transfer.
2012, 31(10): 1564-1568.
Abstract:
It is difficult to directly measure the key parameters of metal droplets during the spraying process,because the size of metal droplet is small and the rupture process is short duration based on the principle of pneumatic drop-on-demand generation.In order to solve this problem,the image acquisition system for the metal droplet forming process was constructed based on delay trigger method.Sn-Pb alloy(60%Sn～40%Pb) droplet spray experiments had been conducted with a generator nozzle of 200 μm in diameter.The steady spray process was captured by the image acquisition system,then the forming mechanism of the metal droplet was analyzed and the key parameters were measured.The results show that the spraying process of metal droplet can be reappeared by combining different photographs of delay time.The coordinates and diameter of droplets were obtained in different delay times,and the flight velocity and deviation angle of droplets were calculated.The generating mechanic of metal droplets was revealed,and the change trends of droplet divergent was predicted along with the increasing of flight distance.
It is difficult to directly measure the key parameters of metal droplets during the spraying process,because the size of metal droplet is small and the rupture process is short duration based on the principle of pneumatic drop-on-demand generation.In order to solve this problem,the image acquisition system for the metal droplet forming process was constructed based on delay trigger method.Sn-Pb alloy(60%Sn～40%Pb) droplet spray experiments had been conducted with a generator nozzle of 200 μm in diameter.The steady spray process was captured by the image acquisition system,then the forming mechanism of the metal droplet was analyzed and the key parameters were measured.The results show that the spraying process of metal droplet can be reappeared by combining different photographs of delay time.The coordinates and diameter of droplets were obtained in different delay times,and the flight velocity and deviation angle of droplets were calculated.The generating mechanic of metal droplets was revealed,and the change trends of droplet divergent was predicted along with the increasing of flight distance.
2012, 31(10): 1569-1572.
Abstract:
In structural non-probabilistic reliability model,structure reliability is typically measured by non-probabilistic reliability index.In this paper,two definitions of structural non-probabilistic reliability index are investigated,which are the ratio of mean value to deviation of structural performance function and the minimum distance from the origin to the failure surface in normal interval variables space.The results show that: 1) when the structural function is a linear function,the consistency of the two definitions is proved.2) when the structure function is a nonlinear function,there are slight deviation in measuring structural reliability using the former definition,whereas no deviation using the latter one.3) the former definition depends on the expression form of structural performance function,but the latter one does not.The conclusions are verified by two examples.
In structural non-probabilistic reliability model,structure reliability is typically measured by non-probabilistic reliability index.In this paper,two definitions of structural non-probabilistic reliability index are investigated,which are the ratio of mean value to deviation of structural performance function and the minimum distance from the origin to the failure surface in normal interval variables space.The results show that: 1) when the structural function is a linear function,the consistency of the two definitions is proved.2) when the structure function is a nonlinear function,there are slight deviation in measuring structural reliability using the former definition,whereas no deviation using the latter one.3) the former definition depends on the expression form of structural performance function,but the latter one does not.The conclusions are verified by two examples.
2012, 31(10): 1573-1577.
Abstract:
An optimization method based on direct simulated annealing algorithm(DSA) and finite element method(FEM) for laminated composite structures was presented and applied to the weight optimization of a composite aircraft engine casing.The optimization goal is to minimize the casing weight while keeping the casing structure in safe state.Fiber orientation angles and number of layers are chosen as design variables.The implementation steps of this combined DSA/FEM optimization approach was describes and a multi-ply composite optimization technology is also proposed.Numerical results shows that the proposed optimization algorithm is very effective in casing weight reduction.
An optimization method based on direct simulated annealing algorithm(DSA) and finite element method(FEM) for laminated composite structures was presented and applied to the weight optimization of a composite aircraft engine casing.The optimization goal is to minimize the casing weight while keeping the casing structure in safe state.Fiber orientation angles and number of layers are chosen as design variables.The implementation steps of this combined DSA/FEM optimization approach was describes and a multi-ply composite optimization technology is also proposed.Numerical results shows that the proposed optimization algorithm is very effective in casing weight reduction.
2012, 31(10): 1578-1583.
Abstract:
In order to clarify the mechanism of attenuated blade tip effect on the aerodynamic performance of compressor rotor,the three-dimensional numerical simulation investigation is performed on the original model and six new models based on the experimental results of a subsonic compressor rotor.Following the analysis of total pressure ratio、efficiency and stall margin we draw the following conclusions: Attenuated blade tip improves the total pressure ratio and efficiency but at the same time decreases stall margin slightly;The improvement of suction surface curvature and the incidence of incoming flow is the main cause of pressure ratio enhancement;Attenuated blade tip weakened the adverse degree of leakage in the rear of blade tip and thus decresed the boundary layer separation loss、 mainstream / leakage mixing loss and wake loss and the pressure surface flow loss increases slightly,the total loss comes down.The increasing of the adverse degree of leakage in the front of tip,together with the improved incoming flow incidence of suction surface,makes the interface of mainstream / leakage move forward which cuts down stall margin of the rotor.
In order to clarify the mechanism of attenuated blade tip effect on the aerodynamic performance of compressor rotor,the three-dimensional numerical simulation investigation is performed on the original model and six new models based on the experimental results of a subsonic compressor rotor.Following the analysis of total pressure ratio、efficiency and stall margin we draw the following conclusions: Attenuated blade tip improves the total pressure ratio and efficiency but at the same time decreases stall margin slightly;The improvement of suction surface curvature and the incidence of incoming flow is the main cause of pressure ratio enhancement;Attenuated blade tip weakened the adverse degree of leakage in the rear of blade tip and thus decresed the boundary layer separation loss、 mainstream / leakage mixing loss and wake loss and the pressure surface flow loss increases slightly,the total loss comes down.The increasing of the adverse degree of leakage in the front of tip,together with the improved incoming flow incidence of suction surface,makes the interface of mainstream / leakage move forward which cuts down stall margin of the rotor.
2012, 31(10): 1584-1587.
Abstract:
In this paper,four kinds of diamond tools were used for the grinding experiments on cemented carbide YG8,with and without ultrasonic vibration.By using the white light interferometer and the microscope which has an ultra-deep observation field,surface qualities of the work-piece can be easily detected.The experimental results show that the diamond tools with big grain size,the surface roughness of the work-pieces machined with rotary ultrasonic vibration are worse than that without rotary ultrasonic vibration;while the roughness differences between the work-pieces machined with and without rotary ultrasonic vibration are not obvious at the small grain size.Furthermore,comparing with conventional diamond machining,it will be easier for rotary ultrasonic grinding to prevent the growth of cracks.
In this paper,four kinds of diamond tools were used for the grinding experiments on cemented carbide YG8,with and without ultrasonic vibration.By using the white light interferometer and the microscope which has an ultra-deep observation field,surface qualities of the work-piece can be easily detected.The experimental results show that the diamond tools with big grain size,the surface roughness of the work-pieces machined with rotary ultrasonic vibration are worse than that without rotary ultrasonic vibration;while the roughness differences between the work-pieces machined with and without rotary ultrasonic vibration are not obvious at the small grain size.Furthermore,comparing with conventional diamond machining,it will be easier for rotary ultrasonic grinding to prevent the growth of cracks.
2012, 31(10): 1588-1591.
Abstract:
157 nm excimer laser is an ideal micromachining tool of semiconductors with advantages of high precision and minimal heat affected zone.In this paper,157 nm laser is used for polishing and scribing of GaN(Gallium Nitride) wafers,and influences of the process parameters on micromachining performance are analyzed.For laser polishing,a better surface roughness would be obtained(about 20 nm Ra) when the accumulated radiation energy is set within a certain range.For laser scribing of GaN wafer,the higher the radiation energy given,the deeper the groove obtained,and the sharper the side-wall formed.Besides,the appropriate shift of the table height is favorable to improve the scribing quality.
157 nm excimer laser is an ideal micromachining tool of semiconductors with advantages of high precision and minimal heat affected zone.In this paper,157 nm laser is used for polishing and scribing of GaN(Gallium Nitride) wafers,and influences of the process parameters on micromachining performance are analyzed.For laser polishing,a better surface roughness would be obtained(about 20 nm Ra) when the accumulated radiation energy is set within a certain range.For laser scribing of GaN wafer,the higher the radiation energy given,the deeper the groove obtained,and the sharper the side-wall formed.Besides,the appropriate shift of the table height is favorable to improve the scribing quality.
2012, 31(10): 1592-1595.
Abstract:
We aim to build the nonlinear mapping relationship between the angular velocity and the steering angle of a certain formula racing car.Its virtual prototype model was built by using the simulation software ADAMS.taking into consideration the nonlinear factors such as tire and damping and their aerodynamics characteristics.Under the steering angle step input condition,the nonlinear mapping relationship between the angular velocity and the steering angle was built by using the radial basis function(RBF) neural network.The input identification results show that the above method is not only feasible but also highly accurate.
We aim to build the nonlinear mapping relationship between the angular velocity and the steering angle of a certain formula racing car.Its virtual prototype model was built by using the simulation software ADAMS.taking into consideration the nonlinear factors such as tire and damping and their aerodynamics characteristics.Under the steering angle step input condition,the nonlinear mapping relationship between the angular velocity and the steering angle was built by using the radial basis function(RBF) neural network.The input identification results show that the above method is not only feasible but also highly accurate.
2012, 31(10): 1596-1600.
Abstract:
The fatigue damage of high power level wind turbine top flange has been studied based on its finite element model.The fatigue stress was analyzed using the nonlinear finite element software MSC.Marc/Mentat,the fatigue load spectrum had also been calculated by the rain flow circulation counting method.A new method which combines the rain flow circulation count method with Palmgren-Miner linear cumulative damage law to calculate the fatigue damage of top flange was then proposed in the pesent study.In the fatigue damage analysis,the S-N curve of top flange material has been modified according to Germanischer Lloyd standard.The results indicate that the proposed method is feasible and relaiable,and it can provide a more accurate idea of fatigue analysis of wind turbine top flange.
The fatigue damage of high power level wind turbine top flange has been studied based on its finite element model.The fatigue stress was analyzed using the nonlinear finite element software MSC.Marc/Mentat,the fatigue load spectrum had also been calculated by the rain flow circulation counting method.A new method which combines the rain flow circulation count method with Palmgren-Miner linear cumulative damage law to calculate the fatigue damage of top flange was then proposed in the pesent study.In the fatigue damage analysis,the S-N curve of top flange material has been modified according to Germanischer Lloyd standard.The results indicate that the proposed method is feasible and relaiable,and it can provide a more accurate idea of fatigue analysis of wind turbine top flange.
2012, 31(10): 1601-1604.
Abstract:
In this paper,experimental and analytical studies were conducted on the Ti-6Al-4V cold expanded fastener hole.The distribution of crack initiation life was determined by metallographic fracture data.Based on the crack growth formula,the equivalent initial flaw size which characterized the initial fatigue quality was obtained by optimizing the reference crack size and the upper limit of equivalent initial flaw size.The rated equivalent initial flaw size was then determined.Referring to a designated economic repair size,the economic repair life with the reliability of 95% was obtained using the theory of probabilistic fracture mechanics.This work provided a theoretical guidance on the economic repair of structures containing cold expanded holes.
In this paper,experimental and analytical studies were conducted on the Ti-6Al-4V cold expanded fastener hole.The distribution of crack initiation life was determined by metallographic fracture data.Based on the crack growth formula,the equivalent initial flaw size which characterized the initial fatigue quality was obtained by optimizing the reference crack size and the upper limit of equivalent initial flaw size.The rated equivalent initial flaw size was then determined.Referring to a designated economic repair size,the economic repair life with the reliability of 95% was obtained using the theory of probabilistic fracture mechanics.This work provided a theoretical guidance on the economic repair of structures containing cold expanded holes.
2012, 31(10): 1605-1609.
Abstract:
Based on the finite element analysis software ANSYS,the 3-D finite element numerical model for analyzing the heat dissipation and holding of liquid in insulating tanker is established.Combining with the actual working condition,the influence of insulation layer thickness,heat insulating materials and vehicle speeds on the transient temperature field of liquid in tanker is discussed.The measure of automobile exhaust heating liquid in tanker is adopted,and the time history relationship of the liquid heated to unloading temperature since critical temperature is established by using finite element transient analysis technology.The comparison of heating efficiency is investigated at different geometries and distribution of heating pipes.
Based on the finite element analysis software ANSYS,the 3-D finite element numerical model for analyzing the heat dissipation and holding of liquid in insulating tanker is established.Combining with the actual working condition,the influence of insulation layer thickness,heat insulating materials and vehicle speeds on the transient temperature field of liquid in tanker is discussed.The measure of automobile exhaust heating liquid in tanker is adopted,and the time history relationship of the liquid heated to unloading temperature since critical temperature is established by using finite element transient analysis technology.The comparison of heating efficiency is investigated at different geometries and distribution of heating pipes.
2012, 31(10): 1610-1617.
Abstract:
To determine the integrated priority ratings of engineering characteristics(ECs) is a crucial step in the process of building house of quality.In order to achieve the improvement goals of performances of ECs in an economic and effective way,a methodology for determining the integrated priority ratings of ECs based on complementary preference is proposed.In this methodology,according to the competitive evaluations of performances of ECs and complementary preference of the products of a company and its competitors,a model for determining the competitive importance ratings of ECs corresponding to every member of quality function deployment team is built by using multiple attribute decision making method,and this model is solved by using Lagrange function,and then the technical points of ECs based on preference evaluations are determined by analytical hierarchy process(AHP).Secondly,based on the integration of scale method and AHP,the priority rating of achieving the improvement target of performances(ITOP) of every EC is determined.Lastly,based on the combination of the customer-satisfaction-based priority rating,the preference-information-based technical point,and the priority rating of achieving the ITOP of every EC,the integrated priority ratings of ECs are determined by using AHP.A case study of product improvement development of a fully automatic dish machine in a corporation was provided to illustrate the application of the proposed methodology.
To determine the integrated priority ratings of engineering characteristics(ECs) is a crucial step in the process of building house of quality.In order to achieve the improvement goals of performances of ECs in an economic and effective way,a methodology for determining the integrated priority ratings of ECs based on complementary preference is proposed.In this methodology,according to the competitive evaluations of performances of ECs and complementary preference of the products of a company and its competitors,a model for determining the competitive importance ratings of ECs corresponding to every member of quality function deployment team is built by using multiple attribute decision making method,and this model is solved by using Lagrange function,and then the technical points of ECs based on preference evaluations are determined by analytical hierarchy process(AHP).Secondly,based on the integration of scale method and AHP,the priority rating of achieving the improvement target of performances(ITOP) of every EC is determined.Lastly,based on the combination of the customer-satisfaction-based priority rating,the preference-information-based technical point,and the priority rating of achieving the ITOP of every EC,the integrated priority ratings of ECs are determined by using AHP.A case study of product improvement development of a fully automatic dish machine in a corporation was provided to illustrate the application of the proposed methodology.
2012, 31(10): 1618-1622.
Abstract:
This paper presents systematically the principle of traditional Chinese medicine grinder and analyzes the function demand of the product.The structural designs of the grinder and its key parts are completed.Both the key parts digital model and the whole grinder model are obtained.Then,the assembly levels and relationships of the product and its key parts are deeply analyzed.With the CAD technology,the digital pre-assembly process of the traditional Chinese medicine grinder is analyzed and finally the digital assembly model is established.
This paper presents systematically the principle of traditional Chinese medicine grinder and analyzes the function demand of the product.The structural designs of the grinder and its key parts are completed.Both the key parts digital model and the whole grinder model are obtained.Then,the assembly levels and relationships of the product and its key parts are deeply analyzed.With the CAD technology,the digital pre-assembly process of the traditional Chinese medicine grinder is analyzed and finally the digital assembly model is established.
2012, 31(10): 1623-1627.
Abstract:
The design and experimental research of dynamic seal of exciter was carried out in order to solve the problem that conventional exciter in lab can't be applied underwater directly,satisfying the need of wide band,stable exciting for underwater structure in engineering.Principles and vibration characteristics of electro-dynamic exciter were described by simplified model,and dynamic seal was designed in reference of J-shaped slip-ring combined seal of Che's seal series,the effects of seal friction on the vibration characteristics were analyzed and verified experimentally.The results showed that the exciter can be applied to underwater single-frequency,narrowband,broadband excitation after dynamic seal design.
The design and experimental research of dynamic seal of exciter was carried out in order to solve the problem that conventional exciter in lab can't be applied underwater directly,satisfying the need of wide band,stable exciting for underwater structure in engineering.Principles and vibration characteristics of electro-dynamic exciter were described by simplified model,and dynamic seal was designed in reference of J-shaped slip-ring combined seal of Che's seal series,the effects of seal friction on the vibration characteristics were analyzed and verified experimentally.The results showed that the exciter can be applied to underwater single-frequency,narrowband,broadband excitation after dynamic seal design.
2012, 31(10): 1628-1633.
Abstract:
In this paper a time-varying dynamic system with varying masses of the high-speed winder spindle is modeled and analyzed.Three formations of the spindle with different kinds of spinning cake diameters,and the spindle with time-varying masses is simulated in the way of the unbalance harmonic excitation analysis,and simulation results are compared.Numerical simulation which is similar to real spindle system with unbalance masses is realized,features of the dynamic response of the spindle system unbalance masses are obtained.It is found that the analysis of single formation without time-varying parameters would not obtain proper response of the spindle system,it is necessary to analyze the high-speed winder spindle in a way which time-varying parameters are considered in the model.
In this paper a time-varying dynamic system with varying masses of the high-speed winder spindle is modeled and analyzed.Three formations of the spindle with different kinds of spinning cake diameters,and the spindle with time-varying masses is simulated in the way of the unbalance harmonic excitation analysis,and simulation results are compared.Numerical simulation which is similar to real spindle system with unbalance masses is realized,features of the dynamic response of the spindle system unbalance masses are obtained.It is found that the analysis of single formation without time-varying parameters would not obtain proper response of the spindle system,it is necessary to analyze the high-speed winder spindle in a way which time-varying parameters are considered in the model.
2012, 31(10): 1634-1637.
Abstract:
To aim the forming grinding of gears parts,a new Computerized Numerical Control(CNC) of grinding wheel dressing is developed.The calculation of the section profile of grinding wheel,for the grinding of gears parts,is achieved by surface meshing theory,based on the software arithmetic with special parameters.With diamond dressing wheel,the grinding wheel is auto-trimming by CNC dressing system.As the proceeding of the grinding and dressing experiment of a practical worm the accuracy of the worm tooth shape reaches level 6 and above,satisfying the practical applicability of the dressing system.
To aim the forming grinding of gears parts,a new Computerized Numerical Control(CNC) of grinding wheel dressing is developed.The calculation of the section profile of grinding wheel,for the grinding of gears parts,is achieved by surface meshing theory,based on the software arithmetic with special parameters.With diamond dressing wheel,the grinding wheel is auto-trimming by CNC dressing system.As the proceeding of the grinding and dressing experiment of a practical worm the accuracy of the worm tooth shape reaches level 6 and above,satisfying the practical applicability of the dressing system.
2012, 31(10): 1638-1643.
Abstract:
In order to help enterprises and universities to share equipment resources effectively and to spread cooperation between enterprises and universities in networked manufacturing environment,combined with SaaS(Soft as a service) service mode,the characteristics of library equipment sharing system equipment B/S architecture,data layer of modeling and key application techniques were studied,respectively.A practical application module was designed using Web2.0 technology.System performance was optimized by using various techniques,which improved the system safety,reliability and browsing speed.Utilizing this system users can effectively supervise their equipments,realizing the opening of the equipment management,improving the equipment utilization efficiency and benefits.the present study provides a new idea to promote the ordering of equipment resources and the popular of the construction,maintenance.
In order to help enterprises and universities to share equipment resources effectively and to spread cooperation between enterprises and universities in networked manufacturing environment,combined with SaaS(Soft as a service) service mode,the characteristics of library equipment sharing system equipment B/S architecture,data layer of modeling and key application techniques were studied,respectively.A practical application module was designed using Web2.0 technology.System performance was optimized by using various techniques,which improved the system safety,reliability and browsing speed.Utilizing this system users can effectively supervise their equipments,realizing the opening of the equipment management,improving the equipment utilization efficiency and benefits.the present study provides a new idea to promote the ordering of equipment resources and the popular of the construction,maintenance.
2012, 31(10): 1644-1648.
Abstract:
Aiming at the 6-DOF active-passive vibration isolation platform,it is studied how to dispose sensors/ actuators on the optimization placement.At first,through coordinate transformation from inertial physical frame to sensor reference frame,the position matrixes of sensors/actuators are given out,and the constrained conditions are provided,which should satisfy the position matrixes.Then,the state space model is set up based on the sensor reference frame,and the objective function is build up with most observability and controllability matrix norm.The problem can be expressed as a nonlinear optimization problem with constraints.Finally,the optimum solution of sensors/actuators collocation is received using the Matlab genetic algorithm toolbox.
Aiming at the 6-DOF active-passive vibration isolation platform,it is studied how to dispose sensors/ actuators on the optimization placement.At first,through coordinate transformation from inertial physical frame to sensor reference frame,the position matrixes of sensors/actuators are given out,and the constrained conditions are provided,which should satisfy the position matrixes.Then,the state space model is set up based on the sensor reference frame,and the objective function is build up with most observability and controllability matrix norm.The problem can be expressed as a nonlinear optimization problem with constraints.Finally,the optimum solution of sensors/actuators collocation is received using the Matlab genetic algorithm toolbox.
2012, 31(10): 1649-1653.
Abstract:
Comprehensive Performance of drilling derrick is evaluated by identifying the modal parameters and modifying the dynamic model.Based on structure characteristics and exciting vibration form of drilling derrick,the identification formula of modal parameters is derived and the revised first order search method of modifying the dynamic finite element model is introduced.The field dynamics test is carried out under transient brake excitation,and the first three natural frequencies and the first two vibration modes are identified.The practical running situations of drilling derrick are analyzed.The finite element model is modified with the revised first order search method based on the first two natural frequencies.The modified model can achieve the accurate inversion of the first three natural frequencies and dynamics characteristic,and it can also be used to take further analysis on the static and dynamic behaviors and the comprehensive performance.The new method to evaluate the safe and steady running of the drilling rig during operations is provided.
Comprehensive Performance of drilling derrick is evaluated by identifying the modal parameters and modifying the dynamic model.Based on structure characteristics and exciting vibration form of drilling derrick,the identification formula of modal parameters is derived and the revised first order search method of modifying the dynamic finite element model is introduced.The field dynamics test is carried out under transient brake excitation,and the first three natural frequencies and the first two vibration modes are identified.The practical running situations of drilling derrick are analyzed.The finite element model is modified with the revised first order search method based on the first two natural frequencies.The modified model can achieve the accurate inversion of the first three natural frequencies and dynamics characteristic,and it can also be used to take further analysis on the static and dynamic behaviors and the comprehensive performance.The new method to evaluate the safe and steady running of the drilling rig during operations is provided.
2012, 31(10): 1654-1659.
Abstract:
To adopt the business processes changing frequently and meet heterogeneous system islanded and manufacturing resource hard to reuse during collaborative manufacturing,a collaborative manufacturing service chain model based on agent were presented.Firstly,the collaborative manufacturing service modes were expounded,and the business process of collaborative manufacturing service chain was constructured.Secondly,application of collaborative manufacturing service chain reconfiguration,associating and matching collaborative manufacturing services,realization method in logical based on intelligent agent was presented.Finally,a platform based on service-oriented architecture for complex products collaborative manufacturing was built.Practice shows this platform would enhance productivity and improve enterprise manufacture collaboration effectively.
To adopt the business processes changing frequently and meet heterogeneous system islanded and manufacturing resource hard to reuse during collaborative manufacturing,a collaborative manufacturing service chain model based on agent were presented.Firstly,the collaborative manufacturing service modes were expounded,and the business process of collaborative manufacturing service chain was constructured.Secondly,application of collaborative manufacturing service chain reconfiguration,associating and matching collaborative manufacturing services,realization method in logical based on intelligent agent was presented.Finally,a platform based on service-oriented architecture for complex products collaborative manufacturing was built.Practice shows this platform would enhance productivity and improve enterprise manufacture collaboration effectively.
2012, 31(10): 1660-1663.
Abstract:
The evaluation of measurement uncertainty plays an important role in the new generation of geometrical product specification(GPS),and it prescribes the verification and specification scheme.But at present,in the coordinate measurement of the gradient,only verification result is given,while uncertainty of the result has not been concluded.Thus the result is not integrated and can not be exactitude.To solve the problem above,a new method to calculate the gradient about two parallel planes is proposed.The method is based on the coordinate conversion fundamental between two parallel planes and the uncertainty transferring formula according to ISO/ TS 14253-2.By the evaluation of the combined standard uncertainty,the uncertainty of gradient about two parallel planes can be obtained.Through measurement experiment,the verification result of two parallel planes can meet the requirement of new GPS,and it is integrated and accurate.
The evaluation of measurement uncertainty plays an important role in the new generation of geometrical product specification(GPS),and it prescribes the verification and specification scheme.But at present,in the coordinate measurement of the gradient,only verification result is given,while uncertainty of the result has not been concluded.Thus the result is not integrated and can not be exactitude.To solve the problem above,a new method to calculate the gradient about two parallel planes is proposed.The method is based on the coordinate conversion fundamental between two parallel planes and the uncertainty transferring formula according to ISO/ TS 14253-2.By the evaluation of the combined standard uncertainty,the uncertainty of gradient about two parallel planes can be obtained.Through measurement experiment,the verification result of two parallel planes can meet the requirement of new GPS,and it is integrated and accurate.
2012, 31(10): 1664-1669.
Abstract:
Acting as a new kind of mechanism,metamorphic mechanisms are widely used in engineering fields.In this paper,a dynamics model is established for a metamorphic mechanism containing closed-loop constraint by using simultaneous constraint method,and the simulation analysis is implemented using Matlab/Simulink.The results of numerical simulation show that its kinematic variables and force have saltation when the configuration changes from one to another and a method is proposed to solve this problem.
Acting as a new kind of mechanism,metamorphic mechanisms are widely used in engineering fields.In this paper,a dynamics model is established for a metamorphic mechanism containing closed-loop constraint by using simultaneous constraint method,and the simulation analysis is implemented using Matlab/Simulink.The results of numerical simulation show that its kinematic variables and force have saltation when the configuration changes from one to another and a method is proposed to solve this problem.
2012, 31(10): 1670-1675.
Abstract:
Manufacturing Execution System is the workshop oriented management system in manufacturing enterprise,it organically integrates the enterprise resource management system with field equipment controlling in workshop.Because the information technology management level of the automobile main reducer assembly line is not high,we use the manufacturing execution system to monitor,control and manage the production assembly line in a real-time.First,the functional requirements and the coverage of the manufacturing execution system are analyzed.Second,the manufacturing execution system functions of the automobile main reducer assembly line are described.Finally,the manufacturing execution system implementation results of the automobile main reducer assembly line are discussed.In a word,practice shows that using manufacturing execution system can enhance the efficiency and improve the management level of the automobile main reducer assembly line effectively.
Manufacturing Execution System is the workshop oriented management system in manufacturing enterprise,it organically integrates the enterprise resource management system with field equipment controlling in workshop.Because the information technology management level of the automobile main reducer assembly line is not high,we use the manufacturing execution system to monitor,control and manage the production assembly line in a real-time.First,the functional requirements and the coverage of the manufacturing execution system are analyzed.Second,the manufacturing execution system functions of the automobile main reducer assembly line are described.Finally,the manufacturing execution system implementation results of the automobile main reducer assembly line are discussed.In a word,practice shows that using manufacturing execution system can enhance the efficiency and improve the management level of the automobile main reducer assembly line effectively.
2012, 31(10): 1676-1681.
Abstract:
The trajectory of cycloid crank is diverse,which could be applied to dwell mechanism.In the process of design,there are some error between the real cycloid trajectory and the ideal cycloid trajectory.In order to reduce the trajectory error of cycloid crank,a common kind of design method for the accurate-dwell mechanism was proposed in this paper.The character of cycloid movement equation was analyzed at first to obtain the movement rule of cycloid crank mechanism.Then,the orbital errors of different cycloid cranks were analyzed and these error expressions were set up.For reducing errors,the required design parameters of the mechanism were calculated based on the minimum error principle.Ultimately these parameters could be applied to design four kinds of dwell mechanism with cycloid crank.
The trajectory of cycloid crank is diverse,which could be applied to dwell mechanism.In the process of design,there are some error between the real cycloid trajectory and the ideal cycloid trajectory.In order to reduce the trajectory error of cycloid crank,a common kind of design method for the accurate-dwell mechanism was proposed in this paper.The character of cycloid movement equation was analyzed at first to obtain the movement rule of cycloid crank mechanism.Then,the orbital errors of different cycloid cranks were analyzed and these error expressions were set up.For reducing errors,the required design parameters of the mechanism were calculated based on the minimum error principle.Ultimately these parameters could be applied to design four kinds of dwell mechanism with cycloid crank.
2012, 31(10): 1682-1686.
Abstract:
In the traditional design of a vehicle's front wheel alignment parameters and steering mechanisms,in general,the effects of uncertainty factors on its performance were not considered,and the mutual interaction between the front wheel alignment parameters and the steering mechanisms also were not taken into account,causing the vehicle's poor performance.In order to reduce the interference of the uncertainty factors,we apply the existing robust design method to analyzing such uncertainty factors as manufacturing error and assembly error of the vehicle's parts and components.We use the preference function to analyze the uncertainty factors such as a designer's subjective factors and objective function weighting and then integrate them into the integrative model for designing the front wheel alignment parameters and steering mechanisms.The design results show our design method improves the robustness of the alignment parameters and steering mechanisms of the vehicle front wheels.
In the traditional design of a vehicle's front wheel alignment parameters and steering mechanisms,in general,the effects of uncertainty factors on its performance were not considered,and the mutual interaction between the front wheel alignment parameters and the steering mechanisms also were not taken into account,causing the vehicle's poor performance.In order to reduce the interference of the uncertainty factors,we apply the existing robust design method to analyzing such uncertainty factors as manufacturing error and assembly error of the vehicle's parts and components.We use the preference function to analyze the uncertainty factors such as a designer's subjective factors and objective function weighting and then integrate them into the integrative model for designing the front wheel alignment parameters and steering mechanisms.The design results show our design method improves the robustness of the alignment parameters and steering mechanisms of the vehicle front wheels.
2012, 31(10): 1687-1689.
Abstract:
We believe there are some deficiencies in the design of the MW50/28-298-type gas aetylene and amonia compressor with oil-free lubrication,for example lower air discharging capacity and short service life.Hence,we propose reforming the oil-free lubrication and piston structure of the gas aetylene and amonia compresso with theoretical and experimental analysis.The experimental results show that a small quantity of lubrication oil contained in the compressor thus reformed has no influence on the mixed gas quality and that the reformed compressor's performance is better than that of the existing design;thus its service life is greatly enhanced.
We believe there are some deficiencies in the design of the MW50/28-298-type gas aetylene and amonia compressor with oil-free lubrication,for example lower air discharging capacity and short service life.Hence,we propose reforming the oil-free lubrication and piston structure of the gas aetylene and amonia compresso with theoretical and experimental analysis.The experimental results show that a small quantity of lubrication oil contained in the compressor thus reformed has no influence on the mixed gas quality and that the reformed compressor's performance is better than that of the existing design;thus its service life is greatly enhanced.
2012, 31(10): 1690-1693.
Abstract:
We design a type of environment-protecting circulation range hood.Its innovative design enables the air purified by three-level filtering to circulate indoors directly.The design consists of two key technologies: 1) the first-level filter uses the swirl-separation technology,which separates gas-solid and gas-liquid with tangential inlet and cone body;2) the second-level filtering carries out centrifuge filtering with g the filtering cloth that rotates with an impeller,thus effectively solving the problems that the circulation filter gets dirty and is hard to clean and has poor ventilation.The circulation range hood can be used not only in kitchen but also in other sealing oil mist environments.Without flue,it reduces construction costs and carbon and conserves energy.
We design a type of environment-protecting circulation range hood.Its innovative design enables the air purified by three-level filtering to circulate indoors directly.The design consists of two key technologies: 1) the first-level filter uses the swirl-separation technology,which separates gas-solid and gas-liquid with tangential inlet and cone body;2) the second-level filtering carries out centrifuge filtering with g the filtering cloth that rotates with an impeller,thus effectively solving the problems that the circulation filter gets dirty and is hard to clean and has poor ventilation.The circulation range hood can be used not only in kitchen but also in other sealing oil mist environments.Without flue,it reduces construction costs and carbon and conserves energy.
2012, 31(10): 1694-1697.
Abstract:
The optimal controller of direct yaw-moment control of tractor-semitrailer was designed,and its effectiveness was verified.The Gim tire model was adopted to set up the nonlinear dynamic model of tractor-semitrailer.Choosing slip angle of tractor,yaw velocity of tractor and semitrailer,and angle of central line of tractor and semitrailer as control variables,the optimal control scheme was proposed.An optimal controller of direct yaw-moment control for the tractor-semitrailer stability was developed based on model tracing control technique.Based on the established nonlinear dynamics model,simulation in Matlab/Simulink software environment is described.The simulation consults suggest that for tractor-semitrailer with optimal controller of DYC,the handling and stability performance on big slip angle can be improved,which makes the driver drive the vehicle normally.
The optimal controller of direct yaw-moment control of tractor-semitrailer was designed,and its effectiveness was verified.The Gim tire model was adopted to set up the nonlinear dynamic model of tractor-semitrailer.Choosing slip angle of tractor,yaw velocity of tractor and semitrailer,and angle of central line of tractor and semitrailer as control variables,the optimal control scheme was proposed.An optimal controller of direct yaw-moment control for the tractor-semitrailer stability was developed based on model tracing control technique.Based on the established nonlinear dynamics model,simulation in Matlab/Simulink software environment is described.The simulation consults suggest that for tractor-semitrailer with optimal controller of DYC,the handling and stability performance on big slip angle can be improved,which makes the driver drive the vehicle normally.
2012, 31(10): 1698-1701.
Abstract:
This paper studies the RE Ion nitro-carbonizing technology for the 4Cr5MoSiVl steel surface treatment by using 4%RE,520 ℃×2h and 1.05 kPa atmospheric pressure.Performance test results of the 4Cr5MoSiVl steel treated layer show that the optimization of these parameters makes the surface hardness,wear resistance,high temperature oxidation resistance,thermal fatigue properties and corrosion resistance to be significantly improved.Another test with using this technology has been done for the 4Cr5MoSiVl steel automotive lamp aluminum casting mold.The experimental results show that the treated layer has optimal qualities,which can meet the requirements in practice and its service life can be increased by 3 to 4 times.
This paper studies the RE Ion nitro-carbonizing technology for the 4Cr5MoSiVl steel surface treatment by using 4%RE,520 ℃×2h and 1.05 kPa atmospheric pressure.Performance test results of the 4Cr5MoSiVl steel treated layer show that the optimization of these parameters makes the surface hardness,wear resistance,high temperature oxidation resistance,thermal fatigue properties and corrosion resistance to be significantly improved.Another test with using this technology has been done for the 4Cr5MoSiVl steel automotive lamp aluminum casting mold.The experimental results show that the treated layer has optimal qualities,which can meet the requirements in practice and its service life can be increased by 3 to 4 times.
2012, 31(10): 1702-1705,1710.
Abstract:
The sensitivity of the surface of optical film to micro-gravity is a key factor in designing a micro-gravity optical sensor.We study the variation of the micro-gravity with the slope of the reflection surface of optical film.Through orthogonal experiments,we analyze the relationship between the slope and the radius,thickness and materials of the optical film.Taking into account the experimental results,we amend the slope formula of the round optical film under concentrated strain.The theoretical calculation and the ANSYS analysis show that there is a linear relationship between the micro-gravity of the optical sensor and the slope of the optical film and that the sensitivity of the optical film to the micro-gravity increases with the increasing radius and with the decreasing thickness and elastic modulus of the optical film.
The sensitivity of the surface of optical film to micro-gravity is a key factor in designing a micro-gravity optical sensor.We study the variation of the micro-gravity with the slope of the reflection surface of optical film.Through orthogonal experiments,we analyze the relationship between the slope and the radius,thickness and materials of the optical film.Taking into account the experimental results,we amend the slope formula of the round optical film under concentrated strain.The theoretical calculation and the ANSYS analysis show that there is a linear relationship between the micro-gravity of the optical sensor and the slope of the optical film and that the sensitivity of the optical film to the micro-gravity increases with the increasing radius and with the decreasing thickness and elastic modulus of the optical film.
2012, 31(10): 1706-1710.
Abstract:
From the view point of energy conversion,the electro-hydraulic parameters coupling mechanism was analyzed based on the Power Bond Graph method.The mathematical relationship between the pressure and current of the system on a steady operation condition was deduced,which showed that the current of power source contains the pressure change information of the hydraulic system,finally,the conclusion that the running state of hydraulic power system can be determined by non-embedded measurement of the current was put forward.Based on the above,the simulation model of the hydraulic power system studied in the paper was set-up and the simulation figures of the impact condition is given,the corresponding experiments were conducted.The simulation results and the test date agree well and it proves that that the running condition can be recognized by monitoring the current signal.
From the view point of energy conversion,the electro-hydraulic parameters coupling mechanism was analyzed based on the Power Bond Graph method.The mathematical relationship between the pressure and current of the system on a steady operation condition was deduced,which showed that the current of power source contains the pressure change information of the hydraulic system,finally,the conclusion that the running state of hydraulic power system can be determined by non-embedded measurement of the current was put forward.Based on the above,the simulation model of the hydraulic power system studied in the paper was set-up and the simulation figures of the impact condition is given,the corresponding experiments were conducted.The simulation results and the test date agree well and it proves that that the running condition can be recognized by monitoring the current signal.
2012, 31(10): 1711-1715,1720.
Abstract:
Because the parameters of the performance of a dynamically tuned gyroscope has degradation,we propose a method for predicting its faults,which combines the self-organizational feature mapping(SOFM) neural network with the hidden Markov model(HMM).Firstly,we gather the vibration,temperature,random drifting,motor power,power source voltage,frequency and other signals of the dynamically tuned gyroscope as the feature information for charactering its degradation,and then use the SOFM neural network to implement the multi-sensor information fusion.Secondly,we use the HMM to transform the early fault signals,which are difficult to detect,into the easily observed information,thus predicting the faults of the dynamically tuned gyroscope.The experimental results show that our method can easily and effectively extract the feature information on the gyroscope's degradation.The training and testing with the HMM show that our method is effective for fault predictions.
Because the parameters of the performance of a dynamically tuned gyroscope has degradation,we propose a method for predicting its faults,which combines the self-organizational feature mapping(SOFM) neural network with the hidden Markov model(HMM).Firstly,we gather the vibration,temperature,random drifting,motor power,power source voltage,frequency and other signals of the dynamically tuned gyroscope as the feature information for charactering its degradation,and then use the SOFM neural network to implement the multi-sensor information fusion.Secondly,we use the HMM to transform the early fault signals,which are difficult to detect,into the easily observed information,thus predicting the faults of the dynamically tuned gyroscope.The experimental results show that our method can easily and effectively extract the feature information on the gyroscope's degradation.The training and testing with the HMM show that our method is effective for fault predictions.
2012, 31(10): 1716-1720.
Abstract:
In order to improve the structure and design a light weight frame of new motorcycle,taking a motorcycle of bestriding 125 as an object,the collection of practical road load spectrum in the proving ground and the treatment of equivalent damage are introduced to compress test cycle significantly while the prototype of fatigue damage are basically the same compared to real road excitation.Using the MTS axis coupled road simulator of four channel test stand,taking the load spectrum for initial input,through the remote parameter control(RPC) system,the closed real road excitation equivalent input signal is obtained by iteration.A time domain fatigue analysis model of the motorcycle frame is built with nSoft software,which is based on the nominal stress method and fatigue damage cumulative theory,taking the equivalent real road excitation as simulation input signal for finite element analysis,the fatigue damage and life of the motorcycle frame are evaluated.
In order to improve the structure and design a light weight frame of new motorcycle,taking a motorcycle of bestriding 125 as an object,the collection of practical road load spectrum in the proving ground and the treatment of equivalent damage are introduced to compress test cycle significantly while the prototype of fatigue damage are basically the same compared to real road excitation.Using the MTS axis coupled road simulator of four channel test stand,taking the load spectrum for initial input,through the remote parameter control(RPC) system,the closed real road excitation equivalent input signal is obtained by iteration.A time domain fatigue analysis model of the motorcycle frame is built with nSoft software,which is based on the nominal stress method and fatigue damage cumulative theory,taking the equivalent real road excitation as simulation input signal for finite element analysis,the fatigue damage and life of the motorcycle frame are evaluated.
