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RSS2014 Vol. 33, No. 12
Display Method:
2014, 33(12): 1773-1776.
doi: 10.13433/j.cnki.1003-8728.2014.1201
PDF 2110KB
Abstract:
The contact problem belongs to nonlinear boundary conditions. The contact problem takes more time than liner analysis when apply finite element analysis to solution. The convergence of numerical methods depends on contact stiffness and the complexity of the model and so on. In finite element analysis,DOF(Degrees of Freedom)coupling for adjacent nodes belongs to liner analysis without convergence problems. In order to solve the difference between these two methods in the calculation of the telescopic boom of hydraulic aerial cage,a contact model and a DOF coupling model for the telescopic boom are established via an ANSYS software. The result shows DOF coupling analysis method is similar to the contact analysis in the simulation of the slider contact. But there is a great difference in the simulation of the hinged support because of the model difference.
The contact problem belongs to nonlinear boundary conditions. The contact problem takes more time than liner analysis when apply finite element analysis to solution. The convergence of numerical methods depends on contact stiffness and the complexity of the model and so on. In finite element analysis,DOF(Degrees of Freedom)coupling for adjacent nodes belongs to liner analysis without convergence problems. In order to solve the difference between these two methods in the calculation of the telescopic boom of hydraulic aerial cage,a contact model and a DOF coupling model for the telescopic boom are established via an ANSYS software. The result shows DOF coupling analysis method is similar to the contact analysis in the simulation of the slider contact. But there is a great difference in the simulation of the hinged support because of the model difference.
2014, 33(12): 1777-1780.
doi: 10.13433/j.cnki.1003-8728.2014.1202
Abstract:
Considering the external load,the Redundant Servo Motor(RSM) approach on dynamic balance of the rigid linkage is employed. According to the actual work requirements,the dynamic equations of the linkage and servo motor are derived. An example shows that the analysis of the dynamic balance characteristics of the linkage based on the RSM approach. The present results verify the effectiveness of the RSM approach on the dynamic balance of the rigid linkage with external load and a comparative study about the relationship between the theoretical input torque when the linkage dynamic balance and the actual output torque is presented.
Considering the external load,the Redundant Servo Motor(RSM) approach on dynamic balance of the rigid linkage is employed. According to the actual work requirements,the dynamic equations of the linkage and servo motor are derived. An example shows that the analysis of the dynamic balance characteristics of the linkage based on the RSM approach. The present results verify the effectiveness of the RSM approach on the dynamic balance of the rigid linkage with external load and a comparative study about the relationship between the theoretical input torque when the linkage dynamic balance and the actual output torque is presented.
2014, 33(12): 1781-1785.
doi: 10.13433/j.cnki.1003-8728.2014.1203
Abstract:
The assembly misalignment is a key factor that influences the meshing performance of gear,the meshing performance worked on no-load or light load conditions is more completely expressed,by the contact pattern and transmission error. According to the contact pattern and transmission error,the effect of assembly misalignment on the meshing performance of hypoid gear is studied,the present method break the limitations relying on experience to adjust the installation. Based on the machining principle and method of Gleason hypoid gears which machined by the HFT method,the mathematical model for machining was established,and the theoretical tooth surface equations were derived,on the above-mentioned,the hypoid gear as an example,the tooth contact analysis(TCA) was carried out by considering assembly misalignment,the effect of assembly misalignment on the meshing performance was studied,the results show that the hypoid gears are less sensitive to the assembly misalignment.
The assembly misalignment is a key factor that influences the meshing performance of gear,the meshing performance worked on no-load or light load conditions is more completely expressed,by the contact pattern and transmission error. According to the contact pattern and transmission error,the effect of assembly misalignment on the meshing performance of hypoid gear is studied,the present method break the limitations relying on experience to adjust the installation. Based on the machining principle and method of Gleason hypoid gears which machined by the HFT method,the mathematical model for machining was established,and the theoretical tooth surface equations were derived,on the above-mentioned,the hypoid gear as an example,the tooth contact analysis(TCA) was carried out by considering assembly misalignment,the effect of assembly misalignment on the meshing performance was studied,the results show that the hypoid gears are less sensitive to the assembly misalignment.
2014, 33(12): 1786-1790.
doi: 10.13433/j.cnki.1003-8728.2014.1204
Abstract:
A model of instability of rotor system caused by cylindrical surface fit was established,and Riccati transfer matrix method was used to get the threshold speed of double-rotor test rig. The relationship between stability of the rotor system and parameters of cylindrical surface was analyzed. Experimentation proved the influence of locknut preload on threshold speed. The results show that increasing preload can effectively improve the threshold speed.
A model of instability of rotor system caused by cylindrical surface fit was established,and Riccati transfer matrix method was used to get the threshold speed of double-rotor test rig. The relationship between stability of the rotor system and parameters of cylindrical surface was analyzed. Experimentation proved the influence of locknut preload on threshold speed. The results show that increasing preload can effectively improve the threshold speed.
2014, 33(12): 1791-1794.
doi: 10.13433/j.cnki.1003-8728.2014.1205
Abstract:
The hopping robot model with three rigid body drived by hydraumatic with underactuated joints is established based on the structural characterization of kangaroo,using torsion spring to simulate the flexible joints and energy storage. The system's underactuated dynamic equations are derived during the touch-down phase.According to the example,the hydraulic driving force's law and the theory profile graph are studied by the simulation with MATLAB7. 0. Then the physical model is established and applied to the underactuated dynamic simulation based on ADAMS. The present results show that the position of underactuated joints controlled by dynamics's coupling is possible. In addition,it is verified that the proposed scheme is feasible and the model is correct by comparing with theoretical stance figure.
The hopping robot model with three rigid body drived by hydraumatic with underactuated joints is established based on the structural characterization of kangaroo,using torsion spring to simulate the flexible joints and energy storage. The system's underactuated dynamic equations are derived during the touch-down phase.According to the example,the hydraulic driving force's law and the theory profile graph are studied by the simulation with MATLAB7. 0. Then the physical model is established and applied to the underactuated dynamic simulation based on ADAMS. The present results show that the position of underactuated joints controlled by dynamics's coupling is possible. In addition,it is verified that the proposed scheme is feasible and the model is correct by comparing with theoretical stance figure.
2014, 33(12): 1795-1797.
doi: 10.13433/j.cnki.1003-8728.2014.1206
Abstract:
The steering system of a 10� typed truck crane is used as the research object,the mathematical model and kinematics model for the steering system are established according to the automotive steering theory,then the kinematics simulation and analysis of the steering performance in the ADAMS are complished. Basing on the analysis of the inner steering angle error between the axes and the error between the inner and outer steering angle of the axis,a few hard point of the steering mechanism are chosen by using the coordinates as design variables.Responsively taking the cumulative error of the inner steering angle between axes and between the inner and outer steering angle as the optimization objective,the inner steering angle between axes and the inner and outer steering angle of the first shaft is optimized,finally the optimization model is verified by using the experiment.
The steering system of a 10� typed truck crane is used as the research object,the mathematical model and kinematics model for the steering system are established according to the automotive steering theory,then the kinematics simulation and analysis of the steering performance in the ADAMS are complished. Basing on the analysis of the inner steering angle error between the axes and the error between the inner and outer steering angle of the axis,a few hard point of the steering mechanism are chosen by using the coordinates as design variables.Responsively taking the cumulative error of the inner steering angle between axes and between the inner and outer steering angle as the optimization objective,the inner steering angle between axes and the inner and outer steering angle of the first shaft is optimized,finally the optimization model is verified by using the experiment.
2014, 33(12): 1798-1802.
doi: 10.13433/j.cnki.1003-8728.2014.1207
Abstract:
The defect of complex computing process exits in several current fuzzy reliability allocation methods by using fuzzy numbers to quantify fuzzy language and the actual application effect is affected. So the explicitation method of fuzzy numbers is introduced by using trapezoidal fuzzy numbers to quantify fuzzy language to simplify computing process. The data processing is carried out by simple programming based on MATLAB. The bias coefficient is introduced after taking full account of the fuzziness during the cognition of human beings to improve the ratio scale of Analytic Hierarchy Process(AHP) so that the computed results of the weight of influencing factors are closer to reality. The improved fuzzy comprehensive evaluation and AHP are combined to allocate reliability of pellet mill and this allocation method is proved practical and reasonable.
The defect of complex computing process exits in several current fuzzy reliability allocation methods by using fuzzy numbers to quantify fuzzy language and the actual application effect is affected. So the explicitation method of fuzzy numbers is introduced by using trapezoidal fuzzy numbers to quantify fuzzy language to simplify computing process. The data processing is carried out by simple programming based on MATLAB. The bias coefficient is introduced after taking full account of the fuzziness during the cognition of human beings to improve the ratio scale of Analytic Hierarchy Process(AHP) so that the computed results of the weight of influencing factors are closer to reality. The improved fuzzy comprehensive evaluation and AHP are combined to allocate reliability of pellet mill and this allocation method is proved practical and reasonable.
2014, 33(12): 1803-1806.
doi: 10.13433/j.cnki.1003-8728.2014.1208
Abstract:
The natural frequency and dynamic response characteristics under external excitation of the Cable Drive Parallel Mechanism(CDPM) for Processing are studied. At first,the vibration model of the CDPM system on the stable position and the orientation based on nonlinear cutting force model is built and the natural frequencies are obtained. Then the cutting-force model is introduced and the equations of the forced vibration are presented. The Runge-Kutta method is used to solve the forced vibration equations. Finally,the feasibility of the algorithm is verified by numerical simulations. The frequency domian solution is obtained from the time domian response by Fast Fourier Transformation(FFT). The effects of the centrobaric offset and the mass of the moving platform on the stability of the system are analyzed.
The natural frequency and dynamic response characteristics under external excitation of the Cable Drive Parallel Mechanism(CDPM) for Processing are studied. At first,the vibration model of the CDPM system on the stable position and the orientation based on nonlinear cutting force model is built and the natural frequencies are obtained. Then the cutting-force model is introduced and the equations of the forced vibration are presented. The Runge-Kutta method is used to solve the forced vibration equations. Finally,the feasibility of the algorithm is verified by numerical simulations. The frequency domian solution is obtained from the time domian response by Fast Fourier Transformation(FFT). The effects of the centrobaric offset and the mass of the moving platform on the stability of the system are analyzed.
2014, 33(12): 1807-1810.
doi: 10.13433/j.cnki.1003-8728.2014.1209
Abstract:
For the exoskeleton accompanying highly with body,the movement of the exoskeleton is simulated based on the biomechanics. For the human movement analysis,the method of continuous-discrete and discrete-continuous is adopted. The continuous-discrete is to use high-speed cameras and optical motion capture system to test groups of three-dimensional coordinates of human joint during exercise. The discrete-continuous is to use the method of least squares fitting analysis of test date and get equations of human motion. The virtual prototype of the exoskeleton is established,the equations of motion is applied to the simulation of virtual prototype of exoskeleton and get the force curve of exoskeleton's joints. The analysis of joint torque driver characteristics shows that the biggest force and torque occurs on the exoskeleton's left knee,respectively for 450 N and 68 N · m. The analysis of joint torque driver characteristics plays an important role on the materials selection and structure design of exoskeleton.
For the exoskeleton accompanying highly with body,the movement of the exoskeleton is simulated based on the biomechanics. For the human movement analysis,the method of continuous-discrete and discrete-continuous is adopted. The continuous-discrete is to use high-speed cameras and optical motion capture system to test groups of three-dimensional coordinates of human joint during exercise. The discrete-continuous is to use the method of least squares fitting analysis of test date and get equations of human motion. The virtual prototype of the exoskeleton is established,the equations of motion is applied to the simulation of virtual prototype of exoskeleton and get the force curve of exoskeleton's joints. The analysis of joint torque driver characteristics shows that the biggest force and torque occurs on the exoskeleton's left knee,respectively for 450 N and 68 N · m. The analysis of joint torque driver characteristics plays an important role on the materials selection and structure design of exoskeleton.
2014, 33(12): 1811-1814.
doi: 10.13433/j.cnki.1003-8728.2014.1210
Abstract:
The servo constraint control theory based on Udwadia and Kalaba equations can be applied in the tracking control of mechanical systems. The numerical solutions under servo constraint control may violate the lowerorder constraint equations,together with the inconsistent initial conditions,which result in control error even unstable problem. In this paper, using the Cholesky decomposition of the generalized mass matrix and the coordinates transformation,the generalized virtual displacements is decomposed in constrained directions and admissible directions,thus the constraint violation of the generalized velocity and configuration are separated,and the modified equations are obtained. Finally,the simulation study of a mechanical manipulator with two degrees of freedom is made and the results show that the algorithm can eliminate the constraint violation and solve the problem caused by inconsistent initial conditions under servo constraint trajectory control.
The servo constraint control theory based on Udwadia and Kalaba equations can be applied in the tracking control of mechanical systems. The numerical solutions under servo constraint control may violate the lowerorder constraint equations,together with the inconsistent initial conditions,which result in control error even unstable problem. In this paper, using the Cholesky decomposition of the generalized mass matrix and the coordinates transformation,the generalized virtual displacements is decomposed in constrained directions and admissible directions,thus the constraint violation of the generalized velocity and configuration are separated,and the modified equations are obtained. Finally,the simulation study of a mechanical manipulator with two degrees of freedom is made and the results show that the algorithm can eliminate the constraint violation and solve the problem caused by inconsistent initial conditions under servo constraint trajectory control.
2014, 33(12): 1815-1817.
doi: 10.13433/j.cnki.1003-8728.2014.1211
Abstract:
Based on the measurement of noise and near sound field spectrum analysis of a 4-cylinder direct injection turbocharged diesel engine,the noise characteristic and noise source of the engine are analyzed. Some measures to reduce noise by changing engine parameters such as fuel supply advance angle,engine power,supercharger type,opening pressure of injector and parameters of fuel pump are adopted while the main structure parameters of the engine are kept the same. The effects of these measures on engine noise are compared and analyzed to select the optimal scheme of comprehensive measure for noise reduction. The results show that the noise of the engine can be reduced by 1.32 d B(A) with the optimal measure.
Based on the measurement of noise and near sound field spectrum analysis of a 4-cylinder direct injection turbocharged diesel engine,the noise characteristic and noise source of the engine are analyzed. Some measures to reduce noise by changing engine parameters such as fuel supply advance angle,engine power,supercharger type,opening pressure of injector and parameters of fuel pump are adopted while the main structure parameters of the engine are kept the same. The effects of these measures on engine noise are compared and analyzed to select the optimal scheme of comprehensive measure for noise reduction. The results show that the noise of the engine can be reduced by 1.32 d B(A) with the optimal measure.
2014, 33(12): 1818-1825.
doi: 10.13433/j.cnki.1003-8728.2014.1212
Abstract:
The space coordinate measuring systems such as coordinate measuring machine,electronic theodolite,laser scanner and online visual measuring are gradually applied to reverse engineering,but as the demand of measuring range,accuracy and measuring environment to increase highly,the existing technology can not meet the industrial demand. Therefore,the space coordinate measuring system via industrial robot takes advantage of the high flexibility,high efficiency,and equipping with a variety of sensors to satisfy the large scale and automatic measuring in complex environment. In this paper,the systematic review about the space coordinate measuring technology via robots is conducted,and the state of space coordinate measuring technology via robots is elaborated,then the difficulties and solutions in the technical theory and application is analyzed,and it is one of the tendency of development that the combinative space coordinate measuring methods via multi-robot.
The space coordinate measuring systems such as coordinate measuring machine,electronic theodolite,laser scanner and online visual measuring are gradually applied to reverse engineering,but as the demand of measuring range,accuracy and measuring environment to increase highly,the existing technology can not meet the industrial demand. Therefore,the space coordinate measuring system via industrial robot takes advantage of the high flexibility,high efficiency,and equipping with a variety of sensors to satisfy the large scale and automatic measuring in complex environment. In this paper,the systematic review about the space coordinate measuring technology via robots is conducted,and the state of space coordinate measuring technology via robots is elaborated,then the difficulties and solutions in the technical theory and application is analyzed,and it is one of the tendency of development that the combinative space coordinate measuring methods via multi-robot.
2014, 33(12): 1826-1829.
doi: 10.13433/j.cnki.1003-8728.2014.1213
Abstract:
The finite element model of square walled straight beam is established. The LS-DYNA software is used for collision simulation. The effect of derivational groove numbers and spacing on the crash performance of thinwalled beams is investigated through the deformation of stringers,energy absorption and impact force. Simulation results show that the derivational groove numbers have little effect on energy absorption,but the increasing of the derivational groove numbers can reduce the peak force of the collision to some extent. The derivational groove spacing has significant effect on both energy absorption and collision force,with the increasing of derivational groove spacing,the energy absorption will be reduced and the peak collision force will bw increased and the crushing process of the thin-walled beam becomes unstable.
The finite element model of square walled straight beam is established. The LS-DYNA software is used for collision simulation. The effect of derivational groove numbers and spacing on the crash performance of thinwalled beams is investigated through the deformation of stringers,energy absorption and impact force. Simulation results show that the derivational groove numbers have little effect on energy absorption,but the increasing of the derivational groove numbers can reduce the peak force of the collision to some extent. The derivational groove spacing has significant effect on both energy absorption and collision force,with the increasing of derivational groove spacing,the energy absorption will be reduced and the peak collision force will bw increased and the crushing process of the thin-walled beam becomes unstable.
2014, 33(12): 1830-1833.
doi: 10.13433/j.cnki.1003-8728.2014.1214
Abstract:
The double circular arc gear GB/T12759-1991 is taken as the object of research,and it is accurately modeled and analysed with finite element method by using the UG software. The gear bending strength is studied before run-in period with load on the theoretical meshing point. The bending strength distribution along tooth depth direction,the change of stress with different load position and the main failure mode of the gear are analyzed. And the reason of why the tooth is broken at deddendum or midposition of the tooth is studied. The relationship between the main profile parameters of the double circular-tooth gear,including the whole depth h,the nominal pressure angle α,tooth profile arc radius ρ,is also analysed and their selection principle is discussed. The results of this paper provide a theoretical support for further analysis.
The double circular arc gear GB/T12759-1991 is taken as the object of research,and it is accurately modeled and analysed with finite element method by using the UG software. The gear bending strength is studied before run-in period with load on the theoretical meshing point. The bending strength distribution along tooth depth direction,the change of stress with different load position and the main failure mode of the gear are analyzed. And the reason of why the tooth is broken at deddendum or midposition of the tooth is studied. The relationship between the main profile parameters of the double circular-tooth gear,including the whole depth h,the nominal pressure angle α,tooth profile arc radius ρ,is also analysed and their selection principle is discussed. The results of this paper provide a theoretical support for further analysis.
2014, 33(12): 1834-1837.
doi: 10.13433/j.cnki.1003-8728.2014.1215
Abstract:
Considering the uncertainty factors,the parameters of machine tool spindle design are regarded as interval variables,and a non-probabilistic reliability model of machine tool spindle based on interval analysis is built by applying the non-probabilistic reliability theory. The measurement method of non-probabilistic reliability with non-linear function for multiple interval variables is proposed and the reliability measurement index of spindle based on torsional strength and deflection is presented. The XH2320/4 machine tool spindle produced by Guilin Machine Tool Plant is analyzed by using this this interval analysis method,and the results show that this method can be applied to the reliability analysis of whole machine in practical engineering.
Considering the uncertainty factors,the parameters of machine tool spindle design are regarded as interval variables,and a non-probabilistic reliability model of machine tool spindle based on interval analysis is built by applying the non-probabilistic reliability theory. The measurement method of non-probabilistic reliability with non-linear function for multiple interval variables is proposed and the reliability measurement index of spindle based on torsional strength and deflection is presented. The XH2320/4 machine tool spindle produced by Guilin Machine Tool Plant is analyzed by using this this interval analysis method,and the results show that this method can be applied to the reliability analysis of whole machine in practical engineering.
2014, 33(12): 1838-1844.
doi: 10.13433/j.cnki.1003-8728.2014.1216
Abstract:
Applying Matlab software,the shearer spiral drum's load calculation program of sequential and punnett arrangements has been developed. The instantaneous load curves,corresponding chips diagram and lump coal rate of drum cutting coal and coal seam contain dirt band have been gotten. The shearer's rigid-flexible coupling models of different picks arrangements have been built and reliability analysis has been done under ten typical working conditions. Result shows that: when the shearer is cutting coal seam,whose consistency coefficient is 3.11,without dirt band by using punnett drum,the haulage speed can reach 9m/min; compared with the sequential,the mean specific energy consumption for cutting will reduce 17.8%,the squareness will increase 21.9% and chip's area of coal will increase by 1. 85 times; when the shearer using sequential picks arrangement mode,the output shaft's stress exceeds allowable stress; when the shearer is cutting coal seam contained dirt band, the sequential arrangement drum should be chosen preferentially,to reduce the force affected on a single pick and to make the cutting stable and reliable; by further spiral angle optimization analysis on the blade of this sequential drum,the best spiral angle of 9癶as been decided.
Applying Matlab software,the shearer spiral drum's load calculation program of sequential and punnett arrangements has been developed. The instantaneous load curves,corresponding chips diagram and lump coal rate of drum cutting coal and coal seam contain dirt band have been gotten. The shearer's rigid-flexible coupling models of different picks arrangements have been built and reliability analysis has been done under ten typical working conditions. Result shows that: when the shearer is cutting coal seam,whose consistency coefficient is 3.11,without dirt band by using punnett drum,the haulage speed can reach 9m/min; compared with the sequential,the mean specific energy consumption for cutting will reduce 17.8%,the squareness will increase 21.9% and chip's area of coal will increase by 1. 85 times; when the shearer using sequential picks arrangement mode,the output shaft's stress exceeds allowable stress; when the shearer is cutting coal seam contained dirt band, the sequential arrangement drum should be chosen preferentially,to reduce the force affected on a single pick and to make the cutting stable and reliable; by further spiral angle optimization analysis on the blade of this sequential drum,the best spiral angle of 9癶as been decided.
2014, 33(12): 1845-1849.
doi: 10.13433/j.cnki.1003-8728.2014.1217
Abstract:
Form error evaluation plays an important role in the processing quality evaluation. To improve the evaluation accuracy and to enhance the theoretical and engineering application value,the cylindricity error is evaluated as a typical example based on the sequential quadratic programming(SQP) algorithm. The evaluation is carried out via three stages. The signed distance function from the measured points to cylindrical surface is defined and the cylinder is located roughly by the traditional least-squares(LS) method firstly; the fitted cylinder and the measured points coordinates are transformed to simplify the optimal mathematical model for the cylindricity error evaluation secondly; and then optimization problem on the cylindricity error evaluation satisfying the minimum zone criterion is solved by means of the SQP algorithm and kinematic geometry. The computer simulation shows that the cylindricity error evaluation algorithm has the advantages of good robustness,high efficiency and accuracy. The obtained cylindricity error is effective.
Form error evaluation plays an important role in the processing quality evaluation. To improve the evaluation accuracy and to enhance the theoretical and engineering application value,the cylindricity error is evaluated as a typical example based on the sequential quadratic programming(SQP) algorithm. The evaluation is carried out via three stages. The signed distance function from the measured points to cylindrical surface is defined and the cylinder is located roughly by the traditional least-squares(LS) method firstly; the fitted cylinder and the measured points coordinates are transformed to simplify the optimal mathematical model for the cylindricity error evaluation secondly; and then optimization problem on the cylindricity error evaluation satisfying the minimum zone criterion is solved by means of the SQP algorithm and kinematic geometry. The computer simulation shows that the cylindricity error evaluation algorithm has the advantages of good robustness,high efficiency and accuracy. The obtained cylindricity error is effective.
2014, 33(12): 1850-1853.
doi: 10.13433/j.cnki.1003-8728.2014.1218
Abstract:
To realize high speed machining for the tiny track of embedded system,and to avoid the impact of the frequent changing of the federate,an adaptive algorithm for look-ahead velocity control is proposed in this paper.This algorithm can discriminate the look-ahead demarcation point by using the small line flag and automatically adjusting the number of look-ahead segments. The algorithm also predigests the convergence speed calculation method of the connection points. The restrictions of the adjacent tracks processing path speed is analyzed,and a method to determine the small line is also presented. Simulation experiment is conducted on the processing of 30 spline track points. The results show that this algorithm can significantly shorten the processing time and ensure the speed changing smoothly.
To realize high speed machining for the tiny track of embedded system,and to avoid the impact of the frequent changing of the federate,an adaptive algorithm for look-ahead velocity control is proposed in this paper.This algorithm can discriminate the look-ahead demarcation point by using the small line flag and automatically adjusting the number of look-ahead segments. The algorithm also predigests the convergence speed calculation method of the connection points. The restrictions of the adjacent tracks processing path speed is analyzed,and a method to determine the small line is also presented. Simulation experiment is conducted on the processing of 30 spline track points. The results show that this algorithm can significantly shorten the processing time and ensure the speed changing smoothly.
2014, 33(12): 1854-1858.
doi: 10.13433/j.cnki.1003-8728.2014.1219
Abstract:
Considering rolling bearing vibration signals exhibit varied complexity in a multiscale form,a novel rolling element bearing fault diagnosis method was proposed based on multiscale entropy(MSE) and feedback Elman neural network. In this method,the feature extraction from rolling bearing vibrations was performed by utilizing the MSE,and then the MSE was input to the Elman neural network as feature vectors for fault detection.The Elman network was exploited to simultaneously judge bearing fault type and severity degree. Experimental data were collected from an induction motor bearing involving various fault types and severity levels. The results verify the effectiveness of the proposed approach in the sense that the Elman network results in decreased false-alarm and missed-alarm rates in comparison with the feed-forward probabilistic neural network(PNN).
Considering rolling bearing vibration signals exhibit varied complexity in a multiscale form,a novel rolling element bearing fault diagnosis method was proposed based on multiscale entropy(MSE) and feedback Elman neural network. In this method,the feature extraction from rolling bearing vibrations was performed by utilizing the MSE,and then the MSE was input to the Elman neural network as feature vectors for fault detection.The Elman network was exploited to simultaneously judge bearing fault type and severity degree. Experimental data were collected from an induction motor bearing involving various fault types and severity levels. The results verify the effectiveness of the proposed approach in the sense that the Elman network results in decreased false-alarm and missed-alarm rates in comparison with the feed-forward probabilistic neural network(PNN).
2014, 33(12): 1859-1864.
doi: 10.13433/j.cnki.1003-8728.2014.1220
Abstract:
Mining Waste Parts are becoming the world's fastest growing components of the waste; the classification and estimation are the basis of remanufacturing recycling. According to the reliability threshold and remanufacturing economy in the special conditions of dusty,corrosion and fast wear,the typical mining waste parts remaining life prediction model is established; by building remanufacturing estimation method based on three dimensional structure of the Hall,a new solution for enterprise to accurately predict the residual life of waste parts and the remanufacturing decision making are provided. The crankshaft of the electric wheel dump truck is taken as an example to illustrate the feasibility of the idea.
Mining Waste Parts are becoming the world's fastest growing components of the waste; the classification and estimation are the basis of remanufacturing recycling. According to the reliability threshold and remanufacturing economy in the special conditions of dusty,corrosion and fast wear,the typical mining waste parts remaining life prediction model is established; by building remanufacturing estimation method based on three dimensional structure of the Hall,a new solution for enterprise to accurately predict the residual life of waste parts and the remanufacturing decision making are provided. The crankshaft of the electric wheel dump truck is taken as an example to illustrate the feasibility of the idea.
2014, 33(12): 1865-1868.
doi: 10.13433/j.cnki.1003-8728.2014.1221
Abstract:
The effect of abrasive belt types,workpiece material properties and different grinding parameters to grinding efficiency and different effects of abrasive wear was analyzed. The process test used two different abrasive belt respectively for grinding three different materials,the amount of material removal and belt wear were measured,the wear mechanisms were revealed. The results shows that the grindability of titanium alloy is low,that of 304 stainless steel is better than that of titanium alloy,that of 45 steel is the most than that of titanium alloy. To increase the belt speed can increase the material removal rate and the wear ratio to some extent. The abrasive grinding ratio of ceramic abrasive is higher than that of alumina oxide,therefore the ceramic abrasive belt can be chosen for large grinding allowance. With the increasing of hardness ratio,the abrasion ratio decreases after an increas,then the abrasive belt can be chosen according to the hardness of abrasive belt.
The effect of abrasive belt types,workpiece material properties and different grinding parameters to grinding efficiency and different effects of abrasive wear was analyzed. The process test used two different abrasive belt respectively for grinding three different materials,the amount of material removal and belt wear were measured,the wear mechanisms were revealed. The results shows that the grindability of titanium alloy is low,that of 304 stainless steel is better than that of titanium alloy,that of 45 steel is the most than that of titanium alloy. To increase the belt speed can increase the material removal rate and the wear ratio to some extent. The abrasive grinding ratio of ceramic abrasive is higher than that of alumina oxide,therefore the ceramic abrasive belt can be chosen for large grinding allowance. With the increasing of hardness ratio,the abrasion ratio decreases after an increas,then the abrasive belt can be chosen according to the hardness of abrasive belt.
2014, 33(12): 1869-1875.
doi: 10.13433/j.cnki.1003-8728.2014.1222
Abstract:
The pumping unit for cluster wells has a good prospect in application due to the characteristics of energy conservation and low cost. This paper presents the kinematic and dynamic analysis of a novel pumping unit based on the phase balance for cluster wells. In addition,a comparative analysis of the novel pumping unit and pumping unit with phased crank counterbalance is made on the basis of actual working conditions. The results show that,the novel pumping unit based on the phase balance for cluster wells does not need the counterweights and can be applied completely in even number or odd number wells; compared with that of pumping unit with phased crank counterbalance,the reducer's maximum net torque has been reduced remarkably and the minimum net torque has been improved remarkably,the curves of reducer net torque becomes less fluctuating; the installed power and effective power is greatly decreased and the CLF value is close to 1.0,which indicates that the new pumping unit has more notable energy conservation effect and better dynamic performance.
The pumping unit for cluster wells has a good prospect in application due to the characteristics of energy conservation and low cost. This paper presents the kinematic and dynamic analysis of a novel pumping unit based on the phase balance for cluster wells. In addition,a comparative analysis of the novel pumping unit and pumping unit with phased crank counterbalance is made on the basis of actual working conditions. The results show that,the novel pumping unit based on the phase balance for cluster wells does not need the counterweights and can be applied completely in even number or odd number wells; compared with that of pumping unit with phased crank counterbalance,the reducer's maximum net torque has been reduced remarkably and the minimum net torque has been improved remarkably,the curves of reducer net torque becomes less fluctuating; the installed power and effective power is greatly decreased and the CLF value is close to 1.0,which indicates that the new pumping unit has more notable energy conservation effect and better dynamic performance.
2014, 33(12): 1876-1879.
doi: 10.13433/j.cnki.1003-8728.2014.1223
Abstract:
To improve the lubrication performance on end-surface clearance of gear in external gear pump,the design method was proposed to strengthen the dynamic pressure lubrication effect on the end-surface clearance.Based on the requirement of simple process,the inner face of floating endplates was divided into three areas,the area above the center point of driving gear was the first part with a slope angle,the area below the center point of driven gear was the third part with the same slope angle,and the central area was the third part with parallel surface mainly used for sealing function. The same slope angle of the first area and the third area was derived from the conditions of the best oil-film force.. The results of design examples showed that the oil wedge structure on inner surface of floating endplate and the derived slope angle was easy to be processed,With the angle of 36�for sealing area in discharge side of pump and the best convergence rate of 1.25 in root circle,a strong oil-film power and a large shear flow could be obtained,and the volumetric efficiency of pump was also improved.
To improve the lubrication performance on end-surface clearance of gear in external gear pump,the design method was proposed to strengthen the dynamic pressure lubrication effect on the end-surface clearance.Based on the requirement of simple process,the inner face of floating endplates was divided into three areas,the area above the center point of driving gear was the first part with a slope angle,the area below the center point of driven gear was the third part with the same slope angle,and the central area was the third part with parallel surface mainly used for sealing function. The same slope angle of the first area and the third area was derived from the conditions of the best oil-film force.. The results of design examples showed that the oil wedge structure on inner surface of floating endplate and the derived slope angle was easy to be processed,With the angle of 36�for sealing area in discharge side of pump and the best convergence rate of 1.25 in root circle,a strong oil-film power and a large shear flow could be obtained,and the volumetric efficiency of pump was also improved.
2014, 33(12): 1880-1883.
doi: 10.13433/j.cnki.1003-8728.2014.1224
Abstract:
Fluent is used to take numerical simulation of three dimensional flow of the inner of the ball valve. There is an exploration on the internal flow fields of the valve when the opening degree gradually increases. The change circumstances of the internal flow fields of the ball valve is analyzed on 5 different opening degrees(20%,40%,60%,80% and 100%). Simulation results show that: when the valve opening is between 20% ~ 40%,the ball valve internal flow is the most complex,the eddy current cyclotron is the most strong,the valve flow resistance is very large,swirls velocity around the boundary is much larger than the velocity at the centre,and the pressure at the center position is the lowest,until the flow reaches steadily. The differential pressure value before and after the valve,the variation values of the flow coefficient and flow resistance coefficient on 5 different opening degrees have been got,the variation curves about three of them are obtained by analysis when the valve is on different open degrees.
Fluent is used to take numerical simulation of three dimensional flow of the inner of the ball valve. There is an exploration on the internal flow fields of the valve when the opening degree gradually increases. The change circumstances of the internal flow fields of the ball valve is analyzed on 5 different opening degrees(20%,40%,60%,80% and 100%). Simulation results show that: when the valve opening is between 20% ~ 40%,the ball valve internal flow is the most complex,the eddy current cyclotron is the most strong,the valve flow resistance is very large,swirls velocity around the boundary is much larger than the velocity at the centre,and the pressure at the center position is the lowest,until the flow reaches steadily. The differential pressure value before and after the valve,the variation values of the flow coefficient and flow resistance coefficient on 5 different opening degrees have been got,the variation curves about three of them are obtained by analysis when the valve is on different open degrees.
2014, 33(12): 1884-1887.
doi: 10.13433/j.cnki.1003-8728.2014.1225
Abstract:
Aiming at main defects,such as the misdescription of existing electronic anti-theft devices,high cost and troublesome maintenance of chip type and network type anti-theft systems. In this paper,we design a passwordantitheft system for ATV based on singlechip. This system consists of a self-locking solenoid switch valve with its driving circuit,an ISD4004 voice module,a liquid crystal display and matrix keyboard-password input panel. The core component,self-locking solenoid switch valve,is embedded into the engine's inlet pipe. By judging whether the input password is correct or not,the opening and the closing of the control valve are determined,and so do the opening and the closing of the engine. Experimental results show that this system is of low cost and good reliability,and can effectively guard against theft.
Aiming at main defects,such as the misdescription of existing electronic anti-theft devices,high cost and troublesome maintenance of chip type and network type anti-theft systems. In this paper,we design a passwordantitheft system for ATV based on singlechip. This system consists of a self-locking solenoid switch valve with its driving circuit,an ISD4004 voice module,a liquid crystal display and matrix keyboard-password input panel. The core component,self-locking solenoid switch valve,is embedded into the engine's inlet pipe. By judging whether the input password is correct or not,the opening and the closing of the control valve are determined,and so do the opening and the closing of the engine. Experimental results show that this system is of low cost and good reliability,and can effectively guard against theft.
2014, 33(12): 1888-1892.
doi: 10.13433/j.cnki.1003-8728.2014.1226
Abstract:
Back Propagation(BP) networks have been widely used in analog circuit diagnosis and have achieved some success. However,there are some inherent disadvantages in traditional BP neural network,such as the low speed of error convergency,easily falling into local minimum and the uncertainty structure of networks. Therefore,a new BP network method optimized by genetic algorithms(GA) and Levenberg-Marquardt(LM) algorithm is proposed. In this method,the structure of BP network is optimized by GA. Then LM algorithm is used to train the BP network. The training results can be used to diagnose the faults of analog circuits,which is able to overcome the inherent disadvantages of traditional BP network. The fault diagnosis of the Leap Frog Filter circuit is taken as the example and the simulation results demonstrate the effectiveness and applicability of the proposed method。
Back Propagation(BP) networks have been widely used in analog circuit diagnosis and have achieved some success. However,there are some inherent disadvantages in traditional BP neural network,such as the low speed of error convergency,easily falling into local minimum and the uncertainty structure of networks. Therefore,a new BP network method optimized by genetic algorithms(GA) and Levenberg-Marquardt(LM) algorithm is proposed. In this method,the structure of BP network is optimized by GA. Then LM algorithm is used to train the BP network. The training results can be used to diagnose the faults of analog circuits,which is able to overcome the inherent disadvantages of traditional BP network. The fault diagnosis of the Leap Frog Filter circuit is taken as the example and the simulation results demonstrate the effectiveness and applicability of the proposed method。
2014, 33(12): 1893-1896.
doi: 10.13433/j.cnki.1003-8728.2014.1227
Abstract:
A new type of intelligent thermostatic mixing valve is designed and the flux model and temperature model of the valve is established. And the inner mixing flow field of hot water and cool water of the valve is simulated by using the Fluent software. By comparing the simulation results and those obtained directly from the mathematical model,the correctness of the mathematical model of thermostatic valve is proved. Finally, a prototype of thermostatic valve is tested to verify the effects of temperature control and flow control. The experimental results show that the valve can accurately maintain the temperature of outlet warm water and the flow rate of the thermostatic valve by self-adjusting with the intelligent controller,even though the temperature of inlet hot water varies continuously,and the response time of constant warm water outlet is about 7 seconds.
A new type of intelligent thermostatic mixing valve is designed and the flux model and temperature model of the valve is established. And the inner mixing flow field of hot water and cool water of the valve is simulated by using the Fluent software. By comparing the simulation results and those obtained directly from the mathematical model,the correctness of the mathematical model of thermostatic valve is proved. Finally, a prototype of thermostatic valve is tested to verify the effects of temperature control and flow control. The experimental results show that the valve can accurately maintain the temperature of outlet warm water and the flow rate of the thermostatic valve by self-adjusting with the intelligent controller,even though the temperature of inlet hot water varies continuously,and the response time of constant warm water outlet is about 7 seconds.
2014, 33(12): 1897-1901.
doi: 10.13433/j.cnki.1003-8728.2014.1228
Abstract:
Aiming at the requirement of fast response and high precision in automatic vehicle leveling device,the leveling strategy of chasing the highest anchor on surface adjusted to surface is employed. The fuzzy PID combining with the traditional PID is used as the inner controller and the PD controller is used as the outer controller to synchronically control the actuator,in which the synchronization error is compensated to the slave actuator by PD controller to ensure the high-precision and fast response. The experiments show that and the leveling time can be reduce to 29 s and the leveling precision is less than 3.4 points. Thus the leveling strategy and control algorithm have the significance in engineering application.
Aiming at the requirement of fast response and high precision in automatic vehicle leveling device,the leveling strategy of chasing the highest anchor on surface adjusted to surface is employed. The fuzzy PID combining with the traditional PID is used as the inner controller and the PD controller is used as the outer controller to synchronically control the actuator,in which the synchronization error is compensated to the slave actuator by PD controller to ensure the high-precision and fast response. The experiments show that and the leveling time can be reduce to 29 s and the leveling precision is less than 3.4 points. Thus the leveling strategy and control algorithm have the significance in engineering application.
2014, 33(12): 1902-1906.
doi: 10.13433/j.cnki.1003-8728.2014.1229
Abstract:
In order to comprehensively reflect the vertical jump,pitch change and roll motion problems of car body,the nonlinear dynamical model of semi-active suspension with seven degrees of freedom and the random road model of four wheels are established,And the brake model and the steering model are added,using an improved Bouc-Wen model of magnetorheological damper. The Fuzzy-PID compound control technology is used,namely using fuzzy control rules to realize the online modification of PID parameters and make the controller automatically adjust according to the initial rules,so that it could have a better control performance. The simulation results show that,compared with the conventional PID control,the fuzzy-PID has a better control effects and can effectively reduce body acceleration,roll acceleration and pitch acceleration,and it greatly improves the suspension dynamic deflection and raises the comfort and safety of the car.
In order to comprehensively reflect the vertical jump,pitch change and roll motion problems of car body,the nonlinear dynamical model of semi-active suspension with seven degrees of freedom and the random road model of four wheels are established,And the brake model and the steering model are added,using an improved Bouc-Wen model of magnetorheological damper. The Fuzzy-PID compound control technology is used,namely using fuzzy control rules to realize the online modification of PID parameters and make the controller automatically adjust according to the initial rules,so that it could have a better control performance. The simulation results show that,compared with the conventional PID control,the fuzzy-PID has a better control effects and can effectively reduce body acceleration,roll acceleration and pitch acceleration,and it greatly improves the suspension dynamic deflection and raises the comfort and safety of the car.
2014, 33(12): 1907-1911.
doi: 10.13433/j.cnki.1003-8728.2014.1230
Abstract:
According to the requirements of vibration control for military tracked vehicle suspension,a hybrid active suspension for tracked vehicle,which is composed of an electromagnetic actuator and a magnetorheological damper,is introduced,and the suspension dynamic model is established. The equation of state of the suspension system is deduced and the random road roughness excitation is generated using the filtered white noise method. Then the LQR optimal control algorithm is designed and the vibration control is simulated. The results show that it is feasible to improves the tracked vehicle driving safety and ride comfort by this control approach. In a certain type of tracked vehicle,when the root mean square(RMS) value of the relative dynamic load between the wheel and the vehicle body is increased by only 2.82% and suspension dynamic travel is less than one-third of the maximum stroke,the acceleration RMS value of the vehicle body can be reduced to 40.74%.
According to the requirements of vibration control for military tracked vehicle suspension,a hybrid active suspension for tracked vehicle,which is composed of an electromagnetic actuator and a magnetorheological damper,is introduced,and the suspension dynamic model is established. The equation of state of the suspension system is deduced and the random road roughness excitation is generated using the filtered white noise method. Then the LQR optimal control algorithm is designed and the vibration control is simulated. The results show that it is feasible to improves the tracked vehicle driving safety and ride comfort by this control approach. In a certain type of tracked vehicle,when the root mean square(RMS) value of the relative dynamic load between the wheel and the vehicle body is increased by only 2.82% and suspension dynamic travel is less than one-third of the maximum stroke,the acceleration RMS value of the vehicle body can be reduced to 40.74%.
2014, 33(12): 1912-1915.
doi: 10.13433/j.cnki.1003-8728.2014.1231
Abstract:
Finite element analysis of engineering structures usually applies coarse grid models,which results in large error when calculating the initial critical buckling loads of stiffened thin-walled structures under in-plane pressure and shear loads. And by using the shell with four edges simply supported to check it strengthens the actual boundary conditions,which makes the error larger. With the help of the spectral element method,the buckling eigenvalue of the simply supported and elastically supported composite laminates is calculated respectively. Then by extracting the real stresses of the coarse grid model,the local initial critical buckling loads of stiffened composite thin-walled structure is analyzed. The results show that the spectral element method(SEM) converges to the theoretical solution of the plate with four edges simply supported,which has high computational efficiency; SEM for local stiffened thin-walled structures can efficiently converge to the local stability solution of the overall reinforced thin-walled structures,and it can involve the elastically supporting effect of the composite plates,which better simulates the actual constraints of the stiffened plate.
Finite element analysis of engineering structures usually applies coarse grid models,which results in large error when calculating the initial critical buckling loads of stiffened thin-walled structures under in-plane pressure and shear loads. And by using the shell with four edges simply supported to check it strengthens the actual boundary conditions,which makes the error larger. With the help of the spectral element method,the buckling eigenvalue of the simply supported and elastically supported composite laminates is calculated respectively. Then by extracting the real stresses of the coarse grid model,the local initial critical buckling loads of stiffened composite thin-walled structure is analyzed. The results show that the spectral element method(SEM) converges to the theoretical solution of the plate with four edges simply supported,which has high computational efficiency; SEM for local stiffened thin-walled structures can efficiently converge to the local stability solution of the overall reinforced thin-walled structures,and it can involve the elastically supporting effect of the composite plates,which better simulates the actual constraints of the stiffened plate.
2014, 33(12): 1916-1920.
doi: 10.13433/j.cnki.1003-8728.2014.1232
Abstract:
A dynamic model for researching the misalignment fault of a twin spool rotor with inter-shaft bearing is established in this paper. The vibration features of high and low pressure rotors are revealed when the twin spool rotor with misalignment fault by analytical analysis,numerical analysis and experiment. The theory analysis and experiment results show that,because of the inter-shaft bearing,the coupling between the high pressure rotor and low pressure rotor is very strong; when the low pressure rotor is misaligned,the vibration characteristics of low pressure rotor can be transferred to the high pressure rotor and will happen double frequency resonance when the speed is half of the critical speed of the twin spool rotor.
A dynamic model for researching the misalignment fault of a twin spool rotor with inter-shaft bearing is established in this paper. The vibration features of high and low pressure rotors are revealed when the twin spool rotor with misalignment fault by analytical analysis,numerical analysis and experiment. The theory analysis and experiment results show that,because of the inter-shaft bearing,the coupling between the high pressure rotor and low pressure rotor is very strong; when the low pressure rotor is misaligned,the vibration characteristics of low pressure rotor can be transferred to the high pressure rotor and will happen double frequency resonance when the speed is half of the critical speed of the twin spool rotor.
2014, 33(12): 1921-1924.
doi: 10.13433/j.cnki.1003-8728.2014.1233
Abstract:
Based on the feature,it is easy to carry out rotor balance in situ of fan rotor for high bypass ratio turbofan engine,using the model of the symmetric rotor with a single disc and elastic support,and according to the relationship between the influencing coefficients of the rotor balance and the vibration response of the rotor,two methods in which influencing coefficients and transfer functions are used to validate the rotor dynamic model and estimate the model parameters(the natural vibration frequency,the equivalent stiffness and the elastic support stiffness) are presented. The methods are validated by experiments and the results show the feasibility and correctness of the above methods.
Based on the feature,it is easy to carry out rotor balance in situ of fan rotor for high bypass ratio turbofan engine,using the model of the symmetric rotor with a single disc and elastic support,and according to the relationship between the influencing coefficients of the rotor balance and the vibration response of the rotor,two methods in which influencing coefficients and transfer functions are used to validate the rotor dynamic model and estimate the model parameters(the natural vibration frequency,the equivalent stiffness and the elastic support stiffness) are presented. The methods are validated by experiments and the results show the feasibility and correctness of the above methods.
2014, 33(12): 1925-1930.
doi: 10.13433/j.cnki.1003-8728.2014.1234
Abstract:
The existing and possible applications of advanced composite grid structures(AGS) are summarized.The manufacturing processes of AGS are classified into seven types,including rigid tooling process,expansion coating tooling process,expansion block tooling process,hybrid tooling process,interlocked grid process,tooling reinforced interlaced grid(TRIG) process and interlocked sandwich panel process. The advantages and disadvantages of these manufacturing processes are discussed and compared. Finally,to improve the performance of advanced composite grid structures,some solutions are proposed.
The existing and possible applications of advanced composite grid structures(AGS) are summarized.The manufacturing processes of AGS are classified into seven types,including rigid tooling process,expansion coating tooling process,expansion block tooling process,hybrid tooling process,interlocked grid process,tooling reinforced interlaced grid(TRIG) process and interlocked sandwich panel process. The advantages and disadvantages of these manufacturing processes are discussed and compared. Finally,to improve the performance of advanced composite grid structures,some solutions are proposed.
2014, 33(12): 1931-1936.
doi: 10.13433/j.cnki.1003-8728.2014.1235
Abstract:
A two-dimensional inlet with multi-wedge plate diffuser is designed to improve the operating characteristics of the inlet in " over/under" TBCC(Turbine Based Combined Cycle). The effects of non-uniform flow on the flow-field characteristic and the performance parameter are investigated and compared with that on the the conventional inlet. The simulation results indicate that the two-dimensional inlet with multi-wedge plate diffuser is slightly influenced by non-uniform flow and the outlet flow field in diffuser is improved significantly. At mode transition,compared with the conventional inlet,the total pressure recovery ratio is increased by 10%,and the total pressure distortion indicator(DPt) is decreased by about 15%,the outlet Mach number of the ramjet diffuser is less than 0. 41 and the outlet temperature ratio(ψ) is decreased. Those make the engine thrust increased and make the specific fuel consumption reduced.
A two-dimensional inlet with multi-wedge plate diffuser is designed to improve the operating characteristics of the inlet in " over/under" TBCC(Turbine Based Combined Cycle). The effects of non-uniform flow on the flow-field characteristic and the performance parameter are investigated and compared with that on the the conventional inlet. The simulation results indicate that the two-dimensional inlet with multi-wedge plate diffuser is slightly influenced by non-uniform flow and the outlet flow field in diffuser is improved significantly. At mode transition,compared with the conventional inlet,the total pressure recovery ratio is increased by 10%,and the total pressure distortion indicator(DPt) is decreased by about 15%,the outlet Mach number of the ramjet diffuser is less than 0. 41 and the outlet temperature ratio(ψ) is decreased. Those make the engine thrust increased and make the specific fuel consumption reduced.
2014, 33(12): 1937-1942.
doi: 10.13433/j.cnki.1003-8728.2014.1236
Abstract:
Uncertainty is one of the main factors that affect the aircraft electro-hydrostatic actuator's(EHA)reliability. In order to eliminate uncertainty effects and improve the reliability of the EHA,the uncertainty modeling and the reliability calculation method of the EHA are studied based on the probability theory in this paper. The uncertainty of the EHA is analyzed qualitatively,an uncertainty modeling method is proposed based on the established linear mathematical model. Considering influence of the single parameter and the multi-parameters to the model respectively,the uncertainty modeling and the reliability calculation methods of the EHA are established.Finally,the established model is verified by taking the influence of the actuator 's cross-sectional area to output displacement as an example,and the availability of the method is verified by comparing with the simulation results of the Matlab.
Uncertainty is one of the main factors that affect the aircraft electro-hydrostatic actuator's(EHA)reliability. In order to eliminate uncertainty effects and improve the reliability of the EHA,the uncertainty modeling and the reliability calculation method of the EHA are studied based on the probability theory in this paper. The uncertainty of the EHA is analyzed qualitatively,an uncertainty modeling method is proposed based on the established linear mathematical model. Considering influence of the single parameter and the multi-parameters to the model respectively,the uncertainty modeling and the reliability calculation methods of the EHA are established.Finally,the established model is verified by taking the influence of the actuator 's cross-sectional area to output displacement as an example,and the availability of the method is verified by comparing with the simulation results of the Matlab.
