最新刊期
期 4 ， 2018
- 摘要：For three-wheeled omni-directional mobile robots that slipping is almost inherently encountered in motion,one suitable trajectory tracking control system based on a improved dynamical model with slip is proposed based,which gives more accurate control result. The kinematics model and dynamics model for omni-directional mobile robots are built. By analyzing the wheel contact friction forces both in the wheel hub rolling direction and in the roller rolling direction,an amendatory dynamics model is presented. This model is introduced into the closed trajectory tracking control system to solve the trajectory tracking problem. The simulation of trajectory tracking control system is carried out on the platform of Matlab/Simulink. The results indicate that the trajectory tracking control system of three-wheeled omni-directional mobile robots based on the improved dynamical model with slip has good stability and accuracy.关键词：Slip;Trajectory tracking;Dynamics model;Robot
- 4
- |
- 258
- |
- 3
发布时间：2022-10-20 - 摘要：Aiming at the tooth surface error measurement results distortion of straight bevel gear which consisted of the of modification error and machining error based on gear measuring center,a method which is proposed to obtain the theoretical coordinates for tooth surface measurement based on the solid modeling.According to the design of the gear structure,the origin of the coordinate system and datum plane can be determined by installation distance,then the rotating projection line model can be established based on the calculated mesh nodes coordinates,a series of points are converted to the tooth surface,combined with UG Open programming technology,the attribute analysis of the points on the tooth surface can be extracted,then the coordinates and unit vector of the tooth surface measurement points can be obtained,which provides a new way for the acquisition of the tooth surface error measurement based on gear measuring center.关键词：Straight bevel gear;Gear measuring center;Tooth surface measurement;Solid modeling;Theoretical data extraction
- 3
- |
- 88
- |
- 1
发布时间：2022-10-20 - 摘要：Aiming at the workspace of existing spherical parallel mechanism is smaller in the field of large spherical workspace application,a decoupling spherical parallel mechanism with sphere workspace is proposed.Firstly,according to the limitation from the friction circle of the revolute joint,the modified mechanism is given,which can provide a sphere workspace,and its number of degree of freedom is analyzed. Secondly,the inverse and forward position for the mechanism is derived with the closed vector method. The expression of the Jacobian matrix is deduced with the relational expression between the input and output parameters of the mechanism. And according to the expression of the Jacobian matrix,the decoupled feature of the proposed parallel mechanism is validated. The theoretical foundation for the application of the mechanism to the sphere workspace is provided.关键词：Spherical parallel mechanism;Friction circle;Sphere workspace;Decoupled
- 4
- |
- 150
- |
- 1
发布时间：2022-10-20 - 摘要：The configuration of electric vehicle equipped with electro-mechanical continuously variable transmission（ EMCVT） is put forward based on the analysis of work principle of EMCVT,and the simulation model of electric vehicle equipped with EMCVT is built by MATLAB/Simulink platform. The hardware in the loop system of powertrain is built by LABCAR platform and the simulation test is conducted to verify the EMCVT function of the control unit and the feasibility of control strategy. Simulation results indicate that the power performance of electric vehicle is improved by using this control strategy and the configuration is feasibility.关键词：Electro-mechanic continuously variable transmission（EMCVT）;Hardware in the loop（HIL）;Electric vehicle;Control strategy
- 6
- |
- 169
- |
- 6
发布时间：2022-10-20 - 摘要：In order to study the effect of manganese phosphate conversion coating on gear meshing temperature,based on gear meshing theory,tribology theory and heat transfer theory,combined with the friction coefficient according to the SRV friction wear tests with coating and non-coating,the friction heat flux density and the convective heat transfer coefficient and load of the gears are calculated accurately. Finally,the steady-state temperature distribution of the gear teeth before and after coating is obtained,and the influence of the speed and torque on the steady temperature field of the gears is analyzed. The results show that the maximum temperature of the gears after coating treatment is lower than that of the uncoated gears,which provides a reference for the study of fatigue resistance and scuffing resistance of gears.关键词：Coated gear;Friction wear;Heat flux density;Convective heat transfer coefficient;Steady temperature field
- 5
- |
- 146
- |
- 1
发布时间：2022-10-20 -
Torque Characteristic Analysis of Permanent Magnet Eddy-current Coupling with Slotted Conductor Disk
摘要：Compared with the traditional permanent magnet eddy-current couplings,one with slotted conductor disk can force eddy current to flow under a designated route which can improve the transmitted torque and enhance the transmission performance of the device. But if a device with a unreasonable slot numbers or structure,the torque will decrease or the ripple will increase. So the over-all properties of the device will degradation,the regulation reliability will going harder. A comparative analysis of the number of the slot and structure is conducted. At the end,a reasonable slotted number is given and can provide an important reference for the design and application of the permanent magnet eddy-current coupling.关键词：Eddy-current coupling;Slotted;Pole-slot match;Cogging torque;Finite element- 4
- |
- 95
- |
- 3
发布时间：2022-10-20 - 摘要：In order to reduce the vibration and noise of the ZC1 worm gear transmission,it needs to make a study of its dynamic characteristics. Based on the theory of the lumped mass method,the dynamical analysis model of the ZC1 worm gear reducer transmission system is established. The Runge-Kutta method is used to solve the normalized equations in MATLAB,and the dynamic response curve of the system is obtained. Furthermore,the influence rule on system vibration characteristics is researched by changing input speed,meshing stiffness and meshing damping. The vibration regularity in y、z and torsional direction evolutes from quasi-periodic motion to nearly chaotic motion,and the results show that the vibration regularity of y、z and torsional direction is more susceptible by changing these three parameters. The results provide the basis for the subsequent dynamic optimization design of the ZC1 worm gear reducer.关键词：Worm gear reducer;Meshing stiffness;Vibration characteristic
- 4
- |
- 174
- |
- 1
发布时间：2022-10-20 - 摘要：On the basis of liquid cavitation two-phase flow theory of hydrodynamic lubrication,the hydrodynamic lubrication model of the step thrust bearing is analyzed by means of computational fluid dynamics（ CFD） simulation,which is based on the numerical solution of the Navier-Stokes. The effects of depth ratio,length ratio,number of steps and rotate speed on the load capacity of the step bearing is investigated. The results of the study indicate that the influences of depth ratio on the load capacity is more dramatically than the length ratio. The depth ratio is 1. 7,and the length ratio is 1. 3,the load capacity is largest. When the rotate speed increases,the load capacity grows linearly. The load capacity increases at first and decreases afterwards with the increasing of the number of steps.关键词：Step bearing;Two phase flow;Load capacity;Optimization design
- 5
- |
- 170
- |
- 1
发布时间：2022-10-20 - 摘要：Considering the viscoelastic properties of belt and combining finite element method and mutibody dynamics theory,a new discrete model of belt using rigid elements describing the rigid property and spring-damping elements describing the flexible property is brought out. Based on Lagrange equations of the second kind,the dynamics differential equations of rigid elements are established. Then,the flexible multibody dynamics equations of belt conveyor system are established by using recursive synthesis method. The running speed of a belt conveyor in starting phase is simulated by this modeling method. The correctness of the simulation results and the practicability of the method are validated by the field testing results of a belt conveyor. The simulation results provides not only the basic data for dynamic design but also valuable theoretical basis for further research on belt conveyor.关键词：Viscoelastic;Rigid element;Spring-damping element;Flexible multibody dynamics;Conveyor belt;Rigid finite element method
- 4
- |
- 160
- |
- 1
发布时间：2022-10-20 - 摘要：A brief analysis of the characteristic of the compound planetary gear technology is carried out,and the performance and the values of the mean load factor of the compound planetary are discussed. The calculation method of the maximum phase difference of the meshing points and the calculation method of mean load share performance for turning angle are put forward. In a compound planetary,there is a certain amount of floating in the inner gear ring,except for the float of the sun,the connecting segments of the twin planetary shaft,inner gear ring and the spindle produce certain torsional deformations. Through numerical examples illustrate that the torsional deformations of the sun and inner gear are more than simple planetary,the compensation manufacturing deviation caused by the uneven load ability is stronger,so there will be a lower mean load factor.According to theoretical analysis and test data which has been obtained and the successful application of actual design,it is appropriate to take 1. 10 as the planetary mean load factor of the compound planetary of four planets in the design of wind power gear.关键词：Compound planetary;Simple planetary;Mean load factor;Torsional stiffness;Torsional angle;Compensation;Float
- 4
- |
- 205
- |
- 3
发布时间：2022-10-20 - 摘要：Based on ANSYS finite element static analysis,the mechanical properties of the water lubricated spiral stepped rubber stern bearings are obtained by orthogonal design and control variable method. Based on the results,the influence of structural parameters on the mechanical properties of the stern bearings is obtained based on Minitab. Finally,the surface structure of the stern bearings is analyzed by Design Exploration module and the multi-objective optimization is used to improve the mechanical property.关键词：Water lubrication;Spiral stepped ladder;Finite element;Multi-objective optimization
- 3
- |
- 164
- |
- 1
发布时间：2022-10-20 - 摘要：In order to obtain the precise contour of the conjugate cam of the rotation variable speed mechanism of the STAUBLI type electronic dobby,the data of original conjugate cam profile and other main parts of the mechanism is measured,the 3D solid model of rotation variable speed mechanism is established based on CREO software and the kinematics simulation analysis is carried out. Then the angular displacement,angular velocity as well as angular acceleration curves of the follower are obtained before the redesign. From the angle of the kinematics design,based on the theoretically derivate conjugate cam contour line of mathematic model,the conjugate cam curve equation is redesigned,the equation is solved numerically and the theoretical conjugate cam contour curve is reached out. After that,conjugate cam 3D solid model is set up on the basis of theoretical contour curve and is plugged to the rotation variable speed mechanism to present kinematics simulation analysis.The analysis results show that the movement curve of redesigned conjugate cam is smooth,which is satisfied with the working requirements.关键词：Conjugate cam;Dobby;Rotation variable speed mechanism;Redesign
- 4
- |
- 100
- |
- 1
发布时间：2022-10-20 - 摘要：Three kinds of scheme of single stage,twin-stage and four-stage transmissions are designed for a light pure electric bus,and then the parameters matching of the power assembly is carried out. The vehicle models are built in Cruise,and then the simulation of the dynamic and economic performance of the three schemes is carried out,the simulation results show that the dynamic and economy performance of multi-gear transmissions are higher than that of single reducer. Because there is no significant improvement of the dynamic and economy performance between the four-stage transmission and twin-stage transmission,in addition,the increase of gear will lead to the problem of shifting difficulties and manufacturing cost increasing,etc. So the twin-stage transmission has a relatively comprehensive advantage.关键词：Pure electric vehicle;Powertrain;Parameter matching;Transmission;Cruise simulation
- 3
- |
- 326
- |
- 2
发布时间：2022-10-20 - 摘要：In order to reduce the material consumption of crowd reducer box of large mine excavator and to realize the box light weight,topology optimization of the upper box is carried out. Based on finite element analysis about stress of electric excavator crowd reducer box,by using the variable density method,the mass of upper box is taken as the optimization objective,and the maximum stress,the wall thickness of box and the remaining percentage are taken as the topology constraint conditions,according to the force transmission path,topology optimization of crowd reducer upper box of mining electric excavator is achieved. The finite element method is used to analyze the maximum stress of the box before and after optimization. According to the standard ISO 6336: 2006 and the standard ISO/TS 16281: 2008,the gear stress（ including the contact stress of teeth surface and the bending stress of teeth root） and bearing life of before and after optimization are analyzed respectively. The optimization results show that the topology optimization of the reducer upper box has a minimal influence on the stress of the box and the fatigue life of the bearing. Although the optimization makes the gear stress increase slightly,the gear still meets the requirement of strength.关键词：Mining electric excavator;Reducer;Box;Topology optimization
- 4
- |
- 109
- |
- 1
发布时间：2022-10-20 - 摘要：According to the requirements of the Fifth National College Students ’ Comprehensive Ability Competition in Engineering Training,the design and production of cam structure based on the 8-shaped carbon-free car is completed. According to the theoretical trajectory of the carbon-free car,the design and parameter calculation of the transmission mechanism and the steering mechanism of the car are carried out. The kinematic equation of the car is obtained,and the motion trajectory of the car is simulated according to Motion analysis in Solid Works. Parameters such as cylindrical cam are optimized. The test results show that the carbon-free car can complete 11 times 8-shaped tracing movement,which archived the purpose of walking according to the intended track and verified the rationality of the mechanism.关键词：Carbon-free car;Transmission mechanism;Steering mechanism;Cylindrical cam;Simulation
- 6
- |
- 1390
- |
- 4
发布时间：2022-10-20 - 摘要：In view of the shortcomings of involute gear drive,the advantages of synthetic face gear drive are summarized. The circular arc profile is applied to the face gear,and the gear drive with circular tooth profile is put forward. By means of theoretical analysis,numerical calculation and physical experiment,the design of the tooth surface of the circular tooth profile is carried out. Based on gear meshing theory and differential geometry theory,the tooth surface equation of the conjugate tooth profile of the basic tooth profile of the circular rack is modeled firstly,and then use the envelope forming theory to derive the equation of gear face machining arc face gear,and the cutter and circular arc tooth profile gear for each envelope forming work on tooth surface and the derivation of the face gear transition surface equation. Finally,the MATLAB software program is used to solve the set of tooth points and imported into the CATIA software. The EXCEL table with macro program runs the macro program and generates the contour curve in the CATIA software. And then the 3D physical tooth surface of the arc gear profile is obtained by surface fitting method. Compared with the simulation model of gear cutting envelope,the accuracy is verified.关键词：Circular arc profile;Face gear;Tooth surface equation;Matlab;CATIA;Simulation
- 8
- |
- 193
- |
- 2
发布时间：2022-10-20 - 摘要：According to the characteristics and requirements of automatic transmission planetary gear,taking equal or close strength as optimization objective,optimization model of considering to minimize gear contact fatigue stress difference and bending fatigue stress difference is built under 40 constraint conditions including keeping reasonable transmission ratio,volume decrease,etc. And optimization calculation is performed by using MATLAB. Compared to the original design,the maximum value of planetary gear contact fatigue stress and bending fatigue stress,stress difference and integral stress decrease after optimization,especially the maximum value of bending fatigue stress decrease 12. 24% and all gears root bending fatigue stress are almost the same,the optimization effects are significant. The volume of optimized planetary gear mechanism is 3. 54%smaller than the original design,and the optimal design is superior in transmission ratio,dimension and processing parameters.关键词：Automatic transmission;Planetary gear mechanism;Optimal design;Gear contact fatigue stress;Gear bending fatigue stress
- 4
- |
- 409
- |
- 3
发布时间：2022-10-20 - 摘要：A new type of hybrid transmission device for plug-in hybrid electric vehicle（ PHEV） is present with planet gearbox. The parameters of the planet gearbox are obtained by using optimization method. In order to assess the economic efficiency and dynamic performance,the simulation model of the PHEV is set up based on the ADVISOR software,the vehicle parameters of a domestic SUV are used. The PHEV are simulated in NEDC cycle for charge depleting mode and charge sustaining mode,the results show that the presented new PHEV system can satisfy the requirement of new standard GB/T 32694—2016. The new system use only one motor and the hybrid device are compact,so that it expend low price and take small space in application.关键词：Planetary gear;Hybrid power;Speed ratio matching;Secondary development of ADVISOR
- 3
- |
- 121
- |
- 1
发布时间：2022-10-20 - 摘要：In order to get the dynamic characteristics of a ball screw reliability teat bench,the finite element dynamics modeling of the test bench is carried out. Aiming at the specific on the feature that ball screw system has too much rolling joints and the Finite Element Method（ FEM） can’t simulate it well,the Hertz contact theory is used to calculate the stiffness of ball screw joint,rolling guide joint and the bearing joint. Then,the improved dynamics model is established. By using impact test method,the modal test of the test bench is carried out,then a contrast between the improved dynamics model and the data obtained from the experiment is carried out. The maximum modal frequency error is no more than 4% which verified the correctness of model.The dynamics basis for the further ball screw faulty diagnosis and life prediction is provide by this model.关键词：Ball screw feed system;Dynamics modeling;Modal analysis;FEM
- 3
- |
- 84
- |
- 2
发布时间：2022-10-20 - 摘要：Taking one new type crane reducer with two supporting points as the research object,the three-dimensional model of reducer is established by using SolidWorks,and the virtual prototype is established by importing the 3D model into the mechanical dynamics simulation software ADAMS. In order to ensure the accuracy of the simulation model,the virtual prototype model is analyzed by the contact force constraint,the angular velocity characteristic curve and the gear meshing force variation curve of each drive shaft are obtained. The simulation of the actual value and the theoretical calculation results are compared and found that the transmission shaft angular velocity and the actual the transmission error value in 0. 17%,engaging in 4% errors are very small,so the simulation model is correct. The research results provide data support for calculate gear strength and fatigue life more accurately.关键词：Crane;Reducer;Adams;Dynamics simulation
- 6
- |
- 158
- |
- 1
发布时间：2022-10-20 - 摘要：The speed integration gear is a new type of gear mechanism,which is meshed with cylindrical gears and non-circular face gear and can achieve speed integration transmission. Based on gear mesh theory,the tooth surface equation of non-circular face gear is deduced. Considering the angle error,intersected axis error and axis shift error,the contact model of tooth surface is established. An analysis of distribution characteristics of the contact path is made to obtain the influence of the assembly error on the point contact trace of the teeth. Simulation results indicate that the gradient of the contact path on each tooth of non-circular face gear increases with rate of change of the transmission ratio. The assembly errors cause the shift of the contact path to inner or outer radius,with its movement direction depending on the error direction.关键词：Speed integration;Assembly error;Point contact path;Non-circular face gear
- 3
- |
- 114
- |
- 1
发布时间：2022-10-20 - 摘要：There is a great significance to study the dynamics characteristics of gear transmission system and analyze the vibrational mechanism in the gear transmission of shift mechanism for 4 WD transfer case.Through building the pure torsion dynamics model of the three-stage planetary gears and two-stage cylindrical spur gears,and based on the torsional vibration method,the multi-body dynamics simulation model of the shift mechanism is established on the LMS Virtual. Lab Motion platform. Considering the time-varying meshing stiffness of the internal excitation of the gear,the BDF method is used to solve the problem. The accuracy of the model is verified by comparing the rotational speed of the output shaft obtained by simulation with the theoretical value,and the dynamic meshing force variation curve between the gears is obtained,which can provide dynamic input for further study on the vibration noise of the system.关键词：Gear transmission system of shift mechanism for 4WD transfer case;LMS Virtual Lab Motion;Multi-body dynamics analysis
- 4
- |
- 288
- |
- 1
发布时间：2022-10-20 - 摘要：By a combination of the intelligent optimization algorithm and the numerical iteration method,a combined algorithm called Adaptive differential evolution and Newton iteration（ ADE-Newton） algorithm is constructed. Taking 3-RPS parallel mechanism for research object and the principle and steps of using ADE-Newton algorithm to solve the forward position of parallel mechanism are expounded in detail. In order to verify effectiveness and generality of ADE-Newton algorithm,the numerical examples of the forward position of different length of driving shaft length are given. The results show that ADE-Newton algorithm can obtain all high accuracy solutions in condition of different length of driving shaft with higher efficiency and lighter computational cost. And the performances of artificial bee colony,particle swarm optimization and differential evolution algorithms in solving forward position of 3-RPS parallel mechanism is compared. The results show that the computational efficiency,accuracy robustness and reliability of the ADE-Newton algorithm are higher than those of the contrast algorithm.关键词：Parallel mechanism;Forward position;Adaptive differential evolution algorithm;Newton iteration method
- 3
- |
- 124
- |
- 2
发布时间：2022-10-20 - 摘要：According to the dynamic characteristics analysis of inner displaced indexing cam mechanism,a dynamic modeling method based on rigid flexible coupling is put forward under the consideration of elastic deformation,inertia load and so on. By using the Solid Works,ADAMS and ANSYS,the rigid flexible coupling dynamics simulation model of Inner displaced indexing cam mechanism is built,the influences of the contact force and the load and rotational speed on dynamic performance of the machine are analyzed. The results of research show that in the same indexing period,the biggest contact force between the cam and single pin appear near the output angle of 20° in certain conditions. With the increase of load,mechanical vibration is increased.And with the increase of rotational speed,the amplitude of the acceleration of the output axis is increased significantly and the contact force between cam and pin is also increased. The different rotational speeds have great influence on the dynamic indexing accuracy of inner displaced indexing cam mechanism.关键词：Virtual prototype;Dynamics analysis;Rigid flexible coupled modeling;Inner displaced indexing cam mechanism;Dynamic indexing accuracy
- 4
- |
- 137
- |
- 1
发布时间：2022-10-20 - 摘要：In order to obtain the vibration response of the automobile gearbox housing accurately,a method of obtaining the dynamic response of the gearbox housing under the variable-speed drive is proposed. The pre-transverse gearbox housing is taken as the research object,the dynamics model of the gear transmission system is built,and the dynamic loads of the bearing holes under the variable-speed drive are obtained by the multi-body dynamics analysis. On this basis,the dynamic response analysis of the gearbox housing is carried out by using the modal superposition method. The vibration displacement,velocity and acceleration response of the gearbox housing are obtained. The experimental results show that the simulation result is very close to the experimental results and the maximum error is less than 10%.关键词：Gearbox;Dynamic load;Dynamics simulation;Modal superposition method;Dynamic response
- 4
- |
- 115
- |
- 1
发布时间：2022-10-20 - 摘要：The strength and fatigue simulation analysis and evaluation method for the transmission gearbox of high-speed train are introduced. A series of high speed gearboxes are developed by using this method. All of them have passed the running test,the accuracy of the method is verified.关键词：High-speed train;Transmission gearbox;Strength;Fatigue;Simulation analysis;Evaluation
- 4
- |
- 187
- |
- 2
发布时间：2022-10-20 - 摘要：In order to analyze premature failure of the car aluminum housing main reducer during the bench fatigue test,the test for measurement,the finite element numerical simulation and the dynamics simulation of the test process are carried out. The research is made on the main effective factors indicates the main cause for premature failure is that the jig is not fit for the aluminum housing. Then the corresponding improved of jig is varied out and the correctly is verified through tests. The technical requirements of the bench fatigue test jig of the car aluminum housing main reducer are proposed based the research results.关键词：Car aluminum housing main reducer;Bench fatigue test;Failure;Dynamics simulation;Test jig
- 4
- |
- 80
- |
- 0
发布时间：2022-10-20 - 摘要：In order to improve the efficiency of driving force and the control ability of special vehicle,dynamic performance and stability,the distribution pattern of the four-wheel independent drive system is studied. A platform physical model with four-wheel independent drive is set up according to the real vehicle structure,and the virtual prototype model is built based on the ADAMS software. Through dynamics simulation under three driving force distribution modes of vehicle on straight road vehicle condition,the influence of vehicles running state is analyzed with equal torque and equal state driving force distribution model,and the influence factors of vehicle running deviation is studied with different wheel torque mode. The simulation results show that the drive torque optimal allocation proportion is associated with the location of the center of mass and equal state pattern is better. When the vehicle driving torque is not equal,vehicle running deviation degree mainly depends on the difference between left and right sides of the driving force.关键词：Four-wheel independent drive;Driving force;Distribution pattern;Virtual prototype
- 4
- |
- 88
- |
- 1
发布时间：2022-10-20 - 摘要：In order to detect the early weak faults of rolling bearings effectively,a method of adaptive stochastic resonance based on variational mode decomposition（ VMD） is proposed. Firstly,the fault vibration signal of rolling bearing VMD is decomposed into finite Intrinsic Mode Functions（ IMF）,IMF components containing fault feature are selected and reconstructed. The reconstructed signal is inputted into the stochastic resonance system,and the system structure parameters are optimized by the quantum particle swarm algorithm with the objective function of the improved weighted kurtosisso as to get the best resonance output,thus realizing the signal de-noising and enhance the fault feature. Finally the fault feature frequency is extracted by the autocorrelation envelope spectrum of output signal. The validity and advantages of the proposed method are proved by the analysis of the measured data.关键词：VMD;Adaptive stochastic resonance;Rolling bearing early fault detection;Characteristic frequency
- 2
- |
- 234
- |
- 1
发布时间：2022-10-20 - 摘要：In view of the nonlinear,non-stationary and massive noise features of reciprocating pump power of rolling bearing vibration signal,a fault diagnosis method of rolling bearing based on EEMD,distance factor,correlation coefficient and wavelet packet decomposition is proposed. By measuring the vibration signals of bearings in the bearing life test and decomposing the signals by using the method of EEMD,a number of IMF components is got. Then,the energy characteristic signal vectors is obtained through wavelet packet decomposing and constructing of reconstructed vibration signals,which got from the selecting and reconstructing of IMF components using the method of combination of distance factor and correlation coefficient. At last,the type of failure is determined based on the absolute value of the difference in the correlation coefficient of the energy characteristic signal vectors. Compared with the direct correlation coefficient analysis of the bearing vibration signal,this method has a high fault recognition rate,and doesn’t require a large amount of data training needed by neural networks,it is a better bearing fault identification method.关键词：EEMD;Wavelet packet decomposition;Distance factor;Correlation coefficient;Rolling bearing;Fault diagnosis
- 3
- |
- 192
- |
- 1
发布时间：2022-10-20 - 摘要：The stochastic resonance（ SR） needs to meet the approximative condition when dealing with the measured bearing fault signal,it needs to meet small signal parameters. That is to meet the small parameter signal（ signal amplitude,signal frequency,noise intensity is far less than 1）. The detection of measured vibration signal is greatly restricted by this problem. Aiming at this phenomenon,the self-adaptive re-scaling stochastic resonance based on genetic algorithm（ GA） and the Variational Mode Decomposition（ VMD） is proposed. Firstly,the compression ratio R is set to compress the measured signal appropriately and it needs to meet the small parameter condition. And then,the signal-to-noise ratio of output signal is defined as the objective function. By using the genetic algorithm,the a and b that are structure parameter of re-scaling stochastic resonance are optimized,and the optimal value is selected to drag-in the re-scaling stochastic resonance,the de-noising of measured signal is carried out,Finally,the de-noising signal is decomposed by VMD,from the component spectrum diagram of each IMF,the bearing fault characteristic frequency can be found. Based on the experimental data,the results show that the method can effectively improve the accuracy of bearing fault diagnosis.关键词：Stochastic resonance;Genetic algorithm;VMD;Fault diagnosis
- 3
- |
- 389
- |
- 4
发布时间：2022-10-20 - 摘要：The multi low speed,high-loaded bearing installed on same axis,different locations of the bearing fault pulse will appear aliasing coupling phenomenon,resulting in fault signal identification difficult. In this regard,based on the characteristic of corner-domain and full vector empirical mode decomposition to identify and diagnose the vibration source of the low speed,high-loaded bearing fault signal is proposed. Firstly,the spline interpolation algorithm is used to transform the acquired time domain nonstationary signal into the angular pseudo-stationary signal to realize the angular area resampling,extract the contact angle of rotation of bearing,and the vibration source recognition is completed. Then,the signal is decomposed and reconstructed by EMD,the dual-channel full-spectrum technique is used to fuse the homologous information. Finally,the fault is identified by after chamfering domain analysis of the reconstructed signal,extract the characteristic parameters of contact times of per circle to complete the signal fault type diagnosis. The experimental results show that the fault diagnosis method based on characteristic of corner-domain and full vector EMD can satisfy the requirement of low speed,high-loaded fault signal diagnosis to a certain extent,and it has certain practicability.关键词：Aliasing coupling;Characteristic of corner-domain;Full vector empirical mode decomposition;Fault diagnosis
- 3
- |
- 91
- |
- 2
发布时间：2022-10-20 - 摘要：Gearbox is the key component of power equipment such as coal mill,its fault has a great impact on the normal operation of equipment. The early fault signal of the bearing is weak and often submerged by the noise signal,so how to remove the noise and extract the fault feature signal is the key to realize the fault diagnosis of equipment. At present,the research of wavelet analysis is mainly based on the determination of wavelet function and the selection of threshold to analysis the effect of noise reduction,the determination of decomposition levels has not been thoroughly resolved. The singular spectrum analysis method and the redundant lifting wavelet method are combined to solve the problem of how to determine the number of decomposition layers in wavelet analysis,which greatly improves the performance of the method. The reliability of this method is verified by analyzing the actual signals of a gearbox of a coal mill in a power plant. The application of this method provides the help for the timely and accurate identification and detection of the fault diagnosis.关键词：Wavelet analysis;Singular spectrum;Gearbox;Fault diagnosis
- 3
- |
- 146
- |
- 7
发布时间：2022-10-20 - 摘要：In order to improve the machining accuracy and stability of the steel cage welding machine and reduce the production cost of the transmission parts,a movable disk walking device is designed. The main core component of the device is a chain transmission mechanism,comprises two chains fixed on the lower track of the movable disk and two groups of sprockets arranged on the side wall of the movable disk base and are mutually mirror symmetrical,wherein each group of sprocket wheels comprises a driving sprocket and two supporting sprockets. In the process of movement,the chain is fixed on the pendulous track,unable to move relatively,drives the disc in a straight line. The prototype test shows that the device has the characteristics of smooth operation,high transmission efficiency,portability and easy installation.关键词：Steel bar cage rolling welder;Movable disk;Walking mechanism;Chain drive
- 4
- |
- 63
- |
- 1
发布时间：2022-10-20
- Technical support is provided by Beijing Founder electronics co., LTD 豫ICP备05013835号-5
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0