最新刊期
期 6 ， 2018
- 摘要：A face milling method to rough processing the pinion of cycloid bevel gears is introduced. On the basis of the difference between face-milling and face-hobbing,the universal mathematical model is established firstly,the high order Taylor expansion of each NC axis in the process of face milling is finished and the corresponding coefficients are calculated. Aiming to reduce the deviation between the roughing surface and the finishing surface,an objective function is structured to optimize all of the coefficients and the related program is written out. A pair of gears is used to analyze the deviation from a theoretical point of view. Finally,the simulation processing is carried out,the feasibility and the correctness of the proposed method are verified.关键词：Cycloid bevel gear;Rough processing;Universal mathematical model;Parameter optimization;Simulation processing
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发布时间：2022-10-20 - 摘要：According to the structure and motion characteristics of the split-power internal parallel moving gear transmission device,the transmission efficiency is studied,and the mathematical model of the transmission efficiency of the split-power internal parallel moving gear transmission device（SIPMGTD） is obtained. Taking the internal parallel moving gear pair（IPMGP） with 2 teeth difference as an example,the meshing efficiency is analyzed.When the transmission ratio is less than 100,the meshing efficiency can reach 96. 7% 98. 2%. The efficiency test bench of the SIPMGTD prototype is set up,the real-time efficiency monitoring software of the experiment platform is compiled,and the real-time monitoring system of efficiency is constructed. The test results show that the test results are in good agreement with the theoretical analysis results. The mathematical model of efficiency is accurate and believable. The SIPMGTD with large transmission ratio has high transmission efficiency.关键词：Internal parallel moving gear transmission;Transmission efficiency;Gear transmission test bench;Monitoring system
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发布时间：2022-10-20 - 摘要：In view of the innovative construction of combined output plate of real-time non-clearance precision ball transmission,the mechanical model of engagement pair contact point is established based on size error of balls and guide groove. The actual contact angle and normal force are deduced by using the torque balance equation and the contact point stiffness coefficient,and result is exact calculated. The normal force is converted to a distributed force on contact zone. The deformation,pressure and dimensionless stress of contact center zone are analyzed and the law of change that effected by error is analyzed. The results show that the mechanical properties of combined output plate are impacted by the two kinds of errors. The distribution of normal force has an obvious change as the varying of the ball size errors,and it is the main factor for mechanical properties of combined output plate. The research result provides theoretical basis for the design and analysis of combined output plate of precision ball transmission.关键词：Precision ball transmission;Combined output plate;Error;Engagement pair;Mechanical property
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发布时间：2022-10-20 - 摘要：On the basis of the analysis of spatial 3-RPS parallel mechanism,the method instruction of the mechanism motion solving and inverse kinematics equation are obtained. For the parallel mechanism,the forward kinematic solution is complex,the kinematic solution of spatial 3-RPS parallel mechanism is achieved by the combining of Pro/E software,MATLAB software and ADAMS software. The 3 D model is established in Pro/E software,and put into ADAMS software to edit and define. Through giving the kinematic position,the rotation angle curves of the rotation joint and the output of the attitude angles are achieved by the MATLAB software. The curves can be used as driving function to the three forearms after editing and conversion with the ADAMS function,then,forward kinematic solution is achieved. The results are identical with the inverse solution,that proved the reliably and correctly of the method. The method can be used in the virtual prototyping technology,because of simple solution process and intuitive kinematic performance.关键词：Spatial 3-RPS parallel mechanism;Co-simulation solution;Motion solution
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发布时间：2022-10-20 - 摘要：Gears in hoist reducer of large mining mechanical excavator are low speed,heavy-duty and hard surface gears. It is inevitable to occur the phenomenon of gear deviation load in mining process. Through gear axial modification,increasing gear carrying capacity and improving gear contact condition are achieved.Based on the gear slice theoretical model,mining process load spectrum of excavator is used to determine the reference load for gear axial modification of hoist reducer,the minimum gear contact stress under the reference load of modification is taken as the target of all levels pinions（ driving gears） helix angle modification,and no excessive tooth surface edge load is taken as the target of all levels pinion axial crown modification. Compare to before modification,the gear surface contact stress is obviously reduced and the edge contact condition of tooth surface is obviously improved after modification. The simulation results show that gears modification of hoist reducer of large mining mechanical excavator contribute to increase gear carrying capacity and improve the contact condition of tooth surface.关键词：Mining excavator;Mechanical excavator;Hoist reducer;Gear;Axial modification
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发布时间：2022-10-20 - 摘要：Aiming at the phenomenon of undercut in the process of circular arc tooth profile face gear,by using the research method combining theoretical analysis,numerical calculation and simulation experiment,the minimum inner radius of the face gear without undercut is studied. Firstly,the tooth surface equation of the tool gear is established,and the working tooth surface and the transition surface equation of the gear are deduced from the combination of the tool and the circular arc tooth profile. And then according to the circular arc tooth profile face gear does not produce undercut conditions theory,through the MATLAB software to write the program for numerical calculation. The calculated results are compared with the results obtained by the simulation experiments,and the correctness of the minimum radius values of the circular arc tooth profile face gear without rooting is verified.关键词：Circular arc tooth profile;Face gear;Undercut;Matlab;Simulation
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发布时间：2022-10-20 - 摘要：According to the topology configuration of the existing pulse CVT,the design requirements of the pulse CVT are summarized and the kinematic chain satisfying the design requirements is calculated by the combination. The structure and motion pair of the found kinematic chain are weighted one by one. A variety of new and some existing pulse CVT mechanism configurations are obtained,which proves the validity and rationality of the type synthesis method and the new configuration based on the kinematic chain. A pulse CVT based on the gear linkage combined mechanism is preferably selected as a preferred mechanism from the plurality of new configurations.关键词：Type synthesis;Pulse CVT;Kinematic chain
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发布时间：2022-10-20 - 摘要：The rotation direction and speed of each element in the planetary gear mechanism can be directly shown by drawing the linear velocity vector diagram of the gear ring,planet carrier and sun wheel in the CR-CR planetary gear mechanism. The transmission ratio of typical transmission scheme is calculated by geometric method based on the obtained line speed vector diagram,which is exactly the same with the transmission ratio calculated by analytical method. The correctness and feasibility of analyzing the transmission scheme of CR-CR planetary gear mechanism by line velocity vector method is verified.关键词：Line velocity vector method;CR-CR planetary gear mechanism;Transmission scheme
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发布时间：2022-10-20 - 摘要：Aiming at an eight-link mechanism of bio-robot legs,the mathematical model of optimal design is established by studying the motion trajectory of the mechanism,which is in order to improve the walking speed,stability and ability to overcome obstacles of robot. The parameterized model of the mechanism is established by using the software ADAMS,and the software is also used for the multi-objective optimization design to find the optimal solution of mathematical model. Then,the optimization results of eight-link mechanism parameters are simulated again. The simulation results show that the parameters of speed,stability and obstacle crossing are improved in one movement cycle and the optimization effect is obvious. Some reference for the optimization design of the similar mechanism can be provided.关键词：Eight-link mechanism;Walking bio-robot;Adams;Trajectory optimization
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发布时间：2022-10-20 - 摘要：The proper axial modification can prevent the load concentration,improve the meshing performance,reduce the noise and improve the carrying capacity. Based on the tooth load distribution model,the meshing longitudinal error and gear tooth deformation,the calculation methods of the effective contact width and crowning value is established,and the axial crowning curve equation is given. Gear pair models with different crowning values are established,and the longitudinal load distribution is calculated by 3 D contact finite element method. According to the theoretical crowning value determined by this method,the minimize value of longitudinal load distribution factor can be achieved.关键词：Cylindrical gear;Crowning modification;Longitudinal load distribution
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发布时间：2022-10-20 - 摘要：The optimal geometric parameters of the flexible shaft in GTF gear reducer are obtained by using response surface design method. Firstly,parameterized programs in Python language are coded based on Abaqus platform for finite element analysis（ FEA） of the shaft,which achieves automatic calculation for higher computation efficiency. Secondly,sixty sampling points in design space are determined by Optimal Latin Hypercube sampling method,and the corresponding values of maximum Von Mises of the shaft are acquired successfully through invoking the programs. Accordingly,the response surface optimization model of the Mises objective function is determined and solved,and it is validated by simulation results of exact finite element model with the optimum solution. Similarly,the response surface optimization results of the stiffness of the shaft are also presented,which provides theoretical foundation for engineering application.关键词：GTF gear reducer;Flexible shaft;Finite element;Parametric modeling;Response surface design
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发布时间：2022-10-20 - 摘要：A waterwave method based on chaotic mapping algorithm for the fast search algorithm of planar parallel mechanism workspace is put forward in the study. Taking the 3-RRR parallel mechanism as a example,the reachable workspace,certain posture workspace and dexterous workspace are analyzed. A rotation ability evaluation index is defined to analyze the mechanism rotation capacity inside workspace and visualization drawing by MATLAB,the distribution of rotational capacity in the working space is intuitively reflected. Finally,the mechanism is optimized by genetic algorithm to improve the mechanism rotational ability.关键词：Chaotic mapping algorithm;Parallel mechanism;Workspace;Rotation ability;Parameter optimum
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发布时间：2022-10-20 - 摘要：Based on the mathematical model of altimetric compensating of lifting weight of single arm crane,a general structure form is obtained by solving and analysis,and combining transmission mode of differential reducer to achieve the lifting and luffing process of single arm crane with one reducer. On this foundation,the change of the height of lifting weight in the luffing process of the system is analyzed by simulation of ADAMS/cable,and comparing with the results of MATLAB mathematical model,the design of the differential reducer is proved to meet the actual needs of the project.关键词：Single arm crane;Altimetric compensation;Mathematical model;Differential reducer;Adams simulation
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发布时间：2022-10-20 - 摘要：To establish a rigid dynamics model of a 3 degree-of-freedom decoupled parallel mechanism（a 3-CPaRR decoupled parallel mechanism） and sliding mode controller,the structure component of the mechanism is described and the kinematics is revealed by analyzing the kinematics constraints. The analysis of kinematics constraint shows that the translational displacement of the mechanism is completely decoupled in the three orthogonal directions,and the rotation joints of the limb distal link are the negative kinematics pairs.According to the result of analysis,the dynamics model of the 3-CPaRR decoupled parallel mechanism is established by using the Lagrange equation. Meanwhile,a controller is designed by means of the sliding mode surface,and the system stability is analyzed via Lyapunov function. Finally,the linear velocity and driving force are analyzed through a numerical example. The validity of theoretical analysis and numerical example are demonstrated by the virtual simulation results in ADAMS. At the same time,the validity and stability of the sliding mode controller are also demonstrated. The research provides a theoretic foundation for research on the prototype manufacturing and real-time control system.关键词：Decoupled parallel mechanism;Kinematics;Dynamics;Sliding mode control;Simulation analysis
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发布时间：2022-10-20 - 摘要：By the theory of equivalent substitution,the FT455 model with high precision FT pin-cycloid is used as the carrier,and based on the way of eccentricity modification,the equivalent substitution of stress balanced tooth profile is carried out. To ensure that the tooth profile error is the smallest as target function,the VB programming and MATLAB optimization is carried out,to optimize the design of eccentricity modification tooth profile to replace the stress balanced tooth profile. So that make the meshing tooth number and transmission error of the equivalent substitution tooth profile are within the allowable range,and the transmission accuracy of equivalent stress balanced tooth profile and the stress distribution of the tooth surface are calculated.Through ANSYS finite element analysis of the theoretical programming results to verify the analysis. It is determined that this equivalent stress equalization tooth profile can replace the stress equalization tooth profile.关键词：Eccentricity modification;Equivalent substitution;Transmission accuracy;Stress distribution;Geometric error
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发布时间：2022-10-20 - 摘要：In order to improve a cleaning robot working performance on the condenser tube inner wall and solve problems of the existing cleaning equipment like low efficiency and high cost,a new type cleaning robot is developed to be used in the condenser tube. Based on the working condition and the actual requirements of the cleaning work,a cleaning robot mechanical body structure,an anti-interference pipe rotary connector,a cleaning operation mode and workflow are designed. Furthermore,the design of the robot transmission system is analyzed,the flow chart of the design and calculation is presented,then the automatic analysis,calculation and the transmission system self-checking can be realized. This research not only provides a new type of embedded on-line cleaning robot for the condenser tube inner wall,but also presents a theoretical basis for the design of similar robots in future.关键词：Robot;Embedded on-line cleaning;Rotary connector;Automatic design
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发布时间：2022-10-20 - 摘要：The compliant hinge of fully compliant parallel mechanism has the defects of creep deformation,backhaul reaction and stress relaxation,two different configurations of fully compliant parallel mechanism are designed based on the spatial parallel mechanism prototype. Firstly,based on hinge replacement method,one kind of fully compliant parallel mechanism is established. Secondly,one kind of integrated fully compliant parallel mechanism is designed by adopting type synthesis and topology optimization method. Finally,the model of static stiffness analysis and modal analysis are established,then the simulation analysis and experiment test are carried out correspondingly. The results show that compared with the first scheme fully compliant parallel mechanism,the integrated fully compliant parallel mechanism has higher motion accuracy,better stiffness characteristics and vibration resistance,the effectiveness of topology optimization design method for integrated fully compliant parallel mechanism is verified.关键词：Fully compliant parallel mechanism;Hinge replacement method;Type synthesis method;Topology optimization;Simulation analysis;Experiment test
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发布时间：2022-10-20 - 摘要：The grinding allowance of large gear ring forming grinding will affect the grinding force and grinding heat,resulting in different grinding deformation,reasonable balance of allowance distribution means a lot to the quality of gear ring. Based on the grinding contact zone model,the grinding force model and the grinding and moving heat source theory,the simulation process of the deformation prediction of the ring gear grinding under the thermo-mechanical coupling is analyzed,and the optimization model of the gear grinding balance distribution is established. Taking a large gear ring as the research object,with the deformation control as the goal,the deformation of several sets of grinding gear is simulated and the optimal distribution value is obtained. The research method had some guidance significance on improving the precision of large gear ring forming grinding.关键词：Gear ring;Grinding allowance;Grinding heat;Grinding force;Deformation prediction
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发布时间：2022-10-20 - 摘要：Taking the worn out tooth surface of walking gear in JOY mining machine which imported from Germany as green re-manufacture study object,the anti-wear and anti-corrosion coating without crack nor pore is successfully produced by two techniques of fatigue layer removal and laser cladding in which parameters are optimized. The bonding state of laser clad coating and substrate interface is test,the wear-resistance of clad coating is systematically analyzed. The green re-manufacturing scheme in this study adopted high efficiency,rectangular spot laser technology combined with nickel based self-fluxing alloy produced comparatively flatter coating/substrate interface to conduct the study of re-manufacturing process. The slag and rust as well as fatigue spotting layer are completely removed from failure gear flank followed by laser incremental manufacturing and then the SEM analysis of the cross-section of laser cladding layer,wear resistance test is carried out. Finally a conclusion can be drawn,the re-manufacturing tooth surface produced by rectangular spot laser cladding has excellent wear resistance property,there is a high quality metallurgical bonding formed between laser cladding layer and the substrate gear,thus the work surface of gear has reached and surpassed the new product and properly matched the green re-manufacturing standard.关键词：Low speed heavy load gear;Re-manufacture;Rectangular spot laser cladding;Metallurgical bonding
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发布时间：2022-10-20 - 摘要：The study of static and dynamic meshing characteristics of gears has high theoretical value for improving gear carrying capacity and dynamics performance. The influence of tooth profile modification on bending stress is studied by experiment and finite element. The standard FZG gear drive test rig is used to measure the bending stress of the tooth root,and carbon slip rings is used to measure the bending stress of the tooth root dynamically. The main conclusions from the test and finite element analysis are as follow: the tooth profile modification can obviously reduce the tooth bending stress of the gear pair during the gear transmission,the higher the rotational speed of the gear pair,the more obvious the improvement of the bending stress of the tooth profile modification.关键词：Gear;Modification;Bending stress;Measurement;Finite element
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发布时间：2022-10-20 - 摘要：An automatic synthesis method for the topological structure of a series mechanism is proposed based on the theory of position and orientation characteristics（ in short,POC） set. The digital modeling of the topology structure of the series mechanism is built,and the flow chart and the main steps are given. Firstly,the series mechanisms are digitally described by using matrices. Then,the locations relationships among kinematic pairs are thoroughly enumerated by using the method of exhaustion,the automatically solving of position and orientation characteristics set is realized by using algorithm,the mechanism that meet the requirement is selected,and the GUI human-computer interaction interface is designed. The proposed automatic synthesis method is of universal significance,and the integrated mechanism is comprehensive that is convenient for the computer to analyze the automation of the mechanical system which make the automation be feasible.关键词：Series mechanism;Topology structure;Digital modeling;Position and orientation characteristic set;Automatic synthesis
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发布时间：2022-10-20 - 摘要：In order to make clear the mechanism of oil churning loss of gearbox and to further improve the efficiency of gear transmission,the factors that effects on oil churning losses are studied. The finite element model of oil fluid in gearbox is established in terms of the condition of the gear transmission under oil-immersed lubrication. The variation of oil splash and pressure on meshing point are analyzed under different speeds and directions of gear rotation,the gear resistance moment and the oil churning loss are calculated. The final results show that,under medium and low speed transmission condition,the change of gear rotating direction has greater influence on oil-pumping volume on the meshing area,oil-throwing volume of the outer circle of the gear,pressure on meshing points,and oil churning loss. The above conclusion may provide theoretical basis for later research on energy saving strategy of gear transmission.关键词：Oil-immersed lubrication;Gear transmission;Finite element;Resistance moment;Oil churning loss
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发布时间：2022-10-20 - 摘要：The dynamics analysis of a face-shovel hydraulic excavator is carried out,and the principle of virtual work is used to build the dynamics model of the working device. Based on the Matlab,the dynamics model is calculated numerically. Under the given load,the driving force change curves of the three groups of hydraulic cylinders in the process of digging are obtained. The dynamics simulation of the working device is carried out by using the ADAMS simulation software,the simulation results are compared with the calculated values and three sets of hydraulic cylinder driving force of the error curve are got. The error is within the reasonable range,and proves the correctness of the proposed modeling method.关键词：Face-shovel excavator;Working device;Dynamics;Principle of virtual work;Adams simulation
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发布时间：2022-10-20 - 摘要：During the early failure of the rolling bearing,the fault signal is very weak and the fault information is difficult to be extracted because of the influence of the background noise,in order to be able to effectively detect the bearing failure. A new diagnosis approach which combines minimum entropy deconvolution（MED） and resonance sparse signal decomposition（RSSD） is put forward. Firstly,the MED is used to reduce noise signal of the bearing fault vibration signal. Then the RSSD is used to decompose the signal into the high resonance component containing the harmonic signal and the low resonance component containing the transient impact signal. Finally,the envelope power spectrum is used to extract the fault characteristic frequency from the low resonant component. Through simulation and experiment,this method is suitable for weak fault feature extraction.关键词：Rolling bearing;Fault diagnosis;Minimum entropy deconvolution;Resonance sparse signal decomposition
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发布时间：2022-10-20 - 摘要：The vibration is a main factor to influence the performance of chain drive. The difference between normal roller chains and constrained conveyor chains is that the main vibration mode of constrained trajectory conveyor chains is longitudinal. The model and its equivalent model are established to solve this problem.The kinetics model is built to resolve the natural frequency and principal mode based on the vibration theory of multiple-degree-of-freedom system. The dynamic response in one period is obtained based on the forced vibration theory of multiple-degree-of-freedom system. The analysis shows that the value of natural frequency of longitudinal vibration of constrained trajectory conveyor chains with long pitch is large and the vibration response in no-load operating condition is weak. In another word,the vibration is improved greatly with the constrained trajectory.关键词：Constrained trajectory;Conveyor chain;Longitudinal vibration;Dynamic response
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发布时间：2022-10-20 - 摘要：The mechanical property of the gearbox directly affects the performance and life of the scraper conveyor controlled start transmission（ CST）. Under the rated load condition,through dynamics analysis simulation and experiments,the supporting dynamic reaction force and boundary condition of gearbox housing are determined,the transient stress and vibration response characteristics of the CST gearbox housing are analyzed,and the weak location of natural characteristic and rigidity of gearbox is acquired. The loading experiment of the CST gearbox is carried out,the surface stress and vibration signal and its spectrum of the housing are analyzed.The analysis shows that the stress of the housing surface is greatly lower than the allowable stress of the material of the housing,and the resonance of housing and gear transmission system could not happen. Also,the intermediate housing is considered as the weak stiffness part of the gearbox housing,and the housing vibration in the front of the output end is greater. The results could provide a theoretical basis and data support for the CST gearbox structure optimization design.关键词：Controlled start transmission（CST）;Gearbox housing;Dynamics analysis
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发布时间：2022-10-20 - 摘要：The Monte Carlo method based on the kinematics positive solution is difficult to obtain the boundary feature when solving the manipulator workspace,furthermore,the shape of the workspace and the cavity of the manipulator with link offset are not obvious. The workspace boundary analysis method based on the link length and joint angle range is proposed for solving this problem. The expression of the inner and outer boundary curves of the workspace of the offset manipulator is obtained,and an intuitive and accurate workspace perspective is drawn. Based on the theoretical analysis and simulation of the two methods,the correctness of the kinematics positive solution and the Monte Carlo method is verified,and can visually see that there is a surface envelope in the workspace which is not included in the cavity. The analysis of the volume and the performance of the unpacked cavities and workspace proves that the manipulator with link offset has good workspace performance. These studies has theoretical significance and practical application value for the study on the workspace of the offset manipulator.关键词：Manipulator with link offset;Workspace;Monte Carlo method;Boundary analysis;Performance evaluation
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发布时间：2022-10-20 - 摘要：Taking the dual-arm robot as the research object and its workspace is analyzed. Firstly,the D-H method is used to establish the linkage coordinate system of the dual-arm robot and the forward kinematics equation is solved. Then,the 3 D workspace is solved based on the Monte Carlo method,which be stratified along the Z-axis direction. Thirdly,the method of partitioning by angle and the extreme value theory are used to extract the boundary points of the workspace. Finally,the least square method is applied to fit the boundary points. The results from the MATLAB simulation show that the extraction effect of boundary points is better,the error of fitting curve is smaller and the cooperation space of the dual-arm robot is larger,which provides a reference value for the dynamics analysis,trajectory planning and motion control of the dual-arm robot.关键词：Dual-arm robot;Workspace;Monte Carlo method;Boundary extraction;Curve fitting
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发布时间：2022-10-20 - 摘要：The calculation of harmonic gear meshing stiffness is the basis of dynamics analysis. According to the finite element analysis theory of loading contact,and combining with its static and dynamic contact properties,taking each different location during one engaging-in and engaging-out cycle of a tooth as the research object. Then,by extracting the meshing data of discrete point on contact location,the curve of single-tooth stiffness and the synthesizing meshing stiffness in one engaging-in and engaging-out is got. Comparing with the previous researching result,the correctness of the method is verified,which provides the basis for dynamics analysis for harmonic gear.关键词：Harmonic gear;Finite element;Contact analysis;Meshing stiffness
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发布时间：2022-10-20 - 摘要：The prebending principle is used to roll the bushing,the gap of the seam can be reduced to a minimum and the fluctuation range of dimension is reduced obviously. The wear-resisting performance of the prebending bushing chain is significantly improved compare with the general bushing chain. The wear is reduced where the bushing contact with the pin,the surface hardness of the bushing is improved under the effect of cyclic hardening.关键词：Bending;Wear-resisting performance;Cyclic hardening
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发布时间：2022-10-20 - 摘要：A measurement system of gear dynamic transmission error based on optical encoder is built.The system first measures the rotation angles of the input and output shafts of a gear pair by two optical encoders. The collected pulse signals are then counted and interpolated to obtain angle sequences based on uniform time sampling. Finally,the dynamic transmission error of the gear pair can be obtained by comparing the angle sequences of two shafts. The nonlinear dynamics model of a gear system is built and it’s solved based on fourth-order Runge-Kutta method. The simulation results（ rotation angles） are sampled by simulating the optical encoder and data acquisition card and the influence of the resolution of the optical encoder and the time resolution of the data acquisition card on the measurement accuracy is studied. The simulation results show that in order to ensure the measurement accuracy for a gear system with a maximum speed of 1 500 r/min,the resolution of an optical encoder should be not less than 200 pulses per revolution and the time resolution of a data acquisition card should be not lower than 3. 3 × 10-9 s. The gear transmission bench test also shows that the dynamic transmission error obtained by the measurement system has good repeatability,and its values are consistent with the noise phenomenon induced by the bench.关键词：Gear;Dynamic transmission error;Optical encoder;Measurement system
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发布时间：2022-10-20 - 摘要：In order to realize the intelligent diagnosis of rolling bearing failure,a fault diagnosis model of vibration signal based on empirical mode decomposition（ EMD） and deep belief network（ DBN） is proposed.Firstly,the vibration signal is processed by empirical mode decomposition,and the statistical parameters of the effective intrinsic modal function（ IMF） component and its Hilbert envelope are obtained as the original feature set. Then,the extreme learning suite（ ELM） classifier feature selection method is proposed to remove the redundancy and interference characteristics of the original feature set and to select the fault state sensitive features. Finally,by using the depth learning advantages in high-dimensional and non-linear processing,the DBN-based fault feature adaptive analysis and fault state intelligent identification is completed. The results show that the ELM method can select the sensitive statistical characteristics of the fault,and the adaptive characteristic of the DBN method can effectively improve the accuracy of fault state recognition.关键词：Empirical modal decomposition;Extreme learning machine;Deep belief network;Rolling bearing;Fault diagnosis
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发布时间：2022-10-20 - 摘要：Aiming at the problem of complex modulation characteristics of vibration signals of the planetary gearbox make the state identification model low accuracy,a state identification method for key components of planetary gearbox based on combinations of ensemble local mean decomposition（ ELMD） energy entropy and artificial fish swarm algorithm finding support vector machine（ AFSA-SVM） optimal kernel function coefficient is proposed. To begin,a number of narrow-band product function（ PF） from vibration signals are obtained by ELMD with after morphological average filter. Then the high dimensional feature vector set is built by calculating the energy entropy of the above PF. At last,the fault diagnosis model is developed based on AFSA-SVM algorithm,in which the extracted fault features are employed as inputs. The experimental results show that the proposed method can show the fault component of the original signal with effectively. It has the state identification accurate of the model is greatly improved.关键词：ELMD energy entropy;Planetary gearbox;Optimal kernel function coefficient;AFSA-SVM
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发布时间：2022-10-20 - 摘要：Aiming at the problems such as the loss of mold powder and the uneven thickness of the mold powder,the automatic slag adding machine with rectangular rectification compensation mechanism is designed to solve the problem of slag wasting. The kinematics model of the mechanism is established,and the angular velocity of the driving link is simulated by MATLAB. The appropriate electronic control command curve is fitted and adjusted in real time to ensure that the central speed of the discharge port is basically stable,which is to solve the uneven problem. Finally,the experimental results show that the error of displacement of the sliding platform between the measured value and the theoretical value is less than 5%. The central trajectory of the discharge port is approximately straight and the swing speed is basically the same. The distribution of the mold powder in the mold is uniform.关键词：Crystallizer;Automatic slag adding;Rectangular compensation of discharge port;Kinematics analysis
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发布时间：2022-10-20 - 摘要：A new type of internal gearing transmission with high contact ratio is investigated,and the design principle and method for the tooth profile is put forward. By applying two pieces of special cycloid,the meshing circle is just between the two pitch circles. This type of gear pair is especially suitable for small tooth difference gear transmission,in the process of the gear transmission,simultaneous meshing of multiple pairs of teeth can be ensured,and the pressure angle is small,the stress state of gear teeth and axis can be significantly improved. Moreover,because only addendum involving in meshing,such defects as root cutting are avoided.Prototype test and EFM analysis show a significant performance,the driving being much more smoothly,the torque delivering capacity being much greater,and the accuracy,the stiffness and the efficiency being much higher. At the same time,a theoretical and technical support for engineering application is provided.关键词：Contact ratio;Internal gearing;Cycloid;Tooth profile
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发布时间：2022-10-20 - 摘要：An on-line detection instrument for synchronizer tooth sets is designed. The instrument can better complete the data acquisition,run-out error processing and display. The whole system is composed of mechanical parts and control parts: the mechanical part automatically completes the detection and stacking of the measured teeth,the control part is controlled by the PLC to the manipulator,the run-out detection and the data processing can be realized by industrial personal computer,and the run-out error is corrected. The results show that the accuracy of the gear set is ± 3 μm. The measuring instrument has high precision and fast speed,and can be applied to the on-line detection of the synchronizer tooth set,which provides a new detection method and idea.关键词：Synchronizer gear set;On-line detection;Error handing;LabVIEW
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发布时间：2022-10-20
- Technical support is provided by Beijing Founder electronics co., LTD 豫ICP备05013835号-5
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