最新刊期
期 11 ， 2017
- 摘要：The slope and vehicle mass are identified in real time by using the variable forgetting factor least square method which have strong adaptability and good following performance. On this basis,the slope shift hierarchical modification control of vehicle automatic transmission is carried out,the gearshift process of vehicle automatic transmission is divided into the upper identification decision layer and the lower shift executive layer. Through the upper decision-making layer acquisition vehicle sensor signal parameters,the slope and vehicle mass identification,the slope shift modification control decision are carried out. The lower shift executive layer receive the correction control instruction from upper identification decision layer to complete gear shift correction execution. The results of simulation and hardware-in-the-loop test show that,the slope and vehicle mass can be accurately identified by using variable forgetting factor least square method,the slope shift hierarchical modification control strategy can solve the frequent shift and unexpected shift phenomenon and reducing the wear of gear shifting parts. On other hand vehicle could full use of the engine braking torque characteristics,reduce the wear of braking system when downhill slopes.关键词：Double-clutch automatic transmission;Variable forgetfulness factor;Slope identification;Mass identification;Shift modification;Hierarchical control
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发布时间：2022-10-20 - 摘要：The transmission ratios optimized by traditional optimization method often have a difference from the actual values decided by gear teeth matching. Based on a battery electric vehicle whose vehicle parameters and dynamics performance requirements are given,the parameters matching of driving motor is conducted firstly. Then,taking the numbers of teeth of transmission as variables,a discrete optimization method of transmission ratios is established,considering the New European Driving Cycle（NEDC） and the economic shift schedule. The results show that the optimal solution of the transmission ratios obtained from proposed method can make the motor driving system working in the high-efficiency area,and the ratios can be actually obtained by the gear teeth matching of transmission.关键词：Battery electric vehicle;Transmission;Transmission ratio;Discrete optimization
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发布时间：2022-10-20 - 摘要：Aiming at the problem that the multi-degree-of-freedom dual manipulator may collide in the same workspace,a simplified model of the robot envelope is established. The joint is simplified as a sphere envelope and the connecting rod is simplified as a cylindrical envelope. And the calculation method of the shortest distance between the points and the point to the line segment and the outermost line segments is proposed by detecting the interference between these two simplified models of the double manipulator. The detection algorithm is implemented in VC ++,and the Staubli six-axis dual-robot model is applied to Solid Works for the simulation,the feasibility of this algorithm is verified by the experimental results.关键词：Two-robot;Coordination operation;Detection collision
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发布时间：2022-10-20 - 摘要：The second-stage drive of the RV reducer,cycloidal pinwheel drive is taken as the research object. By analyzing the motion relationship of the cycloidal pinwheel drive,the tooth contact analysis（TCA）model is established. Based on the gear meshing principle and the condition for the continuous contact of the gear,the TCA equations are established. The difficulty of solving the initial reference points in the TCA calculation is described. The instantaneous meshing state,the meshing area and the transmission error of the cycloidal pinwheel drive with the traditional modification are solved. And then the return error is also solved. This method will provide a theoretical basis for the loaded tooth contact analysis of the cycloidal pinwheel drive.关键词：RV reducer;Cycloidal pinwheel drive;Tooth contact analysis;Transmission error;Return error
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发布时间：2022-10-20 - 摘要：The quadruple-arc spiral bevel gear is a new type of spiral bevel gear which is obtained by apply the quadruple-arc tooth on the bevel gear. The meshing points of quadruple-arc spiral bevel gear are increased compare with double-arc spiral bevel gear,and the carry capacity is also increased. The mesh line figure is obtained by analyzing the cutting process of quadruple-arc spiral bevel gear,the multi-meshing points coefficient and multi-meshing teeth coefficient are calculated. The basis of calculation for the strength calculation and dimensions design of quadruple-arc spiral bevel gear is provided.关键词：Quadruple-arc spiral bevel gear;Multi-meshing points coefficient;Multi-meshing teeth coefficient
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发布时间：2022-10-20 - 摘要：Aiming at the measuring difficulty of small modulus gear,a measuring method of gear tooth profile total deviation based on machine vision is proposed. On the basis of building measurement vision system,firstly,processing gear digital image with Gaussian filter and edge extraction,then the sub-pixel edge of gear tooth profile is obtained. Because the influence of gear center to tooth profile total deviation is relatively sensitive,by means of radius constraint data to fit round hole center in calibration disc,more accurate center position is obtained. Finally,on the basis of establishing mathematical model to realize tooth profile total deviation measurement. Through the experiment,the measurement result of measuring method and three coordinate measuring machine have higher consistency,the maximum absolute error is less than 3 μm,and the effect of gear position center error on the tooth profile total deviation is one quarter of its error value. The experimental results show that adopting measuring method can accurately reflect the gear tooth profile total deviation,and meeting the requirements of measurement precision reach micron level.关键词：Vision measurement;Sub-pixel;Radius constraints;Gear center;Tooth profile total deviation
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发布时间：2022-10-20 - 摘要：In order to analyze the influence of the related factors on the body temperature of high-speed gear in the meshing process,taking the standard involute gear as study object,based on the finite element analysis of temperature field and using the control variable method,the influence law of related factors on gear temperature is analyzed quantificationally. The results show that,the body temperature on tooth surface increase as rotation rate or torque increases,and the temperature increase amplitude decrease as rotation rate or torque increases. The temperature on tooth surface uniformly increase when tooth width increases,the change of modulus cause the changes of multiple factors and temperature on tooth surface decrease and then increase as modulus decreases. When rotation rate or torque is higher,the influence of rotation rate,torque,tooth width,modulus on gear temperature become bigger. The maximal body temperature increases or decreases as air and lube oil temperature,and the change has nothing with rotation rate or torque. The influence of heat transfer coefficients of gear end and meshing surface on gear temperature is relatively small,and temperature decreases as heat transfer coefficients increase. A reference for reducing the risk of gear high-temperature failure is provided.关键词：High-speed gear;Temperature field analysis;Influence factor
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发布时间：2022-10-20 - 摘要：For coordinating the body change and leg movement to promote jump and over-obstacle ability of a bionic robot,a new type of quadruped bionic robot configurations with spine is introduced. On this basis,the forward kinematics problem of this kind of the robot is studied. Firstly,according to the structure of the robot,the motion equations are established which contain the all driving angles. The motion equations contain many redundant drive angles,which is very difficult to solve the redundant drive angles,a dimensionality-reduction method is adopted. By using the dimensionality-reduction method,one of the formulas is translated to the constraint condition,the iteration procedure is used for the rest of equation sets to seek solutions of the redundant drive angles which satisfy the constraint condition. On this basis,the pose of mass center for the quadruped bionic robot with spine is solved and analyzed. An example is given to illustrate the process,this research is helpful to accelerate the use of this kind of robot.关键词：Quadruped bionic robot;Spine;Forward kinematics;Dimensionality-reduction method
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发布时间：2022-10-20 - 摘要：The uncertainty modeling and reliability analysis and the influence on contact static stiffness for ball screw pair with a large number inherently uncertain parameters are very important in engineering. Considering uncertainty of structural parameters and applied loads of ball screw pair,when evaluating the reliability of ball screw pair through traditional methods,structural parameters and applied loads of ball screw pair are supposed to random variables,but the accurate value of distribution parameters can hardly be known in practical engineering. The uncertain parameters and errors of ball screw pair and the load applied and so on are described as interval variables. A contact deformation interval model and an interval method for sensitivity analysis of plate preloaded double-nut ball screw pair are put forward based on Hertz contact theory. According to the contact static stiffness failure criterion of ball screw,a non-probability reliability model of plate preloaded double-nut ball screw pair is established based on interval model. A numerical example has been used to illustrate the proposed method. The result shows that the proposed method is feasible and reasonable and practicable for the contact static stiffness reliability analysis and sensitivity analysis of plate preloaded double-nut ball screw pair.关键词：Ball screw pair;Axial contact stiffness;Sensitivity analysis;Non-probabilistic reliability
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发布时间：2022-10-20 - 摘要：When gear topology modification using the forming method grinding,the tooth profile modification is achieved by trimming the wheel truncation,while the tooth modification is achieved by adding an additional movement of the wheel or gear. But when the gear wheel or wheel there is additional movement,the relative position between gear and grinding wheel will change,the actual contact point of the surface will also be a corresponding change,the tooth modification and tooth profile modification will interfere. Therefore,there is a certain error between the topological modification tooth surface and the theoretical tooth surface. The topological errors are analyzed and discussed through calculation examples. The results show that the variation of center distance is linear to the topological tooth surface error which can guide the topology modification of gear.关键词：Topology modification;Topological tooth surface;Change in center distance
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发布时间：2022-10-20 - 摘要：To investigate the influence of manufacturing parameter adjustment errors of machine tool on the tooth surface geometrical precision of curvic coupling,the general tooth surface deviation equation which contained multiple processing parameter adjustment errors is inferred,and combined with two error index of tooth surface deviation（describe the deviation of theoretical offset tooth surface from standard one） and pitch deviation,the error analysis model of tooth surface geometry is constructed. With an example,the influence of manufacturing parameter adjustment error on tooth surface deviation and pitch deviation is analyzed,and the relational graph to describe its influence is drawn up.关键词：Curvic couplings;Manufacturing error;Tooth surface deviation;Deviation analysis
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发布时间：2022-10-20 - 摘要：For the objects with different sizes and shapes,grasp planning and control problems of the robotic multi-fingered hands have not been solved perfectly till now. After summarizing varieties of the existing robotic palms,it is concluded that some novel palm structures can improve the dexterity and working space of the robotic multi-fingered hands,and make the structure and control simpler. Based on the analysis of the motion mechanism of the octopus arms,the generalized arms-palm structure is put forward,which can be configured to any size and shape of the polygon. Then a bionic robotic multi-fingered hand with 12 DOF is designed. In order to simplify the control and structure,a novel bionic palm structure with 5 DOF is proposed,named the alterable arms-palm. For the objects with different sizes and shapes,the alterable arms-palm will change into the suitable configuration of the palm,shifting the fingers to the optimal contact point locations on the objects. In this way,the dexterity and working space of the robotic multi-fingered hands are improved significantly by the alterable arms-palm. The configuration analysis shows that the adaptive palm-configuration of various sizes and shapes can be realized simply and rapidly by the alterable arms-palm,the grasp quality is improved and the complexity of grasp planning and control is reduced.关键词：Robotic multi-fingered hand;Palm structure;Bio-inspired design;Configuration analysis
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发布时间：2022-10-20 - 摘要：The coupling relationship between the position coordinate and the attitude angle of the 3-RPS parallel mechanism is obtained from the structure constraints of the platform. Thus an analytic expression of the workspace boundary is derived. The relative motion of a member connected by a motor can be described by motion screw. According to the property of the reverse helix,the reverse helix of the branch motion screw system is obtained,which represents the structure binding force of the branch on the moving platform. In turn,the singularity of the mechanism is transformed into the analysis of the linear correlation condition of moving platform motion screw system and the constraint screw system. Therefore the singularity of mechanism is divided into kinematics singularity and constraint singularity. The physical essence of the influence of the two kinds of singularity on the performance of the mechanism is given,and the analytical expression of the singular configuration is derived. An example is given to show the distribution characteristics of the working space and the division of the working space.关键词：Parallel mechanism;Workspace;Motion screw;Singular configuration
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发布时间：2022-10-20 - 摘要：In order to realize the digital closed loop manufacturing,the tooth surface should be discretized and the spatial coordinates and the normal vectors of the discrete points on the tooth surface should be calculated. Based on the machining principle of spiral bevel gears and according to the relative position and relative motion relationship between the gear blank and the cutting tool,considering the cutter tilt modification and roll ratio modification motion,and using the method of vector operation,the mathematical model of working tooth surface and the fillet is established. Based on the mathematical model of the whole tooth surface,a method for calculating the spatial coordinates and the normal vector of the discrete points of the tooth surface is established and verified.关键词：Spiral bevel gear;Mathematical modeling;Modification of roll ratio;Cutter tilt modification
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发布时间：2022-10-20 - 摘要：According to the functional requirement of beakers subassembly in blended fabric quantitative detecting system,a planar six-bar mechanism composed by two oscillating guide bar mechanisms is selected for achieving flip function. The angular displacement,angular velocity and angular acceleration of the guide bar are achieved by establishing kinematical equations of the six-bar mechanism. According to the special consideration of vibration performance when turning over beakers subassembly,a constrained optimization model for solving the minimum acceleration fluctuation is built. The constrained optimization problem is solved by complex method in MATLAB,and the results are displayed after optimization. When considering the stability improvement of beakers subassembly turnover movement in blended fabric quantitative analysis system,the research conclusions achieved here have important practical significance.关键词：Beakers subassembly;Six-bar mechanism;Matlab;Complex method;Optimal design
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发布时间：2022-10-20 - 摘要：Considering the factors such as the deformation of the box body,the bearing and the shaft and the assembling clearance,the finite element method is used to analyze the contact state and load distribution of the traction gear. According to partial load in the meshing process,the optimum gear profile modification curve is optimized by using genetic algorithm. Through the comparison and analysis of the two meshing states of the forward and reversal of the locomotive gear,it can be found the load distribution on the teeth is more uniform,the stress concentration phenomenon caused by partial load is improved,and the maximum value of contact stress and bending stress significantly is reduced. The result shows the modification curve has a good effect.关键词：Helical gear;Longitudinal modification;Optimization calculation
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发布时间：2022-10-20 - 摘要：In order to study the twin joint structure of bird wings,a flapping wing structure based on four-bar mechanism is designed based on the principle of bionics. The brushless motor driving two stage reducer,provides input for four-bar mechanism. The robot has a function of the periodic flapping motion,the frequency change and size of the attitude angle adjustment. According to the range of bird joint angular motion,the output angle of the robot linkage mechanism is determined so that it can move within the expected range. The model is established by MATLAB/SimMechanics,and the four-bar mechanism of the robot is simulated and integrated into the iSIGHT software to optimize the parameters and obtain the design variable value similar to the expected trajectory. The results show that the ornithopter scheme design based on the design of the four-link mechanism is feasible,and the frequency is controllable. In addition,the optimized simulation curve can well approach the given task trajectory. The design method proposed in this paper has the characteristics of fast and efficient,and the result is intuitively visible,which provides a feasible scheme for parameter setting and optimization of other mechanical structure.关键词：Four-bar mechanism;Ornithopter;Bionic;MATLAB/SimMechanics iSIGHT;Parameter optimization
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发布时间：2022-10-20 - 摘要：A test rig for RV reducers is developed,which can measure the mechanical transmission property of the RV reducer,fault monitoring and fatigue life test. The RV reducer test rig mainly consists of mechanical system,measurement and control system and software system,which can acquire the mechanical parameters of the RV reducers and the signal of fault quickly and automatically. The transmission efficiency,transmission error and backlash of domestic SHPR-20 E RV reducer are investigated with the test rig,and the measurement efficiency is high and the results are accurate. It is verified that the RV reducer test rig can measure the performance of RV reducers quickly and accurately,and can be used to investigate,optimize and enhance the performance of RV reducer.关键词：RV reducer;Test rig;Transmission efficiency;Transmission error;Backlash
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发布时间：2022-10-20 -
Cutting Processing and Experimental Verification of Epicycloid Bevel Gear based on Four-axis Linkage
摘要：The cutting principle of epicycloid bevel gears is analyzed,the operation mode and characteristics of five-axis with four-linkage epicycloid tooth bevel gear CNC machine are introduced,the feasibility of cutting epicycloid bevel gears based on the four-axis linkage is proposed and analyzed. The equivalent transformation for the processing mode of CNC machine and traditional mechanical machine is completed by analyzing the distinctions of mathematical models between the two kinds of machine. The tooth surface equation of the gear processed of the CNC machine is obtained. The relations among motion axes real-time motion coordinates are analyzed,and real-time coordinates of each motion axis of CNC machine are calculated. The ideal contact region is obtained by the gear cutting processing and rolling-inspection test. The correctness of the theory of cutting cycloid bevel gears based on four-axis linkage is verified and a theoretical support for the domestic independent research and development of spiral bevel gear processing equipment is provided.关键词：Epicycloid bevel gear;Four-axis linkage;Mathematical model;Experiment- 5
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发布时间：2022-10-20 - 摘要：Based on a gear tooth fracture case,which is caused by diesel engine crankshaft axial movement. Aiming at the situation that it’s difficult to simulate this fault by experiment,the displacement and movement type can’ t be control. And there is no effective method to extract gear load during the crankshaft axial movement for analysis by experiment. By using Creo,ADAMS software,the gear transmission system dynamics simulation model is built and the no axial movement,one-way axial movement and reciprocating axial movement scenarios is simulated. The gear load change rules during the shaft axial movement is got by extracting the shaft displacement,the gear load and analyzing the relationship between them. The shaft axial movement can cause gears over load,amplitude modulation and impact vibration is verified. The feasibility of the study on the influence of spindle axial movement based on dynamics simulation is proved.关键词：Spindle axial movement;Gear tooth fracture;Dynamics simulation;Failure influence study
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发布时间：2022-10-20 - 摘要：The elastohydrodynamic lubrication model of gear rack transmission is established,considering the gear that is modified and thermal effect,comprehensively considering the variation of equivalent radius of curvature,entrainment velocity and the alternating load along the line of action and the gear tooth modification,the numerical solution of unsteady-state elastohydrodynamic lubrication of the gear rack with time-dependent loads is analyzed. The influence of modified coefficient on the oil film pressure and film thickness of the gear rack is studied and the influence of positive modification and negative modification on central film thickness and minimum film thickness are also analyzed. The results show that the positive modification could reduce the oil film pressure and increase the film thickness which could improve the lubrication of the gear rack,negative modification causes the oil film pressure rises and the film thickness become thinner. Therefore,in order to in accordance with the requirements of the premise when designing the gear rack mechanism,the positive modification gear should be selected to avoid the negative modification gear.关键词：Gear rack;Modification;EHL;Load time-dependent;Thermal effect
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发布时间：2022-10-20 - 摘要：For the automobile engine timing belt system,by using the AVL-Excite Timing Drive to carry out a periodic dynamic simulation analysis. The variation law of the load when the loose and tight of belt contact with pulley is studied. The results show that dynamic tension and its fluctuation of the belt between the idler and the exhaust camshaft pulley are the largest. And the peak mechanism of the belt toot load is studied. Based on the analysis of the vibration performance of the main vibration source,the system parameters are optimized. The results show that the vibration of the main vibration source is reduced and the transmission error of is reduced.关键词：Synchronous belt;Timing system;Dynamic tension;Meshing drive;Vibration
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发布时间：2022-10-20 - 摘要：Based on the finite element analysis model of the low speed stage of the MW wind turbine gearbox,the fatigue damage of the low speed gearbox is studied. Based on the analysis of the ANSYS-workbench and the ANSYS classic,the stress condition of the low speed level planet carrier of the wind turbine is obtained.The S-N curve of planet carrier is got based on the design specification of GL2010. The fatigue load spectrum of the planet carrier is calculated by the rain flow cycle counting method. Finally,based on the combination of presents a rain flow counting method with Palmagren-Miner damage theory and safety factor to calculate the fatigue damage method by using the n Code/design life software,the fatigue damage and minimum safety factor of the low speed level planet carrier of the wind power gearbox is obtained. The analysis results show that the proposed method is reliable and practical,a more accurate analysis method for the fatigue analysis on planet carrier in MW level wind turbine gearbox is provided and it also has a certain practical significance.关键词：Wind power gearbox;Planet carrier;S-N curve;Fatigue load spectrum;Fatigue analysis
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发布时间：2022-10-20 - 摘要：The cycloid pin wheel drive is essential to RV reducer. It is the basic point to determine the contact stiffness of cycloid and pin wheel. The equivalent contact stiffness is calculated based on Hertz contact theory. The parameters to solve the contact stiffness is checked and the stiffness model with teeth number in meshing simultaneously as a parameter is established. The dynamics simulation of RV reducer is processed based ADAMS to determine the pin numbers in meshing in consideration of modification of cycloid and dimension error of pin-wheel circle diameter,furthermore,the model of cycloid is treated as flexible body. It can be intuitive to observe the relations between load and number of pins in meshing or pin force.关键词：Dynamic characteristic;Vector method;Cycloid pin wheel drive;Equivalent contact stiffness;Meshing characteristic
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发布时间：2022-10-20 - 摘要：The outer gear ring plate is the key part of the translation in gear reducer drive,its strength is directly related to dynamic performance of the machine. In view of the new type of translation within three axial symmetry type three-ring gear reducer,its basic structure and transmission principle are analyzed,and combining the static moment equilibrium conditions and the deformation coordination equation,the tooth plate bearing load is analyzed. For 10 different working condition of external gear plate finite element static analysis and modal analysis,in order to further explore the translational reducer provides the theory basis for extensive practicability. The results show that the external tooth plate bearing load is smooth,no dead point operation,and the tooth plate stress strength meet the requirements. The resonance region is avoided,can work normally.关键词：Internal translational gear reducer;External toothed plate;Finite element analysis
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发布时间：2022-10-20 - 摘要：In view of the stress of flexspline calculated on the basis of the theory of thin-walled cylinder,there are many assumptions of the theory,which will lead to the difference between the calculated value and the actual value. Considering the boundary constraint and force,from theoretical model to actual model,six analysis model are constructed based on the geometric model of flexspline to research the difference between theoretical and actual by finite element method. The result of analysis indicate that the maximum value appears in the gear root which is close to the cup bottom of flexspline,and accompanying the transition from theoretical model to actual model,the stress of all direction is increased gradually,which the circumferential stress has a larger increasing range. The reason of that is the stress concentration caused by the boundary constraint.关键词：Flexspline;Boundary constraint;Finite element;Stress
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发布时间：2022-10-20 - 摘要：Three-dimension solid model of helical gear limited slip differential is built by using CATIA,and then the virtual prototype model is established through importing the 3D solid model into ADAMS/View. In the virtual environment,based on the kinematics dynamics simulation and analysis with two different typical work conditions,including straight-line driving on good pavement and double tire-road friction coefficients,the torque curve,the force and angular velocity curves of helical gear of limited slip differential are acquired.By comparing with theoretical calculations values,the correctness of model and the effectiveness of simulation method are verified. The study results provide the basis for the dynamic optimization and fatigue life prediction of the helical gear limited slip differential.关键词：Limited slip differential;Helical gear;Kinematics;Dynamics;Simulation
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发布时间：2022-10-20 - 摘要：The operation of gearbox is under a varied working condition with the change of speed and load,and the vibration signal is non-linear and multi-components,so it’ s difficult to realization of gearbox fault diagnose in varied working condition. Firstly,The original vibration signal interpolated by uniform angle re-sampling time through order tracking based on numerical differentiation,which transforms non-stationary vibration signals into angle domain stationary signal. Subsequently,the shock component,harmonic component and noise component are separated from angular domain stationary signal through morphological component analysis（MCA）,which can extract the fault feature from non-linear and multi-component signal in gearbox.Then,the angle domain averaging of shock component highlight the fault characteristic. Finally,by using instantaneous power spectrum（IPS） to identify failure of gearbox. The experimental results show that,using this method,the distribution of IPS in domain of angle and order can identify gear faults,and further testing the method also apply to gearbox fault diagnose under the condition of variable condition.关键词：MCA;Varied working condition;IPS;Order tracking;Gearbox fault diagnose
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发布时间：2022-10-20 - 摘要：In order to study the effect of dynamic load on the tooth root bending stress of hypoid gears,both static and dynamic test of hypoid gear bending stress of the driving axle are carried out by using electromotive strain method,which are compared and analyzed with results from finite element simulation. The static test shows that the tooth contact position is from the big side to small. The tooth root is under the application of tensile stress when the contact is begin while under compressive stress when the contact is finish. The stress value is consistent with the results of finite element calculation. The dynamic test shows that the mean value and amplitude of the maximum bending stress increased gradually with the increase of gear speed. This method is reliable and can be used in the reliability research on gear.关键词：Driving axle;Hypoid gear;Bending stress
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发布时间：2022-10-20 - 摘要：A new measuring method setting the node as single tooth reference point for manufacturing error of cycloid wheel is proposed. The theoretical model and error measurement model of the cycloid wheel drive are established. The measurement path is planned,and measurement driver software is developed. By using the meshing principle of the pin-swing drive and the measuring theory of the complex surface,the manufacturing error of the cycloidal wheel is obtained. The tooth profile and pitch deviation of the fact cycloidal profile are measured on the domestic gear measuring center. The measurement results under different reference points are compared and the correctness of the new method is verified.关键词：RV reducer;Cycloidal gear;Reference point;Manufacturing error;Measurement
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发布时间：2022-10-20 - 摘要：With the development of coal mining industry,mining loader to become the largest demand for acquisition equipment. As China loader design mainly in the traditional design methods,the lack of systematic design. In the design stage,in order to determine its service life,it needs to carry on indoor bench fatigue test,so the compilation of load spectrum becomes more and more important. Taking the transmission system of mining loader as research object,a real vehicle road test is carried out according to typical designed condition. The signals eliminates and outliers eliminating for the acquisition of load signals is carried out. It has a statistical counting for the acquisition of load signals by using rain-flow counting method. Then it makes a load data extrapolation and weaves into an 8 program load spectrum,therefore,it can provide a basis for the design of mining loader in the future.关键词：Mining loader;Load spectrum compiling;Rain-flow counting method
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发布时间：2022-10-20 - 摘要：An impact-resistant flexible joint with passive compliant mechanical structure and active compliant control is designed to cope with the dynamically-changing work environments and human-robot interaction issues. A series elastic actuator which uses a novel torsional elasticity instead of traditional torsional spring as elastic element to make the joint more integrated is embedded between the joint motor and load. The dynamics model of the flexible joint is established. Then,the impedance control strategy for the joint are made based on the sensory ability of multiple sensors. At last,the effectiveness of the control strategy is verified by the combined simulations on the joint virtual prototype with ADAMS and Simulink,which shows that the flexible joint has good property of torque compliant and impact-resistant,making it possible to adapt to variable environments.关键词：Flexible joint;Series elastic actuator;Combined simulation;Impact-resistant
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发布时间：2022-10-20 - 摘要：It is a basic problem to solve the principal curvature and direction of conjugate surface. Aiming at the complex and complicated problem of the conventional method to solve the principal direction and the principal curvature of conjugate tooth surface,a kind of calculation method to solve problem based on numerical differentiation is proposed. The meshing coordinate system is established and the conjugate tooth surface equations are deduced,with a pair of space staggered shaft drive hypoid gear as the research object. The calculation of principal curvatures and directions of conjugate surface of pinion is carried out. The advantages and disadvantages of common methods of numerical differential method,LITVIN method and the method of induced curvature are compared and analyzed. It is shown that the numerical differential method is clear and easy to be used in calculating by the computer,and this result is precise.关键词：Numerical differentiation;Induced normal curvature;Conjugate tooth surface;Principal direction;Principal curvature
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发布时间：2022-10-20 - 摘要：Aiming at the fault diagnosis problem of rolling bearing,a fault diagnosis method of rolling bearing based on local characteristic-scale decomposition（LCD） cross approximate entropy（CAE） and relevance vector machine（RVM） is proposed. Firstly,the bearing vibration signals is decomposed into several intrinsic scale components（ISC） which with different frequency components. Secondly,some ISCs that contain main fault information are shifted out by the energy analysis criterion and CAE values are calculated as fault feature vectors that could represent the operating conditions of bearings. Finally,the fault feature are put into RVM to identify different faults. The effective of the proposed method is verified by the different fault type and different fault degree of rolling bearing experiment.关键词：Local characteristic-scale decomposition;Cross approximate entropy;Relevance vector machine;Fault diagnosis;Rolling bearing
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发布时间：2022-10-20 - 摘要：Aiming at a medium bus driving speed at 60 to 80 km/h,it is found that the problem of vehicle overall noise level is too large and greater vibration of the floor. By using the analysis of noise figure and the vibration waterfall map data,the transmission shaft intermediate support bracket course resonance is confirmed.According to the theory of vibration isolation and finite element analysis,by reducing the stiffness of the intermediate support rubber and increasing the natural frequency of the intermediate support bracket,the vehicle resonance phenomenon is greatly reduced and the vehicle noise is reduced by 4 dB（A）. This method has important reference significance in solving the noise of transmission shaft,structural optimization design and test verification.关键词：Transmission shaft;Noise;Intermediate support;Resonance
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发布时间：2022-10-20
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