最新刊期
期 1 ， 2017
- 摘要：In order to grasp the dynamics characteristic of gear cutting fault under variable load excitation,considering the quality imbalance of gear caused by the cutting tooth fault and the influence of the fault on meshing stiffness of gear system,the dynamics model of the 4 freedom degree gear including cutting gear fault is established. On the basis of that,the variable step size four- order Runge- Kutta numerical method is used to solve to the dynamics model and the dynamics mechanism of gear cutting tooth is studied. Comparison of the dynamics characteristic of gear cutting tooth with non- load and variable load excitation,the dynamics characteristic of gear cutting tooth are analyzed. The result shows that,with variable load excitation,gear cutting tooth system has obvious low frequency components,and the more intense the external load changes,the low- frequency component is more obvious; the vibration displacement of the gear is similar to the external load. The size of the variable load also has effect on the dynamics characteristic of gear cutting tooth. The larger of variable load,the impact phenomenon and modulation phenomenon of the time- domain diagram is not more obvious and side band spectrum is no longer a cutting tooth gear rotating frequency. Therefore,for the gear fault diagnosis,the fault diagnosis should be carried out with the condition of stable and small load.关键词：Dynamics characteristic;Gear fault;Cutting tooth;Variable load
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发布时间：2022-10-20 - 摘要：The coexisting periodic trajectory and its stability of a single- stage gear rotor transmission system with 3 degree- of- freedom are studied by using the method of CPNF（ Continue- Poincare- Newton-Floquet）. The finite difference method is used to approximate instead of the Jacobi matrix of non- smooth system,and the defect that the nonlinear dynamic system must be smooth of the CPNF method is improved.Through calculation results of improved CPNF method comparing with the results of numerical calculation for example,the improved CPNF method is verified to be effective. The coexisting periodic motion of the gear rotor system is studied by using the method of improved CPNF,the stability of each periodic motion is determined at the same time. Through the CPNF,the stability of the periodic trajectory under different speeds is determined,the bifurcation characteristic of the gear rotor system under certain dimensionless rotational speed is studied.The results show that a nonlinear gear rotor system with certain parameters may have several coexisting stable or unstable periodic trajectories. Moreover,the motion of the system could also evolve into chaos by way of period- doubling bifurcation as the speed decreases in 1. 54 1. 42.关键词：Gear rotor transmission system;Nonlinear dynamics;Coexisting periodic trajectory;Stability;CPNF
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发布时间：2022-10-20 - 摘要：Taking the rolling mill oil film bearing as the research object,the model of oil- water two-phase flow of elastohydrodynamic lubrication is established by using with thermal effect of the Reynolds equation. The effects of three common liner materials are compared on rolling mill oil film bearing lubrication property. Combining with the special working condition of rolling mill oil film bearing,the lubrication characteristic of oil- water mixture are analyzed under different water contents,spindle speed and rolling force. The results show that,the babbitt in three liner materials,the maximum and center pressure are minimum,whose the overall,center and minimum film thickness are maximum to be best for lubrication performance,while its maximum temperature is maximum to be best for heat dissipation. Therefore,selecting the babbitt as liner material is most suitable for oil film bearing. The oil watering with the increasing of water content,the maximum pressure is decreased,the inlet zone pressure and minimum film thickness are increased to be promoted lubrication performance. As the rotational speed increase,the maximum pressure is decreased,the inlet zone pressure and minimum film thickness are increased. As the rolling force increase,the maximum pressure is increased,the inlet zone pressure and minimum film thickness are decreased.关键词：Rolling mill oil film bearing;Liner material;Oil-water two-phase flow;Elastohydrodynamic lubrication
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发布时间：2022-10-20 - 摘要：The Orthogonal neighborhood preserving embedding（ ONPE） is an unsupervised feature dimension reduction method and only use global neighborhood parameter,when it is used to high- dimension fault feature for feature dimension reduction,it is incapacity of using sample class label information and adaptive adjust neighborhood parameter while the space distribution of samples changed. Aiming at the problems above,a fault identification method based on improved supervised orthogonal neighborhood preserving embedding（ IS-ONPE） for feature dimension reduction is proposed. In IS- ONPE,the distance between different points is adjusted by utilizing class label information,thereby a new distance matrix is formed and the neighborhood is constructed through this new distance matrix,at the same time,the neighborhood parameter are adaptive adjusted according to local cluster coefficient. With the low- dimensional feature as inputs of support vector machine（ SVM） for identifying fault types. The experiment results of gear fault identification indicate that the proposed method can identification gear fault in high accuracy,it has some superiority.关键词：Fault identification;Feature dimension reduction;Improved supervised orthogonal neighborhood preserving embedding;Gear
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发布时间：2022-10-20 - 摘要：In order to analyze the dynamics characteristic of the hip joint simulator which taking the 3HUS+ S spatial parallel mechanism as the core module,starting from the kinematics of parallel mechanism,the relationship between the velocity,acceleration of moving platform and the linear module slider and active branched- chains are established. By the forces and torques of the centroid of the moving platform,active branched- chains and linear module,the dynamics model is established based on the principle of virtual power. The driving torques and powers of the linear module are obtained by simulating on the dynamics model,a reference for the simulator in the analysis of dynamics characteristics and research of control strategy is provided.关键词：3HUS+S parallel mechanism;Hip joint simulator;Dynamics model;Principle of virtual power
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发布时间：2022-10-20 - 摘要：The reachable workspace of 2- RPR + RRP spherical hybrid mechanism is researched. Firstly,the degree of freedom of the mechanism is solved by the modified Kutzbach- Grvbler formula,the degree of freedom of the mechanism and the motion characteristics of moving platform are obtained. Secondly,taking the geometric relation of mechanism as the constraint condition and combining with the rotation matrix,the mathematical model of the closed positive solution of the kinematics position of the mechanism is established. Finally,according to the positive kinematics solution model,the Matlab software is used to draw up the workspace of the reference point in the specific condition,and the reachable workspace of the same conditions is verified by using the Solid Works simulation software. The correctness of the positive solution model is proved,a theoretical basis for the further analysis and optimization of the mechanism is provided.关键词：Degree of freedom;Closed positive solution;Reachable workspace
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发布时间：2022-10-20 - 摘要：The vector motion model is built to study the trajectory tracking of the orbital forming press head,the motion trajectory of the orbital head with different speed and direction is simulated by using MATLAB software,the motion trajectory is multi- branches rose curve when the outer eccentric speed ω1> 0,and the inner eccentric speed ω2< 0,and ω1≠ | ω2|. The formation process of multi- branches rose curve trajectory motion are analyzed,the branch numbers of multi- branches rose curve and the law of the its trajectory are studied.关键词：Gear;Orbital forming;Multi-branches rose curve
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发布时间：2022-10-20 - 摘要：A structure scheme for a novel 3T2 R gantry hybrid machine tool（ HMT） is proposed. In this scheme,a novel（ 3- RPR + R） &UPS parallel mechanism is proposed as the parallel processing module,which can realize four motion,with assistance of a direction linear guide,5- axis machining can be realized.Firstly,the three- dimensional translations and two- dimensional rotations motion of this machine tool are analyzed based on screw theory of motion and constraints. The DOF of the mechanism is calculated,and the driving joints are chosen. Then,the inverse position solution equation of the mechanism is built by using analytical vector method and the geometric relation. At last,the position inverse solution equation is solved by using MATLAB and the results simulation verification is carried out by using ADAMS,which verify that the correctness of the inverse displacement analysis model and the feasibility of the mechanism.关键词：Gantry hybrid machine tool;Large swing angle;Degree of freedom;Screw theory;Inverse position solution
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发布时间：2022-10-20 - 摘要：According to the equivalent mapping relation of decision variables,the constrained discrete optimization problems for gear transmission design are transformed into nonlinear constrained non- negative integer programming problems（ CNIPPs） and a discrete differential evolution（ DDE） algorithm is used to solve these problems. An index of average gene distance is introduced to evaluate quantitatively the population diversity. On this basis,this work presents an adaptive escape strategy in which an opposite- based learning operator is employed to generate new individuals to overcome the drawback that the basic DDE algorithm easily traps into local optimal regions for solving discrete optimization problems. Thus this study embeds the escape strategies in DDE algorithm,adopts feasibility rules to handle constraints,and forms to an escape DDE（ EDDE）algorithm for solving CNIPPs. The proposed EDDE algorithm is applied to approach a real case of gear transmission optimization and an index of relative comprehensive performance is presented to compare several algorithms on optimization performances. The experimental and analytical results show that this novel algorithm has good robustness and reliability and is better than compared ones in term of the comprehensive index. Furthermore,the obtained result is better than one of the published literature and the corresponding gear mass is decreased by27%.关键词：Differential evolution algorithm;Discrete variable;Adaptive escape operator;Constrained optimal design;Gear transmission
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发布时间：2022-10-20 - 摘要：Based on virtual power theory,the power flow and efficiency analysis of differential gear train and closed planetary gear train are accomplished. Firstly,the gear train power flow and virtual power flow diagrams are established with or without considering the gear meshing power loss,the flow of power and virtual power is analyzed. Then,the gear meshing power loss and gear train transmission efficiency are calculated,the expression of gear train transmission efficiency is obtained. Finally,the influence of related design and manufacturing parameters on the efficiency of the gear train is analyzed and discussed. The results show that reasonable transmission type,number of teeth,speed ratio and gear manufacturing grade can efficiently increase gear train transmission efficiency. The proposed method is simple and can be used for the design of gear train.关键词：Differential gear train;Closed planetary gear train;Virtual power theory;Power flow;Efficiency analysis
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发布时间：2022-10-20 - 摘要：The heavy load gear system is widely used in large petrochemical industrial equipment. Because of the bad running conditions,the wear condition of the gear system is severe. According to the wear status of monitoring and forecasting analysis,the running condition of the gear system can be grasped,and to ensure the safe and reliable operation of the industrial units. The changing tendency of the wear quantity of the gear system can be represented by the grey prediction method,and the residual series of the predicted value can be analyzed by the time series method. The two kinds of methods can be combined to adjust and correct the predicted value.Then,the weight coefficient μ of the grey prediction model is improved. The sum of deviation square of the predicted value and the original value are set for investigation target to determine the optimum weight coefficientμopt,and the predicted precision is improved. The quantitative values of ferrography of the using heavy load gear system is analyzed as an example to test the effect of the improved grey time series combination model. The result shows that the improved grey time series combination model is superior to the traditional one.关键词：Oil analysis;Grey time series combination model;Gear wear;Ferrography
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发布时间：2022-10-20 - 摘要：A kind of the mechanical fault diagnosis method based on feature fusion and sparse representation is proposed. The energy of every subband of gear vibration signal is extracted with wavelet packet decomposition,and the energy constitutes original feature vector. The feature fusion is implemented with KPCA,and the dimension reduction of original feature vector is used as the input of classification based on sparse representation. The experiment demonstrates that the different fault type of gear is detected by the presented method.关键词：Fault diagnosis;Feature fusion;Sparse representation;Gear
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发布时间：2022-10-20 - 摘要：Aiming at the controlled model of a designed new type of multi- joint robot wrist structure which can be built in ADAMS and used in the MATLAB,the co- simulation with ADAMS and MATLAB is carried out. On the basis of analyzing the dynamics model of new type of robot wrist structure,the control is carried out by using the method of combining computed torque method and slide mode control method,and the method of slide mode variable structure control is improved to eliminate chatter phenomenon existing in the control,the more accurate trajectory tracking effect is got. Lastly,the control effect comparison among PID method,traditional computed torque method,the proposed control method is carried out,and the validty of the proposed control method is verified.关键词：ADAMS MATLAB;PID control;Computed torque;Slide mode control
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发布时间：2022-10-20 - 摘要：To study the power performance of electric vehicle with permanent magnet synchronous motor（ PMSM）,the integrated control algorithm based on the space vector and sliding mode variable structure is proposed. The vehicle parameter matching,PMSM selection,space vector modeling and the design of sliding mode variable structure controller are introduced in detailed. Then the model of PMSM electric vehicle is built and simulated under NEDC cycle. The simulation results show that the design of transmission ratio and the PMSM power parameter are reasonable,the power performance of PMSM electric vehicle obtained by the integrated control method with space vector and sliding mode variable structure is good,which has good rationality and stronger real- time performance and doesn’t affect the vehicle comfort.关键词：PMSM;Electric vehicle;Space vector;Sliding mode variable structure;Simulation
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发布时间：2022-10-20 - 摘要：A finite element analysis of gear broken tooth fault of diesel engine based on the ANSYS Workbench is presented. The model of a pair of involute helical gear which is built by Pro / E parametric modeling is imported into ANSYS Workbench transient dynamics analysis module and the finite element analysis results under three conditions including normal gear,half- tooth broken gear and full- tooth broken gear are obtained.Then the results are compared with the experimental vibration data of gear broken tooth fault of diesel engine and comparison result shows that,during the operation of involute helical gear of diesel engine,the contact stress changes periodically and fluctuates obviously,clearly impact phenomenon exists and with the increasing of the degree of gear tooth damage,the impact force of the gear increase distinctly. The frequency of the maximum amplitude is the ignition frequency,the amplitude of rotating frequency corresponding to fault vibration is significantly greater than the normal rotating gear.关键词：Diesel engine;Helical gear;Contact stress;Broken teeth fault;FEM analysis
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发布时间：2022-10-20 - 摘要：In order to study the influence of the vibration finishing process on the fatigue property of gear,two pairs of gear with the same design parameters is used for the contrast test,one pair of gear is treated by vibratory finishing,the other one pair with no vibratory finishing. The roughness meter is used to measure the roughness respectively,then using two kinds of methods for gear fatigue property comparison tests,the Locati fatigue limit rapid determination method and working conditions of constant load determination. The gear pairs meshes partly when the gears is installed in the gearbox,and then the test is carried out on the mechanical seal power gear test bed,by which the fatigue contact limit is obtained. The test results show that the vibration of finishing technology can improve the tooth surface finish,and also can improves the fatigue strength of gear effectively,what is more important,the life is prolonged apparently.关键词：Gear;Vibration finishing;Contact fatigue test
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发布时间：2022-10-20 - 摘要：At present,the problems of the poor accuracy and low efficiency etc exist in the solar tracking system,one of the main reasons is that the hourglass worm drive pair is not the right conjugating transmission form. Aiming at the wrong transmission form of the hourglass worm drive in the solar tracking system,based on the differential geometry and the space meshing theory,the accurately mathematical model of involute enveloping hourglass worm is deduced. The precise 3D model of the hourglass worm tooth surface is established,and the contact areas are shown based on the graphics. The involute enveloping hourglass worm is manufactured in the DMG turning and milling machining center,and the contact pattern comparison test is carried out. The results show that the mathematical model and the 3D model are correct,as well as the manufacture method is feasible.关键词：Solar tracking system;Involute enveloping hourglass worm;Manufacturing and experiment
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发布时间：2022-10-20 - 摘要：The influence on oil jet flow in nozzle of lubrication system for the main reducer is researched based on the one- dimensional Flowmaster fluid simulation,a more comprehensive and accurate analysis model is put forward. By using the Flowmaster software,the simulation model of oil jet of the main transmission lubrication system is built. Taking the oil pressure 0. 35 MPa and 0. 40 MPa as a single- variable to study the model. Then the simulation and the experimental results are compared and analyzed,the validity and accuracy of the calculation method and model are verified.关键词：Main reducer;Lubrication system;Oil jet;Simulation study
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发布时间：2022-10-20 - 摘要：The spherical cylinder coupling is the key connection device between sand roller and hydraulic motor of beach- cleaner. To study the fatigue life of spherical cylinder coupling of sand roller,firstly,the fatigue calculation with L- P theory of point connection carried out,the numerical analysis model of coupling with finite element method is built and the multi- body contact finite element analysis with augmented Lagrange algorithm is completed. Then,the cylinder load spectrum is obtained through kinematics analysis with Impact function in ADAMS. The fatigue life is analyzed based on the Miner theory in Fatigue Tool. The results demonstrate that the finite element calculation is consistent with theoretical calculation. The spherical cylinder coupling can satisfy the design requirements. The result proved the rationality of theoretical calculation. A basis for other coupling fatigue life research and simulation in the later is provided.关键词：Spherical cylinder coupling;Fatigue life;Augmented Lagrange algorithm;Kinematics
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发布时间：2022-10-20 - 摘要：Taking the last gears of the mine reducer named JS75 as the research object,by using the gear microscopic modification module of MASTA,the comparison and analysis of the contact spots,transmission error and harmonic amplitude before and after modifying are carried out. The determination of optimum modification method and amount is completed. The test of vibration and noise and spectrum analysis are carried out on the reducer under no- load and load by using M + P testing system. It is proved that the modification of the heavy load gears in last stage is very effective to control the vibration and noise of the transmission system,and the high speed spiral bevel gears has a very important influence on the dynamic performance of the reducer.关键词：Microscopic modification;Transmission error;Spectrum analysis;Vibration and noise
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发布时间：2022-10-20 - 摘要：As a whole,the automobile transmission producing vibration and noise is an inevitable result under the action of exciting force,the bearing,shaft and box has influence on the vibration and noise of the gearbox. The time- frequency domain signal of a certain type of automobile transmission is collected and analyzed by means of simulation operation mode. Through the time- frequency domain analysis of vibration noise of automobile transmission,the vibration and noise characteristics can be controlled,a solid foundation for the follow- up of structural dynamics optimization design with the purpose of reducing vibration and noise is laid.关键词：Automobile transmission;Noise signal;Vibration signal;Time domain analysis
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发布时间：2022-10-20 - 摘要：Using appropriate series geneva mechanism can eliminate the flexible impact in theoretically,but the unavoidable clearances between pin and slot exist in practical engineering application. In order to research the effects of the independent two- stage clearances on eliminating the flexible impact of the whole mechanism,a simulation model of series geneva mechanism containing the clearances is built by using ADAMS software firstly,and the influence mechanism of the clearances affect eliminating the flexible impact of output wheel is conducted. Then the experiment group aiming at finding the influences of different clearances of two stages geneva mechanism on the last geneva wheel is set up. The results illustrate that when the clearances exists,although the output geneva mechanism can eliminate the flexible impact,the impact brought by the clearances has greater influence on it. The peak angular acceleration of the last stage geneva wheel is affected by the first stage pin- slot clearance more greatly than the second one. Finally,a guidance of using series geneva mechanism in actual is brought up: the minimum clearance that ensures the geneva mechanism in normal working condition of the first stage geneva mechanism should be guaranteed with a certain machining accuracy firstly.关键词：Clearance;Series geneva mechanism;Flexible impact;Adams
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发布时间：2022-10-20 - 摘要：In order to acquire the S- shaped carbon- free car steering mechanism with symmetrical motion law and easy to adjust,the cam- slider- crank mechanism model is proposed. the model’s motion is symmetrical. The kinematics simulation is carried out by using ADAMS software,the rocker- slider mechanism is studied and designed by using the method of parametric modeling,then cam profile is got by the method of reverse design,finally the cam- rocker- slider simulation model is set up,the simulation results show that the motion law is symmetrical,this model is conforms to the requirements of the steering mechanism. At the same time,a set of test device is designed to verify the simulation results,the test data shows that the correctness of the simulation model and the feasibility of the method,the reference for the design of the S- shaped carbon-free car cam steering mechanism and related applications are provided by the simulation model,the ideas for simulation model validation and accuracy detection are provided by test method.关键词：Carbon-free car;Cam steering mechanism;Kinematics simulation;Adams;Test
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发布时间：2022-10-20 - 摘要：Based on the transient dynamics principle,a finite element model of a friction clutch system is established by using explicit dynamics method of software ABAQUS. The vibration acceleration and stress distribution are studied during clutch engagement,and the validation test is carried out. According to the relevant bionics design,three kinds of different groove textures are machined on the friction surfaces of clutch to study their effects on contact vibration. Finally,the influence of the setting of groove on vibration and the diagonal groove texture is analyzed. The results show that there is a severe change on vibration signal,and the disperse of vibration is slowly,and the validation test has a good agreement with the simulation results. The compound groove texture can reduce vibration efficiently,radial groove texture can eliminate vibration efficiently,while the ring groove texture can’t reduce continuous vibration. It is found that vibration of the friction clutch system with single sides groove can ’t be as efficient as double sides groove. The contact vibration amplitude of diagonal groove texture is lower than ring groove texture but higher than compound groove texture.关键词：Transient dynamics;Clutch;Groove;Vibration acceleration;Stress
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发布时间：2022-10-20 - 摘要：In order to solve the problem of large flow ripple of gear pumps,an active design method for gear pumps with low flow pulsation is proposed. The basic design thought is to control the shape of the tooth profile by specifying the values of the flow pulsation. The mathematical characterizations of equations for instantaneous flow rate and flow pulsation coefficient are deduced by using the polar distance and the pressure angle function according to gear meshing theory. The mathematical model of the active design of gear pump with low flow pulsation is established,the critical condition of the flow pulsation coefficient is deduced and the design procedure is given. A design for an example gear pump with low flow pulsation is taken to illustrate the proposed method. The characteristics of the gear pump are analyzed. A comparison study of the above characteristics of the involute gear pump is also carried out. It is significant to reduce the flow pulsation,improve the working stability and extend the service life of gear pumps.关键词：Gear pump;Flow pulsation;Active design;Pressure angle function;Tooth profile
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发布时间：2022-10-20 - 摘要：In allusion to the study of flapping- wing air vehicles（ FAV） with double- crank and double- rocker kind construction at present,the optimization design method of the flapping- wing driving mechanism with maximum value of minimum transmission angle is studied and analyzed. Based on classic graphical method on four- bar linkage mechanism,the function relation model of minimum transmission angle and the length of FAV is established. According to the bionic condition of birds flapping- wing flight,the installation angle and flap- wing flapping range and the function of crank driven angle are introduced. An optimization design scheme of the driving mechanism is obtained by utilizing Matlab. The virtual prototype of flapping- wing driving mechanism is built and a virtual kinetic simulation is conducted by utilizing ADAMS,the result shows that the optimization design model of driving mechanism is conformed with theory parameter model of FAV flapping,thus this design method is proved to be practicable and efficient.关键词：Driving mechanism of flapping-wing air vehicle （FAV）;Double-crank and doublerocker;Optimization design and simulation;Maximum value of minimum transmission angle
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发布时间：2022-10-20 - 摘要：The 6- DOF joint robot with offset wrist can’t satisfy the Pieper rule,thus there are no closed- form inverse kinematics solutions for them. Compared with non- offset robot,a numerical iterative algorithm that integrates the closed- form inverse solutions of non- offset robot with the modified Newton iteration method is obtained,and the inverse method is utilized to obtain the closed- form inverse solutions of the non- offset robot with the same configurations,and the solutions are considered as the initial values of the subsequent iteration. According to the forward kinematics,by combining the three components of position vector with the three independent elements of attitude matrix,a non- liner equation set which contains all joint variables can be obtained,and then the numerical inverse kinematics solutions for the robot with offset wrist can be searched with the modified Newton iteration method. A large number of tests indicate that the algorithm can meet the requirements of real- time control.关键词：Inverse kinematics;Newton iteration method;Offset wrist;6-DOF robot
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发布时间：2022-10-20 - 摘要：The linkage point trajectory curvature theory on the existing literature is summarized and improved. Another method determining the linkage point trajectory curvature center by the absolute and relative instantaneous center is working out. The undecided parameters method and auxiliary vertical line method for determining diameter and direction of the inflection circle in the four bar mechanism are elaborating out. The new general formula of calculation and graphic method for determining the linkage point trajectory curvature center are explained. The parallel position of side link cases that are not involved in every literature are discussed. The actual graph shape of the stationary curvature point curve in the connecting rod of the crank rocker mechanism is drawn. Two practical design examples of the crane hoisting mechanism and six bar dwell mechanism are given out.关键词：Linkage point trajectory curvature;Undecided parameter method;Auxiliary vertical line method;Baobilier method;Parallel position of side link;Crane hoisting mechanism;Six bar dwell mechanism
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发布时间：2022-10-20 - 摘要：A set of method which applies to the design and optimization of the sprocket in FSAE racing drivetrain is presented. Focusing on the process of the 75 m straight line acceleration,after determining the parameters of the large sprocket,the maximum impact on the large sprocket is calculated. By using the ANSYS optimization module,the position and the size of the lightening holes are optimized to try to arrange rationally and lose weight on the basis of meeting intensity of use.关键词：FSAE racing drivetrain;Large sprocket;Lightening hole;ANSYS optimization
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发布时间：2022-10-20 - 摘要：In order to get better meet the actual needs of trajectory,and to find a better method of trajectory planning,a combined space planning method for trajectory planning which combine Descartes space with joint space planning is found based on the former. Through the closed loop vector method,kinematics equation is established and the space trajectory is fitted based B spline function model,the motion curve of the joint space planning and the motion curve of Descartes space planning and the motion curve of combined space planning are obtained. Finally,through the prototype,the test verification is carried out. Through the analysis of the obtained results,it is found that the changes of the velocity and acceleration in the cycle time of combined space trajectory planning is better than the joint space trajectory planning or spatial planning of Descartes alone,and it will improve the quality of the whole movement of high level stability and reduce the impact in the movement process. Comparing with the experimental results,the movement trend tend to be consistent,the part of the curve have subtle difference and need further optimization but the method has very important significance for machine operation.关键词：Five link mechanism;Closed loop vector;Joint space;B spline;Trajectory planning
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发布时间：2022-10-20 - 摘要：The two stage helical gear reducer is widely used in different reduction occasions,of which the mode will directly affect the dynamic characteristics of the whole system. Based on the modal analysis theory,taking both the characteristic of the two stage helical gear deceleration system and the specific conditions into consideration,the geometry model of the gear transmission system is established by using the Solid Works,and it is imported into ANSYS Workbench by the seamless connection channel. After that,the finite element modal analysis with actual load and rotational speed is accomplished in a new loading approach,the low order natural frequency and the main vibration type of the gear transmission system is obtained,and the relative torsional vibration of gears is particularly analyzed. Comparing with non prestressed state modal analysis,the results suggest that the prestress of the gear transmission system has a great impact on the modal,the level of which is highly relative to the structural stiffness of gear.关键词：Helical gear;Reducer;Modal analysis;Vibration characteristic;ANSYS Workbench
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发布时间：2022-10-20 - 摘要：The optimization design method of 3Z（ Ⅱ） planetary gear train is studied. The multiple object optimization model,whose objective functions are the minimum of volume of gear train and the maximum of transmission efficiency is built. The constrained optimization is transformed into unconstrained optimization by penalty function,and a solution algorithm is proposed based on parallelism selection genetic algorithm（ GA）.The case shows,the proposed method can apply to the optimization methods of 3Z（ Ⅱ） planetary gear train and the optimization effects are noticeable. There is much for reference of this method to other optimization of planetary gear train.关键词：3Z （Ⅱ） planetary gear train;Multiple object optimization;Penalty function;Parallel selected genetic algorithm
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发布时间：2022-10-20 - 摘要：Taking the gear pair meshing stiffness,meshing damping and transmission error into consideration,the six degree of freedom pure torsion model differential equation of multi- gear transmission is set up based on lumped parameter method,the vibration accelerated speed of each component is obtained by adopting harmonic balance method. Setting minimal mass and vibration accelerated speed of total components as optimization objective function,the teeth number,module,helical angle as optimization design variable,the gear strength,transmission ratio and contact ratio as constraint condition,the vibration optimization modal of multi-gear transmission system is built. The best design variables are solved by compiling mixed- discrete optimization codes based on branch and bound algorithm. Then,the vibration response is recalculated,the results point out that the mean vibration acceleration and total mass are decreased by 33. 5 percent and 12. 96 percent respectively,which indicates the remarkable effect of vibration optimization.关键词：Mixed-discrete method;Multi-gear transmission;Vibration optimization
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发布时间：2022-10-20 - 摘要：Aiming at solving the problems of relative sliding between the robot driving wheel and the tube wall and the adaptation of the robot body to the pipe diameter,the pipe robot with the characters of autonomous differential motion and adaptive variable diameter is designed by adopting the single motor to drive. The transmission characteristics of the differential mechanism are analyzed,the force equation of working state for the variable diameter mechanism of pipe robot is theoretically deduced,and the mechanical relation between the driving wheels and pipe wall in robot operation is obtained. The movement model of robot in pipe is built,and the relationship between each variable in the model under the condition of different pose is analyzed. The virtual prototype model of robot operating in combined pipe is built through the simulation analysis. The robot characters of autonomous differential motion is validated. The results indicate that the pipeline robot can through bends without interference,and show a good driving characteristics.关键词：Differential mechanism;Pipe robot;Variable diameter mechanism;Movement position
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发布时间：2022-10-20 - 摘要：Due to the larger radial dimension of the tire coupling,the additional axial force making the bearing load is increased and life is reduced,in order to solve this problem,using TRIZ to analyze the radial dimension problem of the tire coupling and find the solutions. The problem of tire coupling is solved by the tire ring and trapezoidal timing belt nested to form a new structure. Through the ANSYS finite element analysis,the rationality of its structure is verified,which is hoped to expand its application.关键词：Tire coupling;Trapezoidal timing belt;TRIZ;ANSYS finite element analysis
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- 135
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- 1
发布时间：2022-10-20 - 摘要：In order to improve the problem of design calculation complex and manufacturing difficulty of non- circular gear pair,taking the high order elliptic non- circular gears as the research object,according to the principle of non- circular gear meshing,the method of calculation and design of the pitch curve of non-circular gear. Taking Solid Works as a development platform,the high order elliptic gears pitch curve design system is developed in the VB 6. 0 environment,the system includes a parameter calculation module,the pitch curve concavity and convexity check calibration module and pressure angle,root cutting,curve plotting module and so on. Finally,by cubic spline curve fitting,the computer aided design of high order elliptic gear pitch curve is realized,and the efficiency and precision of the elliptical gear drive design are improved.关键词：VB;SolidWorks;Non-circular gear;High order elliptic gear pair;Pitch curve
- 4
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- 147
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- 2
发布时间：2022-10-20 - 摘要：In order to solve the problem of the oil film traction transmission characteristic of the most of test machine under the transient condition can’t study at present in domestic,a test machine is designed to study the oil film traction transmission characteristic under transient condition. Then,a virtual prototype model of the reciprocating traction drive test machine is built by using Pro / E software,and the characteristics of kinematics and dynamics are studied,the characteristic curve of corresponding parameters is obtained. The results validated the correctness of the model,and the motion parameters and trajectory changing with the time of the reciprocating traction drive test machine is obtained. A certain reference for dynamics characteristic research of traction drive test machine under transient conditions is provided.关键词：Virtual prototype;Reciprocating traction drive;Test machine design;Simulation
- 3
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- 82
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- 0
发布时间：2022-10-20 - 摘要：In order to improve the efficiency of gearprocessing,a kind of CNC hobbing automatic programming system is presented. Firstly,the mathematical model of the hober- axial roll cut method is established.Then,the hober hardware platform of CNC gear hobbing automatic programming system is established,the several functional modules and the software page set are designed. Finally,the object- oriented software programming technology,communications technology,multi- threading technology and decoding technology in the system development are analyzed. The automatic programming technology provides some convenient reference and experience for the future gear hobbing CNC machining.关键词：Hobbing;Automatic programming;CNC
- 3
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- 99
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- 3
发布时间：2022-10-20 - 摘要：The theoretical analysis and calculation of gear tooth of two- input planetary reducer used in aerospace craft steering engine are carried out by using the general mechanical design method and by disposable mechanical design method separately. Through analysis of the result,when the condition cannot meet the strength requirement by using general mechanical design method,the theoretical security coefficient calculated by using the disposable mechanical design method is 3. 96 under the same conditions. The performance test of the prototype reducer shows that the double planetary gear reducer meets the design requirements. It turns out that the disposable mechanical elements design theory is fairly effective and practical.关键词：Disposable mechanical design;Two-input planetary reducer;Gear design
- 3
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- 100
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- 1
发布时间：2022-10-20 - 摘要：The cross- term interference caused by multi- modulator and multi- carrier makes it limited the use of the cyclic autocorrelation demodulation. A new method called the MCKD（ Maximum correlated Kurtosis Deconvolution）- cyclic domain demodulation is proposed. Firstly,the strong background noise of the original signal is decreased by the MCKD method in order to extract the interest period component,the above given signal is processed by the cyclic autocorrelation function demodulation. The new method can decrease the cross- term interference caused by multi- modulator and multi- carrier and improve the reliability of the analysis. As the application of the MCKD- cyclic domain demodulation theory in fault diagnosis,the method is used to extract fault feature from vibration signals successfully.关键词：MCKD;Cyclic autocorrelation demodulation;Fault diagnosis;Periodic signal
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- 204
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- 2
发布时间：2022-10-20 - 摘要：The background and necessity about the construction of the public service platform for gear strength and reliability test technology of strengthening foundation engineering project of the Ministry of Industry and Information Technology are briefly introduced. The function of eight sub- platforms are outlined. The key generic technology research and demonstration application progress are introduced. It has guiding significance for the design,manufacture,testing etc. of the gear production.关键词：Gear;Strength;Reliability;Test detection;Public service platform
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- 248
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- 2
发布时间：2022-10-20 - 摘要：The hybrid electric vehicles are the mature product that transits from conventional vehicles to electric vehicles and have a great development prospect. The typical transmission structure of series hybrid electric vehicles,parallel hybrid electric vehicles and series- parallel hybrid electric vehicles is briefly introduced.Then,relevant control strategies and their advantages and disadvantages are deeply discussed. Further,based on the conclusion and analysis of the existing hybrid vehicle control strategies,the optimization status of various control strategies respectively,such as regenerative braking optimization,fuzzy logic optimization,power system parameter optimization and dynamic coordination optimization are significantly described. Lastly,the development trend of control strategies for hybrid electric vehicles in the future is pointed out.关键词：Hybrid electric;Control strategy optimization;Fuzzy logic;Algorithm
- 7
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- 768
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- 1
发布时间：2022-10-20
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