最新刊期
期 3 ， 2019
- 摘要：The aeronautical gear has the characteristics of light weight and low rigidity. It is easy to take lateral vibration under the internal excitation of the gear pair. It is necessary to study the inherent characteristics of the lateral vibration of the aeronautical gear for the design of the aeronautical gear. The flexibility of the gear web， the stiffness of the bearing and the gear meshing stiffness are considered， the finite element model of the gear rotor is established by the finite element software for rotor dynamics named Samcef， and the natural frequency， vibration mode and the critical speed of the high-speed gear rotor system are calculated. Compared with the inherent characteristics of the gear rotor system without consideration of flexibility， it is shown that the frequency values and modes of the lateral vibration of the gear rotor system can be obtained by considering the flexibility of the gear web. Without considering the flexibility of gears， the frequency and mode shapes of lateral vibration of gears can′t be obtained.关键词：Flexible gear;Natural frequency;Critical speed;Campbell diagram;Lateral vibration of gear
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发布时间：2022-10-03 - 摘要：In order to analyze the influence of bearing preload on the dynamic characteristics of high-speed and heavy-load planetary gear transmission system， a dynamics model of high-speed heavy-load planetary gear transmission is established. Considered bearing preload factors， the preload of planetary pin bearing influence is analyzed for system support stiffness， natural frequency， internal and external Engagement vice dynamic meshing force. The results show that the planetary pin bearing preload can effectively increase the support stiffness of the planetary pin； the natural frequency of the system decreases with the preload and then increases， and increases with the increase of the clearance；the peak value of the dynamic meshing force of the internal and external meshing pairs of the planetary gear increases with the preload and then decreases， and increases with the increase of the clearance. The research results can provide support for optimizing the bearing preload of high-speed and heavy-load planetary gear transmission.关键词：Bearing preload;Planetary gear transmission;Support stiffness;Dynamic engagement force
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发布时间：2022-10-03 - 摘要：In order to analyze the influence of key parameters on the contact and lubrication performance of the inner meshing worm gear of the roller envelop， the mathematical model of the new worm drive is built. And the lubrication angle and the induced normal curvature equation are constructed by the meshing equation. Then the influence of the key parameters on the lubrication and contact performance of worm drive are analyzed by the numerical calculation method. These key parameters include the center distance，the transmission ratio，roller radius and the worm-wheel rotational deflection. The analysis shows that in these key parameters，the deflection angle of the worm wheel has a great influence on the contact and lubrication performance of the inner meshing worm gearing of the roller envelope. It is suggested that the deviation angle of the worm wheel is the best in the range of 0°to 40°. And the corresponding parameters are selected for 3D modeling analysis to verify the validity of the analysis parameters. The study provides a reference for further research on the roller enveloping internal worm drive.关键词：Worm-wheel rotational deflection angle;Key parameter;Internal engagement worm gear;Lubrication performance;Modeling
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发布时间：2022-10-03 - 摘要：Taking into account factors such as input speed fluctuation， structural characteristics and gear meshing characteristics of the transmission， the flexible characteristics of the transmission box are considered， boundary conditions are properly set up， and transmission gear rattle rigid-flexible coupling simulation analysis models are established to reproduce the gear rattle. Then， refer to speed of idle gears， the effectiveness of the analysis model is verified by bench test. According to the gear rattle mechanism，gear rattle evaluation index based on the speed fluctuation vector sum of the driving and loose gears is proposed. Based on the validated simulation model， jerk and speed fluctuation vector sum evaluation indicators are calculated and analyzed under the gear rattle conditions， and comparing with the subjective evaluation results. The results show that the speed fluctuation vector sum of the driving and loose gears has good consistency with subjective evaluation result. It provides a methodological reference for the objective evaluation of gear rattle noise.关键词：Transmission;Gear rattle;Rigid-flexible coupling model;Speed fluctuation;Evaluation
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发布时间：2022-10-03 - 摘要：Aiming at the difficult about lost motion calculation of micro-segment planetary gear transmission accuracy. Considering the influence of gear natural error， assembly error and the time-varying mesh stiffness of gears， the lost motion model of planetary gear transmission is proposed based on the backlash of micro-segment gear. Aiming at 3K-I planetary gear train， the theoretical calculation lost motion of micro-segment gear is 5.92% smaller than involute gear by Monte Carlo simulation. Experiment under the same conditions shows that the lost motion of micro-segment planetary gear is within the theoretical model calculation and the lost motion of micro-segment planetary gear is 6.25% smaller than involute gear， which proves that the lost motion model of micro-segment planetary gear is correct.关键词：Micro-segment gear;Transmission accuracy;Lost motion;Meshing stiffness;Monte Carlo
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发布时间：2022-10-03
Theory·Reserach
- 摘要：In order to investigate the load-sharing performance of the 2K-H planetary gear transmission system， a translation-torsion coupling dynamics model is established with considering the nonlinear factors of time-varying meshing stiffness and the overall meshing error and so on， the dimensionless differential equations with 18 degrees of freedom of the system are deduced in this model. By solving the differential equations， the influences of the support stiffness of the center component and the clearance floating on the load-sharing performance of the planetary gear train are analyzed. It is shown that the floating amount of the component increases with the reduction of the support stiffness of the center component and the increase of the clearance of the shaft hole within a certain range， the load-sharing factor of the system decreases when the floating amount of the component increases.关键词：2K-H planetary gear train;Center component;Support stiffness;Clearance floating;Load characteristic
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发布时间：2022-10-03
Theory·Research
- 摘要：Based on the motion mechanism of human joints and reconfigurable concept， a P（2-RPS）&U reconfigurable rehabilitation mechanism is proposed. By locking the kinematic pairs to change the movement mode of the moving platform， the rehabilitation training of human elbow joint， knee joint and ankle joint can be realized， respectively. The inverse solution of the P（2-RPS）&U reconfigurable rehabilitation mechanism is analyzed and its position singularity is analyzed based on the screw theory. And the two singularity positions of the mechanism are obtained. The singularity positions can be avoided by adding the driver. The kinematics simulation of the P（2-RPS）&U reconfigurable rehabilitation mechanism is carried out by using Adams software. The simulation results show that the mechanism could reach the range of rehabilitation movements of human elbow， knee and ankle joints， and satisfy the rehabilitation requirements of damaged joints.关键词：Reconfigurable rehabilitation mechanism;Elbow joint;Knee Joint;Ankle joint;Kinematics
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发布时间：2022-10-03 - 摘要：The simple single-stage reducer used in traditional electric vehicles is not enough to meet the requirements of electric vehicle for transmission efficiency， therefore， it is necessary to introduce two or more speeds transmission to electric vehicles to improve the efficiency of the whole power assembly. A new type of electric vehicle two-speed transmission is presented， which is composed of a wedge changing mechanism and a planetary gear system， and it can realize the efficient shift without power shock. In addition， the basic structure and working principle are introduced， and Lagrange method is applied to analyze the dynamics modeling of each component of the transmission， a two-degree of freedom Lagrange equation is established， the shift process model is built based on MATLAB/Simulink， the shift process is analyzed and the accuracy of the mathematical model is verified. It provides a certain basis for the study on dynamics modeling and shift quality optimization of the same type of transmission.关键词：Electric vehicle;Two-speed transmission;Planetary gear train;Lagrange equation;Dynamics modeling
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发布时间：2022-10-03 - 摘要：The kinematics solution of Stewart platform is to figure out the relationship between actuator length and posture of moving platform. The inverse kinematics can be easily derivated by space coordinate transformation. Due to the highly multivariate nonlinear function， the forward kinematics solution method is hard to be both fast and accurate. To figure out a solving method， the Improved Non-dominated Sorting Genetic Algorithm （NSGA-II） combined with Least Square（LS） method algorithm is implemented. The moving platform posture is randomly generated by algorithm and the corresponding length solution is solved by inverse kinematics. While the corresponding length solution fits the known length solution best， the best forward kinematics solution is appeared. According to the example calculating， this algorithm can export the best forward solution within 102 iterations， the output time of a single result is less than 1 min. The RMSE value is lower than 0.1 during 10 times solve. In conclusion， the NSGA-II with LS algorithm is fast and of high accuracy while using on forward solution of parallel platform.关键词：Stewart platform;Forward kinematics solution;Improved non-dominated sorting genetic algorithm;Least square theory
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发布时间：2022-10-03 - 摘要：Aiming at the working process of the press crimping device for paper tape crimping machine，on the basis of analyzing the movement process of the swing roller， the swing roller is regarded as the follower of cam mechanism. Its rotation angle is defined as equivalent to the stroke of the follower， and the action electronic cam curve of the swing roller is constructed. Thus， the control of the swing roller can be realized based on the electronic cam control mechanism. The definition of the electronic cam curve， especially the curve forms in the acceleration and deceleration area， and the angle relationship between the swing roller and the driving shaft in the acceleration and deceleration area are discussed in detail. It is concluded that the rotation angle of the driving shaft is twice as much as the rotation angle of the swing roller in the acceleration and deceleration area. Taking this as a guide， the parameters setting of the electronic cam function of servo motor are discussed， and it can be set off-line at different speeds of paper tape. Finally， the design idea of the PLC program to realize the above control is discussed and applied to the actual system. The reliability and stability of the press crimping device have achieved the desired effect.关键词：Electronic cam;Servo control;Paper tape crimping machine;PLC
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发布时间：2022-10-03 - 摘要：The carbon-free car is a three-wheeled car with periodic obstacle avoidance function and with the energy of heavy hammer gravity as the sole source of power. At first，a concrete analysis for the track of car is carried out，and the ‘double 8-shaped’ track of the car is abstracted into a mathematical model. Through curvilinear integral， the design of the best ‘double 8-shaped’ track is finished. Secondly， the parameters affecting the trajectory are studied to complete the design of the overall structure of the car. Finally， the simulation of the designed car is carried out， and the parameter is corrected. Based on the simulation results，a ‘double 8-shaped’ carbon-free car with low energy loss and high track repeatability is produced.关键词：Carbon-free car;Double 8-shaped;Tracing principle;Structure design
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发布时间：2022-10-03 - 摘要：The configuration and pure translational performance of 3-UPU parallel mechanism is analyzed by using spatial mechanism screw theory. The continuous polynomial algebraic topology method is proposed， the positive kinetic non-linear equations of 3-UPU parallel mechanism is built， and the solution of the equation set is calculated. By this approach， the solution of nonlinear kinetic equations of parallel mechanism can be found effectively without giving initial values. Meanwhile， the problems of divarication and divergence are also eliminated in the solving process， which have vital reference significance to the nonlinear transcendence problem solving. Based on Matlab/ Simmechanics， the kinetic PID control model of 3-UPU parallel mechanism is built and its workspace is analyzed to verify the accuracy in the application of spiral theory on parallel mechanism configuration design. This method provides feasible and practical reference significance to solve and analyze the kinematics problem of multiple degrees of freedom parallel mechanism.关键词：Spatial mechanism screw theory;3-UPU parallel mechanism;Continuous polynomial algebraic topological method;Positive kinetic position solution;Workspace
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发布时间：2022-10-03 - 摘要：At present， the operate time of the most manipulators are not optimally during the working process. In order to improve the working efficiency of the manipulator， a time optimal manipulator trajectory planning method based on the complex method is proposed. The method of 5-7-5 polynomial interpolation method is taken as the basis of trajectory planning， the motion angle， motion velocity and motion acceleration are taken as constraint， the optimization is carried out by using the complex method， the time optimal motion trajectory that meets the motion requirements is obtained. The FS20N robot is used as the object for research and analysis， and imported into MATLAB for verification， the simulation structure shows that the complex method effectively optimizes the time.关键词：Manipulator;Polynomial interpolation;Trajectory planning;Motion constraint;Complex method;Time optimal
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发布时间：2022-10-03 - 摘要：According to the physiological characteristics of human ankle and parallel mechanism， several 0T3R parallel mechanisms are synthesized based on the Position and Orientation Characteristics （POC） set by taking the Single-Opened Chain （SOC） as the unit. Then combined with the characteristics of human ankle， one of the 0T3R parallel mechanisms is selected， and its kinematics analysis is carried out. Based on the established inverse displacement solution equation and by using the Matlab， the data solving is carried out. Finally， the obtained data is used as the driving function to simulate the mechanism in Adams. The simulation results verify the feasibility of the parallel mechanism， and a theoretical basis for the subsequent optimization design of mechanism size is provided.关键词：Rehabilitation robot;Ankle joint;Parallel mechanism;POC set;Kinematics analysis;Simulation
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发布时间：2022-10-03 - 摘要：A new 4-DOF partially decoupled parallel mechanism which can move along the y-axis， z-axis and rotate around the x-axis and y-axis is proposed. The mechanism is supplemented by a moving platform which can move the x-axis and rotate the x-axis of the spindle. The mechanism is designed for machining turbine blades. The kinematics analysis of the mechanism carried out， the kinematics equation and Iacobian matrix are obtained. The workspace of the mechanism is analyzed by using the geometric method， the Jacobian matrix is used to prove that the scheme has no singularities in its workspace， the required stroke length of the actuator for the defined task is obtained.关键词：Hybrid machine tool;Kinematics;Blade machining;Workspace analysis;Singularity
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发布时间：2022-10-03 - 摘要：The 3-（2SPS） parallel machine tool is taken as the main research object， the 3D solid model is established by using SolidWorks software. On this basis， the machine coordinate system is first established， and the Jacobian matrix and the parallel machine tool stiffness matrix are obtained. Using MATLAB programming， under the three working conditions， the simulation stiffness of the parallel machine tool is distributed according to the position of the platform. Then the ANSYS Workbench software is used to carry out the finite element analysis of the machine tool. Under the same working conditions， the overall displacement cloud image and the finite element simulation stiffness of the machine tool are obtained. The two analysis results prove the validity of the simulation results and lay a foundation for the subsequent optimization and good dynamic performance of the machine tool.关键词：Parallel machine tool;Force Jacobian matrix;Stiffness matrix;Finite element analysis;Simulation
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发布时间：2022-10-03 - 摘要：With the increasing of temporomandibular joint disorder syndrome and the increasing number of patients with oral external trauma，the development of the mandibular rehabilitation robot is very important. In order to meet the training requirements of different patients in different rehabilitation periods，an opening and closing mandibular rehabilitation robot with crank-rocker mechanism as main actuator is designed. The joint design modeling and motion simulation are carried out by using CERO and MATLAB，and the generated trajectory is consistent with the design requirements. The simulation results show that the designed mandibular rehabilitation robot can meet the training requirements of different patients in different rehabilitation periods，which lays a foundation for the design of the mandibular rehabilitation robot.关键词：Temporomandibular joint disorder syndrome;Mandibular rehabilitation robot;Motion track;Motion simulation
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发布时间：2022-10-03
Design· Calculation
- 摘要：The planar sinusoidal steel ball transmission mechanism with fixed disk output and retainer fixed and no eccentric is studied， which has good heat dissipation and make up for the shortage of cylindrical sinusoidal movable teeth transmission mechanism. By establishing the mechanical model of the steel ball in the planar sine ball transmission mechanism，the change law of the contact force and inertia force are obtained at the same time，and the accuracy of the mechanical model is verified by the simulation， which provides the theoretical basis for the strength checking and the vibration analysis of the mechanism.关键词：Planar sine;Mechanical analysis;Oscillating tooth gear drive;Theoretical model;Simulation
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发布时间：2022-10-03 - 摘要：The kinematics analysis of the 3-PRS+2P hybrid mechanism is carried out. The inverse kinematics equation of the mechanism is established by combining the geometric method with the coordinate transformation，and the analytical solution of the inverse kinematics of the mechanism is obtained. The position of the cutter location is transformed into the three vertex coordinates of the moving platform，and the positive kinematics model of the mechanism is established. At the same time，the two parameter numerical extension homotopy algorithm is used to find the numerical solution of the positive kinematics. The analytic expression of the inverse solution is calculated based on Maple. The structure of the solution is simple and easy to be programmed. The iterative process of the positive solution is realized based on the Matlab programming，and the numerical solution reaches the precision requirement. The correctness of the positive and inverse solutions is verified through the modeling，computation and simulation of UG and Matlab.关键词：Parallel robot;Positive kinematics;Inverse kinematics;Homotopy algorithm
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发布时间：2022-10-03 - 摘要：According to the engagement characteristics of wet clutch， average Reynolds equation and elastic contact model of two rough surfaces are applied to establish a dynamic transfer torque model for wet clutch engagement. Dynamics model of joint start for wet dual clutch is established based on the dynamic transfer torque model of wet clutch engagement in vehicle start， and the model is simulated and validated in Matlab/Simulink platform. Taking the startup with 20% throttle opening as example， two joint start process of wet dual clutch are analyzed and compared respectively on the basis of the dynamic and static transfer torque model. Results show that the simulation based on dynamic transfer torque model can more actually characterize the changes of rotation rate， jerk and friction work in the start process of wet DCT.关键词：Automatic transmission;Wet dual clutch;Torque model;Joint start;Simulation
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发布时间：2022-10-03 - 摘要：The rotational speed fluctuation will worsen the internal contact state of roller bearings，which has important influence on the dynamic characteristics of cage. Considering the characteristic of periodic fluctuation of rotational speed of roller bearings，it is simplified as a simple harmonic wave. Taking cylindrical roller bearing NU306 as investigation object，a nonlinear dynamic finite element model for plastic material flexible contact of a bearing is established. Based on explicit LS-DYNA，the dynamic simulations for nonlinear operation process under different fluctuation frequency and different fluctuation amplitude condition of rotational speed are carried out，and the angular speed curve of cage and the contact force curve between roller and cage are obtained. The influences of fluctuation frequency and fluctuation amplitude on the dynamic characteristics of cage are analyzed. The study results show that the fluctuation period of the angular speed curve of cage is mainly determined by the fluctuation period of the rotational speed of inner ring，and the greater fluctuation frequency of rotational speed，the more the number of collisions between rollers in and out of load zone and cage. The greater fluctuation amplitude of rotational speed，the greater maximum speed of angular speed curve of cage，and the smaller minimum speed of angular speed curve of cage，but the change of average speed is very small，so the fluctuation range of angular speed curve of cage will increase obviously. The simulation results are in good agreement with the experimental results， and the correctness of the finite element model is verified.关键词：Cage;Rotational speed fluctuation;Dynamic characteristic
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发布时间：2022-10-03 - 摘要：Based on the analysis of the new five-degree-of-freedom hybrid machine tool mechanism （（3-RPR+R） & UPS） +P， the Jacobian matrix of the velocity of the mechanism is obtained， and the mapping matrix of the centroid velocity of each branch and the generalized velocity of the centroid of the moving platform is obtained. The dynamics model of the new five-degree-of-freedom hybrid machine tool mechanism is established by applying the principle of virtual work. Finally， the theoretical dynamics analysis of machine tool mechanism is verified by using Matlab and ADAMS simulation software， and the results verify the correctness and feasibility of the theoretical analysis.关键词：Hybrid machine tool;Adams simulation;Virtual work principle;Dynamics model
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发布时间：2022-10-03 - 摘要：Aiming at the problem of the diaphragm coupling is affected by snap loads which lead to diaphragm fatigue broken and fracture failure， the structural and dynamic performance of the redundant diaphragm coupling are carried out. The overall structure of the redundant diaphragm coupling is designed， and the finite element analysis model of diaphragm disk is established， the optimum thickness of the diaphragm meets the design requirement is obtained by calculating. Then， the safety factor of the redundant structure is verified based on the strength analysis of redundant structure of diaphragm coupling， and the transmission of the torque can be realized. Finally， the frequency response curve is obtained based on the dynamic performance research of the diaphragm coupling. The results can provide the effective basis for the analysis of mechanical transmission devices in this field.关键词：Diaphragm coupling;Fracture failure;Redundant;Frequency response
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发布时间：2022-10-03 - 摘要：The sources of the harmonic gear reducer gap clearance are complicated， the gap clearance is the main factor affecting the operation accuracy of the mechanism. According to the work principle of the harmonic gear reducer， the main factors causing the gap are the torsional deformation of the parts（the flexible wheel and output shaft），and the clearance between the rigid and flexible wheels， and the radial clearance of the flexible bearing. Secondly， using the theory of involute， material mechanics， stiffness and so on， the mathematical model of the gap clearance and above factors is established. Finally， a gap-free test of one kind of harmonic gear reducer is carried out， the measured results are in good agreement with the theoretical calculation.关键词：Harmonic gear;Gap clearance;Flexible bearing;Radial clearance
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发布时间：2022-10-03 - 摘要：The firing pin of chain demolition equipment are prone to fatigue damage under repeated loads， threaten the quality of chain products. In order to study the rule of firing pin fatigue damage， using the workbench software to perform the finite element analysis of the firing pin. Firstly， through the static strength analysis， the weak parts of the firing pin are determined， on this basis， the fatigue life is calculated， and the fatigue life of the firing pin is obtained. Comparing the data with the actual verification， the results show that the effect of the two methods is consistent and the validity of the finite element analysis is verified， it also provides some technical reference for the following equipment maintenance and structure optimization.关键词：Workbench;Demolition equipment;Firing pin;Fatigue life;Structure optimization
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发布时间：2022-10-03 - 摘要：A new type of driving system for bedrock drilling is proposed. The structure and working principle of the driving system are expounded， and the structure design of the reduction transmission device and the parameter selection are completed. The force analysis of the reduction transmission device is carried out， and the design of the driving system for bedrock drilling is perfected. Finally， dynamics analysis and reliability analysis of the driving system are carried out by using ANSYS Workbench. The results show that the structural design of the driving system for bedrock drilling under polar ice is reasonable.关键词：Driving system for bedrock drilling;Sine movable tooth drive;Force analysis;Reliability
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发布时间：2022-10-03
Test·Analysis
- 摘要：As the main mechanism of the opener， the cam mechanism has detailed dynamic characteristics analysis， which will have important guiding significance for the dynamic performance improvement of the opener. The cam link and the camshaft are flexibly processed to create a multi-flexible body model of the cam mechanism， and the simulation results of the multi-rigid body model and the multi-flexible body model are compared. Based on the multi-flexible body model， the effects of input speed， damping coefficient， material parameters and structural parameters on the dynamic characteristic of the mechanism are analyzed. The results show that the simulation results of the multi-flexible model have guiding significance for the initial assembly of the opener. Reducing the cam thickness and increasing the damping can improve the dynamic characteristics of the mechanism and enable the opener to run at a faster speed. At the same time， using ANSYS to perform modal analysis on the cam with varying thickness， a basis for avoiding resonance and more comprehensive dynamic analysis is provided.关键词：Cam mechanism;Cross impact;Dynamic characteristic;Modal analysis
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发布时间：2022-10-03 - 摘要：The flexible wheel is the core part of the harmonic reducer， and it is also the part that is prone to failure. The flexible wheel of a certain type of harmonic reducer is taken as the research object， and the structure is greatly changed. The 3D model of flexible is established in SolidWorks， and the model is then imported into the Workbench for finite element analysis， and the equivalent stress of the two models under working conditions is compared. The analysis results show that the aspect ratio of the new structure of the flexible wheel is greatly reduced， and the maximum stress occurs and the position is greatly reduced. Comparing the different parameters of the new structure of the flexible wheel， the improvement of the overall structure of the flexible wheel is obtained.关键词：Flexible gear;Finite element analysis;Maximum stress value;Structure improvement
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发布时间：2022-10-03 - 摘要：To achieve the abundant relief of high-speed trapped-oil for gear pump，based on the same tooth profile parameters and working conditions，the experiment，simulation and theoretical analysis are carried out successively. Secondly，the shape，position and size of the new groove are given. Finally，the case calculation of trapped-oil pressure were carried out. The results show that the theoretical analysis is correct by the consistency of experiment，simulation and theoretical results. Under the speeds of 1 000 r/min， 3 000 r/min， 5 000 r/min and 0.03 mm small backslash， the increase rate of the pressure peak of the new groove and the rectangular groove are 1.75%，15%，41.5% and 9.50%，85% and 236.25% respectively. It shows that the rectangular groove can meet the relief requirement of trapped-oil under low speeds， and the new groove can meet the relief requirement of trapped-oil under medium speeds. Under the high speeds of 5 000 r/min and 0.2 mm large backlash， the pressure increase rate of the new groove is 22.75%， which indicates that it can meet the relief requirement under high speed.关键词：Gear pump;Trapped-oil phenomenon;Relief-groove;Gear backslash;Trapped-oil pressure
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发布时间：2022-10-03 - 摘要：A new hexapod walking robot based on asymmetric 3-UPU is proposed， it has the advantages of large carrying capacity， strong passing ability， easy control and so on. Firstly， the structure of hexapod walking robot is designed， then the stability of the robot and the interference of the legs are considered synthetically， the maximum transverse moving stride is designed. The gait planning of the hexapod walking robot is carried out， including the duty cycle coefficient of the two groups of legs， the order of motion， and the moving stride， the movement trajectory and the equivalent rod length of each branch vary with the movement of the robot.关键词：Hexapod walking robot;Asymmetric 3-UPU;Stride planning;Trajectory planning
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发布时间：2022-10-03 - 摘要：In view of the demand for real-time acquisition of information and the superior performance of the robot in environmental detection，the system composition of the designed hexapod spider crawling robot and the analysis and calculation of the obstacle performance are introduced. The robot is composed of six mechanical legs and robot bodies，based on the Stm32f407 chip as the main controller，and uses the PID algorithm to control the whole robot to keep the balance，and completes the real-time response to the operation instruction through the image acquisition system. Based on the center of gravity transcendence，through theoretical study，centroid analysis and numerical calculation，the ability of the robot obstacle surmounting is analyzed，and the maximum height of the climbing staircase and the maximum width of crossing the transverse groove are obtained. This study provides a further basis for the design of a crawling robot.关键词：Hexapod;Crawl robot;System of composition;Analysis of obstacle ability
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发布时间：2022-10-03 - 摘要：In order to improve diagnosis accuracy of gear，a fault diagnosis method of gear based on variational modal decomposition （VMD） and symbol entropy （SE） is proposed. Firstly， the gear vibration signals is decomposed into several intrinsic mode Function （IMF） which with different frequency components. Secondly，SE values of each IMF are calculated as fault feature vectors that could represent the operating conditions of gear. Finally，the fault feature is put into SVM to identify different faults. Experiment results of gear show that the proposed method has certain superiority.关键词：Variational modal decomposition;Symbol entropy;Support vector machine;Fault diagnosis;Gear
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发布时间：2022-10-03 - 摘要：The hirth coupling is widely used in the centrifugal air compressor unit due to its characteristic of high torque capacity，self centering and so on. A feasible method for the measuring of pitch plane is illustrated and the offline detection for the accuracy of hirth coupling is carried out by using gear tester， some reference for the measurement of relevant parts and the offline detection are provided.关键词：Hirth;Pitch plane;Offline detection
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发布时间：2022-10-03
Development·Application
- 摘要：The development course of gear manufacturing technology is reviewed， the characteristics of three generation manufacturing technology are compared， the advancement of ‘no stress concentration’ anti-fatigue manufacturing is interpreted. The development situation， advanced technology and its mechanical property of three kinds of gear surface hardening precision heat treatment as key basic technology are discussed including carburization， nitriding and induction quenching. By optimizing and controlling the hardness gradient， residual stress field， micro structure and distortion of surface metamorphic layer， the innovation and development of gear precision heat treatment， the gear anti-fatigue performance is greatly improved， and then solve the three major problems of gears such as heavyweight， short life and low reliability. The development trend of gear anti-fatigue precision heat treatment is predicted to be ‘super hardening’， deep case hardening’， ‘combined hardening’， and ‘vacuum ion heat treatment’.关键词：Gear precision heat treatment;Anti-fatigue manufacturing;Case hardening;Gear fatigue strength
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发布时间：2022-10-03
Review
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