最新刊期
期 6 ， 2019
- 摘要：In order to solve the interference between the rigid wheel and the flexible wheel tooth profile caused by the theoretical value of the cam radial deformation is inconsistent with the reality in the harmonic drive， taking the double arc harmonic gear without common tangent as research object, based on the improved kinematics method，the harmonic gear finite element model is established in ABAQUS. The maximum radial displacement of the long and short axes of the flexible wheel is extracted. Combined with the principle of double arc profile modification，the simulation analysis is carried out by MATLAB to study the influence of different cam radial deformation on the modification of the flexible wheel. The results show that with the increase of the radial deformation of the cam， the amount of tooth modification of the front end of the flexible wheel increases sharply，and the amount of tooth modification of the rear wheel teeth decreases slowly. When the radial deformation of the cam is about 0.49 mm， no interference engagement under no-load can be achieved after the modification. The finite element method further improves the principle of harmonic drive tooth profile modification.关键词：Harmonic drive;Radial deformation;Double arc tooth profile;Tooth profile modification;Finite element method
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发布时间：2022-10-01 - 摘要：The cylindrical gear with arcuate tooth trace is regarded as the research object. Based on the processing principle of parallel link mechanism，the gear tooth surface equation is derived，and the 3D model of gear is established，and the dynamics analysis model of gear pair is further established. Through the dynamics analysis simulation，the influence of tooth line radius， tooth width，load and speed on the meshing characteristics is analyzed. The results show that, the maximum meshing force， average meshing force and RMS of meshing force all decrease first and then increase with the increase of the tooth width. The maximum meshing force，average meshing force and RMS of meshing force all decrease first and then increase with the increase of tooth line radius，it’s optimum at RT=120~240 mm，the fluctuation range of average meshing force and RMS of meshing force is small，while that of maximum meshing force is large. The meshing force increases gradually with the increase of load，but the positive/negative fluctuation amplitude decreases with the increase of load. The transmission stability is poor at low loads，and even the gear transmission appears to be out of mesh. With the increase of rotating speed，the average meshing force and maximum meshing force increase，while the minimum meshing force decreases， that is， the more severe the fluctuation of gear meshing force，the greater the impact of gear transmission.关键词：Cylindrical gear with arcuate tooth trace;Meshing characteristic;Tooth width;Tooth line radius;Speed and load
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发布时间：2022-10-01 - 摘要：At present, there are few in-depth analysis and detailed data on undercut of cylindrical helical circular arc gears, which affect people's accurate, specific and profound understanding of this undercut and the extensive application of the existing theories. For cylindrical helical circular arc gears, the undercut boundary equation and no undercut condition are derived， and the undercut probability as well as determination of point most easy to be undercut at tooth profile and minimum number of teeth to avoid undercut are studied in detail. When applied to the pure rolling circular arc gear and W-N circular arc gear, above results are verified and extended, and new conclusions and undercut calculation data that gear workers want to know are obtained. This study provides a theoretical basis for the non-undercut design of various mechanical parts with cylindrical circular arc teeth.关键词：Undercut and meshing interference;Undercut possibility;Minimum number of teeth without undercut;Pure rolling circular arc gear;W-N circular arc gear
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发布时间：2022-10-01
Theory·Research
- 摘要：The energy management strategy (EMS) and the powertrain parameter of hybrid electric vehicles are highly coupled. In the process of hybrid electric vehicle optimization, there is a continuous cycle, which makes it difficult to achieve parameter optimization and find the optimal solution. Aiming at this problem, a multi-parameter decouped optimization method is proposed, which adopts hybrid optimization strategy, taking the dynamic targets as constraint conditions and using particle swarm optimization algorithm to optimize powertrain parameter, the Particle swarm optimization (PSO) is used to optimize the energy management strategy and shifting strategy under different parameters. Aiming at a parallel hybrid vehicle, a forward model that includes a fuzzy PID driver is established by using Matlab/Simulink to self-adapt to the changing powertrain configurations. The results show that the hybrid optimization methodology is able to squeeze the potential of the vehicle, compared with the optimization method that simultaneously optimizes the logic gate threshold, the economy performance is enhanced by 4.55% and simultaneously, the energy management strategy and shifting strategy for the HEV under these parameters are obtained.关键词：Decoupled optimization;Logic gate energy management strategy;Powertrain parameter optimization;Particle swarm optimization;Fuzzy PID driver
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发布时间：2022-10-01 - 摘要：Based on the viscoelasticity of rubber bearing material, an infinite line contact bearing lubrication model with transient effects is established. Based on three-parameter solid creep model and coupled vibration load, the elastohydrodynamic lubrication analysis of rubber bearings is carried out. The maximum pressure and minimum film thickness of the rubber bearing lubricant film under three load vibration situations are calculated and analyzed, compared with the case that the creep effect is not considered. The changes of lubrication film pressure and film thickness of rubber bearing under the same load and different time are discussed. The multigrid method is adopted to solve the pressure, Newton iteration is adopted to solve the bottom layer and multigrid integral method is adopted to solve the elastic deformation in order to improve the convergence accuracy. The results show that when the viscoelasticity of the rubber bearing is taken into account, the pressure of the lubricant film vibrates in the same form as the load vibration. The pressure will reach a larger value at the beginning of the creep and the whole pressure profile declines to stability with the running time increases. The thickness of the lubricant film vibrates in the opposite form with the load vibration. The film thickness will take a smaller value at the beginning, the overall increases and tends to be stable with the running time increases. The supporting region becomes larger over time under the same load, the pressure profile of the lubricant film decreases and the film thickness becomes thicker.关键词：Rubber bearing;Viscoelasticity;Vibration load;Transient;Couple;Creep
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发布时间：2022-10-01 - 摘要：The principal directions and corresponding curvatures at grinding point on face gear tooth surface are derived according to meshing theory and differential geometry theory. Based on instantaneous elliptic contact theory and grinding heat theory, the theoretical formula of grinding temperature field of face gear is established. The finite element model of grinding temperature field of face gear is established based on ANASY, and the finite element simulation of grinding temperature field is completed. The experiment of grinding temperature field is designed and the correctness of finite element method is verified. Based on orthogonal experiment, the influence of grinding process parameters on tooth surface temperature distribution is studied.关键词：Face gear;Grinding;Temperature field;Finite element analysis
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发布时间：2022-10-01 - 摘要：To improve the absolute positional accuracy of the serial six-DOF robot， the joint stiffness error of industrial robots after geometric parameter error compensation is studied. Firstly，the one-dimensional joint stiffness error model of industrial robots is established based on the virtual joint model. Secondly，in order to improve the identification accuracy and efficiency of joint stiffness parameters, the BP neural network is applied to fit the stiffness error model to optimize the initial population fitness of genetic algorithm. Finally，the laser tracker AT930 and ER10L-C10 robot are used to verify the above error model and joint stiffness parameter identification algorithm. The experimental results show that the average distance error and maximum distance error of the robot are 0.248 5 mm and 0.333 2 mm respectively after the joint stiffness error compensation. Compared with the distance error before error compensation，the positional accuracy of robot is improved by 33.7%. Therefore，through the proposed improved genetic algorithm can identify the joint stiffness parameters accurately and improve the positional accuracy effectively.关键词：Industrial robot;Parameter calibration;Joint stiffness;Error compensation;Genetic algorithm
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发布时间：2022-10-01
Theory·Reserach
- 摘要：Aiming at the problem of low transmission torque caused by the magnetic flux leakage phenomenon of the traditional magnetic gear permanent magnet，a coaxial magnetic gear model with double modulation structure is established based on the relative permeability derivation analysis of the permanent magnet air gap. The finite element method is used to simulate the model. The role of auxiliary flux modulation is analyzed and the flux density and transmission torque are calculated. The magnetic flux density and transmission torque of the conventional magnetic gear are compared. The simulation results show that the coaxial magnetic gear with double modulation structure can effectively enhance the air gap flux density，and reduce the magnetic flux leakage and increase the transmission torque. This double-modulated magnetic gear structure is of great significance for the research and application of the improvement of the torque density of the coaxial magnetic gear.关键词：Finite element analysis;Torque transmission;Magnetic gear;Magnetic flux leakage
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发布时间：2022-10-01 - 摘要：In order to study the influence of the tooth contact flash temperature on the dynamics in the gear system，the tooth contact flash temperature （TCFT） distribution along the line of action of driving gear and driven gear is calculated based on the H.Blok flash temperature theory. The influence of parameters such as speed，load，contact ratio and center distance variation coefficient on TCFT are analyzed. According to Hertz contact theory，the formulas of TCFT and the meshing stiffness，the backlash and the tooth profile error are deduced. A nonlinear dynamics model of a single-stage spur gear system is established when the nonlinear factors such as TCFT，the backlash，the time-varying meshing stiffness and the transmission error are considered. The influences of TCFT on the bifurcation，the tooth surface impact，the take off the meshing and dynamic load coefficient are analyzed by CPNF（Continuous-Poincaré-Newton-Floquet） numerical method in the two-parameter plane pseudo-color mappings. The calculated results show that the load and rotate speed have great influence on TCFT and it reaches the extreme value in entering and exiting the meshing region，therefore，the tooth surface gluing is more likely to happened in here. And，the nonlinear dynamics characteristic of the system are degraded by TCFT. So， TCFT should be controlled.关键词：Nonlinear dynamics;Tooth contact flash temperature;Spur gear pair;Modeling;Parameter coupling
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发布时间：2022-10-01 - 摘要：Based on the theory of metamorphic，a novel parallel metamorphic mechanism of 2-PrRS-PR（P）S mechanism is proposed which the revolute pair of two limbs can change its rotation axis to achieve the metamorphic configuration. Firstly，the DOF of working configurations are analyzed by using the screw theory. Secondly，according the characteristic of the mechanism，the kinematics model of the parasitic motion is established and the relationship between the parasitic motions and the parameters of the mechanism in different configurations are obtained. Finally, the diagram of the parasitic motion in different configurations is analyzed by simulation software Matlab. The results show that the parasitic motion of the proposed mechanism has different directions in different configurations. The magnitude of the parasitic motion has symmetry with the change of the structure parameters. The analysis of the parasitic motion provides theoretical basis for optimization design and error analysis of the mechanism.关键词：Parallel mechanism;Metamorphic mechanism;DOF analysis;Parasitic motion
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发布时间：2022-10-01 - 摘要：The modified gear involute equation under Cartesian coordinates system is established and the theory foundation is provided for parameterization modeling of modified gear. The character of drop arm thickened-tooth segment of steering gear is analyzed. The modified gear involute parameterization equation is established based on the CATIA and the method of parameterization three-dimensional modeling of the thickened tooth segment is detailed. Then the space analysis and motion simulation are implemented for the Digital Mock-Up of steering gear. This method is high modeling accuracy, it is very convenient and the accurate thickened-tooth segment models can be obtained quickly by changing the relevant parameters, which provide the basis for digital assembly and NC machining.关键词：Thickened-tooth segment;Modefied gear;CATIA;Parameterization modeling
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发布时间：2022-10-01 - 摘要：In order to improve the control precision of the omnidirectional mobile manipulator, its kinematics model and dynamics model are established. Firstly，the kinematics model of the omnidirectional mobile platform is established according to the characteristics of the Mecanum wheel. The kinematics equation of the 5-DOF manipulator is derived according to the DH rule， and the unified kinematics equation is derived by combining the basis coordinate of manipulator with the centroid of mobile platform. Then，based on the kinematics model，by using the second type of Lagrangian equation，considering the coupling relationship between the mobile platform and the manipulator，considering the energy dissipation problem，the unified dynamics model of the omnidirectional mobile manipulator is established. Finally，the experimental prototype is built according to the design，and two different torque indirect measurement methods are used. The real-time torque is measured in different motion modes of the prototype，and compared with the calculated torque value calculated by the dynamics equation. The result shows that the built dynamics model is correct and reliable，which provides a theoretical basis for future motion control.关键词：Mecanum wheel;Mobile manipulator;Lagrange equation;Torque measurement
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发布时间：2022-10-01 - 摘要：The rubber track wheel generally transmits power by the engagement of the driving teeth of the rubber track and the driving pin of the driving wheel. The driving teeth are likely to be destroyed when they are subjected to excessive load or load impact. The mathematical model and calculation analysis for the driving tooth stress distribution are carried out. Firstly，based on structure parameters and transmission principle，the drive tooth profile equation is established and determining mapping parameters by the improved Powell algorithm. The optimization results show that the accuracy of the mapping tooth profile obtained by this method is 0.12%，which effectively improves the mapping accuracy. Secondly，based on the complex function method， the mathematical model for stress and deformation is established，and the stress distribution laws under different meshing positions are analyzed. Finally，the calculation conditions are set as boundary conditions，and the analysis results are verified by using Abaqus software. The simulation results show that the maximum error between the simulation data and the calculation data is about 11.76%，so the mathematical model can be applied to the analysis of the driving tooth stress. This calculation results can provide theoretical basis for structural optimization of driving teeth and improvement of local rubber materials.关键词：Rubber track wheel;Stress analysis;Complex function;Optimization algorithm
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发布时间：2022-10-01 - 摘要：Aiming at the requirements of high machining accuracy and high production efficiency for large workpieces such as aircraft wings in the field of aviation manufacturing. Firstly, the degree of freedom of 6-SPU parallel robot is analyzed by using screw theory, and the trajectory planning of moving platform of the 6-SPU parallel mechanism is analyzed and studied based on the inverse kinematics method and three element space vector according to the Frenet-Serret, the movement platform corresponding position and gesture in the processing process is got. Then, the homogeneous coordinate transformation matrix and the inverse solution calculation formula are used to further determine the movement rules exerted on the end actuator when it is moving on the desired trajectory. Finally, the virtual model of this mechanism is created in SolidWorks software and the planning trajectory is verified through simulation in Simulink simulation module in MATLAB modeling simulation, and the theoretical foundation for the engineering design of mobile parallel processing platform is provided.关键词：Parallel robot;Inverse kinematics;Trajectory planning;Virtual prototype technology
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发布时间：2022-10-01 - 摘要：The driving performance of low-noise and high-strength spiral bevel gears（include spiral bevel gear and cycloid bevel gear） is required to be improved by advanced equipment. Through tooth surface topology design to improve the stiffness and bearing capacity，reduce vibration noise and the sensitivity of installation error is a research hotspot at present. The development of spiral bevel gear tooth surface topology design is briefly introduced，the basic principle of the latest tooth surface design is discussed，and the characteristics are analyzed. The reference is provided for the tooth surface design of high performance spiral bevel gears.关键词：Spiral bevel gears;Tooth surface design;Tooth surface modification;Mismatch;Conjugation
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发布时间：2022-10-01 - 摘要：Wind tunnel test is an important part of the development of the aircraft, and the aircraft position and attitude adjustment mechanism is an indispensable part of the test. An adjusting mechanism capable of achieving multi-path angle coupling output is proposed. Firstly, the implementation principle of the mechanism is introduced. The kinematics equation derivation is performed. Combine with Matlab and set the aircraft under two kinds of motion conditions, the drive the displacement and velocity of mechanism are solved, and the spatial motion trajectory of the aircraft is calculated. On this basis, the drive extreme displacement is set. The boundary mapping method is used to analyze the workspace of the mechanism. The results show that the mechanism has a large workspace and could complete the adjustment of a wide range of aircraft path angles within the set of two extreme displacement. As a wind tunnel test adjustment mechanism has application prospects.关键词：Wind tunnel test;Parallel mechanism;Path angle;Workspace
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发布时间：2022-10-01 - 摘要：Current researches on load sharing characteristic concentrate on fluctuation of load sharing under the condition of single factor changing， which results in a poor comprehension on the load sharing behavior under the condition of multi-factors changing together，that’s to say， it’s difficult to find the most essential excitation among multi-factors affecting load sharing behavior，to improve the load sharing characteristic efficiently. To solve this problem，a multiple-factor analysis model is built and incorporated with “translational-rotaional” dynamic model of compound planetary gear set to give load sharing coefficient under different confugurations. By using single to noise analysis， and the contribution of each control parameter on load sharing behavior is quantified. The results indicate that， the impact of internal excitations on load sharing behavior is much bigger than that of external excitations， increasing bearing clearance contributes to load sharing behavior， and decreasing the transmission error of central parts is the most efficient way to improve load sharing behavior.关键词：Compound planetary gear set;Multiple-factor analysis model;High efficiency to improve load sharing performance;Orthogonal test
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发布时间：2022-10-01
Design· Calculation
- 摘要：Aiming at the problem of vibration reduction and noise reduction of bevel gear transmission system，a method for solving the vibration of bevel gear by using an integral squeeze film damper（ISFD） is proposed. An experiment bench of bevel gear transmission system is built，and a comparative study is conducted on the vibration characteristics of the bevel gear transmission system with rigid support and ISFD elastic damping support. The experimental results show that the ISFD elastic damping support can reduce vibration significantly in a wide frequency range with excellent damping performance，and the reduction of vibration acceleration of the bearing block is up to 40%. Comparing the vibrations of bevel gear transmission system at different speeds，it is verified that the ISFD elastic damping support has a great effect on vibration reduction over a wide speed range.关键词：Integral squeeze film damper（ISFD）;Elastic damping support;Bevel gear transmission;Vibration;Vibration reduction
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发布时间：2022-10-01 - 摘要：The constant-depth tooth hypoid gear is one of the important parts of the main reducer. The distortion of consistency directly affects the consistency of the gear contact area. In order to facilitate the control of the consistency of the heat treatment distortion of the constant-depth tooth，the gear heat treatment distortion under different furnace loading methods is studied. The study shows that the distortion of the main teeth at the edge position is slightly larger than the center； the deformation of the main bottom layer is significantly lower than that of the upper and middle layers； the deformation consistency of the sparse charging gear is significantly lower than that of the intensive loading furnace. At the same time, the tooth mounted charge frame is improved, the basis for the optimization of heat treatment fixture and improve the gear heat treatment distortion consistency is provided, some suggestions on improving the heat treatment distortion consistency of the gear are put forward.关键词：Constant-depth tooth hypoid gear;Heat treatment;Distortion of consistency;Furnace loading method
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发布时间：2022-10-01 - 摘要：Based on the actual structure and work conditions of wet multi-disc clutch, a finite element analysis model of wet clutch is established by using Abaqus. The temperature field of friction pairs in wet clutch is analyzed by the direct thermal structure coupling method，and the influence of the applied load way of piston in wet clutch on the temperature field of friction pairs is studied. The results show that the applied load way has an important effect on the temperature field of separator plate，and the most obvious effect is on the separator plate which is directly affected by the piston. The maximum temperature under partial load way is higher than that under uniform load way and the maximum temperature under partial load way appears earlier. The bandwidth of high temperature on separator plate is narrower and the radial temperature gradient is larger which under partial load way.关键词：Wet clutch;Temperature field;Applied load way;Thermal structure coupling
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发布时间：2022-10-01 - 摘要：The push-back system is the main component of the well diameter measuring instrument to achieve the diameter measurement of the wellbore, the motion and dynamic characteristics are closely related to the accuracy of the logging data. In order to further improve the transmission performance of the push-back system，the closed vector polygon projection method and the matrix method are used to analyze the motion characteristics of the push-back system to open and measure the two motion states. Based on the kinematics analysis of the six-arm caliper logging tool push-back system，the dynamic statics method is used to analyze the dynamic characteristics of the two movements of the push-back system. Based on the example simulation of Adams software， the regularity curves of the displacement， velocity and acceleration of the components of the push-back system are changed with time，and the force of each component is analyzed. The motion law of the system is analyzed and verified. The theoretical design of the optimal design of the arm caliper logging tool push-back system provides a theoretical reference.关键词：Caliper logging tool;Push-back system;Matrix method;Dynamic statics method;Simulation
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发布时间：2022-10-01 - 摘要：Aiming at two different kinds of power coupling devices with dual planetary gear sets， the equivalent lever is established to analyze the power split characteristics and the transmission efficiency of the devices. At the same time， the common operation modes of hybrid systems with these power coupling devices are divided. On this basis, the power component model of the engine，motors and the battery are also established. By introducing dynamic programming algorithm, taking the battery SOC as state variable and engine torque and speed as control variable, the fuel consumption of the vehicle is set as the objective function for global optimization. Simulation results show that, under NEDC driving cycle, the compound-split power coupling device has superior fuel economy to the input-split power coupling device.关键词：Dual planetary gear set;Hybrid electric vehicle;Dynamic programming;Fuel economy
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发布时间：2022-10-01 - 摘要：The dynamics factors affecting the intermittent motion of the transmission chain system are analyzed. The dynamics modeling method of the transmission chain system is discussed. The dynamics equation of the transmission chain system is established, and then the equation is solved by the modal superposition method. In order to verify the accuracy of modeling, taking the die-cutting machine intermittent transmission chain system as an example，a dynamics experimental device is established to test and analyze the dynamic characteristics of chain intermittent motion. The experimental results show that the modeling method has higher precision. It provides a basis for in-depth study of the characteristics of the intermittent transmission chain system.关键词：Transmission chain;Intermittent motion;Dynamics modeling;Experimental research
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发布时间：2022-10-01 - 摘要：The escapement mechanism is the most important element of a mechanical watch movement with a complicated motion， though little is known about it. A dynamics Finite Element model of escapement mechanism is established，and based on the real micrograin structure of the key elastic element in the mechanism, the elastic properties of the hairspring are quantitatively calculated. The model is able to predicts the stress state of the parts of escapement speed regulating mechanism during the working process, which is consistent with ROLLAND simulation results. At the same time, the influence of the pendulum oscillation amplitude on the instantaneous daily rate is predicted and compared with the experimental data, it has good precision to some extent, the simulation results are in line with Airy Theorem. This model could be used to provide useful support in order to optimize the structure of the domestic mechanical watch movement in the future.关键词：Escapement mechanism;Mechanical watch movement;Grain structure;Dynamics analysis;Finite element method
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发布时间：2022-10-01
Test·Analysis
- 摘要：In order to reduce the picking technical difficulty and cost of fruit，a mechanical device used for picking high-branch fruits is designed and developed，which based on frequency control of vibration. Based on mechanical analysis and theoretic calculation，the design scheme of main transmission is determined by bevel gear and crank slider mechanism，and then fruits picking is realized through converting output torque of DC motor into reciprocating vibration of the branches. The vibration process of the branches is simulated by linear spring，and an equivalent mechanical model based on rigid-flexible coupling is designed and created. After that，the rationality and reliability of the prototype are verified by kinematics and dynamics simulation. Picking experiment of the physical prototype shows that，the device has good practicability and fruit picking efficiency. The results provide an important technical reference for innovative design and practical application of the fruits picking machinery.关键词：Picking;Oscillation frequency;Elastic coefficient;Rigid-flexible coupling;Mechanical model;Experiment
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发布时间：2022-10-01 - 摘要：In the fault diagnosis of complex gearbox system under the rotation frequency fluctuation，the orders of meshing frequency interfere with one another，so it is difficult to estimate gear meshing frequency. For this problem，a tacho-less order tracking technique combining with time-varying filter and continuous wavelet transform（CWT） is proposed. Time varying filter is set based on short-time Fourier transform（STFT）. The smooth instantaneous frequency estimation（IFE） is obtained based on time-varying filter and CWT. The phase of the reference shaft is calculated with Vold-Kalman filter（VKF）. The order spectrum obtained by the proposed method is basically consistent of the computed order tracking（COT）. Lastly，the position of fault gear can be accurately judged by Fast-kurtogram algorithm. The results of simulation and experiment show that the proposed method can provide a new effective method for mechanical fault diagnosis under the condition of strong noise and apparent speed variation.关键词：Time-varying filter;Short-time Fourier transform;Continuous wavelet transform;Vold-Kalman filter;Fast kurtogram
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发布时间：2022-10-01 - 摘要：In order to improve the assembly yield of RV reducer， combined with its assembly dimension chain design parts tolerance，the use of CATIA is for three-dimensional modeling of RV reducer. Combined with 3D tolerance analysis software 3DCS， the relative dimension tolerance and geometric tolerance are added to the parts，eccentricity and clearance of measurement parameters are set，and 3DCS tolerance simulation model is established to simulate the actual static assembly process, tolerance optimization and sensitivity analysis of parts are carried out. After optimization， the backlash is 0.25'~1'， which meets the requirement of backlash. The clearance between the cycloidal wheel and the pin gear is greater than or equal to 0.001 mm，and the sensitivity analysis result has certain reference value for the tolerance design of the RV reducer.关键词：RV reducer;Tolerance optimization;3DCS;Sensitivity analysis
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发布时间：2022-10-01 - 摘要：The hot-fit-tooth process of helical gear countershaft is a new process developed by our company for the new platform product in recent years. By means of theoretical analysis and experimental verification, the determination of hot-fit temperature, the influence of heating on the metallographic structure and tooth profile and helical line of gear, the design principle of gear fixture, and the quantitative analysis of various influencing factors in the process of hot-fit on teeth are studied. Finally, the reasonable temperature range is determined，the mass production of the product is realized by design the non-standard fixture. The process is precise and controllable. There is no damage to the shaft and gears. The position error is small，the noise and damage to the shaft during the traditional countershaft cold press are avoided，which has great promotion significance.关键词：Hot-fit-tooth;Helical gear;Countershaft
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发布时间：2022-10-01 - 摘要：In order to meet the requirements of multiple terrain environments，a new reconfigurable multi-mode mobile robot with walking，deformation and rolling ability is proposed，which can change different motion modes according to terrain and improve the adaptability to unstructured terrain. The singularity of the robot in each motion mode is found out by using screw theory，and the feasibility in each motion mode is analyzed. Simulation experiments in the multiple feature terrain are carried out with ADAMS software. The simulation results demonstrate the advantages in gait，stability and multiple environment adaptability. Finally the feasibility of various motion modes is also verified by the prototype experiments.关键词：Mobile robot with multiple-mode;Reconfigurable;Singularity;Gait analysis
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发布时间：2022-10-01 - 摘要：In the process of data-driven rolling bearing state identification model construction，the improper selection of the radial width parameter σ of the Gaussian kernel function in the Kernel Extreme Learning Machine（KELM）algorithm is very easy to cause poor classification accuracy. A method for identifying the state of rolling bearings based on the kernel arrangement preferred kernel parameter σ is proposed. Firstly，the rolling bearing vibration signal is decomposed by Ensemble Local Mean Decomposition（ELMD）and its energy entropy and permutation entropy are calculated to construct a high-dimensional eigenvector set. Then，the Kernel Target Alignment（KTA） parameters of maximum KTA value Ai and the kernel parameter σi are initialized, and the different kernel parameter values are adjusted by judging the distance between the kernel matrix and the ideal target matrix，so as to obtain the minimum corresponding maximum kernel arrangement value when the kernel matrix distance is obtained，and the kernel parameter at this time is optimal. Finally，the high-dimensional feature vector set of the above rolling bearing is used as input to learn the KTA-KELM algorithm, the state recognition model of rolling bearing is built based on KTA-KELM algorithm. The simulation results show that compared with KELM and ELM，the KTA-KELM algorithm improves the accuracy of rolling bearing state recognition from 92.5% and 90% to 98.75%， which is increase 6.25% and 8.75%.关键词：Rolling bearing;Kernel parameter optimization;State identification;Classification precision
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发布时间：2022-10-01
Development·Application
- 摘要：Industrial robot is an outstanding representative of modern new industry, a concentrated expression of advanced productivity, and also a new engine for China to enter the new normal economy and take off the economy. The technological development process of industrial robots is summarized，the current status of industrial sales at home and abroad are summarized and surveyed in detail, and the encouraging situation of the increasing sales ratio of our robot in the world is mainly introduced. The future development is looked forward, and the problem of technical support and industrial expansion of Chinese products are summarized. In the light of the new era's policies at home and abroad and the environment of production and research, some suggestions are put forward.关键词：Industrial robot;Sales;Industrial expansion;Suggestion
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发布时间：2022-10-01
Review
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