最新刊期

    3 2021
    本期电子书

      Theory·Reserach

    • Zhongshuang Wang,Jiuzheng Yin
      Vol. 45, Issue 3, Pages: 1-7(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.001
      摘要:For the dynamics modeling, simulation and analysis of a triangular connecting rod toggle press mechanism with considering the kinematic pair clearance, the corresponding vector bond graph procedure is proposed. Based on the kinematic pair clearance model of massless-link/spring damper, the vector bond graph model of a triangular connecting rod toggle press mechanism with kinematic pair clearance is built. By the corresponding method, all the energy storage elements of the mechanism vector bond graph possessed integral causality. Based on these, the computer modeling and dynamics simulation of a triangular connecting rod toggle press mechanism with kinematic pair clearance is realized by Matlab, the influences of kinematic pair clearance on the press mechanism kinematics and dynamics performance are analyzed, and the reliability and validity of the procedure proposed are illustrated.  
      关键词:Vector bond graph;Kinematic pair clearance;Triangular connecting rod toggle press;Dynamics analysis;Integral causality   
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      发布时间:2022-11-10
    • Runlin Chen,Qin Han,Menghao Zhang,Yanchao Zhang,Longlong Li,Yahui Cui
      Vol. 45, Issue 3, Pages: 8-14(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.002
      摘要:In order to research the influence of the time-varying stiffness of rolling bearings on the precision of spindle rotation of machine tools, a time-varying stiffness model of rolling bearings are established by considering the radial clearance. And the average stiffness and stiffness amplitude change rate are proposed to characterize the time-varying characteristics of stiffness. Taking deep groove ball bearings as an example, the influences of different radial clearances, loads, and numbers of bearing rolling elements on the time-varying stiffness of rolling bearings are analyzed. The results show that the average stiffness of the bearing is negatively related to the radial clearance and positively related to the load and the number of rolling elements; the stiffness amplitude change rate generally increases with the increase of the radial clearance, and decreases with the increase of the load and the number of rolling elements. But when the number of equivalent bearing rolling elements is an integer, the time-varying characteristics of rolling bearing stiffness are the most significant. In order to reduce the time-varying characteristics of bearing stiffness, a reasonable clearance and number of rolling elements should be selected according to the working conditions such as load and speed.  
      关键词:Rolling bearing;Stiffness model;Time-varying characteristic;Clearance   
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      发布时间:2022-11-10
    • Xuetao Qiao,Ke Jia,Chunshan Chen,Changlu Wang,Leyu Wei,Liyong Zhang,Weigong Wang
      Vol. 45, Issue 3, Pages: 15-18(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.003
      摘要:Transmission accuracy and dynamic stability of industrial robots precision reducer depend on the meshing performance of cycloid pin gear to a great extent. Therefore, 3D parametric modeling and transient dynamics analysis are carried out on the meshing transmission part of cycloid pin gear in the second stage of the precision reducer through the digital design and dynamics analysis platform combined with Creo and ANSYS Workbench, the model of precise reducer parameter and the stress and strain nephogram of cycloid pin gear tooth surface during dynamic meshing of cycloid needle wheel can be obtained quickly and accurately, thus the contact stress distribution law of cycloid and pin wheel in meshing process is obtained. The theoretical calculation results of Hertz contact theory are compared with the above simulation results, the correctness of the model is verified, which provides the necessary theoretical basis for the cycloid gear tooth profile optimization and modification.  
      关键词:Robot reducer;ANSYS Workbench;Transient dynamics;Stress and strain   
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      发布时间:2022-11-10
    • Linna Zhao,Long Wang,Jin Fang,Deyong Li,Kai Wang,Haiyue Li,Huanbin Xu,Guangqiang Xing,Yue Zhang,Ning Wang
      Vol. 45, Issue 3, Pages: 19-24(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.004
      摘要:Transmission error of harmonic reducer is coupled by eccentric vectors such as geometric eccentricity and motion eccentricity during parts machining and assembly, and has frequency domain characteristics. The probability of transmission error distribution caused by various single factors conforms to Rayleigh distribution. The multi-factor coupling model of transmission error based on Rayleigh distribution is established through spatial kinematics and harmonic engagement principle, and a prediction model of transmission error of harmonic reducer with confidence interval up to 99% is completed. The weight coefficient of each transmission error source can be calculated by the prediction model. An inverse analysis method based on weight coefficient of error source to re-optimize allocation of transmission error from control of machining and manufacturing accuracy of parts is proposed, which can reduce the difficulty and cost of machining and manufacturing to the greatest extent while meeting the design index of transmission error and has important engineering application value. Finally, the reverse theoretical analysis and experimental verification comparison of transmission accuracy of 40 type harmonic gear reducer are carried out. The measured results agree with the theoretical calculation values.  
      关键词:Harmonic reducer;Transmission accuracy;Probability model;Inverse analysis   
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      发布时间:2022-11-10
    • Changqing Du,Huan Zhang,Xiliang Cao,Huawu Wang
      Vol. 45, Issue 3, Pages: 25-34(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.005
      摘要:The engagement process control quality of the clutch after AMT shift has a great influence on the impact of the system. For the engagement process of the P2 single-shaft parallel hybrid vehicle clutch, the two control targets of the clutch is engaged as soon as possible during the clutch engagement phase and the impact is as small as possible, the dynamics process of the clutch engagement phase in different driving modes is analyzed, a clutch engagement control strategy based on model predictive control is designed, an Amesim-Simulink joint simulation model is built to simulate and analyze the control strategy. The effect of predictive control is compared with the fuzzy PID control. The results show that the model predictive control method will slightly increase the clutch engagement time within an acceptable range, and the slip wear and impact will be reduced to varying degrees, of which the reduction in impact is particularly obviously, the degree of impact is reduced by 43% when the engine is driven alone, and by 35% when the drive is hybrid.  
      关键词:Hybrid vehicle;Model predictive control;Clutch engagement   
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      发布时间:2022-11-10
    • Zheng Zou,Rupeng Cao,Qing Qu,Zhezhan Tang,Kangqu Zhou,Wei Chen
      Vol. 45, Issue 3, Pages: 35-39(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.006
      摘要:In order to determine the assembly quality of a certain type of gearbox, the common assembly faults of gearbox are briefly introduced based on the internal structure of gearbox, the characteristics frequencies of common faults of each gear and bearing in each gear position of gearbox are theoretically analyzed, an acoustic signal acquisition experimental platform is built and used to collect the acoustic signals of targeted gearbox in different gears. The collected signals are further processed through using the wavelet threshold de-noising method and then decomposed by using the wavelet analysis. Through spectral analysis of the corresponding frequency band signals and combining the results of theoretical analysis and experimental analysis, the assembly fault characteristics of the gearbox are obtained, which provides a basis for checking the assembly quality of the gearbox. This research has a certain reference significance for gearbox assembly quality detection.  
      关键词:Gearbox;Assembly quality;Fault diagnosis;Wavelet analysis   
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      发布时间:2022-11-10
    • Dengfeng Jia,Xiaojin Wan
      Vol. 45, Issue 3, Pages: 40-45(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.007
      摘要:For the improvement of off-road vehicle seat stiffness, a scheme of using parallel mechanism as the main structure of the seat suspension is proposed. The coupling between chains and the natural frequency are studied to ensure that the suspension mechanism has high precision and high stiffness. Firstly, generalized mass and generalized stiffness matrices of the mechanism can be obtained by means of energy method, virtual work principle and disturbance theory. Secondly, elastic coupling and inertial coupling are two indexes defined based on the above two generalized matrices to measure the coupling degree of the parallel mechanism. Cholesky decomposition method is used to obtain the natural frequency of the mechanism. Then, in order to obtain the small elastic coupling, the inertial coupling and a large natural frequency, the natural frequency is used as the objective function to optimize the structural parameters of the suspension mechanism. Finally, the optimization results are comprehensively analyzed and the optimal structural parameters are obtained to improve the structure of the device.  
      关键词:Parallel suspension;Natural frequency;Inertial coupling and elastic coupling;Stiffness optimization   
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      发布时间:2022-11-10
    • Zihan Wang,Fuzhou Feng,Hua Cong,Jie Wang
      Vol. 45, Issue 3, Pages: 46-51(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.008
      摘要:For a certain type of tank planetary gearbox K3 planet row, in order to research the influence of the fault gear on the dynamic characteristic of planetary transmission system, by using Solid works, Adams and Ansys software, a rigid-flexible coupling dynamic model is established, as well as conducting joint simulation analysis. It is verified that the rigid-flexible coupling model has more obvious vibration response in the time and frequency domain than the pure rigid body model. By drawing the stress change curve of the dangerous node, the equivalent stress distribution cloud graph at the time of the maximum stress is obtained. The cause of gear spalling fault is clarified and fault operation is simulated. By comparing and analyzing the simulation signals of contact force and acceleration under normal conditions, the time and frequency response characteristics of gear spalling faults are obtained. The simulation results can provide basic basis and theoretical support for the research on the fault mechanism and fault diagnosis technology of the planetary gearbox.  
      关键词:Planetary gear transmission system;Rigid-flexible coupling model;Dynamics joint simulation;Fault characteristic response   
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      发布时间:2022-11-10
    • Xu Liu,Song Wang,Aihua Liu,Mingwei Hu
      Vol. 45, Issue 3, Pages: 52-56(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.009
      摘要:With the requirement of pose repeatability of robots, searching the optimal arrangement scheme of random motion accuracy of joints can make robot design more reasonable and reduce the development cost of robots. Firstly, based on the analysis of pose repeatability of robots, a mathematical model of pose repeatability is established. The model includes position repeatability and orientation repeatability of robots. Then, with the accuracy optimization evaluation function of maximization of joint motion error, the optimal synthesis of pose repeatability for collaborative robot KUKA iiwa 7 is performed. And the optimal arrangement scheme of random motion accuracy of joints can be obtained. Finally, the method is verified by carrying the pose repeatability test of KUKA iiwa 7, and the results of accuracy design by this method can make robot design more reasonable.  
      关键词:Collaborative robot;Pose repeatability;Optimal synthesis;Accuracy design   
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      发布时间:2022-11-10

      Design· Calculation

    • Ziqiang Sheng,Yuedong Wang,Xiaoning Bai,Shenxuan Wang
      Vol. 45, Issue 3, Pages: 57-63(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.010
      摘要:Considering that the modification parameters and performance parameters of gear are affected by various influencing factors during manufacturing and operation process, a robust modification design method for EMU transmission gears based on improved tolerance model and fuzzy theory is proposed. The controllable and uncontrollable factors in gear robust modification are firstly determined, and then the sample points are obtained by combining orthogonal experimental design and Romax motion simulation. The polynomial response surface model is used to fit the response surface function of peak-to-peak value of transmission error. On this basis, the fuzzy theory is introduced, the mathematical model of gear modification robust optimization is established based on improved tolerance model, the NSGA-III algorithm is used to find the optimal solution, and the comparison with other modification schemes is completed. Finally, the simulation verification of each modification scheme is carried out. The results show that the robust modification result based on the improved tolerance model is better than the traditional tolerance model. Considering the influence of fuzzy factors in the design of gear robust modification based on the improved tolerance model, it is not only improves the offset load condition of the tooth surface, but also improves the robustness and rationality of the modification results.  
      关键词:Transmission gear;Robust modification;Tolerance model;Peak-to-peak value of transmission error;Fuzzy theory   
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      发布时间:2022-11-10
    • Zhiguang Ma,Kangkang Wang,Leile Zhang,Shaowei Jia,Can Chen
      Vol. 45, Issue 3, Pages: 64-68(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.011
      摘要:As the existing bionic humanoid manipulator has large inertia impaction, poor continuity and stability, a novel humanoid manipulator is presented. The humanoid arm can simulate the wrist joint, elbow joint and shoulder joint. The (2SPS/U)&(2SPS/RR) two-stage coupling parallel mechanism is used to drive each joint action In order to obtain its inverse and forward kinematics, the closed vector method and Newton iteration method are used to calculate the positive and negative kinematics solutions of the two-stage parallel mechanism, and then the mechanism configuration of the whole artificial arm is simplified. Based on the D-H method, the forward and inverse position solutions of the whole mechanism are given and validated.  
      关键词:Humanoid manipulator;Parallel mechanism;Kinematics   
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      发布时间:2022-11-10
    • Meng Zheng,Heng Li,Hangfei Ren,Hongyong Zhang,Junqiang Xue,Yongle Zhang,Wanying Yan
      Vol. 45, Issue 3, Pages: 69-74(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.012
      摘要:In view of the fact that the existing robotic mobile mechanisms on the market are driven more, the control is cumbersome, and the stability is poor, a synchronous movement steering mechanism for dodge robots with all-round rapid movement in the plane is studied. The driving motor and the steering motor cooperate to achieve all-round movement. In order to check the rationality of the establishment of the moving mechanism model, the Lagrangian equation is used to complete the dynamics analysis of the moving mechanism. The Adams software is used to complete the simulation of the virtual prototype of the mobile mechanism, and the relevant torque curves are obtained. Finally, the experimental test of the moving mechanism is completed. Through theoretical calculations, simulations, and experimental tests, the mutual verification between the three has further verified the accuracy of the establishment of the dodge robot mobile mechanism model.  
      关键词:Move fast;Mobile mechanism;Dynamics analysis;Adams   
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      发布时间:2022-11-10
    • Qi Zhu,Hua Long,Zhihong Zhou,Qichuang Zhang
      Vol. 45, Issue 3, Pages: 75-81(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.013
      摘要:Aiming at the problems of low calculation efficiency and conservative optimization design method of link in multi-arm mechanical arm system, taking the concrete pump truck as a typical engineering equipment component, the cylinder and link between the arm units are considered as one link group, the ANSYS APDL language is applied for the parametric modeling, and the optimization analysis is carried out under multiple working conditions, the optimal structure model of the link group is obtained. The feasibility of the calculation method is verified by the structural stress test. The results show that, the calculation efficiency of links is greatly improved with the methods of parametric modeling and optimal design, a feasible and effective method is provided for the design of links in the multi-arm manipulator system, and an important reference is provided for the design of components with similar structures.  
      关键词:Multi-arm mechanical arm system;Link group;ANSYS APDL;Parametric modeling;Optimal design   
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      发布时间:2022-11-10
    • Zenglin Ye,Liang'an Zhang,Hua Chen,Hao Wu
      Vol. 45, Issue 3, Pages: 82-89(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.014
      摘要:Based on the mechanism of leg joint rehabilitation, a 2URR-SRR-RUPUR four-degree-of-freedom parallel leg rehabilitation robot is proposed, which can realize the abduction and adduction of ankle joint, flexion and extension of knee joint, hip joint abduction and adduction movements and leg stretching movements. Based on the spiral theory, the constrained spiral system and the degree of freedom properties of the mechanism in the general configuration and the initial configuration are analyzed. The kinematics model of the 2URR-SRR-RUPUR parallel mechanism is established. The closed-loop vector method is used to solve the inverse kinematics of the mechanism and the velocity Jacobian matrix of the mechanism is analyzed. On this basis, the working space and singularity of the mechanism are studied, the workspace map and singularity configuration of the mechanism are obtained. The trajectory planning of the mechanism is based on the rehabilitation path of leg joints, and the planning results are analyzed by SolidWorks Motion software. The simulation results show that the movement of the mechanism is continuous and smooth, suitable for leg rehabilitation training and has good application potential.  
      关键词:Leg rehabilitation parallel mechanism;Degree of freedom;Spiral theory;Inverse kinematics;Singularity analysis;Motion simulation   
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      发布时间:2022-11-10
    • Ruigang Han
      Vol. 45, Issue 3, Pages: 90-94(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.015
      摘要:Aiming at the problem that the stability index r value of star-wheel climbing mechanism is large, which affects the operation stability, a kind of crank rocker climbing stair device is proposed. The influence of crank rocker mechanism rod length on trajectory is studied. The structure size of the crank rocker type climbing mechanism is designed while the r is reduced by 22%.The modeling of crank rocker type climbing stair device and the simulation of the process of climbing stairs are carried out by SolidWorks software, the motion trajectory diagram when the vehicle is unloaded and loaded is obtained, the feasibility of the scheme is determined. A prototype test is carried out to verify the stable operation of the device. The results show that the design idea of crank-rocker stair climbing device is correct, and it has reference significance for developing similar products.  
      关键词:Crank rocker mechanism;Climbing stair device;SolidWorks simulation;Prototyping testing   
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      发布时间:2022-11-10
    • Zhifang Zhu,Zhijie Zhang,Jiawei Pan,Zeping Zou,Bingliang Ye,Baoling Liu
      Vol. 45, Issue 3, Pages: 95-98(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.016
      摘要:Based on the comparison and analysis with the climbing mechanism of the existing electric wheelchair, the linear connecting rod climbing mechanism is proposed. The design research of linear connecting rod climb mechanism is carried out, the endpoint trajectory upper part as the semicircle, the approximate linear the lower part of the string, the trajectory and animal walking gait extremely similar, so use it as a climbing mechanism design basis, and by using the SolidWorks software climb straight connecting rod mechanism modeling, and during the process of climbing stairs trajectory of climbing mechanism is analyzed. The simulation results show that the design scheme of the climbing mechanism is reasonable, the climbing trajectory of the climbing mechanism is approximately linear, and the turbulence is greatly reduced, which provides a new theoretical reference for the design of the climbing mechanism.  
      关键词:Climbing wheelchair;Linear connecting rod mechanism;Kinematics analysis   
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      发布时间:2022-11-10

      Test·Analysis

    • Hao Yu,Dongchen Qin,Jiangyi Chen,Feng Yuan
      Vol. 45, Issue 3, Pages: 99-103(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.017
      摘要:The stiffness characteristics of cylindrical roller bearings will have great impact on the dynamic performance of machine tools. Based on the analysis for the double-row cylindrical roller bearing, considering the influence of the lubricant oil film on the stiffness, the stiffness variation characteristics under different operating conditions and lubrication parameters are analyzed. The analysis results show that the lubricating oil film produced by elastohydrodynamic lubrication will reduce the comprehensive stiffness of the bearing. When the external load increases, the hertz stiffness, the oil film stiffness and the comprehensive stiffness both increase. Increasing the preload value of bearing is conductive to improving the comprehensive stiffness. When the rotation speed increases, the comprehensive stiffness of the bearing shows a downward trend. The increase of the lubricating oil dynamic viscosity coefficient or the pressure viscosity coefficient will both make the comprehensive stiffness of bearing decrease.  
      关键词:Double-row cylindrical roller bearing;Hertz contact;Lubricating oil film;Comprehensive stiffness;Elastohydrodynamic lubrication   
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      发布时间:2022-11-10
    • Ting Geng,Yuting Wei,Aiping Deng,Jiang Ding
      Vol. 45, Issue 3, Pages: 104-110(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.018
      摘要:Focusing on a planetary gear transmission that uses line gear as core transmission elements, and the influence of assembly errors on its transmission precision is studied. The structural composition of the line gear transmission and the characteristics of different transmission schemes are analyzed, the space meshing coordinate system for the gear train are established, and the quantitative relationship of the parameters at the meshing moment is established among the sun line gear, the outer ring line gear and the planetary line gear. The causes of the angle error and displacement error are analyzed, both between the planetary line gear and the sun line gear and between the outer ring line gear and the planetary line gear. Tooth Contact Analysis (TCA) is subsequently adopted to carry out the numerical analysis of the assembly errors model for the line gear transmission. The results show that, among assembly errors of the planetary gears, the angular errors of its rotation around the horizontal axis, the displacement errors in the longitudinal section of the outer ring line gear, and the displacement errors in the cross section of the planetary line gear, are of more effect on its transmission. That is of significant to design and assembly of the planetary gears.  
      关键词:Line gear;Transmission;Assembly error;Transmission precision   
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      发布时间:2022-11-10
    • Songcheng Xie,Rongsong Yang,Qinghua Zhou
      Vol. 45, Issue 3, Pages: 111-116(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.019
      摘要:Taking the RV reducer as the research object, the 3Dmodel of RV reducer is established. Then, it is imported into Adams for kinematic simulation, and the acceleration of spur gear is obtained. The natural frequency of RV reducer is solved by ANSYS Workbench, and then the power spectral density (PSD) function is derived according to the probabilistic statistical analysis technology. Finally, the peak power spectral density is extracted and imported into the Random vibration module of ANSYS Workbench for random vibration analysis. This method considers the influence of random vibration factors on the stress and safety margin of the mechanism, and a new method for solving the reliability problem of RV gear reducer is provided.  
      关键词:RV reducer;Kinematics simulation;Power spectral density(PSD);Random vibration analysis   
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      发布时间:2022-11-10
    • Baolei Zhang,Guanghao Liu
      Vol. 45, Issue 3, Pages: 117-126(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.020
      摘要:A new planar 5R parallel mechanism with nine driving methods is proposed to solve the problem of system performance degradation caused by different driving methods of parallel mechanisms. Firstly, based on the transmission scheme of the 5R parallel mechanism, the kinematics model of the 5R parallel mechanism is established. Secondly, on the basis of matrix orthogonality, the operating performance index of 5R parallel mechanism is defined, and the operating performance under different driving modes is evaluated according to the index requirements. Finally, the size of the 5R parallel mechanism is optimized based on the atlas method, and the best geometric parameters and the best execution mode transformation diagram of the 5R parallel mechanism are obtained. The experimental results show that the proposed performance evaluation index and optimization method have good universality. The new driveable mechanism constructed can significantly improve the kinematic performance of the parallel mechanism by reasonably changing the drive mode.  
      关键词:5R parallel mechanism;Variable drive mode;Performance index;Atlas method;Optimization   
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      发布时间:2022-11-10
    • Jinxia Liu,Lei Liu,Aibo Wang
      Vol. 45, Issue 3, Pages: 127-133(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.021
      摘要:In order to effectively reduce the fuel consumption of the whole vehicle, development of a multi-speed four-row planetary gear mechanism (PGM) automatic transmission (AT) transmission scheme, with a reasonable transmission ratio interval, has become a new trend. Based on the principle of lever method, the input and output positions of single-row and three-row parallel PGM series are analyzed separately. On the basis of the possible arrangement of the engaging elements, the lever structural diagram of single-row in series with three-row parallel PGM (referred to as "1-row+3-row parallel PGM") is proposed. Through the analysis of the "1-row+3-row parallel PGM" lever speed diagram, according to the design requirements of AT, the five reasonable transmission schemes are compared and the optimal transmission scheme is selected. Comparing this optimal transmission scheme with the Chrysler 45RFE AT, adding a row of PGM based on the 45RFE AT can design a "1-row+3-row parallel PGM" AT transmission scheme with more gears and better performance. Compared with the four-row hybrid PGM AT transmission scheme formed by two double-row parallel PGM in series, also increases 2~3 forward gears and reduces the difficulty of shift control.  
      关键词:Lever method;Automatic transmission;Planetary gear mechanism;Multi-row planetary gear mechanism connection;Transmission scheme   
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      发布时间:2022-11-10
    • Xuhui Liu,Zhijuan Ding,Qiwen Luo,Zhen Jian,Yuanfang Zhang
      Vol. 45, Issue 3, Pages: 134-139(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.022
      摘要:Knee joint is an important part of normal movements of human body. In order to meet the needs of lower limb amputees to restore normal motor function, a prosthetic knee joint with double rocker mechanism is designed. Firstly, a simplified model of the lower prosthesis is established, and the relevant parameters such as joint angle, angular velocity and angular acceleration are obtained through kinematic analysis of the model. The equilibrium equations between output damping force and driving torque were obtained through the dynamic static analysis method. The highly similar tracks and ankle motion knee instantaneous center curve contrast figure were obtained through Adams simulation analysis. The results indicate that this design of double rocker prosthetic knee joint has favorable stability and bionic performance, and can meet the demand of the movement of the amputee. It provides theoretical basis for the design, processing and real-time control of the whole structure of the double rocker prosthetic knee joint.  
      关键词:Double rocker mechanism;Prosthetic knee joint;Kinematics;Dynamics;Adams simulation analysis   
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      发布时间:2022-11-10
    • Xia Yuan,Xiaohua Hao,Xuewen Song,Jianli Zhang,Gang An
      Vol. 45, Issue 3, Pages: 140-146(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.023
      摘要:The double motor hybrid vehicle distributes the power on both sides through the parallel planetary gear mechanism. The meshing force of the two rows of planetary gears affects each other, resulting in the increase of dynamic load coefficient and vibration excitation. The harmonic analysis method is used to obtain the frequency ratio of meshing force under multiple working conditions, so as to establish RBF neural network model, and a prediction of meshing force in a certain working range is carried out. The maximum meshing force and dynamic load coefficient are calculated on the prediction results, and the meshing force is proportional to the difference between speed ratio and output torque ratio minus 1, and the dynamic load coefficient on the low-speed side is greater than that on the high-speed side, which can be expressed as a multiple or reciprocal multiple relationship. It provides a theoretical basis for the study of dynamics of hybrid vehicles with dual motors.  
      关键词:RBF neural network;Parallel planetary gear;Frequency coupling;Dynamic meshing force   
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      发布时间:2022-11-10
    • Kai Yang,Jinying Huang
      Vol. 45, Issue 3, Pages: 147-152(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.024
      摘要:An 8-DOF manipulator with prismatic pair is proposed for space environment, which can complete equipment maintenance and object grabbing in space environment. The pose transformation matrix and forward kinematics equation of 8-DOF manipulator are derived by standard D-H parameter method. The simulation model of the manipulator is established by Matlab robotics toolbox, and the simulation model is compared with the kinematics equation of the manipulator. Monte Carlo method is used to solve the workspace of the manipulator, and the point cloud of the workspace of the end effector of the manipulator is drawn. The trajectory planning of the manipulator is simulated by Matlab, and the displacement, velocity and acceleration curves of each joint in the motion process are drawn. The rationality of the structure design of the manipulator is verified, it provides a reference for the follow-up research work.  
      关键词:8-degree-of-freedom manipulator;Forward kinematics;Workspace;Monte Carlo method;Trajectory planning   
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      Development·Application

    • Chang Gao,Zhongqing Yu,Qiang Zhou
      Vol. 45, Issue 3, Pages: 153-160(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.025
      摘要:Aiming at the problems of low fault recognition rate, slow convergence speed and difficult parameter selection in the process of fault diagnosis of planetary gearbox based on BP neural network improved by optimization algorithm, a GA-ACO algorithm is proposed to optimize the parameters of neural network. The basic principle and main steps of GA-ACO-BP algorithm are given. At the same time, this method is applied to the fault diagnosis of planetary gearbox. Comparing the performance of ACO-BP neural network algorithm and GA-ACO-BP algorithm, the results show that the convergence speed of ACO Optimized BP neural network is slow and the recognition accuracy is not high, while GA-ACO-BP algorithm can accurately and quickly diagnose and identify the fault of planetary gearbox.  
      关键词:GA-ACO-BP algorithm;Planetary gearbox;Fault diagnosis;Genetic algorithm;Ant colony optimization algorithm;BP neural network   
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      发布时间:2022-11-10
    • Minghui Xu,Wanli Li
      Vol. 45, Issue 3, Pages: 161-164(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.026
      摘要:The key technology and method of RV Reducer digital design by using C# language and SolidWorks secondary development technology are introduced. Through in-depth study of the parameterization process of the RV reducer, the digitization process from the input of the overall target parameters to the specific parameters of the parts is realized. A CAD system platform for RV reducer parameter optimization design is developed, and combined with the database, the management of part parameters is realized.  
      关键词:SolidWorks secondary development;RV reducer;Parametric   
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    • Kexin Liu,Huer Sun,Fuwang Liang
      Vol. 45, Issue 3, Pages: 165-170(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.027
      摘要:Aiming at the problem that the vibration signals for rotating machinery rotors are usually accompanied by strong noise, it is difficult to extract its effective information. A method of fault feature extraction based on time-varying filter empirical mode decomposition (TVF-EMD) and Teager energy operator (TEO) is proposed. Firstly, the TVF-EMD method is used to adaptively decompose the bearing vibration signal to obtain a set of intrinsic modal functions. Then, the kurtosis calculation is performed on the decomposition result, and the sensitive component is selected with the highest kurtosis value according to the maximum kurtosis criterion. Furthermore, the Teager energy operator is used to demodulate the selected sensitive components, and the weak fault feature extraction of the bearing is realized by observing the obvious periodic fault feature frequency. Simulations and experiments are carried out, and the results prove that this method can effectively diagnose the weak faults of bearings.  
      关键词:Rolling bearing;Weak fault;TVF-EMD;TEO   
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      发布时间:2022-11-10
    • Chengjun Si
      Vol. 45, Issue 3, Pages: 171-176(2021) DOI: 10.16578/j.issn.1004.2539.2021.03.028
      摘要:In order to solve the problems of low freedom of five fingers dexterous hand and complicated disassembly and installation, a modular, easy disassembly and installation, direct drive 11 degrees of freedom five fingers dexterous hand is designed. Each finger joint has a rotation range of at least ±90°. Through the special design of the rotation angle of the thumb, the left/right hand mode of the dexterous hand can be directly switched and both sides can be grasped at the same time. A five-finger dexterous hand prototype is made through 3D printing. Aiming at the complex control system caused by multiple sensors of the dexterous hand at present, the current feedback control algorithm is proposed, through signal acquisition and post-processing of the motor drive current, the mathematical model of current-rotation angle-fingertip force is established, and the grasping experiment is carried out. The results show that the designed modular dexterous hand has strong grasping ability, and the control algorithm of current feedback can control the movement state and grasping force of the dexterous hand, and complete the target grab operation.  
      关键词:Modular;Magnetic suction joint;Current feedback algorithm;Double side grasp   
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