最新刊期
期 7 ， 2017
- 摘要：The cubic polynomial interpolation with midpoints is applied to the path planning of robot leg in the complex tunnel environment. A new spider biomimetic robot with 18 joints and 6 legs is designed,which can be flexible movement in tunnel space. The kinematics model of the robot leg is built with D-H modeling method,and the inverse kinematics equation is deduced. Based on Monte-Carlo method,the working space of the foot end is analyzed,and based on the cubic polynomial interpolation algorithm with midpoints for path planning of obstacle avoidance is simulated. Simulation results show that the application of the cubic polynomial interpolation method with midpoints in path planning on spider biomimetic robot leg could guarantee the smoothness of foot movements,avoid the impact caused by mutations of moment,and meet the requirements of obstacle avoidance.关键词：Spider biomimetic hexapod robot;D-H modeling;Cubic polynomial interpolation with midpoints;Path planning
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发布时间：2022-10-20 - 摘要：Based on a modified thin slice method,the static transmission error of cylindrical gear pair with tooth surface error is calculated efficiently. The transmission error is separated into composite deformation and composite mesh error,and the change of transmission error for gears with and without errors is studied. The results show that the transmission error of the ideal gear pair is related to the applied load and the theoretical contact length. Under the same loading condition,the transmission error will have local minimum fluctuations when the overlap（ or transverse） contact ratio is close to integers,while it will have local maximum fluctuations when the total contact ratio of a helical gear pair is close to integers. For a gear pair with tooth surface errors,the mesh stiffness,the composite mesh error and the actual contact length in a mesh cycle are similar to each other.The transmission error produced by gear errors is the crucial factor in light loading,while the tooth deformation becomes dominating in heavy loading. The conclusion can provide some references for the design of transmission error and vibration reduction of gear systems.关键词：Gear;Static transmission error;Thin slice method;Mesh stiffness;Composite mesh error
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发布时间：2022-10-20 - 摘要：The torsional vibrations of traction drive shafting system of EMU is one of key factors on heavily influence the running smoothness,safety and reliability of high-speed train. The torsional vibrations of a typical traction drive shafting system of EMU are investigated. After a concise introduction,the traction drive shafting system is simplified and equivalent to a lumped-parameters model with five moment of inertias and four torsional stiffness coefficients. Then,considering the meshing relationship of driving and driven gears,an undamped free torsional vibration equation of this lumped model is established by using direct stiffness method. At last,the natural frequency and mode shapes of this shafting system are obtained with the help of MATLAB software. On the other hand,a MATLAB/Simulink simulation model is also constructed according to above lumped-parameters model equation. And subsequently,the acceleration and displacement Bode plots of shafting system are calculated from this simulation model,these amplitude-frequency results are very useful to verify the natural frequencies obtained directly from the lumped model equation. Results show that the established lumped mass model is available to simulate the torsional vibration characteristics of traction drive shafting system,and the torsional resonance and fatigue problems may mainly happen on the driving side of shafting system. The research works are very useful for the future study on the dynamic design and optimization of traction drive shafting system of EMU.关键词：Traction drive shafting system;Torsional vibration characteristic;Lumped-parameter model;Simulation model
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发布时间：2022-10-20 - 摘要：According to the definition of planetary gear transmission with small teeth difference,the selection of value of modification coefficient is the key in the design of planetary gear reducer with small teeth difference. By analyzing and comparing common modification coefficient selection method,based on the constraints theory of the displacement gear modification coefficient selection and using Matlab software assisted calculation,a small teeth difference planetary involute gear modification coefficient value selection method is presented.Through the examples of validation,the external gear modification coefficient calculated by Matlab programming is smaller than calculated by conventional design,but has a large degree of the contact ratio,the results show the feasibility of Matlab programming is higher.关键词：Small teeth difference;Planetary transmission;Modification coefficient;Matlab
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发布时间：2022-10-20 -
Effect of Structure Parameter on Stress Distribution of Double Helical Tooth Synchronous Timing Belt
摘要：The Spiral angle and dislocation quantity is important structural parameters influencing the transmission error,noise and lifespan of the double helical tooth synchronous timing belt. A three dimensional model of double helical tooth synchronous timing belt tooth and pulley under complete meshing is established based on the spatial meshing transmission principle. The hierarchical model of the synchronous timing belt is built concerning with the structural composite material properties. The large deformation and nonlinear static analysis of the above models are conducted with finite analysis software ANSYS Workbench. The results show that there has geometrical distortion deformation of the belt tooth along the lateral direction with the varying stiffness,resulting in maximum stress in the tooth root distributed uniformly along the lateral of the belt tooth and stress concentration in the strengthening layer. Under the same dislocation coefficient,the tooth root stress of the double helical tooth synchronous timing belt with spiral angle of 30° has minimum value,during which the maximum tooth root stress is the smallest.关键词：Double helical synchronous timing belt;Spiral angle;Dislocation quantity;Stress- 3
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发布时间：2022-10-20 - 摘要：Based on the topologic theory,the topology structure of the crank-group driving mechanism is researched,and the similarities and differences of the crank-group driving mechanism structure between them are determined by combining with the topology structure matrix. It has a certain referential significance for the further research of the crank-group driving mechanism.关键词：Crank-group driving mechanism;Topologic theory;Structure
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发布时间：2022-10-20 - 摘要：In view of the influence of elastic deformation of ball reducer gear meshing point on the transmission performance,a method for locating the positioning accuracy by using the stiffness coefficient of the mesh point is proposed. The mechanism of the coupling positioning accuracy is analyzed. The mechanical model of the meshing pair is established,the delay angle of meshing pair is derived by using the torque balance equation. The position precision of the meshing pair is introduced by applying the backward rotation angle of meshing. The influence of structural parameters on the accuracy of positioning is analyzed. The results show that the hysteresis curve of the transmission mechanism is periodic fluctuation. The mechanism behind the angle of the main source of the reduction of the gear mesh. The amplitude variation is mainly influenced by the constant velocity engagement. The change of structure parameters has obvious influence on the accuracy of the positioning. The theoretical support for the transmission performance improvement and structural optimization of the planetary transmission of the steel ball is provided by research results.关键词：Cycloid ball planetary transmission;Stiffness coefficient;Contact deformation;Lag angle;Positioning accuracy
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发布时间：2022-10-20 - 摘要：In order to predict the transient meshing efficiency of bevel gear pairs,a theoretical model of friction coefficient is established under boundary lubrication,elastohydrodynamic lubrication and mixed lubrication based on the principle of equivalent gear theory,by simplifying bevel gear into equivalent straigh gear,and by computing oil film-thickness ratio. Considering the impact of transitioning factor of mesh point relative sliding velocity,normal load,and friction coefficient,a computing model of friction power losses for bevel gear is established,the math model of sliding and rolling friction power loss is established with a variable of pressure angle and pitch radius by double integration for a meshing cycle,and the simulation analysis of mesh power losses of bevel gear is carried out based on MATLAB.关键词：Bevel gear;Integrated lubrication;Friction power losses;Meshing efficiency
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发布时间：2022-10-20 - 摘要：Taking spinning pulley with a slit in the automobile booster pump as study object,the stress limit diagram with different cycle characteristics are discussed. The fatigue life of spinning pulley under the complexity of the stress are assessed by using the stress limit diagrams and safety factor method by ANSYS. The results show that,the spinning pulley with a slit in the automobile booster pump are in different cycle characteristics and complex state of alternating stress,but it works safely. The reliable basis is provided for designing fatigue life of the actual spinning pulley without S-N data.关键词：Spinning pulley;Cycle characteristic;Stress limit diagram;Fatigue life
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发布时间：2022-10-20 - 摘要：According to the main pin four wheel alignment angle error problem in the verification process,a new type of automatic verification device of four wheel alignment based on multi degree of freedom space tangent mechanism is developed. The main pin of the verification device after the tilt adjustment simulation movement and main pin inclination can independently accomplish the work step by step,the main pin movement due to interference angle error are avoided. On this basis of this device and based on the space geometry analysis,the model of four wheel alignment main pin inclination verification is established. Through the analysis and derivation of the geometric relationship of the model,the main factors affecting the accuracy of the kingpin inclination angle are obtained. According to the national standard,the accuracy of the main pin back angle and the main pin inclination value are detected,the result is conformed to the national standard. The design will provide reference for the design of the four wheel alignment device verification.
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发布时间：2022-10-20 - 摘要：By adopting the principle of kinematic inversion and the mathematical tools such as rotation matrix,the general analytic formula of cam contour of flat evolution type of high-speed printing press mechanism from German is obtained through deduction. The study and discussion surrounding the different values of the angle σ between flat and connecting rod are carried out,the problem of cam contour design of flat evolution type mechanism of is solved successfully,the important theoretical basis for further popularization and application of this evolution type is provided.关键词：Floating flat push rod;Angle of flat and connecting rod;Kinematic inversion;Design of cam profile
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发布时间：2022-10-20 - 摘要：The low speed and high torque of the electric drive wheel truck requires a relatively large transmission ratio gear reducer,so the planetary gear wheel hub reducer system is widely used in such truck. According to the structural characteristics of the two-stage planetary gear wheel hub reducer,the traditional design method is used to analyze the reliability of the planetary gear system,and the parameters of the gear system are optimized according to the calculated reliability. The system maximum reliability is changed into the gear reliability maximum as multiple objective functions. Based on the actual conditions,the constraints are established. By using the MATLAB,the multi-objective optimization function is solved,the optimal parameters of the gear are obtained. Based on the optimal parameters of the planetary gear system,the reliability of the whole system is analyzed. The analysis results show that,after the optimized design,transfer efficiency is 0. 969,and the transfer ratio is 30. 54,which meet the requirements. The sun gear tooth surface contact strength reliability coefficient is 2. 52,and the second stage ring gear tooth root bending fatigue strength reliability coefficient is2. 59,and the second stage gear reliability is 0. 989,so the reliability is obviously improved. The safety level of coefficient parts is high. The service life of the system can meet the design requirements,which provide reference for the optimization design of the similar planetary gear system.关键词：Wheel hub reducer;Planetary gear;Reliability;Model;Optimization design
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发布时间：2022-10-20 - 摘要：The detailed elaboration of main technical conditions and the main dimension parameters of drop forged rivetless for conveyors chains is carriedout. The data processing method for the one-way extreme value parameter in the standards ASME B29. 22-2001 is given. Some important parameters not specified in the standards are obtained by dimensional chain calculation or strength calculation methods,and the main dimension tolerance is given. Meanwhile,according to the use of the characteristics and the use of different operating conditions of the chain,the selection of different materials and heat treatment requirements for chain part are recommended,and the strength checking formula for the inner link,the outer link and pin are given.关键词：Drop forged rivetless chain;Dimension chain;Strength calculation;Optimization design
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发布时间：2022-10-20 - 摘要：Through the theoretical analysis of a three stages NGW planetary gear transmission wrench,the mathematical model with the optimal object of minimizing wrench volume is established. Under the condition of meet the constrain,the design method of mixed discrete variable method and second optimization is proposed.Through the example calculations,it shows that the method can be used to solve this kind of mixed discrete variable optimization problems in the engineering design,the optimization reliability is improved and it has some reference for structure optimization and cost controlling.关键词：NGW planetary gear transmission;Optimal design;Mixed discrete variable;Second optimization
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发布时间：2022-10-20 - 摘要：A new type of eccentric cylindrical gear rack mechanism is introduced. The gear is normal cylindrical gear which is eccentrically installed and the pitch curve of the rack is plane curve. The gear and rack are engaged with each other so that a special request of movements can be achieved. According to the fundamental law of mating profile,the equations of the pitch curve of the rack can be deduced. And further,the tooth profile equations of the rack are calculated based on the concept of the counterpart rack. Eventually,the3-dimentional modeling and motion simulation of the mechanism are carried out,through which the correctness of the design and modeling is preliminarily confirmed.关键词：Eccentric cylindrical gear;Gear rack mechanism;Counterpart rack;Tooth profile equation
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发布时间：2022-10-20 - 摘要：The modeling precision of hydraulic torque converter is investigated and various factors affect the modeling precision are analyzed,a new high precision modeling method is proposed. Based on the meridional path line equation,the calculation formula of curvature radius and curvature center coordinates is derived.By using numerical calculation method,the curves of curvature radius and curvature center coordinates versus the polar angle are obtained. According to this law,by using a non-elementary function multi-section circular arcs uniformly approximation,the maximal absolute error of approximation reaches a minimum. A parametric program code is developed and all equations are verified. By using the program,the radius and center coordinates of each circular arc,and polar angle of each arc joining point are obtained directly. In addition,the absolute error and percentage error of approximation can be obtained as well,which is convenient to discriminate if the approximation meets the precision requirement. The investigation results indicate that the method is feasible,can improve modeling accuracy significantly,and is of engineering application value.关键词：Hydraulic torque converter;Modeling precision;Meridional path line;Multi-section arc uniform approximation
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发布时间：2022-10-20 - 摘要：The mathematical model is established with the minimum volume of the three pinions synchronous drive system of shield cutter,and the model is solved by the genetic algorithm. Then the load sharing characteristic of different installation arrangement of the three pinions synchronous drive system is analyzed. The results show that the design efficiency and accuracy can be improved by the genetic algorithm. The optimization results met the requirements of reducing weight and saving energy. The load sharing characteristic of system is good in type of 30°-150°-270°. The study can provide theoretical basis for the design and manufacture of the multiple pinions parallel drive system.关键词：Shield cutter;Multiple pinions synchronous drive system;Genetic algorithm;Load balancing;Optimum design
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发布时间：2022-10-20 - 摘要：Taking the common diaphragm with the conical profile as example,the distribution of stress and security coefficient in profile are analyzed by ANSYS software. According to the analysis results,the original conical line type can be improved and the multi-parameter optimization is carried out by ANSYS OPT module.After optimizing,the stress in profile is reduced and the security is improved.关键词：Diaphragm;Profile;Structure;Size;Multi-parameter optimization
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发布时间：2022-10-20 - 摘要：Aiming at the problems of the work profile of globoidal cam in automatic tool changer（ ATC） is difficult to design,manufacture and both side of cam groove meshing with the roller in indexing period,taking the globoidal cam of a certain machining center as example,the motion and position relationship between globoidal cam and indexing plate are analyzed,the mathematical equation of globoidal cam contour surface is derived and modified. By using the segment modeling method,the cam profile curve groups in both indexing period and dwell period are created in Pro/E software. By the physical modeling of line and surface,the accurate 3D solid model of the globoidal cam is established. After globoidal cam profile performance analysis and machining practice,the designed globoidal cam model is verified to meet the design and machining requirements,which provides technical support for improving its finish grinding accuracy.关键词：Automatic tool changer;Globoidal cam;Mathematical model;Segment modeling;Profile surface
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发布时间：2022-10-20 - 摘要：According to the need of the stability and complexity of the robot trajectory path,a method of Cartesian space trajectory planning based on the Jerk optimal is presented,a smooth and stable robot motion trajectory is obtained. The trajectory path is imposed through limits on the waypoints in the Cartesian space,the continuous differentiable cosine curve is used to interpolate the robot trajectory path between the waypoints,and the expected joint angle of robot is calculated by solving the inverse kinematics. Finally,the trajectory planning method is validated through simulations and experiments on NAO robot. The experimental results show that the smoothness and stability of the trajectory path is excellent,the experiment task action are completed successfully.关键词：Robot;Jerk optimal;Cartesian space;Trajectory planning
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发布时间：2022-10-20 - 摘要：The implement of gear contact fatigue life prediction（ CFLP） is critically important for maintenance and operation of gear transmission system. A novel method for gear CFLP based on vibration data collected from the run-to-failure test of involute spur gear is proposed. The multifractal detrended fluctuation analysis（ MF-DFA） is used to analyzed vibration data. As a result,the multifractal spectrum（ MFS） are obtained and the indicator for assessing gear contact condition deterioration is designed based on the width of MFS. Subsequently,the gear CFLP model is developed based on the proposed indicator and GM（ 1,1） model. The efficiency of this model is demonstrated by using experimental results. The results show that the proposed method delivers satisfactory performances with high precision and the prediction results can be used as a reference to gear life estimation.关键词：Gear contact fatigue;Life prediction;Multifractal spectrum;Vibration signal;Grey model
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发布时间：2022-10-20 - 摘要：In order to improve the automation degree of the massage robot,the structure design and kinematics analysis of a four fingered,motor-driven robotic hand for massage robot is completed. Each finger has two joints: the first joint and the second joint. And the degree of freedom of the hand is four by connecting the first joints and second joints of index finger,middle finger and ring finger respectively. In addition,the crank-rocker mechanism is creatively adopted to driven the second joint,which is conducive not only to enhance the continuity and the periodicity of pinching manipulation,but to also avoid frequent reversing the rotation of motor,prolonging the service life of the motor. At last,to verify the design,the model of dexterous hand is developed. The rationality and feasibility of the mechanism of hand are proved by ADAMS motion simulation and MATLAB numerical analysis.关键词：Massage;Dexterous hand;Simulation
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发布时间：2022-10-20 - 摘要：According to the traditional excitation coil magnetorheological device,it is powered on for a long time to produce high temperature resulting in brake efficiency failure problems of MRF. A novel cylindrical magnetorheological device using permanent magnet instead of coil as magnetic source is designed. Aiming at the transmission device,the working principle of brake is analyzed,the magnetic circuit model is buit. The analysis of the brake magnetic circuit model is simulated by using ANSYS to verify the correctness of the theoretical model. The simulation results show that the addition of isolation ring can increase the strength of the magnetic field,but the magnetic field fluctuations. The magnetic field strength can be increased within a certain range of magnetic declination and without magnetic saturation phenomenon.关键词：Magnetorheological brake;Permanent magnet;Isolation ring;Polarization direction
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发布时间：2022-10-20 - 摘要：Through the analysis of the influence factors on transmission efficiency of gearbox,a theoretical analysis model of gearbox transmission efficiency is set up from the power consumption,and the influences of gear meshing loss,bearing friction loss,oil loss,oil seal friction loss and windage loss on gearbox transmission efficiency are considered. The analysis model is validated according to the test data of a low speed and heavy duty gearbox,and the influences of speed and torque on the transmission efficiency of gearbox are discussed,the changing curves of gear efficiency with the rotational speed and torque are obtained,the foundation for further research on the efficiency of the gearbox is laid.关键词：Gearbox;Efficiency calculation;Data processing
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发布时间：2022-10-20 - 摘要：In order to improve the measurement accuracy of eccentric shaft,the eccentric shaft is tested and analyzed by secondary projection method. The measurement principle of the secondary projection method is analyzed. The projection data of the eccentric axes on the two planes perpendicular to each other are obtained by using the optical image measuring machine to perform the secondary projection measurement on the eccentric shaft. The projection data is processed to obtain the coordinate values of the center line end points of the eccentric axis in the spatial coordinate system,so as to further establish the true vector of the center line of each axis segment in space. According to the obtained vector data,the various parameters needed for the analysis of the eccentric shaft structure can be extracted,so that the eccentricity and concentricity of the eccentric shaft can be analyzed reasonably. The results show that the secondary projection method can greatly improve the measurement accuracy of the eccentric shaft.关键词：Eccentric shaft;Optical image measuring machine;Space vector;Secondary projection
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发布时间：2022-10-20 - 摘要：Aiming at the factors that affect kinematic accuracy of planer mechanism is more and cannot be ignored,the influence factors of the reliability in kinematic accuracy of planar mechanism are classified as non-cumulative factors and cumulative factors. The reliability simulation trial for kinematic accuracy of planar mechanism under the condition of coupling non-cumulative and cumulative factors is proposed. According to the reliability simulative trial,the allowed maximum wear capacity in mechanism is obtained,the wear rate of hinge is analyzed by using Archard wear model. The life evaluation model of probability reliability and the life evaluation model of fuzzy reliability are established on the basis of the allowed maximum wear capacity and the wear rate. The life evaluation of mechanism is carried out respectively by each model and the evaluation model is compared one to the other. Taking slider-crank mechanism as an example to analyze,the kinematic accuracy under the conditions of different hinge gap and reliable life of mechanism is obtained,the feasibility of method is verified.关键词：Kinematic accuracy;Simulative trial;Coupling;Reliability life
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发布时间：2022-10-20 -
Study on the Model of Slider-crank Mechanism with Clearance based on Parameter Identification Method
摘要：In order to solve the problem of the clearance on the slider-crank mechanism and improve the position precision of the slider-crank mechanism. Starting from the simple mechanism of slider-crank mechanism,the simplified model is established. By using the sensor to measure the movement parameters of artifacts of the slider-crank mechanism,then system parameters of the slider-crank mechanism are identified by using the method of parameter identification. Finally,the model of the slider-crank mechanism with clearance is established and the simulation analysis is carried out. The comparison results show that the model of using the method of parameter identification has high accuracy and modeling process is simple,a new train of thought for complex nonlinear modeling of the electromechanical system is provided.关键词：Slider-crank mechanism;Clearance;Parameter identification method;Mathematical model- 4
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发布时间：2022-10-20 - 摘要：On the development of miniaturization,lightweight and energy efficiency for mechanical transmission device,asymmetric gear with small teeth number attracts a lot of interests in both fundamental research and application,but the study of the bending fatigue stress characteristics is few. Based on the principle of gear machining,the gear tooth profile equations is built,the analytic calculation method including asymmetric tooth profile and tangential displacement of asymmetric gear with a small number of teeth gear bending stress is proposed and the calculation results are compared with the results of finite element method. The asymmetric and symmetrical gears with small teeth number are high efficiency machined by numerical control machining method. Their bending fatigue strength is tested by high-frequency fatigue testing machine,and the results for different stress level are analyzed and discussed by using the fatigue cumulative failure hypothesis. The complete and true C-R-S-N curves are obtained,which provides the basis for the estimation of the bending fatigue life of the asymmetric gear with small teeth number. The results show that,by the analytical method,the asymmetric gear bending strength is 13. 64% higher than that of symmetric gear,by finite element method is14. 78% higher than that of symmetric gear. Under the same load,the bending fatigue life of asymmetric gear with small teeth number is average increased 46. 86%. The same trend with the analytical method and the finite element method calculation results,a reference for such research method is provided.关键词：Asymmetric gear with a small teeth number;Bending stress;Fatigue characteristic;Test;Finite element method;Analytical method
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发布时间：2022-10-20 - 摘要：The transmission is a key part of the drive train,and it has a direct impact on the vehicle NEDC fuel consumption. In order to improve the NEDC integrated fuel consumption of a MPV model,a test method of transmission efficiency based on NEDC is proposed. The influence of different lubricating oil viscosity,temperature,additive and other factors on gearbox transmission efficiency is compared. The results show that the viscosity of lubricating oil is lower under NEDC,the transmission efficiency of transmission is higher.The decrease of the oil film thickness caused by the increase of oil temperature has greater influence on the transmission efficiency than that caused by the increase of the oil film thickness due to the increase of the rotation speed and the transmission efficiency of the transmission. The viscosity-temperature characteristic of lubricating oil viscosity enhances the viscosity-temperature characteristic of oil,The influence of transmission efficiency is greater than that of lubricating oil viscosity on transmission efficiency.关键词：Transmission;Transmission efficiency;NEDC;Lubricant
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发布时间：2022-10-20 - 摘要：The evaluation indexes of vehicle shift quality,including the shifting-impact,the friction work and the shifting-time are given,combining with the ZL50 loader transmission system and the changes of the shift torque of the power shift clutch in the hydraulic control,several main factors of shift quality are summarized,the impact of the evaluation index is simulated and analyzed by using Matlab/Simulink. Finally,the improved control strategy is given through the experiment.关键词：Shift quality;Transmission system;Matlab/simulink;Power shift clutch;Impact degree simulation
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发布时间：2022-10-20 - 摘要：Reducer is the key component of hoisting equipment,and the case is the carrier of the gear system and plays the role of support and fixation. The three-dimensional finite element model of the gearbox is established by Solid Works software and imported it into ANSYS Workbench. The statics analysis is accomplished for each actual loading condition,the changing curve of the maximum stress and the deformation is obtained,the analysis results can provide the data support for the subsequent structure improvement and light-weight design. The natural frequency and vibration type is obtained by completing the modal analysis of the case,and whether the resonance phenomenon happens can be determined by comparing the natural frequency of the reducer with the meshing frequency and the rotational frequency.关键词：Reducer case;ANSYS Workbench;Statics analysis;Modal analysis
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发布时间：2022-10-20 - 摘要：An electronic cam based on the electromagnetic linear actuator is proposed,by tracking the given trajectory to realize the required linear motion law and substitute the traditional cam mechanism. The electric cam is controlled by the iterative learning control algorithm to realize the track of the target trajectory. Moreover,the adoption of both iterative learning control algorithm and fuzzy sliding mode control can effectively improve the convergence speed and robustness of the electric cam. The fuzzy sliding mode iterative control is inputting the error function in sliding mode controller,which takes the function of a sliding mode control as the input of fuzzy control and takes the fuzzy control output as the control increment of iterative learning control. The simulation and the experiment shows that electronic cam based on the electromagnetic linear actuator can effectively substitute traditional cam mechanism,and the fuzzy sliding mode iterative control algorithm can satisfy the requirements of the precision of trajectory tracking,response speed,convergence speed and robustness of electronic cam.关键词：Electronic cam;Electromagnetic linear actuator;Linear motion control;Iterative learning control;Fuzzy control;Sliding mode control
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发布时间：2022-10-20 - 摘要：According to the requirement of automatic cutting tape,through studying the motion law of the intermittent mechanism,a novel incomplete gear intermittent mechanism is proposed,in which the intermittent ratio can be adjusted continuously. With detail structure design and parameter calculation,the problem of time interval between the tape clamped and cut of the intermittent mechanism in the automatic tape cutting device is solved by using the related program developed with software MATLAB. The continuous adjustment of the intermittent ratio is realized according to the tape width and length. The intermittent mechanism gives full play to the performance of equipment and the production efficiency is improved.关键词：Intermittent mechanism;Incomplete gear;Intermittent ratio;Continuous adjustment;Tape cut
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发布时间：2022-10-20 - 摘要：The chain plate structure of double pitch silent conveyor chain is the variation structural of internal and external composite engaged standard silent chain. The chain cannot normally internal and external composite engage with sprocket because there is no specific numerical relationship of protrusion length,one of the design parameters of silent chain structure,in the meshing principle of silent chain. A parametric model of the chain plate and a simplified model of motion analysis of double-pitch silent conveyor chain drive system are created by Solidworks/Motion software. In order to realize the composite engagement mechanism and the minimum meshing impact force,the height Y of protrusion length and the value δ of protrusion length are defined as variable,and the simulation analysis is carried out. The results show that protrusion length is important influencing factor for realizing internal and external composite engage process of double-pitch silent chain drive system. By the general comparison,the optimal construct parameters are obtained. When the sprocket tooth number is 38,the height Y of protrusion length is 0. 25 PS,and the value δ of protrusion length is 0. 013 PS,the internal and external composite engage process of chain can be realized,and the meshing impact force is smallest and structural is optimum at that time.关键词：Chain plate of double-pitch silent chain;Structure parameter;Protrusion length;Engage force
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发布时间：2022-10-20 - 摘要：The roll-angle of test model often needs to be changed automatically in wind tunnel,and then a roll supporting system is needed. Considering that the model of trans-super-sonic wind tunnel bears impulsive loads,and its supporting device profile is defined strictly,a new type of auto-roll supporting device is proposed. A servo-motor and a harmonic reducer,whose dimensions meet the size requirements of the roll supporting device,are chosen as the drive source and the high-speed transmission mechanism respectively. At the same time,a electro-magnetic brake is used to lock turning model. The planetary gear train which can hold and drive the rotating model is chosen as the last stage link. The structure and suitable machining process of the planetary gears train are analyzed and designed. Calculation results show that the shell and solar gear have enough mechanical strength. The running and loading experiments are performed and the results show the roll supporting device with control system can be used as test device of trans-super-sonic wind tunnel.关键词：Wind tunnel;Planetary gear train;Roll;Load;Strength
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发布时间：2022-10-20 - 摘要：Taking the bucket lifting mechanism of meal and kitchen truck of a company as research target,the mechanical and hydraulic integration virtual prototype model of bucket lifting mechanism of the meal and kitchen truck is built by the multi-body dynamics software ADAMS. The four geometric design points coordinate is parameterized and the articulated points of bucket lifting mechanism are optimized by multi island genetic algorithm in the optimization software i SIGHT,with the bucket lifting mechanism hydraulic cylinder maximum driving force minimum as the optimization target. Through the comparison of the original design data and the optimization results,the hydraulic cylinder maximum driving force is 8. 51% lower than before optimization of bucket lifting mechanism and the lifting arm maximum lifting force to rod is 5. 98% lower than before optimization in the working process,which has certain reference significance for the design and research of bucket lifting mechanism.关键词：Meal and kitchen truck;Bucket lifting mechanism;Genetic algorithm;Optimization design
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发布时间：2022-10-20 - 摘要：The genetic algorithm can effectively handle some complex optimal problems that the conventional optimization methods can’t solve. However,the traditional genetic algorithm has many defects,such as falling easily into local solution,slower convergence speed and the poor effect of optimal problems with constraints. An improved float-encoding genetic algorithm（ FGA） solving optimal problems with inequality constraints is proposed. This method has the advantages of high convergence efficiency,good stability and strong local search capability. It is used to the optimal design of crank-link mechanism,and the optimal results show that the improved genetic algorithm has a better effect than the traditional genetic algorithm.关键词：Improved FGA algorithm;Crank-link mechanism;Inequality constraint;Optimal design
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发布时间：2022-10-20 - 摘要：The planetary wheel hub reducer has the advantages of compact structure,high bearing capacity and large transmission ratio,which is widely used in heavy duty truck. According to the structural characteristics of double-stage planetary wheel hub reducer system,the double-stage wheel hub reducer is designed based on the fuzzy reliability optimization design with the multi-objects. The first-level objective function is the minimal volume,the second-level objective function is the greatest reliability. Based on the characteristic of genetic algorithms,improving the weight coefficients of the search methods and increasing the optimization searching space,compared with other optimization methods,the result is improved. Based on the results,the fuzzy theory is applied to the Taguchi method. The robust design of double-stage wheel hub reducer is carried out. The results of robust design are compared with the above results. According to the optimal design results,the simulation analysis of main components,gear,bearings of the double-stage wheel hub reducer system is carried out. The simulation result met the design requirements,which verified the feasibility of the optimized design.关键词：Double-stage wheel hub reducer system;Multi-objective;Model;Reliability;Fuzzy theory
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发布时间：2022-10-20 - 摘要：In order to comprehensive analysis of research status and existing problems in macro/micro dual-drive technology,the analysis of research status for four commonly drive ways of macro system and two commonly drivers of micro system which used in the technology with macro/micro dual-drive are completed. The existing problems in this research are analyzed based on summary of the research status,such as the research on rotary motion is lags behind linear motion,the volume of macro/micro dual-drive system is large and structure is complex,the control of the system is lags behind the structure design,and achievement transformation is serious lags behind the technology research. As to solve the problems existing in the process of the technology development,the corresponding solutions are presented.关键词：Macro/micro dual-drive;Macro drive;Micro drive;Rotary motion;Linear motion
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发布时间：2022-10-20
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