最新刊期
期 2 ， 2020
-
Research of the Global Space Work Characteristic of Linear Delta Robot Versus Rotational Delta Robot
摘要：It is significant for Delta robot design to research on the work characteristics of the whole reachable workspace. The closed-loop vector equation is taken to solve the inverse kinematics of Delta robots， and vector expression of Jacobian matrix is deduced， the global stiffness index and the global dexterity index is established. The relationship between stiffness index and transmission angles of branched chains is obtained and verified， which make it possible to predict the stiffness performance by transmission angles. On the basis of the workspace and Jacobian matrix， the global stiffness index and the global dexterity index in the whole reachable workspace of two Delta robots with different configurations is obtained by Matlab， and the mechanism of the work characteristics difference between two kinds of Delta robots is researched. The conclusion shows that with the similar volume of reachable workspace， the stiffness of the linear Delta robot is superior to the rotational Delta robot， while the kinematics performance of the rotational Delta robot is better.关键词：Delta robot- 5
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：Aiming at the new double sinusoidal generating wave pushrod movable tooth drive， the tooth profile synthesis and meshing force characteristic analysis are carried out. Firstly， according to the structure and the transmission principle， the profile of double sinusoidal generating-wave is designed， the tooth profile equation of center gear and the variable curvature calculation formula is deduced. According to the curvature curve of the tooth profile of center gear， the condition that the tooth profile of center gear does not interfere is gotten， and the factors to affect the actual tooth profile interference of the center gear are analyzed. Then， the changing law and the influencing factors of the meshing force on the meshing pair of the movable tooth are analyzed based on the deformation coordination relationship. The maximum meshing force of the pushrod movable tooth on the center gear and the generator is gotten respectively. Finally， the calculation formula of the pressure angle of the transmission mechanism is conducted， and the variation law and influencing factors of pressure angle are analyzed. The results show that the transmission ratio is the main factor affecting the actual profile interference of the center gear， and the amplitude is the second. The amplitude is the main factor affecting the meshing forces， and the radius of the base circle ρ0 that forms the theoretical profile of the double sinusoidal generating-wave cam is the second. The amplitude is the main factor affecting the pressure angle α1， and the ρ0 is the main factor affecting the pressure angle α2. A theoretical basis for the design and performance analysis of this mechanism is provided by this study.关键词：Double sinusoidal generating-wave
- 3
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：Non-orthogonal modified face-gear drive is a kind of cross-shaft transmission mode with universal application. At present， there is no analytical formula for contact stress， only finite element software can be used to calculate the contact stress. The calculation method and formula of the contact stress are given in this study. Firstly， based on the principle of surface meshing transmission， the tooth surface equation of non-orthogonal modified face-gear drive with helical pinion is derived. Secondly， the contact analysis coordinate system with installation error is established， and the contact point and its curvature calculation equation are obtained by the tooth contact analysis (TCA) theory. Finally， the general form of the contact stress analytical formula is derived according to the Hertz contact theory. The contact stress calculation formula can calculate the contact stress of various types of face gears， such as orthogonal and non-orthogonal， modified and unmodified， spur and helical teeth， and quickly calculate the corresponding contact stress by programming. Taking a certain design parameter of the face-gear drive as an example， the contact stress calculation formula is used to calculate the contact stress， and the Abaqus finite element software is used to calculate the tooth surface contact stress of face gear， and then the tooth surface contact stress value of face gear is extracted in Abaqus. The results of analytical calculations are compared with the finite element， the error is about 5.23%. The results show that the calculation method of contact stress of helical face gear tooth surface is correct and feasible.关键词：Contact stress
- 5
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：To explore the coupling effect of gear dynamics characteristics and elastohydrodynamic lubrication， considering the influence of surface roughness and the time-varying meshing stiffness on gear dynamics behavior， the six-degree-freedom friction dynamics model is established based on the dynamics theory. The decoupling method is adopted to solve the model to get the dynamic meshing force and the gear teeth surface wave velocity which are used for elastohydrodynamic lubrication analysis. And the elastohydrodynamic lubrication characteristics of gears under dynamic and static load models are studied by an example. The results show that， compared with the stationary load， the elastohydrodynamic lubrication research based on dynamic load model can more accurately reflect the transient lubrication characteristics of gear. Under the incentive of time-varying stiffness， the oil film pressure and oil film thickness during lubrication show certain oscillation effect. There is greater impact on the entry point， single-tooth entry point and single-tooth exit point which are the dangerous points of elastohydrodynamic lubrication.关键词：Involute spur gear
- 6
- |
- 5
- |
- 0
发布时间：2022-10-25 - 摘要：The trade-off between the high NOx catalytical efficiency and low NH3 leakage are difficult to tackle， especially during engine cold start of plug-in diesel engine hybrid electric vehicle. The NH3 desorption rate model， SCR temperature model and dynamic response model are established based on SCR reaction mechanism. According to Pontryagin's minimum principle， the shortest light-off time control strategy of SCR and the multi-objective integrated optimization control strategy of fuel consumption and emissions where SOC and SCR temperature designated as state variables are proposed. The simulation results from shortest light-off time control strategy show that ammonia storage capacity is apt to exceed the limit of ammonia storage capacity during the process of rapid heating. The resultant peak concentration of ammonia leakage is 4.362×10-5. By comparison， the multi-objective integrated optimization control strategy for fuel consumption and emissions can not only achieve rapid light-of but also reduce the peak concentration of ammonia leakage to 2.122 6×10-5. Meanwhile fuel economy is improved by 7.13%. Finally， the hardware-in-loop experiment based on dSPACE real-time simulation platform is implemented to validate the real-time performance and effectiveness of the proposed control strategy.关键词：Minimum principle
- 3
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：A finite element model of heat conduction process between the friction components in a multi-disc clutch is setup. With coupled algorithm， the heat partition coefficient between friction components in multi-disc clutch and the temperature variations in the cases of engagement with the same initial rotating speeds and the same time are studied. The temperature field is non-dimensionalized and compared， the results show that， during both cases of engagement， the heat partition coefficients are higher than that of sliding with fixed rotating speed and approach to 1 rapidly at the end of engagement. The contact pressure in the case of engagement with the same initial rotating speed makes influence on its peak temperature， and thus there exists a critical pressure with which the lowest peak temperature can be obtained. This critical pressure benefits the thermal stability of the multi-disc clutch. In the case of engagement with the same time， the heat partition process will not change even though the contact pressure is changed， and the variation processes of the dimensionless temperature will not be changed neither. This will facilitate the thermal status estimation of the clutch.关键词：Vehicle engineering
- 2
- |
- 3
- |
- 0
发布时间：2022-10-25
Theory·Reserach
- 摘要：Using the coordinate transformation principle，the parametric equation for the trajectory generated is derived by the coupler point of spherical 4R linkage. On this basis，a constrained optimization model is constructed to formulate the approximate synthesis problem of spherical 4R linkage for the path generation without prescribed timing. The model takes the minimizing sum of squares for path errors as the objective function， and the existing crank，length coordination，and transmission angle restriction as the constraints. Combining the self-adaptive penalty function method，this study employs the social cognitive optimization (SCO) algorithm to solve the aforementioned problem. In order to enhance the convergence speed and accuracy of SCO algorithm，a novel accelerating social cognitive optimization (ASCO) algorithm is proposed in which the differential evolution (DE) operators are used to local search. Numerical examples of mechanism synthesis are given，and trajectory analysis results show that the established model and presented ASCO algorithm are feasible and effective. Furthermore，comparative tests on computational performance to address the examples are implemented with SCO，DE，and ASCO algorithm，and the numerical experiments indicate that ASCO outperforms SCO and DE in terms of robustness，convergence speed and accuracy.关键词：Spherical 4R linkage
- 4
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：For the problem of computer modeling and kineto-static analysis for a single-DOF double crank six-bar press mechanism， the corresponding vector bond graph method is proposed. From the mechanism structure and composition principle， the corresponding vector bond graph model is built. By the effective method， all the energy storage elements of the mechanism vector bond graph posses integral causality. As a result， the algebraic difficulty of computer modeling for mechanism kineto-static analysis is solved. By the corresponding algorithm， the computer modeling and kineto-static analysis of a single-DOF double crank six-bar press mechanism is realized， the effect of the pulse working resistance on mechanism driving moment and joint constraint force is analyzed， and the reliability and validity of the procedure proposed is illustrated.关键词：Vector bond graph
- 4
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：A systemic research on configuration design and kinematics analysis of a new 3-DOF translational parallel robot， Delta， which involved T-type hinges， is carried out based on Delta widely used in food fields， pharmaceutical fields， electronic fields and other light industry. The displacements characteristics of minimal branch are obtained based on analysis of the freedom constraints relationship. And some branch types 3T0R parallel mechanism may contain are selected prudently. And some 3-DOF translational parallel robot mechanisms are synthesized. New Delta parallel robot mechanism that contains T-type hinges is synthesized by mechanism evolution method， whose branch type is
- 2
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：A new type of indexing cam-planetary gear composite mechanism is designed and studied. The input shaft is coaxial with the output shaft， the input shaft is fixedly connected to the swing rod， the swing rod is hinged to the planetary gear shaft， and the planetary gear， the two swing arms and the planetary gear shaft are fixedly connected. The swinging rod rotates with the input shaft， and the rollers on the two swinging rods are kept in contact with the two cams respectively. The contact point changes continuously with the rotation of the swinging rod， and the swinging arm rotates relative to the swinging rod to drive the planetary wheel connected thereto to swing. Finally， the intermittent movement of the center wheel is realized， that is， the indexing movement. The working condition parameters of the mechanism motion are defined. According to the specific parameters， the actual contour equation of the cam is designed， and the 3D modeling and motion simulation of the mechanism are completed， which verifies the correctness of the design modeling process.关键词：Indexing cam mechanism
- 4
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：In order to make the V-belt CVT match the Racing Baja condition and engine characteristics， its key parameters are optimized. A V-belt CVT mechanical model is established， and the CVT speed regulation characteristics are analyzed and simulated in Matlab. The genetic algorithm is used to optimize the key parameters of CVT with the aim of improving the power. The bench is set up for test verification. The test results show that the simulation results are basically consistent with the test data. The CVT transmission ratio changes according to the actual working conditions， and the engine always works in the peak torque and power corresponding speed range (2 800 ~3 600 r/min)， and the vehicle power performance is significantly improved. This study has a certain guiding role in the parameter matching and optimization of V-belt CVT.关键词：V-belt CVT
- 3
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：In order to study the platform of orthogonal three-degree-of-freedom translational parallel mechanism， the platform configuration of the parallel mechanism is designed， and the corrected Kutzabach-Grubler freedom formula is used to verify that the output of the parallel mechanism platform is a three-degree-of-freedom motion. According to the geometric relationship between different components， the various movements of the branched chain constraint equations between angle and swing arm are explored. The position positive solution equation and inverse solution equation are established according to the geometric constraint relationship between the motion coordinates and fixed coordinates. The speed and acceleration expressions of the parallel mechanism platform are obtained. Finally， the kinematics simulation is carried out according to the set motion law parameters， and the reference point is set on the motion platform. And the motion trajectory of the motion platform and the related motion law curve are obtained， and the dynamic performance of the parallel mechanism platform is verified.关键词：Orthogonal translational parallel mechanism
- 3
- |
- 3
- |
- 0
发布时间：2022-10-25
Design· Calculation
- 摘要：Based on the principle of gear shaping， the process of non-orthogonal face gear shaping is simulated by using VERICUT. In addition， the influence of gear shaping error on tooth surface accuracy is explored by using the Matlab. First of all， the tooth surface equation of non-orthogonal face gear including machining error is deduceed based on the theory of gearing， and the coordinates of points of tooth surface is calculated by using the Matlab. Then， the machine tool model， cutter and gear billet are built in SolidWorks， and import them into VERICUT， the CNC program is written， the processing simulation is carried out， and comparing the processed model with the theoretical model， the correctness of NC shaping of face gear is verified. In the end， the coordinate system of measuring is established， a plan of measuring point range of working tooth surface is carried out， a method of calculating error of tooth surface is presented. A point-to-point quantitative and accurate comparation between the tooth surface with machining error and the theoretical tooth surface is carried out by numerical simulation of Matlab， and the influence of 3 common machining errors on tooth surface accuracy is summarized.关键词：Non-orthogonal face gear
- 13
- |
- 7
- |
- 0
发布时间：2022-10-25 - 摘要：The strength degradation and dependent failure， which have not been taken into account yet in the existing RV reducer reliability analysis methods， have a significant impact on the reliability of mechanical systems. According to the structural characteristics of the RV reducer， a dynamic reliability analysis model with main load bearing components based on strength degradation theory is established and the rule of the effect of strength degradation on the dynamic reliability is analyzed. The Copula function is derived to describe the dependent failure among the components of the RV reducer. The dynamic reliability analysis model of RV reducer is established， the rule of the influence of the dependent failure on the RV reducer reliability is studied. The sensitivity sequence of each parameter is obtained by adopting the sensitivity analysis on the main design parameters that affecting the RV reducer reliability. The research results lay a foundation for the optimal reliability design of the RV reducer.关键词：RV reducer;Dependent failure;Strength degradation;Dynamic reliability;Sensitivity analysis
- 2
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：In order to measure the transmission error of the robot RV reducer accurately and analyze the influence of the load and input speed during the measurement process, then guide the measurement and application of the robot RV reducer, a robot RV reducer comprehensive test bench consisting of a control module, a measurement module, a software module and a mechanical module is built by selecting key test components, the transmission errors of RV-40E and RV-320E under different conditions are measured, and the transmission error curves are obtained. The relationships of transmission error between load, input speed and different models is fitted based on the experimental data, and the influence of load, input speed and stiffness on the transmission errors is analyzed. The results show that the transmission error of the robot RV reducer increases with the increase of the load and input speed, and decreases with the increase of the rigidity, and find that the influence of the load on the measured transmission error is third order, which has a greater impact.关键词：Robot
- 9
- |
- 4
- |
- 0
发布时间：2022-10-25 - 摘要：For the hypoid gear， there is distortion in the heat treatment process， and the quality of the contact zone after heat treatment is poor. A method to analyze the contact zone offset by using the first-order relative tooth surface error of the main tooth is proposed. Through the experimental research， the influence law of the relative helical angular error of the main tooth on the contact zone offset is obtained， and the correctness of the contact zone offset principle is verified. At the same time， the contact deformation principle and the heat treatment deformation law are used to compensate the heat treatment deformation in the cutting stage， and a new cutting tooth model is obtained for production. The results show that the tooth surface error after heat treatment is within the standard range by this method， and the quality of the contact zone after heat treatment is also controlled.关键词：Hypoid gear
- 4
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：A graphical analysis model is proposed to explore the possible structural patterns and efficiency. The research shows that the existence of cycle power is determined by the structure itself and has nothing to do with the characteristic parameter P. Six structural types with wide transmission ratios were proposed. In combination with the analysis model， the relationship between the transmission ratio and efficiency is discussed， and the transmission ratio range that there must be a cycle power in the condition of characteristic parameter P in [3，8] is obtained. Finally， the efficiency of a scheme is analyzed with this method， and the efficiency is improved by changing the tooth ratio.关键词：2K-H closed epicyclical gear trains
- 8
- |
- 6
- |
- 0
发布时间：2022-10-25 - 摘要：Thermal power loss and transmission efficiency of gearbox is one of the important indexes to evaluate the quality of gear transmission. Based on the meshing parameters of gears， the mathematical expression of thermal power loss in gear meshing is deduced. Considering oil film thickness and friction factor， the relationship between rolling power loss and sliding power loss in gear meshing and the corresponding relationship between them is analyzed， and the influence law of gear parameters on thermal power loss in gear meshing is obtained. The results show that rolling power loss is positively correlated with oil film thickness， while sliding power loss is positively correlated with friction factor. Based on the influence of gear parameters on the thermal power loss of gear meshing， the principle of selecting high efficiency herringbone gear parameters is proposed.关键词：Thermal power loss
- 5
- |
- 7
- |
- 0
发布时间：2022-10-25 - 摘要：Taking the ultra-high-speed cigarette making and tipping machine as object， the offset adjustment and rigid-flexible coupling analysis method of the ultra-thin paper tape is studied. By using the spatial flattening projection method， the effects of the spacing of the inclined rollers or the angle of the inclined pads on the paper tape offset is investigated. The kinematics and dynamical models of the ultra-thin paper tape are built， and the elastic modulus of the paper tape is measured. Herein， a rigid-flexible coupling model of offset adjustment mechanism is developed by dispersing the paper tape into flexible body units and the roller into rigid body units. The results show that the numerical and measured lateral offsets at the output tape are consistent. These findings can be available for the offset parameters optimization and smooth conveying of the ultra-thin paper tape.关键词：Cigarette making and tipping machine;Ultra-thin paper tape;Space offset adjustment;Rigid-flexible coupling
- 3
- |
- 3
- |
- 0
发布时间：2022-10-25
Test·Analysis
- 摘要：The globoidal cam planetary mechanism is difficult to machine， the assembly precision is difficult to guarantee， and its manufacturing cost is high. These problems are caused by the toroidal structure of the outer annulus cam. A new type of squirrel-cage globoidal cam planetary mechanism is proposed to solve this problem. The new type of mechanism mainly improves the structure of the outer annulus cam in the mechanism. The new structure not only reduces the difficulty of machining the outer annulus cam， but also avoiding the problem that the assembly accuracy is not high due to the outer annulus cam split structure. Through the three-dimensional modeling and motion simulation of squirrel-cage globoidal cam planetary mechanism， the accuracy of the mechanism movement is verified by the simulation results.关键词：Globoidal cam planetary mechanism
- 4
- |
- 4
- |
- 0
发布时间：2022-10-25 - 摘要：Aiming at the lack of measurement methods for ellipsoidal arc-toothed cylindrical gears， a precision measuring device based on laser displacement sensor for elliptical arc-toothed cylindrical gear is designed. The geometric shape feature of the elliptical arc-toothed cylindrical gear is expounded， the composition and measurement principle of the laser non-contact measuring device are introduced， and the contour data model of the gear measuring section is established by laser measurement of the multiple radial cross-section profiles of the gear. The coordinate transformation of the cross-section contour data model is carried out to calculate the pitch deviation of the middle section of the gear. The tooth profile measurement data of different sections of the same tooth are analyzed， the coordinate values of the intersection points of the different section index circle and the tooth profile are calculated， and the overall deviation of the elliptical arc tooth is calculated. The method can effectively fill the measurement technology blank of the curved toothed cylindrical gear， and has high measurement accuracy and efficiency; it is also suitable for other cylindrical gear measurement.关键词：Elliptical arc-toothed cylindrical gear
- 3
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：A new type of hand rehabilitation training device based on shape memory alloy spring is proposed for the existing hand rehabilitation training device with complex structure and poor portability. The device realizes miniaturization， portability and easy operation of hand rehabilitation training device through underactuation mode， driven by single memory alloy spring and multiple common springs. The relationship between the output force and the output stroke of the shape memory alloy spring is investigated and experimentally verified. The influencing factors of knuckle output force are analyzed. By comparing PID control and fuzzy control， the control efficiency of the device is improved. The simulation and experiment on the device verify the rationality of the device， and provide a research basis for the optimization of the device in the next step.关键词：Underactuated
- 4
- |
- 3
- |
- 0
发布时间：2022-10-25 - 摘要：For variable-speed bicycle need to manually shift， and after the manual shift the resistance ratio does not match the current situation of problem， a set of utilizing the continuity of spring force to realize continuously variable transmission mechanical bicycle scheme of continuously variable transmission device is put forward， and through the spring force direction and the resistance between a change in the direction angle method， make the drive sprocket pitch circle diameter variation with a non-linear relationship between amount of spring compression， increase the effective resistance range of continuously variable transmission. Then the functional relationship between the diameter change of the dividing circle of the active sprocket and the spring compression is obtained through calculation. Finally， the scheme is simulated and the stress cloud diagram is obtained. The simulation results verify the feasibility of the scheme.关键词：Continuously variable transmission (CVT)
- 4
- |
- 4
- |
- 0
发布时间：2022-10-25
Development·Application
- 摘要：With the development of robotics technology， industrial robots are widely used in automation production， which greatly improves the production efficiency and automation degree. Trajectory planning is the key link to complete the task， and trajectory optimization further improves the quality of mission completion and meets the needs of industrial development. The research progress of trajectory planning and optimization for joint space of industrial robots is reviewed. Firstly， the algorithm of joint space trajectory planning is briefly described. It is pointed out that polynomial interpolation is the main mode， and B-spline curve is an inevitable trend of future development due to its excellent characteristics. Then， the trajectory optimization under different objectives is comprehensively summarized， and the existing problems such as the determination of the optimization objectives and the improvement of the algorithm are pointed out. Finally， the future development direction is prospected. The multi-objective optimization solution and dynamic adjustment of constraints will be the focus of future research.关键词：Industrial robot
- 9
- |
- 8
- |
- 0
发布时间：2022-10-25 - 摘要：Unpowered exoskeleton assist robots have the advantages of no energy consumption， low cost and convenient use， which can be widely used in industry manufacture， medical rehabilitation and other fields. The definition and classification are expounded systematically and the principles are introduced. The kinematic diagram of typical domestic and foreign unpowered exoskeleton assist robot is drawn and the corresponding structure principle is briefly described. Finally， the shortcomings， key technologies that need to be broken through are summarized based on the survey results. It should be helpful for those researchers devoted to unpowered exoskeleton support robots.关键词：Unpowered
- 6
- |
- 4
- |
- 0
发布时间：2022-10-25
Review
- Technical support is provided by Beijing Founder electronics co., LTD 豫ICP备05013835号-5
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0