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- 01Tribological Behaviors Comparison of Several Stainless Steels under Seawater Lubrication
- 02Comparison of different optimization algorithms used in torque converter design optimization
- 03Research on High Efficient Flank Milling Machining Technology for Similar Ruled 〖JZ〗Surface Integral Impeller Based on Inspection at Original Position
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Efficient Disinfection Control of Mobile Robots Driven By Multi-sensor Measurement
XU Jianping; CHEN Zejian; WEN Ke; REN Mingyan; ZHANG Junhui; LI Guang
Abstract:Under the epidemic situation,in order to solve the requirements of narrow space,complex curved surface,non-contact and safe automatic disinfecting operation,a mobile automatic disinfecting mechanical control system based on double-vehicle splicing based on multi-sensor measurement was designed.A dual-vehicle splicing omnidirectional auto guided vehicle (AGV) that could be quickly disassembled and assembled was designed to solve the problem of transportation in narrow spaces.At the same time,a laser navigation sensor was used to build a scene coordinate system to precisely locate the equipment position,so that the positioning accuracy during equipment operation could reach ±5 mm.A scanning and disinfecting machinery with laser ranging sensor,obstacle avoidance sensor,and disinfecting device was designed,and a correction algorithm was designed based on the KUKA robot sensor interface (RSI) to realize online pose adjustment and safety protection of the machinery during the disinfecting process.Finally,for the need of unmanned operation on site during the disinfecting process,a remote control network consisting of remote terminal-AGV-robot system was build.Once the disinfection instructions were issued on the remote terminal,the optimal path according to the scene parameters was calculated to autonomously complete the task.Furthermore,a vertical wall and arc top scene were built.During the disinfection process,the position deviation is ±3 mm,and the angle deviation is ±1.5°.The control results has a high fitting accuracy with the actual object,which increases the effective disinfection area.
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Research on Solving Nonlinear Problems in Robot Tool Coordinate System Calibration
CHEN Jushuai; LIU Yuqi; TANG Qing
Abstract:In the calibration of robot tool coordinate system,the constraint equation was established by using the distance between any two points in the robot space to remain unchanged in the robot base coordinate system and the measuring instrument coordinate system.For solving such nonlinear problems of the equation,biased random key genetic algorithm (BRKGA) was introduced.In order to enhance the stability of algorithm and accelerate the convergence of algorithm,local search was added for improvement.The simulation results show that the solution accuracy of improved BRKGA is improved by 17% and 18% than the least square iteration and Newton method respectively.The results of physical experiments show that the solution accuracy of improved BRKGA is improved by 22% and 8% respectively.The solution accuracy variance of improved BRKGA is smaller than that of BRKGA,and the number of iterations is less than that of BRKGA while it converges,indicating that improved BRKGA has better stability and faster convergence.
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Research on Adaptive Impedance Control Algorithm for Grinding Manipulator
SHEN Xiaolong; WANG Jifang; ZHANG Yuetao; SU Peng
Abstract:When traditional position-based fixed impedance controller conducting compliant control,the performance of force tracking depends on the various uncertain disturbance factors.Besides,the control parameters input in the controller are determined by a series of experiments.Once factors of the disturbance are changed,these parameters also need to be recalibrated.To reduce the effect on force tracking caused by the uncertainty of various disturbance,and to avoid the inconvenience of recalibrating,a trajectory adjustment compensator was designed based on the force deviation and velocity at the extremity,so that the factors of impedance were able to be adjusted indirectly and eventually the adaptivity of the system was enhanced.The simulation results show that the steady-state error of force tracking under 20 N expected force is within 5%,and the time of transiting back to steady-state is shorter compared to the fixed impedance control method,which shows the system with this compensator is able to adapt to the uncertainty better.
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Application Research of Robot Built-in Visual Recognition Software Based on FANUC
CAO Jinjiang; GAO Shiping
Abstract:Aiming at the situation that it is difficult for field engineers to develop robot vision program using machine vision system based on PC platform or embedded module,the relationship between robot and built-in visual recognition software was studied.Taking the integrated built-in visual recognition function software of FANUC robot as the research object,the physical connection between industrial camera and robot was introduced.Meanwhile,the principle and process of camera calibration were analyzed.Taking 2D shape and bar code workpieces as example,the processing process of visual recognition program,the key instructions of robot visual program and the flow of handling program were introduced in detail.By mixing and placing multiple models,the built-in vision system can accurately identified,the robot could make accurate sorting and carrying.The integrated built-in machine vision system of robot has simple hardware connection,abundant recognition tools,convenient application,as well as convenient interaction between robot program and visual data.Based on this,it has expanded the application scope of robot technology.Integrated built-in visual recognition function of robotis the development trend of automation field and machine vision system.
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Analysis on Rigid-Flexible Coupling Characteristics of Flexible Transmission Line-Live Working Robot
LI Huaxu; ZOU Dehua; LIU Lanlan; KUANG Jianghua; JIANG Wei
Abstract:The power transmission line live working robot travels on the high-voltage cable through two wheels.A complex rigid-〖JP〗flexible coupling system is formed between the rigid robot system and the flexible transmission line,especially at the wheel-line contact of the rigid system and the flexible system.In order to ensure the stability of the robots operation process and obtain better dynamic performance,flexible wire,rigid robot and flexible wire-rigid robot coupling dynamics models were established.Based on the model,the dynamic characteristics of the online operation behavior of the live working robot were simulated under several different typical working conditions in ADAMS.Through the simulation characteristic curves,the validity of the rigid-flexible coupling dynamic model is verified on one hand,appropriate robot dynamics parameters can be obtained to optimize and control the robot operation on the other hand.Finally,the on-site drainage plate fastening operation test was carried out on the live line.The results also verify the engineering practicability of the proposed rigid-flexible coupling dynamics model.
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Research on AGV Obstacle Avoidance Path Planning Based on Improved A* Algorithm
QI Fenglian; WANG Xiaoqing; ZHANG Guoying
Abstract:In view of the fact that the path planned by the traditional A* algorithm in the complex grid map is not smooth,there are redundant turning points and redundant collinear nodes,and when the traditional octree search strategy is used,it is easy to cause the AGV to collide with obstacles.Facing complex environments obstacles randomly appearing on the global path cannot achieve dynamic obstacle avoidance and other problems,an improved A* algorithm was proposed.Since the search efficiency of the traditional A* algorithm mainly depended on the design of the evaluation function,the weight coefficient of the heuristic function was introduced to improve the search efficiency of the A* algorithm.The obstacle safety distance was set as the judgment obstacle,which provided a reference for whether the current obstacles in the object area affected AGV passage,the original octree search strategy was improved again to improve the obstacle avoidance performance,and then path optimization was performed on the obtained collision-free path to retain key turning points,and finally the fusion of A* and DWA algorithms was realized,further the path was optimized,and global dynamic path planning was realized.The experimental results show that the fusion algorithm makes the path smoother,improves the obstacle avoidance performance of the algorithm,and shows the feasibility of the fusion algorithm in the robot path planning.
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Multi-objective Trajectory Optimization of Industrial Robots
XU Yongqiao; NI Yanguang; LIU Yu; CUI Yongcun; ZHANG Zhanli
Abstract:Based on the trajectory optimization problem of industrial robots under multi-objectives such as time,energy,and impact optimization,a multi-objective optimization method was used for research.The seven B-spline interpolation curve was adopted to construct the continuous trajectory of the industrial robot and the parameters at both ends could be set,which ensured the motion performance of the industrial robot.Then an improved genetic algorithm was used to optimize the industrial robot,and the result was Paretos optimal solution set.The simulation results on a self-developed 6-DOF industrial robot show that the seven B-spline interpolation can be used to get continuous robot trajectory,and the improved genetic algorithm can make the B-spline trajectory perform effective multi-object optimization,then a good Pareto frontier is obtained.
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Design of Bionic Jellyfish Robot Based on Cam Drive
ZHOU Xiaoyang; TANG Ruizhi; LIN Hai; CAI Peizhou; WANG Jiaxuan; WANG Yan
Abstract:A novel bionic jellyfish robot was present to solve the problems that relatively little research about the motion performance,volume,emergency ability and so on for bionic jellyfish robot at present.Cam was used as the main part of power transmission,the bionic tentacles were used to squeeze water to generate thrust,so as to improve the motion performance of the bionic jellyfish robot.Simultaneously,the internal transmission structures relied on a single cam to drive,which reducing the volume of the vehicle and provide more space to carry additional units.The additional unit included separating the shedding structure and air bag,which enhanced the emergency response ability of the robot in the face of complex underwater situations.The relaxation and contraction time functions of the bionic jellyfish robot were established,and the theoretical value of time was obtained after inputting the corresponding design parameters.Finally,the bionic jellyfish robot prototype was made to measure its volume,and the no-load experiment and underwater experiment were conducted to verify that the designed bionic jellyfish robot had smaller volume,emergency ability and better motion performance.
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Uncertainty Evalution of Industrial Robots Position Repeatability
ZHANG Yanju; ZHANG Bo; HUANG Fei
Abstract:In order to evaluate the dispersion of the position repeatability measurement results of industrial robots more scientifically and reasonably,based on the study of the measurement principle of laser tracker and the position repeatability measurement method of industrial robots,the various uncertainty factors affecting the measurement results were analyzed,a method for evaluating the measurement uncertainty was proposed,and the measurement uncertainty results were verified.The results show that the analysis result of this method is reliable.The measurement uncertainty results meet the standard requirements.
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Research on Sliding Trajectory Tracking Control Strategy of Wheeled Mobile Robot
SHA Sha; WANG Huiping
Abstract:Aiming at the trajectory tracking problem of wheeled mobile robot under sliding condition,an adaptive fuzzy control strategy was proposed.The fuzzy state observer was used to estimate and compensate the speed of the unknown complex system model,the position constraint was transformed into the output constraint by designing the output vector,and the Barrier Lyapunov function was constructed to ensure the motion constraint of the robot.On this basis,a simpler longitudinal sliding model was designed,and the stability of the closed-loop system was analyzed by Lyapunov theorem.It is proved that all signals in the closed-loop system are bounded.Finally,the effectiveness and practicability of adaptive fuzzy control strategy in the case of longitudinal sliding of wheeled robot are verified by simulation and experiment.
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Research on Assembly Quality of a Missile Based on Correlation Analysis
WANG Yanzhong; YU Xiangyun; MENG Xiangwen; DOU Delong
Abstract:The quality interaction relationship in the automatic assembly process of a missile was discussed.The data were divided into types,the continuous variables in the assembly process were analyzed by Pearson correlation,and the grey correlation analysis method was used for comparison and verification.The contingency analysis of discrete variables was carried out,and the correlation was visually displayed by using the corresponding analysis diagram.Then,through the correlation analysis results of the assembly process data,the upstream process indicators B1 and m1 should be improved,so as to greatly improve the quality of the downstream process B2.For the key process h,a more significant assembly quality improvement effect could be obtained through the strict control of the parts batch and the guidance and training to the assembly workers.Finally,the correlation analysis software was designed to lay the foundation for the improvement of acquisition means,comparison and verification before and after,and data fusion analysis.
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Design and Experimental Study of a New Magnetic Adsorption Crawler Climbing Mechanism
ZHAO Quanliang; LIU Zhenyu; ZHANG Jie; SU Tingting; LIANG Xu; DI Jiejian; HE Guangping
Abstract:Aiming at the problem of small climbing force and poor carrying capacity of traditional magnetic adsorption climbing robot,the design and manufacturing method of magnetic adsorption crawler climbing mechanism with high climbing force/weight ratio was studied.A new structural design scheme of magnetic adsorption crawler was proposed,the prototype of climbing mechanism was developed,and the performance was tested.Based on ANSYS finite element analysis,the best combination modes of four Halbach magnet array elements were compared and analyzed,the lightweight design of the attachment mechanism was realized,and the adsorption force and self-weight ratio of the magnet array element were effectively improved.For the purpose of applying the magnet arrays in a climbing robot system,a crawler type climbing mechanism was designed by integrating chain drive and synchronous belt drive.The climbing mechanism was tested through experiments,and it was used in the magnetic adsorption climbing robot system to complete the vertical climbing and inverted climbing.The maximum adsorption force and self-weight ratio of the climbing mechanism is about 2.54.
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Milling Surface Roughness Grade Detection Based on Broad Learning
FANG Runji; YI Huaian; WANG Shuai; NIU Yilun
Abstract:Most of current methods used for machine-vision surface roughness detection are artificially designed indices based on image information or using deep learning.However,the former is a complex computational process,and the latter takes a long time for model training and classification,which is not suitable for online inspection occasions with fast judging.To address this problem,abroad learning based milling surface roughness grade detection method was proposed.The pictures of milling workpiece surface under normal lighting environment were acquired by industrial camera.Then they were input into the constructed broad learning model for training to realize the grade detection of milling surface roughness.The method not only enables feature auto-extraction but also has fast model training,which offers a new strategy for online visual roughness measurement.
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Simulation and Experimental Research on the Bending Strength of Composite Gears
LIU Fengfeng; WANG Xupeng; TANG Xinyao; LIU Shuwei; ZHANG Weiliang
Abstract:Mechanical property of 3-D braided composites is closely related with braiding parameters.In order to study the bending performance of carbon fiber braided composite gears and its relationship with braiding parameters,a prediction model of composites and gears bending performance was proposed.Based on the representative volume cell method and the idea of homogenization,a mesoscopic and macroscopic model of composites was established.The volume average method and the finite element method were used to predict the bending performance of composites and gears.In addition,two pairs of carbon fiber braided composite gears were prepared by four-step braiding and compression molding methods,and the bending performance of the composites and the gears under specific braiding parameters was obtained through experiments.The prediction results are in good agreement with the test results,which verifies the accuracy of the prediction model.Finally,the bending performance of composites and gears was predicted under multiple sets of braiding parameters,and the influence of braided angle and fiber volume fraction on the bending performance of composites and gears was obtained,and the braiding parameters that made the bending performance of composite gears to be the best were given
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Design of Temperature Control System Based on Improved GWO Wavelet Neural Network
CHEN Kele; REN Tianping; GUO Shuai; LI Baoqiang
Abstract:Aiming at the poor temperature control performance and low combustion efficiency of casting sand core surface drying furnace,a new hot air circulation temperature control system was designed.Based on the variable limiting amplitude double cross combustion strategy,the wavelet neural network with improved gray wolf optimization (GWO) algorithm was used to adaptively adjust the PID control parameters.The system simulation shows that compared with the traditional PID control,the overshoot is close to 0,the system regulation time is reduced by 50%,and the temperature switching control speed is increased by 47%.Finally,through the sand core drying test,compared with the traditional ratio cascade PID control,the variable limiting amplitude double cross combustion strategy and the improved GWO wavelet neural network PID have a great improvement on the control effect of furnace temperature.
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Coal Mine Equipment Maintenance Knowledge Named Entity Recognition Model Based on BERT
CAO Xiangang; WU Kexin; ZHANG Mengyuan; DUAN Yong; LI Pengfei
Abstract:In order to solve the problems of complex semantics and difficult entity recognition in coal mine equipment maintenance knowledge,a named entity recognition method of coal mine equipment maintenance knowledge based on BERT was proposed,taking the self-built coal mine equipment maintenance knowledge corpus as the research object.BERT was used to obtain the semantic,attribution and location information of words to enhance the semantic representation ability of word vector.Then,word vector sequences were input into BiLSTM layer to obtain context information and extract long-distance features.Finally,CRF was used to constrain the validity of sequence markers.The model was optimized by hyperparameter to reduce feature loss and improve learning efficiency.The experimental results show that the accuracy rate,recall rate and F1 value of the proposed method are significantly improved,reaching 90.32%,93.82% and 91.54% respectively,which proves that the model can effectively improve the difficult problems of polysemy and overlapping entity recognition in coal mine equipment maintenance entities.
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Research and Development of OPC UA Bus Bridge Communication System for Intelligent Manufacturing
ZHONG Hua; ZHANG Yu; LI Ming; CHA Xianming
Abstract:The communication between various heterogeneous information sources and industrial equipment is the key technology to realize intelligent manufacturing.A bus bridge communication system based on OPC UA (OPC unified architecture) was developed for this problem.An embedded bus bridge was built,which supported the use of I2C interface and RJ45 interface in hardware,and UATCP protocol stack was transplanted on the basis of Linux system in software to realize the communication between sensor and 828D CNC system.The experimental results show that using the bus bridge to communicate the underlying equipment with the CNC system is cross-platform and simple,making intelligent manufacturing possible.
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Research on Parameter Identification and Modeling Method of Rotating Inverted Pendulum
DAI Fuquan; ZHANG Xikang
Abstract:The rotating inverted pendulum is a typical high-order,multi-variable and nonlinear complex system,and it is a classic model in the research and teaching of control theory.An accurate mathematical model is the premise of using a rotating inverted pendulum in research and teaching.However,it is usually difficult to establish a mathematical model that is consistent with the actual prototype due to the complexity of the rotating inverted pendulum.The mathematical model of the rotating inverted pendulum system was established by using the Lagrange equation,and then the parameters of the actual prototype were identified to determine the specific parameters of the model,thereby an accurate mathematical model of the rotating inverted pendulum was established.This method specifically shows how to build accurate mathematical models for practical electromechanical systems.On this basis,the model is simulated by using the S-function of MATLAB,which verifies the effectiveness of the method.
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Research on Starting Method and Control of Sensorless BLDC Motor
YIN Jianbing; HUO Jiali; CHEN Lin
Abstract:The traditional sensorless control detects the motor position by using the back electromotive force of the motor,which can effectively reduce the hardware cost and occupied area,but there are some problems such as start-up difficulty and start-up reverse rotation.Aiming at those problems,a method of applying pulse current and detecting the change of winding inductance was proposed to determine the initial rotor position,and cooperated with FOC algorithm to control the smooth and efficient operation of BLDC motor.In addition,the optimization of control advance angle and the anti-load disturbance performance of the motor were analyzed,which further improved the operation efficiency and anti-interference ability of the whole system.Finally,an experimental prototype was built to verify it.The experimental results show that the prototype can realize no reverse rotation,efficient and reliable start-up without position sensor,and realize efficient operation under FOC closed-loop control.
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Research and Implementation of an Efficient Direct Drive Hydraulic Angle Position Servo Control System
GUO Dayong; CHEN Zhaodi; SI Guolei
Abstract:A position bi-core control method was proposed based on high efficiency of direct drive volume control (DDVC) hydraulic system and high accuracy of hydraulic valve control servo system.The 1st core control was a closed loop valve servo control system,which was composed of digital control valve with stepper motor,actuator,and their mechanical feedback mechanism.The 1st core achieved accurate position control.The 2nd core control was that servo synchronous motor drove piston pump.During 1st core large position error control zone,2nd core system ran in high efficiency by the way that servo motor speed and related piston pump flow were controlled based on stepper motor speed chart,which was determined by actuator accelerating and decelerating capacity,actuator displacement,and difference between initial position and final position.During 1st core small position error servo control,servo motor and piston pump would be stopped when accumulator pressure got the set point.This could avoid pump to run in low speed and low efficiency zone.The stored energy in accumulators would help position servo control.So,2nd core can let system run in high efficiency based on 1st core situations.Bi-core control method has two concise mechanisms and targets.It is practicable and reliable.
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Effect Experimental of Particle Size on Particle Flow Drop Lubrication Cutting
ZHANG Zhilin; XU Lanying; QIN Mengyang; LIANG Chuanjian; WU Wei
Abstract:Particle flow drop lubrication is a new green cutting lubrication technology,which can solve problem of medium introduction in traditional particle flow cutting.In order to investigate the influence of particle size on cutting effect,Al2O3 particle flow with different particle size was used to cut 45 steel,and the relationships between cutting force,cutting temperature,finish,tool life and particle size were analyzed to find out reason.The experimental results show that particle size has an influence on cutting effect,and there is an optimal particle size.Too large or too small particle size can lead to deterioration of cutting effect. Too large particle size affects the penetration of particle flow into friction surface,and too small particle size cannot adapt rough and violently changing friction surface.Both of them limit separation and leveling effect of particle flow,resulting in poor antifriction effect.Particle flow drop lubrication adopts reasonable particle size,and cutting effect is even better than pouring lubrication.
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Design of a Swing Cylinder Driven Tray Exchange Mechanism
WANG Xue
Abstract:The 630 mm tray exchange mechanism was studied with the horizontal processing center as the parent machine,and its structure was also elaborated.Its main structure included installation base,support cavity,upper base,gear center shaft,exchange arm,hydraulic cylinder,hydraulic piston,spline shaft,etc.The swing cylinder drive tray switching mechanism took the hydraulic pressure as the driving force to achieve the lifting and rotation of the exchange mechanism.The lifting and rotation were achieved by combining piston structure,bearing and swing cylinder.The lifting process was completed by the piston structure,and the rotation process was completed by the swing cylinder.It is of such advantages as simple installation,high stability,high efficiency etc.
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Study on Balance Method and Structure Design of Electromagnetic Ball Balance System
LYU Hengzhi; ZHANG Zhen; LIANG Jingwei; ZHANG Chaoyang
Abstract:For the electromagnetic ball active balance system,its working principle was analyzed,the calculation method of the corresponding compensation capacity of steel balls was summarized,the process of calculating the phase of two steel balls from the known unbalance was discussed,the multi ball situation was simplified into two ball situation according to certain rules,and the relationship between the measurement of unevenness and the number and phase of steel balls was obtained.Under the specific rotor diameter,the three-dimensional model of the balance system structure was established.Based on Ansoft Maxwell finite element analysis platform,the influence laws of permanent magnet arrangement mode,diameter,thickness and electromagnetic structure on the balance speed and compensation were studied by using the control variable method.Finally,the structure design was completed.The results show that when the adjacent permanent magnets are alternately arranged with opposite polarity,the diameter of permanent magnets is 6 mm and the thickness of permanent magnets is 4 mm,and the length of electromagnetic structure shell is slightly less than the length of iron core,the balance system can obtain more reasonable speed and maximum compensation.
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Dynamic Response Analysis of MR Damper
MA Shengnan; WU Jingyu; LIANG Guanqun; ZHOU Fuqiang; WEI Yintao
Abstract:The dynamic response of MR damper determines the real-time control effect.In order to increase the response speed and reduce the response time of MR damper,the influencing factors of its dynamic response were analyzed.Therefore,for a certain type of MR damper,the composition of its response time was defined,and the time-delay model was established.The current and magnetic field response models of two-stage coils in series in forward direction and in reverse direction,in parallel on the same side and on the opposite side were established.The two-stage rheological response model of MR fluid was analyzed.The results show that the electromagnetic response time of reverse series and in parallel on the opposite side are small,and the rheological response is only related to the gap and dynamic viscosity.Based on the transient finite element magnetic field analysis,the dynamic response process of the damper is measured from the perspective of the average effective shear yield strength.The influence of different magnetic circuit structures on the response time of the damper is obtained,and the reasons are analyzed.
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Modal Analysis and Optimization Design of Ultra-high Acceleration Macro-Micro Motion Platform Base
ZHANG Lufan; JIANG Boshi; ZHANG Pengqi; TANG Jingjing; REN Caixia
Abstract:The resonance between the ultra-high acceleration macro-micro motion platform base and the voice coil motor can seriously affect the positioning accuracy of the platform.Taking the base as the research object,with the aim of improving the first-order natural frequency of the base and reducing the mass,the methods of modal analysis,topology optimization,direct optimization and response surface optimization were made by using SolidWorks and ANSYS Workbench.The modal mode shape,natural frequency and optimization scheme were obtained,and the finite element analysis were performed on the optimized model again.The results show that the first-order natural frequency of the base increases by 6.8%,and the mass decreases by 8.0%.The first-order natural frequency is improved,and also the base lightweight is realized.
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Tangential Leakage Flow Characteristics and Numerical Analysis of Micro Scroll Compressor
HUANG Lei; WANG Yu; HE Hongbin; ZHANG Yuxi; LIU Wei; CHEN Xuehui
Abstract:For those problems arising from the motion state of the flow field and tangential leakage characteristics in the working cavity of a micro scroll compressor are hard to catch through experimental tests,taking the 3-D fluid model formed by the meshing of dynamic and static scroll disks with radial clearance as the research object,CFD dynamic mesh technology was applied to establish a structured mesh and define the marginal motion,the transient distributions of fluid in the working process of crescent compression cavity were explored.The transient distribution laws of temperature field,velocity field and pressure field in the compression working chamber caused by radial clearance were studied.The results show that the tangential leakage has a massive impact on the inhomogeneous distribution of temperature and velocity field,and it has a small influence on the pressure field,at the meshing gap,the pressure and temperature change in a gradient,and the velocity has an extreme value;the average inlet and outlet mass flows and leakage are directly proportional to the speed.
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Dynamic Characteristics Co-simulation of Vibration Hydraulic System of Single Steel Wheel Vibratory Roller
YAN Qingyao; SHEN Zhenzong; CUI Chengquan; LYU Wenlong; YAO Yunshi; TANG Zheng
Abstract:In order to study the dynamic characteristics of steel wheel vibration,vibration hydraulic system pressure and driving torque with the change of compaction degree under actual compaction conditions,the flexible pavement model was established by ANSYS APDL,and the rigid-flexible coupling dynamic modeling of steel wheel and pavement was carried out in Adams.The co-simulation model of vibratory hydraulic system of single steel wheel vibratory roller was established by AMESim and Adams,and the compaction simulation under different compaction degree was carried out.The results show that the simulation model is accurate;with the increase of compacting degree,the vibration of steel wheel is prone to double frequency and jump vibration,the steady pressure of vibration hydraulic system decreases,the vibration onset time is shortened,and the driving torque is reduced.
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Effect of Stator Tooth Slotting on Cogging Torque of Six-Phase Motor
LIANG Jianwei; LIU Huan; LIU Xiping; WANG Xinhua; SHEN Linhui
Abstract:Aiming at the vibration and noise problems caused by the excessive cogging torque of the six-phase permanent magnet motor,a 12-slot 10-pole surface-mount permanent magnet motor was taken as an example,and a method of opening auxiliary slots on the stator teeth was proposed to reduce the cogging torque.The working principle of cogging torque of permanent magnet motor was analyzed,and the analytical relationship between cogging torque and slotting structure was deduced.The stator tooth slotting method was designed.The position,number and size of the auxiliary slots were further analyzed and optimized.Finally,finite element simulation analyses for the motor before and after slotting were carried out,and performance comparisons were made with the initial motor.The research results show that the auxiliary slot of the stator teeth has a significant effect on suppressing the cogging torque,and the maximum reduction is about 91.8%.The experimental results prove the feasibility and validity of this method.
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Performance Optimization of Variable Flow Axial Piston Pump
SUN Zegang; HE Dewen; LEI Dequan; YANG Mang
Abstract:The stability of the output flow of variable flow axial piston pump is an important index to judge its performance.The throttling groove on the valve plate has a significant impact on the flow pulsation,which will cause pressure pulsation.In order to reduce the flow pulsation of variable flow axial piston pump,the variable flow axial piston pump model was established with AMESim,the calculation formulae of throttling groove overflow area were given,the throttling groove overflow area diagrams were drawn with MATLAB,and the numerical values were imported into the column plug model for simulation analysis.It is found that when the plunger cavity is just connected with the oil pressure cavity,the flow backflow phenomenon is positively correlated with the overflow area,and the flow pulsation is negatively correlated with the overflow area as the plunger cavity continues to rotate.Then,according to the research,a V-trapezoidal throttling groove was designed to effectively improve the performance of variable flow axial piston pump.
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Research Progress of Metal Additive Manufacturing Process,Materials and Structure
ZHANG Chaorui; QIAN Bo; ZHANG Lihao; MAO Jian; FAN Hongri
Abstract:Metal additive manufacturing technology has great advantages over traditional manufacturing technology and has been applied in many fields.Based on the research status of metal additive manufacturing process,materials and structures,the current research hotspots and development trends were analyzed.The results show that the current research hotspots of metal additive manufacturing are material application,simulation,intelligent detection and heat treatment strengthening,and there is no uniform standard for quality assessment.The future development trend of metal additive manufacturing is to establish standard material process database,multi-material printing process research and development,simulation optimization,intelligent monitoring management and heat treatment strengthening process research and development.
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The Latest Research Progress of Digital Hydraulic Valve
WANG Yiting; CHANG Xuesen; WEI Tianxi; YAO Yao; WU Haiming; ZHANG Zhenjie
Abstract:Based on a large number of domestic and foreign digital hydraulic valve related literature and websites,the latest development and research status of digital hydraulic valve were fully analyzed and described.The various types of digital valves were summarized,the development and research status of different types of digital valves were analyzed,and its control strategy from the digital valve itself to the large-scale remote control in the factory was expounded and explained.
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Optimization of Opportunistic Maintenance Strategy for Series Systems Considering Human Resource Constraints
XUE Chaogai; YU He; LI Shumin
Abstract:Aiming at the problem of human resource constraint in the maintenance of multi-part series system,an opportunistic maintenance strategy model considering human resource configuration was proposed.According to the characteristics of components deterioration under the influence of external environment,the aging regression factor and failure rate increasing factor were introduced to establish the preventive maintenance strategy for single components.The opportunistic maintenance was introduced,and the maintenance coefficient was taken as the optimization variable to optimize the maintenance strategy combination of the system.The configuration of maintenance tasks and the downtime of the system were determined under the condition of limited maintenance personnel,and the opportunistic maintenance strategy model of the serial system with human resource constraints was further established.Finally,the model was applied in a case study,and simulation analysis was carried out by using the cellular automata algorithm and MATLAB to obtain the optimal opportunistic maintenance scheme of the system.The results show that compared with the traditional preventive maintenance,the strategy of considering opportunistic maintenance can effectively reduce the maintenance cost by 13.6% and improve the system availability by 2.05%.Compared with the strategy without personnel constraints,the opportunistic maintenance strategy with human resource constraints can effectively reduce the maintenance cost by 7.3%,and the economic benefit is the highest.
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Remote Real-Time Hydraulic System Condition Monitoring Based on LabVIEW
DING Shen; JIA Wenhua; LIU Yanyan; WANG Yiran
Abstract:Aiming at the limitation of hydraulic system fault on the efficiency of construction machinery and equipment,a remote hydraulic cylinder status detection system based on LabVIEW was proposed.The system architecture was divided into three layers.The field device layer is based on the NI data acquisition card as the core to realize data acquisition and preliminary processing hardware platform.The data control layer mainly uses serial communication and host computer programming to realize data acquisition,processing,data storage and position alarm and other functions.The monitoring access layer is mainly based on the TCP communication protocol to realize remote data transmission and remote fault diagnosis.The test results show that the data transmission effect of the LabVIEW remote monitoring system is stable and reliable.
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Bayesian Reliability Evaluation of Cycloid Gear Grinding Machine Based on Multi-source Data
LI Jie; WANG Huiliang; SU Jianxin
Abstract:In the reliability evaluation of cycloid gear grinding machine,aiming at the problem of less field test data,a Bayesian reliability evaluation method considering the multi-source of prior data was proposed.A mixed prior distribution was established by using the credibility between different samples,and then the multi-source prior information was fused by using the Bayesian method.The fusion information was used as the integrated prior information by combining a likelihood function of the simulation data,the posterior distribution of the parameters was obtained.The simulation example shows that the MTBF point estimation value obtained by this method is 997.37,and the MTBF error is 3.2 %,which is smaller than that obtained by traditional Bayesian method.The fitting reliability curves are closer to the actual conditions,the proposed method is more accurate in the reliability evaluation of the gear grinding machine.
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Fault Identification Method of Gas Valve for Reciprocating Compressor Based on OVMD and 3D Singular Spectrum Feature Fusion
LIU Yan; KANG Li; SU Qingyong; WANG Jindong
Abstract:Aiming at the variation characteristics of fault vibration waveform caused by the fracture fault of gas valve of reciprocating compressor,in order to improve the recognition rate of common late fracture type fault in valve plate,a diagnosis algorithm based on optimal variational modal decomposition (OVMD) and 3D singular spectrum fusion was proposed.Through VMD parameter optimization,multifractal detrended fluctuation analysis (MFDFA) was used to extract 3D singular spectrum parameters of modal components to analyze,eigenvalues of modal components under different working conditions were extracted through dimension reduction combined with kernel principal component analysis,and a complete diagnosis and recognition fusion scheme of OVMD_MFDFA was established.Simulation test and algorithm comparison show that this method can be used to effectively improve the efficiency and accuracy of fault diagnosis of annular gas valve plate crack.
