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    Volume 52,2024 Issue 5
    • Research on Control Method of Five Degree of Freedom Manipulator Based on OpenMV
      ZHANG Yuhao; PANG Chenhua; SONG Zihan; QIAN Jiayi; JIANG Shubo

      Abstract:Taking the five degree of freedom manipulator as the research object,the D-H mathematical model was established,the process of calculating the joint angle by geometric method and algebraic method was explored,and the motion trajectory planning algorithm using quintic polynomial interpolation was used.By establishing the simulation model,the effectiveness of the kinematic solution method and trajectory planning algorithm was verified.An inverse kinematics analysis method based on the geometric model of manipulator was adopted to design the image recognition and processing algorithm of OpenMV camera to precisely locate the target,and the position and pose of the target were sent to the main control system to realize the function of the five degree of freedom manipulator to grab the target autonomously.Table tennis was used as the target for experimental verification.The experimental results show that using the design,the target object can be precisely located,the effective grasp is completed,and the control performance is stable and reliable.

    • Spot Welding Robot Path Planning Based on Improved Multi-objective Equilibrium Optimizer Algorithm
      ZHAO Yuntao; GAN Lei; LI Weigang

      Abstract:Spot welding robot is widely used in industrial field,and reasonable welding sequence can improve production efficiency.In order to achieve the optimal path planning of spot welding robot,a multi-objective problem model for spot welding path and working time was established,and a multi-objective equilibrium optimizer algorithm (DMONEO) combined with improved fast non-dominated sorting was proposed.Adding fast non-dominated sorting and adopting survival scoring strategy instead of crowding factor can better maintain the diversity of the population and prevent premature convergence of DMONEO.TSPLIB benchmark experiment results show that the proposed DMONEO algorithm performs better than other algorithms.Finally,the simulation experiment was carried out in the path planning model of the actual spot welding robot and compared with other algorithms.The results show that the optimization effect of the proposed algorithm is better and the time consumption is shorter.

    • Finite Element Simulation of Robotic Milling Based on Beam Structure Equivalent Model
      ZENG Zhengrong; ZHOU Yong; HU Kaixiong; LI Weidong

      Abstract:The end deformation in milling process caused by the weak stiffness of robot is an important factor affecting the surface quality of parts.On the basis of the typical tool and workpiece finite element model,a finite element model suitable for robotic milling was established by adding equivalent robot end with a beam structure.Then,the equivalent mechanical parameters of the beam structure were obtained through the force hammer experiment on the actual robot.The proposed finite element model was verified by milling 6061 aluminum alloy with a ball end milling cutter.The two different stiffness performance indexes of robot were compared and analyzed through simulation.The results show that the established model can correctly simulate the milling process of the robot,and can be used to optimize the robot milling posture;considering processing efficiency and requirements,the surface normal flexibility coefficient index based on workpiece geometry is more suitable for optimizing the posture of robot milling surfaces.

    • Research on Identification Method of Pipe Bar Binding Seam and Wire Based on Linear Structured Light
      MA Hechen; MA Lidong; MA Ziyong

      Abstract:The finishing process of special steel tubes and bars requires bundling and unbundling operations,while manual unbundling has poor environment and high strength.A method for identifying the seam and wire of the bundle was proposed based on line structured light.A binarization threshold algorithm was proposed based on the number of pixels of each luminance value of the image,and the binarization threshold was obtained by calculating the number of pixels that satisfied the luminance to reduce the influence of ambient light.For the problem that the maximum binding seam position could not be determined through the view field of a single image, a laser image mosaic algorithm based on arc vertex and endpoint features was proposed.Finally,a bundle number and state identification algorithm based on Hough transform and connected domain analysis was proposed to achieve accurate identification of the bundle characteristics of pipe and bar bundles with different sizes at the production site.The experimental results show that the proposed binarization threshold algorithm has a higher recognition rate to laser streaks compared with the traditional algorithms,and the speed is increased by 17%,the detection error of the maximum binding seam and wire identification algorithm is less than 3 mm.It fully meet the actual production needs.

    • Improved RRT* Algorithm Based on Sparse Nodes and Bidirectional Interpolation
      WANG Guoan; JIANG Chunying; TAO Guanghong; YE Changlong

      Abstract:Inspired by the negative effects of the asymptotically optimal rapidly-exploring random tree (RRT*) applied to the robot path planning,such as the low accuracy and worse environmental adaptability,an improvement of RRT* algorithm based on sparse nodes and bidirectional interpolation was presented.RRT* algorithm was carried out with the application of both target bias sampling and sparse node methods.The initial path searching efficiency was enhanced considerably by avoiding excessive searching of the local region.In addition,the redundant nodes in the initial path were eliminated using the principle of triangular inequality.By comparison,the sub-optimal path was achieved in a shortened time caused by the optimized path nodes under the approach of the bidirectional interpolation.Experimental results with a variety of simulation conditions reveal that compared with RRT* algorithm,Informed-RRT* algorithm,and Q-RRT* algorithm,for the initial path planning efficiency,up to 61% enhancement is observed with the proposed algorithm.Meanwhile,the sub-optimal path planning efficiency is increased by 59%,exhibiting an excellent stability with a variety of environments.Finally,the effectiveness of the proposed algorithm is verified experimentally in the tests of practical robot path planning.

    • Research on Calibration Accuracy of Robot Arm with Different Versions of Kinematic Error Models
      JIANG Zhouxiang; SU Rui; QIN Pengju; MENG Yuechen; LONG Zhongjie; SONG Bao; TANG Xiaoqi

      Abstract:In order to improve the kinematics calibration accuracy of robot arm,the effects of different D-H kinematics error models on identification accuracy of kinematic errors were studied for a theoretical basis of accurate modeling.The performance and linearization error of variants of SD-H and MD-H kinematic error models were compared.And their comprehensive effect on the kinematic calibration accuracy was analyzed.The results show that the x-z-y Euler transform breaks the minimality of the MD-H model and is not recommended;the performances of other full-rank MD-H model is superior to SD-H model,and the linearization error of MD-H modeling is the same with that of SD-H;with the effect of model performance and linearization error,the calibration accuracy (from 0.1% to 39.3%) using SD-H model under strong noise is better than that using MD-H model (from 0.1% to 71.2%);a significant difference between the identification accuracy of angular and positional errors is also observed.The results provide a theoretical basis for the calibration modeling methods and selection of identification methods of different types of kinematic errors.

    • Analysis on Structure Design and Motion Characteristics of Modular Robot
      TAO Guanghong; GENG Shixiong; ZHAO Jiaqi; NIE Fuxiang

      Abstract:Aiming at the problem that the deflection angle and pitching bearing capacity of traditional robot joints are limited in the process of motion,and aiming at improving the deflection and pitching motion capacity of the robot,a single motor driven biaxial deflection joint module with large deflection angle characteristics was proposed,and a pitching joint module based on parallelogram structure and spring components with low power consumption and high bearing capacity characteristics was proposed.The motion characteristics of the deflection module and pitch module were analyzed.The kinematics model of the robot based on the new modules was established,and the workspaces of the new robot and the robot based on the traditional joint under the same size and working conditions were compared and analyzed.The results show that the workspace of the new robot is significantly larger than that of the traditional robot under the same conditions,and the new joint module proposed can effectively improve the mobility of the robot.

    • Bridge Detection Robot Motion Analysis and Motion Planning Research
      DU Wenlong; CHANG Yong; ZHOU Dongyi

      Abstract:According to the convenient detection needs of bridge inspection robots for different parts of high piers and high thickness bridges,the motion analysis and motion planning research of five-degree-of-freedom bridge inspection robot were carried out.The improved D-H method was used to model forward kinematics,the two forms of kinematic inverse solutions were solved by analytic methods,the Jacobian matrix was derived,and the singular form of the robot was analyzed.The robot working space was obtained by the Monte Carlo method,the working space could cover the area to be detected.The force relationship between each joint was derived from the connecting rod force and moment balance equation,and the motion planning research was carried out based on the joint load capacity.The feasibility of the method is proved by the simulation analysis results,which shows that the robot can complete the predetermined work task requirements.

    • Analysis of Key Factors of Overhead Bare Conductor Coating Robot Operation and Optimization of Its Parameters
      CHEN Shuisheng; YANG Bo; CAI Zhiguo; CHEN Jun; WANG Jun

      Abstract:In order to improve the safety and reliability of power grid’s live operation,a robotic device,which automatically coated insulating glue,was proposed to achieve uninterrupted insulation of overhead bare conductors.By analyzing the effects of the convergence angle,inner diameter of the hose,and the working parameters of the glue injection on the coating quality of the robotic device’s glue injection system,the simulation study was carried out;the distribution laws of the pressure field and speed field of the glue injection system were obtained.The multi-objective genetic algorithm was used to solve the optimization problem of the key technical parameters of the coating operation.The optimal structure and working parameter combination of the robotic device’s injection system were obtained by taking the large hose outlet pressure,glue dispensing speed,and better colloid flow stability as the optimization goals to improve the coating quality of the glue injection system.Experimental results show that with LGJ-120/20 specification wire as an example,when the glue injection barrel convergence angle is about 23° and the glue injection pressure is about 1.925×105 Pa with a 12 mm pipe diameter,it can achieve better coating quality and meet the requirements of safe and reliable power grid live operation.

    • Design Method and Simulation Analysis of Gravity Balance of Space Tandem Mechanism
      HU Songhua; YANG Junhao; SUN Lixiong; LI Shudong

      Abstract:Taking the gravity compensation mechanism of the wearable robot space tandem mechanism as research object,a design method of centering the rotation center of the balance link and the axis of the compensator was proposed.A plane gravity compensation unit was designed in the yaw surface rotation of the balance link,then the compensation unit was modified into a space gravity compensation unit to adapt to the general rotation of the balance link.The gravitational potential energy of the tandem mechanism was regarded as the sum of the gravitational potential energy of multiple subsystems.The action mode of the space gravity compensation unit on the balance link and the compensation performance of deflection were analyzed.Finally,combining the space gravity compensation and synchronous belt structure,the gravity compensation mechanism of the space tandem mechanism was constructed.Through the simulation analysis of space gravity compensation,the gravity balance performance and the effectiveness of the proposed design method were verified.

    • Research on Contour Reconstruction Method for Ultrasonic Measurement of Pipeline Robot
      CHEN Xuanfeng; ZOU Dapeng; CHEN Shaowei; SUN Han; WU Lei; LIU Jianqun

      Abstract:Aiming at the high-precision measurement requirements of the state of biological attachments in large pipelines,a contour reconstruction method using homogeneous transformation was proposed.Through coordinate transformation,the coordinates of the offset contour were corrected back to the coordinates of the accurate contour,and the contour measurement error caused by the motion position deviation was eliminated.Through the establishment of pipeline ultrasonic measurement experimental device for experimental verification,the absolute error generated after offset reconstruction is 9 mm and the relative error is 2.36%,the absolute error generated after deflection reconstruction is 6 mm and the relative error is 1.6%.The error falls within the cm-level resolution of the ultrasonic detection system,and the contour detection accuracy can be improved by improving the resolution of the ultrasonic detection system.This method can be applied to underwater pipeline contour detection and underwater robot contour-based automatic centering detection.

    • Study on Speed Control Device for ϕ 610 Pipeline Inspection Robot
      ZANG Yanxu; JIANG Haiyang; CHEN Feng; BAI Gangsheng; LIANG Xueting; LIU Yunjie

      Abstract:The problem that the conventional pipeline inspection robot cannot be used in large flow rate natural gas pipeline because of high running speed should be solved,a speed control device was proposed to actively adjust the running speed of the robot.The ϕ 610 pipeline robot speed control device was designed,and static test,dynamic test and industrial test were carried out.The static test pressure reaches 10 MPa,the tightness and action accuracy of the bypass valve of the speed control device are effectively verified.The dynamic test results show that the pressure difference generated by the speed control device is most obviously affected when the opening amount of the bypass valve is in the range of 1/2,but which is very small when the opening amount exceeds the range of 2/3.The starting force of the pipeline robot with fixed discharge hole and actual speed reduction ability of the speed control device were tested in industrial test respectively,and starting pressure difference equation of the robot under discharge state was also established.The theoretical and experimental basis for the speed control technology of pipeline robot under the condition of large diameter and high flow rate are provided.

    • Comprehensive Performance Evaluation of Inspection Robot for Petrochemical Storage Tank
      WANG Zitong; ZHANG Shuzhong; ZENG Qinda; ZHENG Gengfeng; CHEN Haolong

      Abstract:The technology of oil tank inspection robot has developed rapidly,but it lacks reasonable performance evaluation methods.To this end,a comprehensive evaluation index system was constructed for storage tank inspection robots.A comprehensive evaluation method was proposed in which the weights were determined by the order relationship analysis (G1) method and the criteria importance though intercriteria correlation (CRITIC),the efficacy coefficient method and the virtual cloud were introduced to improve the cloud model.The index data set of 7 robots was established.The effectiveness of several evaluation methods was compared with the sum of serial numbers theory and mode theory.The results show that the evaluation method of cloud model is more practical,and the performance of the robots is mostly at the medium level,and there is still much room for improvement.

    • Design of Hydrodynamic Test System for Low Speed Underwater Vehicle
      ZHANG Liang; JI Shengjun; LI Shuzhen; SHEN Jiangjie; SHI Lei

      Abstract:Aiming at the requirement of measuring hydrodynamic characteristics for low speed underwater vehicle,a small indoor low speed open water tunnel was designed which met the similar theoretical requirements.Fluent was used to calculate the velocity distribution of each cross section for the test section,and the cross section range that met the test conditions was selected.Finally,the test platform was built,and its flow field was calibrated.The result shows that the test steady section velocity reaches 2 m/s,meanwhile,the flow field is uniform and stable,and the range is larger than 200 mm×68 mm×300 mm,which conforms to the blocking rate is not more than 25%,the length of the test section is usually three times the length of the model.The correctness of the simulation results is verified and the expected test requirements for low velocity underwater vehicle model is met.This test system is suitable for experimental conditions:velocity is not more than 2 m/s,the model length is not more than 200 mm,and cross section area of flow direction is not more than 5 000 mm2.

    • Design of Flexible Sorting System Based on ABB Robot
      CHEN Dongqing

      Abstract:Under the background of high labor cost of bottle sorting and the traditional mechanical structure cannot meet the requirements of multi-bottle flexible sorting,the flexible sorting system based on ABB robot was designed by replacing the traditional mechanism with the industrial robot,so as to realize the cylindrical bottle surface detection workstation suitable for multi-dimensional flexible production.By analyzing the formula of cylinder bottle size change and sorting operation position,two ABB industrial robots were used as actuators,and the translation function was used to realize the flexible adjustment of feeding,testing,sorting and other actions.The servo gripper was used as the end actuator to achieve the clamping of bottle with different mouth diameters.Mitsubishi PLC was taken as the control center,touch screen was taken as man-machine interaction interface,the system equipment coordination control and the interface monitoring of various functions were achieved through process design and program interface design.The debugging result shows that the system can realize automatic sorting of bottles with different sizes in the applicable range on the basis of the instruction of reference bottles,and the touch screen operation is convenient to meet the demand of flexible production.

    • Design of Pneumatic Flexible Robot Steering Mechanism Based on Heat Shrinkable Materials
      LIANG Yaosheng; LIU Xiaowei; PENG Qunjia

      Abstract:Pneumatic flexible robots have the advantages of light weight,strong environmental adaptability,no need for component drive,and good reliability under harsh conditions.However,steering motion control has always been the biggest challenge in the development of pneumatic flexible robots and restricts their large-scale application.In response to this issue,an inflatable arm type flexible robot was designed which achieved active steering function by electrically heating the heat shrink film.The end effector was modeled and designed,and the inflatable wall material and heat shrink film material were experimentally selected.On this basis,a mathematical model for thermal induced shrinkage steering control was constructed,and an experimental prototype was built to verify the steering effect.The conclusions are as follows:a PE cylinder film with a thickness of 0.08 mm is selected as the inflatable wall strip film,and a PVC heat shrink film with a thickness of 0.075 mm and a width of 20 mm is selected as the heat shrink film.The optimal heat shrink temperature is 80 ℃.Through pulse control,right angle steering is achieved.This flexible robot has good application potential in pipeline inspection.

    • Vibration Control Technology of Cantilever Joint of High Torque Robot Based on Big Data Analysis
      SONG Qinzhong; HU Hualiang

      Abstract:The problem of cantilever joint tremor of high torque robot has always affected the working efficiency of the robot.Considering the low success rate of vibration suppression due to poor signal processing ability of vibration control technology,a vibration control technology for cantilever joint of large torque robot based on big data analysis was designed.The kinematics model of the cantilever joint of the large torque robot was constructed,and the kinematics analysis results of the cantilever joint were obtained.The adaptive filter was used to obtain the working signal of the robot,and the data mining technology was used to obtain the vibration characteristics of the cantilever joint of the robot.Linear Fourier fitting method was used to design the robot cantilever joint tremor control algorithm to realize the robot cantilever joint tremor control.Application testing links were built to verify this technology.The test results show that the success rate of vibration suppression is high after the application of this technology, the problem of cantilever joint tremor can be effectively solved.

    • Dynamic Analysis and Experimental Research of Linear Cylinder with New Cushioning Structure
      ZHONG Longfeng; DU Qungui

      Abstract:The high-speed cylinder has a built-in relief valve cushioning structure,which uses the pressure adjustment to achieve the cushioning effect in the work.But there will be a energy loss and difficulties in valve adjustment.In view of this,a new type of electromagnetic cushioning structure was proposed,the electromagnetic cushioning structure and the dynamic model of high-speed cylinder were established.The test data and simulation results were basically consistent,a good cushioning effect was gotten when the cylinder run to the end of the stroke.At the end of the stroke,the speed oscillated and decelerated to 0,and reached the end point gently.The correctness of dynamic model and simulation model is verified.At the same time,the cushioning effects of relief valve,new electromagnetic cushioning and their co existence were compared and analyzed.It is found that the best cushioning effect is gotten when the two co exist,the new electromagnetic cushioning is second,and the traditional relief valve cushioning effect is not ideal.

    • Parameters Tuning of Shaking Table Based on LSTM
      ZHANG Wenpeng; JI Jinbao; WANG Dongyue

      Abstract:The control of shaking table mostly adopts three-parameter control as the underlying basic control algorithm,and there are many three-parameter control parameters,the parameters tuning is time-consuming and laborious.A three-parameter control parameter tuning algorithm of shaker based on LSTM (long short-term memory network) was proposed.The test acceleration input and output data of the shaking table system were divided into training set,test set and verification set,and an LSTM deep network was established and trained to simulate the system model of the shaking table.For the LSTM deep network model,a new three-parameter control link was introduced,and the gradient descent method was used to perform offline tuning of the control parameters.Finally,the parameters tuning were combined with the original parameters of the control system for real machine verification.The simulation results show that the proposed tuning method can achieve better results than manual parameter adjustment,and the tuning process is completed offline through the system model,without the need for real machine operation,which has the advantages of high efficiency and good effect.

    • Path Planning of pL Micro-volume Adhesive Distribution
      LI Fuxuan; LIU Huifang; JIANG Shenhui; CHEN Xi; LIU Zhanqi; CHANG Yunlong

      Abstract:In the process of pL micro-volume adhesive distribution,the itinerary of the transfer needle is repetitive,and the work is inefficient.To solve this problem,machine vision and improved GA-ACO algorithm were used to plan the path quickly and accurately,and improve the efficiency.The experimental platform of micro-volume adhesive distribution was built which consisted machine vision system,adhesive distribution system and drive control system.The location information of the fixed point on the acquired image was gotten by template matching.The path planning of micro-volume adhesive distribution was completed.Finally,the performance of the designed algorithm was compared with common algorithms.The results show that based on machine vision and improved GA-ACO algorithm,the volume of transfer adhesive reaches the pL level;the average diameter of the adhesive is 68.6 μm,and the adhesive falls exactly at the preset point;the itinerary of the transfer needle is cut by 67.9%,the working time is reduced drastically.It can improve the efficiency of pL micro-volume adhesive distribution significantly.

    • Research on Internal Surface Measurement System of Hole Parts Based on Low Coherent Interference
      CHEN Jun; DING Bin; MAO Min; CHEN Ning; GUO Gangxiang; ZU Hongfei

      Abstract:The measurement of the inner surface of a hole part is an important means to judge its machining quality and service life.A method of measuring the inner surface and signal processing based on low coherent interference was proposed for the needs of measuring the inner surface of precision hole parts,and a complete inspection system was built.The measuring principle of low coherence interference was analyzed.A detection system based on Michelson interferometer was built,including light source,detector,data acquisition instrument,reference arm,measuring arm and so on.Then,interference signal filtering and envelope peak extraction algorithm were studied.Finally,it is experimentally verified that the system can characterize the internal features of hole parts and measure the internal diameter with an accuracy of up to 10 μm.

    • Design of Temperature Control System of MPCVD Equipment Sample Table
      ZHANG Wei; REN Tianping

      Abstract:As the temperature control of the sample station of traditional MPCVD equipment requires manual adjusting the displacement of the sample station from plasma source,and the adjustment accuracy is poor,a temperature control system for the sample station was designed.At the same time,a hardware controller of the temperature control system for the sample station was designed.In the controller,STM32F407 single chip microcomputer was taken as the core,stepper motor,lead screw and metal bellows were taken as the actuator.To control the displacement of the sample table from plasma source in the cavity body,temperature control was achieve.A control method combining the improved whale optimization algorithm (WOA) and neural network PID control algorithm was proposed to realize the adaptive adjustment of PID parameters.The simulation and experimental results show that,compared with the traditional PID algorithm,the overshoot is smaller,the control accuracy is higher,and the control effect is greatly improved when using the designed temperature control system.

    • Design of Hydraulic System for Short Distance Self Crane
      JIA Shilin; RUAN Xueyun

      Abstract:At present,in the auxiliary transportation industry of coal mine,the short distance material handling and loading and unloading work in the underground basically depends on manual work,which is characterized by high labor intensity and low work efficiency.In view of the above problems,the hydraulic system of short distance self crane was designed.Through the introduction of the mechanical structure of the transport crane and the analysis of the work flow,the initial data of the relevant hydraulic cylinders were determined.The parameter calculation of the hydraulic cylinder,the selection of the hydraulic motor,the parameter design of the hydraulic pump and the design of the oil tank were completed.The work flow of the entire hydraulic system was analyzed,PLC control system was determined to control the hydraulic circuit,and the hydraulic schematic diagram of the transport crane was designed.Through the calculation of various pressure losses in the hydraulic system,it is shown that the pressure loss is within a reasonable range,which proves the reliability of the designed hydraulic system.

    • Algorithm Development and Software Design of White Light Interferometry System Based on LabVIEW
      ZHU Jing; DING Bin; MAO Min; ZHANG Xiang; CHEN Xuwen; ZU Hongfei

      Abstract:In order to fully realize the establishment and application of white light interferometry system,the software system was designed and developed on the basis of the hardware structure.The graphic programming language LabVIEW was used as the development tool.The communications with motion controller and data acquisition instrument were established to realize the coordination control of five motion axes and real-time data acquisition and analysis processing through.NET control and ActiveX control,respectively.Finally,through the test of the standard ring gauge,it is verified that using the software,not only the test task of the white light interferometry system can be completed accurately and efficiently,but also the output point cloud data can be further processed to obtain the geometric tolerance information such as diameter and cylindricity.

    • Study on the Influence of Running-in Method on the Overall Efficiency of Swash Plate Plunger Motor
      GAO Wei; WANG Zhaoqiang; WANG Jinbo; WANG Xiaoqiang; GE Zhiwei; SUN Lingtao; DONG Zhuangzhuang

      Abstract:In view of the influence of running-in method on the overall efficiency of swashplate plunger motor,through analyzing the factors affecting the overall efficiency of the motor,five newly assembled motors were tested.The tests were divided into three groups.The influence of running-in only in forward or reverse direction on the overall efficiency,the influence of only running-in with large or small displacement on the overall efficiency,the influence of full running-in of forward and reverse rotation on total efficiency under large and small displacement,were analyzed respectively.The test results show that:under the test method,if only forward or reverse running-in is carried out,there is a deviation in the total efficiency of forward and reverse rotation after a period of time,the deviation value is from 2% to 3%; if only large displacement forward and reverse running-in is carried out,the total efficiency under large displacement will reach the maximum value after a period of time,while the total efficiency under small displacement will be slightly less than the maximum value,with the difference less than 1%; if only small displacement forward and reverse running-in is carried out,the result will be opposite; if the full running-in of forward rotation and reverse rotation is carried out under large and small displacement,the total efficiency is basically close to the maximum after 12 min of running-in,and the total efficiency has stabilized after 24 min of running-in.Therefore,it is suggested that before testing the overall efficiency in the factory test,it is necessary to conduct a full running-in of forward and reverse rotation under large and small displacement according to the running-in method in the industry standard Hydraulic Motor (JB/T 10829—2008).The total running-in time is not less than 12 min.If you want to measure the overall efficiency more accurately,the total running-in time is not less than 24 min.Different motors may have differences.

    • Active Vibration Suppression of Ball Screw Feeding System Based on Magnetorheological Damper
      ZHANG Zhongkui; GAO Feng; LI Yan; ZHANG Han; YAN Yangyang

      Abstract:Aiming at the problem that the axial vibration of the ball screw feed system affects the machining quality and accuracy retention of the workpiece,the magnetorheological damper was applied to the axial vibration suppression of the ball screw feed system of machine tools.The magnetorheological (MR) damper was designed,and the damping force was identified by the least square method and BP neural network through the MR damper damping characteristics experiment.A single degree of freedom vibration model of machine tool ball screw feed system with MR damper was established,and the dynamic response of the system was calculated based on Runge-Kutta method.The results show that:the system can quickly tend to be stable as the input current of the damper increases; it can be seen from the amplitude frequency curve that it is feasible to suppress the vibration of the ball screw feed system with the MR damper.Finally,the experiment verifies that the MR damper can well restrain the vibration of the ball screw feed system.

    • Research on Flow Rate Prediction Method of Aeroengine Fuel Atomization Nozzle
      PENG Shuting; CHEN Fuzhen; YAN Hong

      Abstract:In order to guide the nozzle design and performance verification,the flow characteristics of fuel in the aeroengine fuel atomization nozzle were numerically simulated.Through the complete modeling and grid generation of the nozzle from the oil supply pipeline to the main and auxiliary nozzles outlet,the pressure drop of fuel in different parts was obtained by calculation,the flow loss of fuel in different parts was analyzed,and a nozzle flow rate prediction model was established.The results show that for the oil in the main and auxiliary oil pipelines,friction loss mainly occurs due to the friction; in the inner core of the main and auxiliary oil circuit valve,the bottom cup of the main oil circuit,the vortex box,the front of the auxiliary oil circuit nozzle and other parts,local resistance loss mainly occurs due to the sudden change of the sectional area.Both cause pressure drop with different degrees.By establishing the relationship between the geometrical parameters of key parts and the flow loss,the nozzle flow prediction model was derived according to the conservation of mechanical energy and the continuity equation.By comparing the experimental data under different oil supply pressure and different critical geometric parameters,the accuracy of the theoretical prediction model is verified,which can be well applied to the design and verification of nozzle flow rate.

    • Dynamic Simulation Analysis of Hydraulic Excavator Based on DEM-MBD Coupling
      LIU Chang; HUANG Di; CAO Chao; MU Xiangdong

      Abstract:Under actual working conditions,the working device of hydraulic excavator is subject to large loads which has strong time-varying characteristics.Therefore,various forms of failure are more likely to occur in each component bar and hydraulic cylinder of the working device.To solve the above problems,a hydraulic excavator was selected as the research object.According to the actual working conditions of the hydraulic excavator working device,the virtual prototype model of the hydraulic excavator was established using the multi-body dynamics software ADAMS and the material model was established using the discrete element software EDEM.Through the DEM-MBD coupling simulation analysis method,the dynamic simulation analysis of the working device of the hydraulic excavator was carried out.The force change curves of the bucket in the process of excavating materials and the force nephograms of the bucket at different times were mainly obtained.Through analyze the results,the force change of the bucket in the process of excavation can be obtained,which provides a theoretical basis for the finite element analysis and optimization design of the bucket.

    • Analysis of Electromagnetic Torque Characteristic of Permanent Magnet Vernier Motor with Split Pole and Concentrated Winding
      MA Zexuan; LIU Xu; LIU Fugui

      Abstract:In order to study the electromagnetic torque characteristics of permanent magnet vernier motor (PMVM) with split teeth and concentrated windings,based on the magnetic field modulation theory,the magnetomotive force permeance model of PMVM was established.The expression of the number and speed of the air gap magnetic density harmonics under the independent action of the permanent magnet and armature winding was given.The harmonics number that generated the average torque and torque ripple was analyzed.Maxwell stress tensor method was used to calculate the torque generated by each dominating harmonics,and the influence of each dominating harmonics on electromagnetic torque was determined.The analysis results were verified by finite element analysis.The results show that the electromagnetic average torque of PMVM is mostly generated by the 16th harmonic,accounting for 98.83%,and the torque ripple is mainly generated by the 16th,34th and 48th harmonic,accounting for 52.29%.The source of PMVM electromagnetic average torque is mainly the air gap magnetic density fundamental harmonic of the permanent magnet,so the amount and shape of the permanent magnet can be changed to increase the air gap magnetic density fundamental harmonic generated by it to improve the electromagnetic torque performance of PMVM.

    • Research on Distribution Characteristics of Orbit Cycloid Hydraulic Motor with Digital Distribution Mechanism
      CHEN Bao; LIU Wanxing; CHEN Gang; FU Jianghua; MA Weiren

      Abstract:In traditional orbit hydraulic motor,mechanical flow distribution is used,resulting in high mechanical and volume loss.At the same time,the motor has a large size and difficulty in processing.Based on this,a hydraulic motor that used a high-speed electromagnet valve group to achieve digital distribution and speed adjustment was studied.The operating mechanism and structural characteristics of the digital distributed hydraulic motor were analyzed;on the basis of the theoretical analysis of the orbit motor and the electromagnetic valve flow characteristics,a valve-motor dynamic model was established to simulate the proposed model;on the basis,the characteristics of the distribution and steering switching of the orbit motor were studied;by changing the PWM duty cycle,the orbit motor can better achieve two-way speed regulation.Compared with mechanical matching orbit motors,structural complexity of the orbit hydraulic motors with digital distribution has greatly reduced and the flexibility of streaming and speed adjustment is enhanced.

    • Analysis of Noise Characteristics Caused by Two-Phase Flow in Shut-off Throttle Valve
      WANG Xufei; WANG Junyu; DAI Lei; SONG Yongxing; YU Yueping

      Abstract:With the development of air conditioning technology,new throttle valves such as electronic expansion valves,shut-off throttle valves and short tube throttle valves are used in air conditioners instead of capillary tubes.However,little research has been done on the shut-off throttle valve,so the flow fields of the shut-off throttle valve were calculated at different flow rates.The distributions of pressure field,velocity field,and sound power level under different operating conditions were obtained by numerical calculations.The results show that:with the increase of valve inlet flow,the maximum flow velocity at the valve throttle increases from 44.331 3 m/s to 77.560 4 m/s;with the increase of valve inlet flow,the pressure drop at the throttle also increases gradually;when the valve inlet flow increases from 0.014 kg/s to 0.024 kg/s,the maximum noise of the valve increases from 104.640 2 dB to 122.751 5 dB;the noise in the flow field is mainly concentrated at the downstream of the valve and the throttle orifice,and the maximum noise appears at the end of the straight pipe section downstream of the valve,the distribution characteristics of noise also provide direction for further optimization of valves.

    • Flow Field Analysis and Key Parameters Optimization for the Decontamination of Dry Ice Blasting with High-Pressure Carbon Dioxide Delivery
      SUN Zhijun; PENG Zhenzhen; LIU Jinlong; ZHANG Yongling; WU Yang

      Abstract:In order to enhance the decontamination capability of nuclear facilities, a high-pressure carbon dioxide fed dry ice blasting decontamination method was proposed.Based on Fluent software,an analytical model of the flow field inside the nozzle and the decontamination chamber was established for the jet decontamination system,and the velocity distribution of dry ice particles was obtained through the flow field analysis.Using target distance,throat radius,nozzle length,dry ice particle size and pressure as key parameters and the product of impact stress of dry ice particles on the contaminated surface and distribution diameter as decontamination evaluation index,orthogonal tests for flow field analysis of 1.5 mm and 3 mm diameter nozzles were carried out respectively.By means of mean response analysis and main effect analysis,the influence law of each key parameter on the decontamination performance was grasped,and the optimal combination of parameters was obtained.The analysis results show that:after the key parameters are optimized,the decontamination performance of 1.5 mm diameter nozzle is improved by 5.64%,and the decontamination performance of 3 mm diameter nozzle is improved by 15.8%; the latter has 1.3 times more decontamination performance than the former,but the former has 3 times more CO2 utilization than the latter,providing better economy.The results of this analysis can provide support for nozzle selection and jet decontamination system parameter calculation.

    • Research on Fuel Injector Fault Diagnosis Based on Grid Search and Voting Classification Model
      ZHAO Yucheng; LI Yingjian; SHEN Shimin; HAN Yuxi; SONG Jie

      Abstract:In order to improve the efficiency of injector maintenance for high-pressure common rail test benches,an automated diagnosis method for injector faults was proposed based on grid search and voting classification models.Due to the difficulty in collecting fault data of piezoelectric injectors,AMESim software was used to simulate various fault conditions that may occurred in piezoelectric injectors under different rail pressures and pulse width states.Subsequently,the collected 1 760 sets of data were trained using a voting classification model composed of random forest,support vector machine,and GBM,and the hyperparameters of each classifier were optimized using grid search method.The experimental results show that the accuracy,precision,recall,and F1-score of this model in diagnosing the 5 fault states and normal state of piezoelectric injectors are 98.86%,99.13%,98.56% and 98.83%,respectively,demonstrating high accuracy and stability.This method can be used to locate injector faults rapidly and efficiently.

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