制造技术与机床

Research on rolling bearing fault diagnosis based on MDFF and DCNN-SVM hybrid network

XU Weixiao, JING Luyang, SUN Xianbin, TAN Jiwen

2023, (5): 13-20. doi: 10.19287/j.mtmt.1005-2402.2023.05.001

[Abstract] FullText HTML PDF(2449KB)

Abstract:
In view of the large number of fault types and obvious uncertainty of rolling bearings, the single signal collected often contains various redundant information and is easy to be interfered by noise signals. In this paper, based on multi-domain feature fusion, MDFF) and DCNN-SVM for rolling bearing fault diagnosis. By collecting bearing vibration signal from multiple sensors, feature extraction is carried out by time domain, frequency domain and complete empirical mode decomposition of noise set, and the sensitive features are screened by random forest algorithm. The feature dimension is reduced, and the optimized sensitive feature values are respectively input into the DCNN network for adaptive feature extraction. DCNN network was used to change the weight value of each sensitive feature quantity, and comprehensive training was carried out to obtain the multi-domain fusion feature quantity, which was input into the support vector machine for fault diagnosis. By setting multiple groups of comparison tests, it can be seen that the recognition accuracy of the proposed method is 96.82%, which is 19.95% higher than that of artificial SVM. It can effectively realize the comprehensive diagnosis of rolling bearing fault state, and has certain application value.

Fault diagnosis research of gearbox based on ICEEMDAN and PFA-ELM

LIU Kai, LI Lei, WANG Lei, CHEN Qinghui, JIN Yiyang, XU Jiawei

2023, (5): 21-27. doi: 10.19287/j.mtmt.1005-2402.2023.05.002

[Abstract] FullText HTML PDF(1702KB)

Abstract:
Gearboxes are commonly used transmission components in industrial equipment. To address the problem of insufficient gearbox fault feature extraction and diagnosis accuracy, a fault diagnosis method based on improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) and pathfinder algorithm (PFA) optimized extreme learning machine (ELM) is proposed. First, the signal is decomposed using ICEEMDAN to obtain intrinsic mode functions (IMFs). Secondly, based on the Spearman correlation coefficient, the valid IMFs are screened out and the fuzzy entropy and permutation entropy of each valid IMF are calculated as the fault feature vector. Finally, the PFA algorithm is used to optimize the weights and biases in ELM and construct a fault diagnosis model based on PFA-ELM. Experiments show that the fault diagnosis accuracy of PFA-ELM is as high as 98.67%. The method can accurately describe the working condition of gearboxes and has high practical value.

Study on the effects of short electric arc milling on TC4 machining performance

TANG Wei, XU Yan, ZHOU Jianping, WANG Bingbing, QIN Caoyang, JI Yu

2023, (5): 28-34. doi: 10.19287/j.mtmt.1005-2402.2023.05.003

[Abstract] FullText HTML PDF(2435KB)

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Short electric arc milling (SEAM) is a new type of discharge machiningmethod to efficiently remove difficult-to-machine conductive materials. Different electrode materials were used to carry out short electric arc milling experiments on titanium alloy TC4, and the influences of different discharge parameters (voltage, frequency, duty ratio) on material removal rate (MRR) and relative tool wear rate (RTWR) during machining were explored. Furthermore, the macro and micro morphology of the workpiece, the change of elements and the determination of hardness are analyzed. The experimental results shows that the factors affecting MRR and RTWR is pulse voltage, pulse duty ratio, pulse frequency. Copper electrode has high material removal rate and good surface quality. There are recast layer, droplet and micropore structures on the machined surface. The surface microhardness decreases gradually from the recast layer to the substrate, and tends to be stable at 90μm from the workpiece surface depth. It is proved that metal electrode materials are more suitable for SEAM processing titanium alloy materials, which provides a theoretical basis for SEAM processing titanium alloy parts in the future.

Laser cutting path optimization using image processing and annealing algorithm with double chain gene

CHANG Cuizhi, GAO Wenliang, YANG Xiao, LI Zicheng, HUANG Yuanfeng

2023, (5): 35-40. doi: 10.19287/j.mtmt.1005-2402.2023.05.004

[Abstract] FullText HTML PDF(1503KB)

Abstract:
To shorten the laser cutting path for improving the processing efficiency, and to avoid damaging the equipment due to cutting collisions, in this paper the cutting element is analyzed, its mathematical description is presented as well, after that it is proposed that a simulated annealing optimization algorithm is applied to seek the near-optimum path, which is based on image processing and the double-chain gene representation of the cutting path, then a program is designed to eliminate the cutting collisions. In the end the simulation by MATLAB shows that this algorithm can optimize the cutting path well ,and can also completely avoid the cutting collisions.

EDM forming precision of metal diamond grinding wheel affected by machining parameters

ZHANG Ziying, LI Xuehui

2023, (5): 41-48. doi: 10.19287/j.mtmt.1005-2402.2023.05.005

[Abstract] FullText HTML PDF(2325KB)

Abstract:
Metal fund rigid stone grinding wheel (metal grinding wheel) with the characteristics of strong grit holding, good wear resistance, abrasion-resistance and long service-life, and withstand large grinding pressure, etc., it is widely used in high performance hard and brittle materials precision, ultra-precision and efficient grinding. As a typical high hardness composite material, the conventional machining of metal grinding wheel has been extremely inferior. Electric machining is the main method of forming surface machining of metal grinding wheel, as the machining difficulties caused by high hardness of materials can be overcome by electric machining. However, there is a big gap between its machining accuracy and practical application requirements. In this paper, the electrical discharge machining(EDM) mechanism of metal grinding wheel is analyzed, and the selection of electrode materials, the selection of electrical parameters and the design of mechanical parameters are systematically studied, the selection basis of reasonable parameters is pointed out. The experimental results show that the arc accuracy and angle accuracy of the forming surface of the metal grinding wheel can reach ±0.003 mm and ±0.1°. Meanwhile, the dressing efficiency of the single grinding wheel is improved by 63.3%. This study is of great significance to improve the dressing precision and efficiency of metal grinding wheel, improve the batch stability of products and reduce the manufacturing cost.

Tool position control for three-coordinates NC milling with ball-end cutter considering geometric errors of machine tools

HUANG Mengxiang, NIU Xinghua, ZHU Haoming, ZHANG Dawei, WANG Xiangdong

2023, (5): 49-56. doi: 10.19287/j.mtmt.1005-2402.2023.05.006

[Abstract] FullText HTML PDF(2503KB)

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The important factors affecting the machining accuracy of machine tools are various errors of machine tools, among which the geometric error of machine tools is one of the main error sources. In order to eliminate the influence of geometric errors of machine tools on machining accuracy, the homogeneous coordinate transformation theory, rigid body kinematics method and topological structure analysis of machine tool kinematic chain are used to map the geometric errors of machine tools to the position errors of the ball head cutter center, taking the ball-end cutter three-coordinates NC milling as the research background.Based on the principle of forming the surface of a workpiece by milling with a ball-end cutter, a forward and reverse calculation model between the tool centre curved surfaces and the workpiece surface/design surface is constructed, taking into account the mapping between the geometric error of the machine tools and the tool centre position. The model is used to solve for a programmed tool centre curved surfaces that eliminates machine geometric errors, which is then imported into CAM software to obtain an NC machining program that eliminates machine geometric errors. The feasibility of the method is verified by the calculation and simulation of surface examples.

Tool wear analysis of titanium alloy parts based on multi-mode perception fusion

YU Zhiyong, SONG Ge, JIANG Zhenxi, LI Weidong, MAO Yiyan

2023, (5): 57-63. doi: 10.19287/j.mtmt.1005-2402.2023.05.007

[Abstract] FullText HTML PDF(1916KB)

Abstract:
Tool wear directly affects the processing quality and the service life of milling cutter. However, the existing methods are difficult to achieve effective measurement of the wear of milling cutter, which brings great quality risks to aircraft manufacturing. In order to realize the direct and effective online measurement of tool wear, a algorithm is proposed, which mainly includes the recognition and acquisition modal feature images based on convolutional neural networks, the tool wear analysis strategy based on multi-modal perceptual fusion to identify the damaged area, the specific quantitative value of tool wear based on multi-modal fusion analysis, and the tool wear evaluation based on the fusion results. Four titanium alloy milling cutters were tested. The proposed method can accurately identify defect areas, and the max standard deviation only accounts for 1.66%, 3.52%, 2.57% and 2.04% of the standard value. The results show that the proposed method has good wear loss perception fusion analysis capability, and the combination device can realize online accurate measurement of wear loss, laying a foundation for engineering application.

Finite element simulation of 304 stainless steel based on DEFORM-3D axial vibration drilling

LV Kang, FU Zhaoxia, CHEN Wei, HU Jian, LIU Shuming, WANG Xiaoyu

2023, (5): 64-68. doi: 10.19287/j.mtmt.1005-2402.2023.05.008

[Abstract] FullText HTML PDF(2752KB)

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Axial vibration drilling method can solve the problems of large drilling force, difficult chip breaking and high drilling temperature in the micro hole drilling process of difficult-to-cut materials. Based on the mechanism of axial vibration drilling, its kinematics and variable-thickness cutting characteristics were analyzed. In this paper, the finite element model of axial vibration drilling was established by using DEFORM-3D software, the axial vibration drilling and conventional drilling simulation tests of 304 stainless steel were carried out under the vibration frequency of 550 Hz, the amplitude of 16 μm, the speed of 3 000 r/min and the feed rate of 50 μm/r. The chip morphology, the axial force and torque in the two machining processes were compared and analyzed. The results show that compared with the conventional drilling, the axial vibration drilling has the better chip breaking effect, which can reduce the average axial force by about 48.1% and the average torque by about 38.2%.

Research on turning method of triple eccentric butterfly valve

CHENG Yinghao, JIA Heng, LI Peng, MA Huan, LU Jia, WEN Wen

2023, (5): 69-73. doi: 10.19287/j.mtmt.1005-2402.2023.05.009

[Abstract] FullText HTML PDF(2534KB)

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A new machining method is put forward by studying the parts of triple eccentric butterfly valve. Based on the analysis of turning and the characteristics of conical parts, by translating and rotating the coordinate system, skillfully using the conic polar coordinate equation and the simultaneous CNC lathe turning relationship, the section equation of the valve plate and the surface equation of the sealing surface are derived, so as to establish a new workpiece processing model. Then, the setting of processing parameters is discussed, and the processing effect is simulated based on MATLAB software. After the actual processing comparison test, this method simplifies the process, The common CNC lathe can also process the eccentric cone workpiece, reducing the programming difficulty, effectively improving the part processing quality and production efficiency, and providing experience and reference for actual production.

Research progress of intelligent optimization design of manufacturing process parameters

DENG Jianxin, LIU Guangming, WANG Ling, YUAN Bangyi, HUANG Haibin

2023, (5): 74-80. doi: 10.19287/j.mtmt.1005-2402.2023.05.010

[Abstract] FullText HTML PDF(1212KB)

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Process parameters are the key factors affecting the forming quality, performance, efficiency and cost of parts. The intelligent optimization design of process parameters is the basic task of current intelligent manufacturing. According to the analysis of the research hotspots and literature on intelligent optimization design of process parameters in recent years, the method of intelligent optimization design of process parameters is divided into three categories, including intelligent optimization design based on neural network, explicit mathematical model and intelligent algorithms, and expert system (knowledge), Then, the research progress and features of the three methods are analyzed, their advantages and disadvantages are summarized and compared, and the development trend of intelligent optimization design of process parameters in the future is proposed. It can provide a basis and direction guidance for the research on intelligent optimization of process parameters.

Research on green machine tool standard system

XUE Ruijuan, HUANG Zuguang, LIU Zhifeng, CAO Huajun, WU Di, ZHANG Ying, LI Congbo, ZHANG Lei

2023, (5): 81-93. doi: 10.19287/j.mtmt.1005-2402.2023.05.011

[Abstract] FullText HTML PDF(1339KB)

Abstract:
This paper introduces the application and development trend of green technology in machine tool equipment, and analyses the current situation of green machine Tool standardization at home and abroad. Based on the research of green machine tool standard system and the method of standardization, the frame of green machine tool standard system is constructed. It is expected that the green technology of machine tool and standardization work can realize coordinate development, to promote the green transformation and improving quality and efficiency of machine tool industry.

Experimental research on tightening assembly of dual arm collaborative robot based on machine vision

CHANG Chenyang, WANG Pingan, LI Bingyang

2023, (5): 94-97. doi: 10.19287/j.mtmt.1005-2402.2023.05.012

[Abstract] FullText HTML PDF(1886KB)

Abstract:
Aiming at the complicated assembly process of engine conrod and the high frequency accidents that operators are vulnerable to injury, a tightening assembly strategy of dual arm collaborative robots based on the cooperative guidance of machine vision and force sensing is proposed. On the basis of establishing the kinematics model of the dual arm collaborative robots, the robots first carries out machine vision identification and guidance through the left arm, and drives the right arm to adjust the position and pose and coarse positioning of the servo mechanism under the PID algorithm; In the precise positioning stage, the torque and tightening can work together through the force sensing information feedback at the end of the robot to achieve the precise force sensing adjustment of the tightening process; finally execute the mechanical tightening assembly program, and achieve the completely tightening process of the engine conrod through the above assembly strategy, which would improve the efficiency and safety of assembly process. The experimental results show that the assembly and installation process of the dual arm collaborative robots under the guidance of machine vision and force sensing is controllable in the whole process, and the assembly results meet the requirements of the production process, which can be well implied in the serial production.

Optimization design of CNC lathe spindle box based on RBF neural network model

QIAO Xuetao, ZHOU Shitao, LI Youhua, CAO Kang, SHENG Kun, ZHANG Hongwei

2023, (5): 98-104. doi: 10.19287/j.mtmt.1005-2402.2023.05.013

[Abstract] FullText HTML PDF(2067KB)

Abstract:
A structural optimization design method based on an RBF neural network model and combined optimization strategy was proposed in order to obtain the explicit functional relationship equation between design variables and performance objectives in the structural optimization of complex machine tools. Taking a type of precision lathe spindle box as the research object, the optimal Latin hypercube experimental design and sensitivity analysis of the spindle box design dimensions was carried out using the joint simulation technology of finite element software ANSYS Workbench and multidisciplinary optimization software Insight and the RBF neural network model was constructed in addition to the spindle box finite element model according to the experimental sample points. A combined optimization strategy combining multi-island genetic algorithm (MIGA) and sequential quadratic programming method (NLPQL) is used to optimize the design of the RBF neural network model. The optimization results show that the mass is reduced by 12.89% while the static and dynamic performance of the spindle box is guaranteed, which achieves the expected results in a more efficient way than the standard optimization.

Research on bearing performance of T-type composite structure aerostatic bearing platform

CUI Xinkuan, LU Zhiwei, ZHANG Xiaobing, LIU Bo, ZHANG Junan

2023, (5): 105-110. doi: 10.19287/j.mtmt.1005-2402.2023.05.014

[Abstract] FullText HTML PDF(1638KB)

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In order to deeply explore the bearing performance and law of aerostatic bearing under radial and axial combined working conditions, a T-type composite structure aerostatic bearing platform had been designed and developed. Combined with the 3D model of the T-type composite structure aerostatic bearing platform, the fluid lubrication theory and the finite volume method had been used to numerically calculate the aerostatic combined bearing and the single radial bearing. The effects of eccentricity, air supply pressure and rotational speed on the bearing capacity and stiffness of the aerostatic bearing had been explored. The results show that the bearing capacity of aerostatic bearing has gradually increased with the increase of eccentricity and air supply pressure. The bearing performance of a single radial bearing was better than that of a combined bearing.

Simulation modeling of rivet nut installation process and study of locking torque recession

WANG Lijun, KE Shuzhong, GAO Jingjing, ZHOU Yubao, LV Huihui, LI Hao

2023, (5): 111-118. doi: 10.19287/j.mtmt.1005-2402.2023.05.015

[Abstract] FullText HTML PDF(2918KB)

Abstract:
Blind rivet nut is a new type of fastener, now widely used in the automotive, aviation and construction fields. In this paper, a 3D finite element numerical simulation model of the blind rivet nut installation and failure process is established with ABAQUS simulation software. Combined the simulation analysis as with the experimental research, the influence of the thickness of the rivet nut deformation zone on the fastener installation forming and closure process parameters on the locking torque were investigated respectively. The results show that the riveted structure has the highest axial pull-off force at a deformation zone thickness of 0.44 mm and is able to closely fit the connected parts. In addition, the use of a rectangular closure ensures that the riveted nut obtains a relatively uniform radial deformation and a sufficient locking torque. Furthermore, the decay of the locking torque was investigated and the decay of the rivet nut after repeated use was investigated. Carry out the influence of the rivet nut deformation zone thickness and the form of closure on the mechanical properties of the jointed, which has a certain reference significance for the design and manufacture of such fasteners.

Design of DOB compensation gain PID damping controller for electromagnetic drive fast tool servo closed-loop system

LU Yinju, LIU Mengmeng, XIE Zhongbing, LI Feng, ZHANG Guoqiang

2023, (5): 119-123. doi: 10.19287/j.mtmt.1005-2402.2023.05.016

[Abstract] FullText HTML PDF(2696KB)

Abstract:
In order to make up for the driving shortage of fast tool servo (FTS) system, an electromagnetic driven DDS system was developed to realize the tracking control method of high bandwidth trajectory. The feedforward compensation of parameters is realized by using static gain, and the disturbance observer (DOB) is established by linear control to compensate the feedforward gain processing. The experimental test and analysis were carried out to collect control instructions from the controller to realize the driving effect on FTS excitation coils and complete the output displacement control. The results show that the resonant peak can be suppressed obviously when using PAVPF controller. The damping control keeps the stability margin constant, and then the higher gain PID controller controls the system to achieve a significant increase in the closed-loop bandwidth of the system. PAVPF damping reaches ±2 μm error; After increasing the DOB gain, the maximum error reduction of the system is close to ±0.16 μm. The research has a good control precision, which plays a theoretical supporting role for high precision tool control.

Effect of welding sequences and welding direction on the residual stress in X80 pipeline steel

WANG Haobo, CHEN Xiaokang, LI Jianjun, WANG Kedian

2023, (5): 124-128. doi: 10.19287/j.mtmt.1005-2402.2023.05.017

[Abstract] FullText HTML PDF(3507KB)

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In response to the problem of a number of cracking accidents in the application of X80 pipeline steel in recent years. Double ellipsoidal heat source model was used and a V-shaped weld filler used raw and dead cell technology to build a numerical simulation process for welding. A combination of experimentation and simulation was used, the effect of two different welding sequences and four different directions on the weld residual stresses of X80 pipeline steel in multi-layer and multi-pass welding were compared and analyzed. The results show that the welding sequence has a significant impact on the residual stress in the weld zone and HAZ, and the peak residual stress is only 296.4 MPa when using the symmetrical welding sequence is 29.3% lower than the peak stress of the sequential welding sequence. The welding direction on the weld zone and HAZ residual stress was not significant. Numerical calculation results match the experimental results better and the calculation results have some guidance for welding experiments.

Research on craft decision making method based on knowledge graph

LV Kuankuan, XUE Jinxue, MIAO Shukang, ZHAO Guoqiang, WANG Yipeng

2023, (5): 129-134. doi: 10.19287/j.mtmt.1005-2402.2023.05.018

[Abstract] FullText HTML PDF(1511KB)

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In the development of CAPP system integration, instrumentalization and intelligence, decision reasoning and intelligent technology of craft scheme are the key points. Traditional craft decision making method has the problem that it can not make intelligent choice in multi-craft scheme. To solve this problem, a craft decision reasoning method based on knowledge graph representation learning was proposed. In this method, the translation distance model is used to represent the craft knowledge vectorially, and the distance between the ideal result and the decision result is obtained by vector operation. After model training, the distance is constantly reduced, which leads to the stability of the loss function. Finally, the optimal result is obtained, and the rationality of the decision scheme is strengthened by fuzzy function calculation and analysis. The problem of intelligent decision in multi-craft scheme is solved. In this paper, P0 class 6203 bearing is used as an example to verify the proposed method. The results show that the proposed method can effectively realize the decision-making of the parts craft scheme and improve the ability of intelligent decision-making of the CAPP system.

Study on micro/nano structure formation process of stainless steel machined by femtosecond laser

XIAO Qiang, HE Xueli, XU Rui

2023, (5): 135-142. doi: 10.19287/j.mtmt.1005-2402.2023.05.019

[Abstract] FullText HTML PDF(3293KB)

Abstract:
The specific experimnt of femtosecond laser processing stainless steel was carried out.By setting different process parameters, the influence law of different variables on various indexes of surface microstructure in single factor experiment is studied, and its formation mechanism is analyzed and summarized; The orthogonal experiment was further designed, the matrix array structures with different morphologies were obtained by changing the process parameters, the comprehensive surface processing under multiple factors was studied, and the effects of various factors on the depth, width and roughness of microstructure were summarized; The range analysis of the results is carried out to determine the most influential processing factors, and the optimal processing level within the set parameters is obtained.

Research on NC machining technology for complex thin-walled shell of a carrier rocket

WU Longmei, KANG Quan, ZHOU Mingjun

2023, (5): 143-149. doi: 10.19287/j.mtmt.1005-2402.2023.05.020

[Abstract] FullText HTML PDF(2498KB)

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Aiming at the problems that large complex thin-walled shell is easy to deform and the machining precision is difficult to meet the requirements, the NC machining technology is studied. Take the tail section of a carrier rocket as an example, in order to effectively control the machining deformation and guarantee the accuracy of the product. The structural characteristics of the workpiece and the main factors affecting the machining deformation are analyzed, targeted to develop a reasonable NC machining process scheme, including reasonable arrangement of machining process, the use of appropriate stress reduction and aging methods, optimization of clamping scheme and reasonable planning of tool path, to achieve the deformation of the workpiece control and effective clamping, to ensure the finished workpiece precision requirements. Finally, the correctness and effectiveness of the process plan are verified by the actual processing application.

Research on working quality evaluation method of cone outer surface mounting manipulator

HUO Kai, LIU Yulin, SUN Jianghong, WANG Zenggang, HE Yufan

2023, (5): 150-154. doi: 10.19287/j.mtmt.1005-2402.2023.05.021

[Abstract] FullText HTML PDF(1870KB)

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A manipulator is designed for the problem of conical surface mounting and its working quality is evaluated. Firstly, the configuration of the manipulator is designed, the working principle is clarified and the spatial degree of freedom is calculated by using the modified GK formula. Secondly, the quality evaluation method of mounting work is proposed. The concept of surface displacement is proposed to evaluate the degree of fit. The surface displacements in the two directions of circumference and generatrix are collected respectively and the range and variance are calculated. The range and variance in the two directions are averaged and the reciprocals are weighted by 0.99 and 0.01 to obtain the original mounting quality evaluation parameter S value. Thirdly, the orthogonal test is designed with the mounting height and mounting strength as variables, and the S value is collected and calculated to obtain the F value of the influence degree of the variable on the mounting quality. Fourthly, the effectiveness of the evaluation method proposed in this paper is verified by the plane paving test which does not involve the change of mounting height. Finally, this method is applied to the conical surface. The results show that any single increase in the mounting strength and mounting height can improve the mounting quality. Under the combined action of the two factors, the corresponding F value of the mounting strength is 10.32, and the corresponding F value of the mounting height is 3.50.

Research on acoustic time difference-surface stress relationship acquisition method based on critical refractive longitudinal wave

DAI Yuhong, NIU Nana, LIU Heqiang, REN Huiling, HAO Xiaoqin, SUN Fan

2023, (5): 155-158. doi: 10.19287/j.mtmt.1005-2402.2023.05.022

[Abstract] FullText HTML PDF(1188KB)

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The presence of stress on key parts of the machine tool will aggravate its friction and wear that seriously affect the machining accuracy and service life of the machine tool, and it is very important to detect the stress on the surface of the structure. In this paper, the detection principle of ultrasonic critical refractive longitudinal wave is explored, and the influence of various factors on the reflection coefficient of acoustic jet lag is analyzed. According to the material parameters of the test piece, the angle of the wedge block was designed; Ten standard experimental pieces were designed and processed, and the acoustic time difference reflection coefficient of ten test pieces was measured by tensile testing machine and ultrasonic testing device. The reasons for the different acoustic jet lag coefficients were analyzed, which provided theoretical and methodological support for the detection of surface stress based on ultrasound.

Research on reliability allocation of mechanical system based on comprehensive factor fuzzy analytic hierarchy process

HU Qiguo, ZHAO Shengdong, LI Zhiming, ZHOU Xiaoming, HAO Jianxu, XU Xiangyang

2023, (5): 159-165. doi: 10.19287/j.mtmt.1005-2402.2023.05.023

[Abstract] FullText HTML PDF(1012KB)

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Reliability allocation is an important method to reasonably allocate reliability indexes to each subsystem and ensure the stability of mechanical system. In order to improve the accuracy of reliability allocation, a reliability allocation method of mechanical system based on comprehensive factor fuzzy analytic hierarchy process is proposed in this paper. Firstly, the system hierarchy is established, and the analytic hierarchy process is used to distribute the weight of different influencing factors. Then, the comprehensive factor fuzzy evaluation method is used to conduct fuzzy evaluation and uncertainty information processing on the subsystem, so as to establish a fuzzy relationship matrix, determine the factor combination weight, and obtain the system reliability distribution scheme. Finally, combined with the analysis of industrial robot system, it meets te requirements of reducing the reliability allocation index of reducer and improving the reliability allocation index of robot arm and controller in industrial robot system.

Research on optimization of balance and sequencing of mixed-model assembly lines in simulation environment

ZHAO Qianhong, ZHU Chengshun, ZHANG Hui, SUN Gaofeng, FANG Xifeng, QI Jie

2023, (5): 166-172. doi: 10.19287/j.mtmt.1005-2402.2023.05.024

[Abstract] FullText HTML PDF(1764KB)

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In view of the problems of long queuing time, low assembly efficiency and failure to meet the order needs of customers arising from the unbalanced station load in the process of mixed-model assembly of wind power brake in an enterprise, on the basis of parallel consideration of the interaction between balance and sequencing of mixed-model assembly lines, a multi-objective optimization model is established to minimize the maximum completion time and the station load index. An improved Fruit Fly Optimization Algorithm based on Pareto is proposed. The hybrid parallel coding is composed of three parts: the number of stations, the type of stations, and the feeding order of the loading frame. Multi-group strategy, adaptive step size, and elite retention strategy are introduced to ensure that good individuals are not destroyed. Based on the example analysis and data basis and through Python language development environment, the algorithm program was developed to obtain the new balancing and sorting scheme and the balancing and sorting scheme for the simple genetic algorithm. The optimal balancing and sorting scheme of the above algorithms were simulated on the Discrete System Simulation Software - Plant Simulation to verify the effectiveness of the algorithm.

An improved genetic algorithm based on multi-objective optimization is used to solve the flexible job-shop scheduling problem

LI Changyun, LI Tingyu, WANG Zhibing, GU Pengfei, LIN Duo

2023, (5): 173-178. doi: 10.19287/j.mtmt.1005-2402.2023.05.025

[Abstract] FullText HTML PDF(1625KB)

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This paper focuses on the multi-objective flexible job-shop scheduling problem. Because in the actual production process, the scheduling results from completion time, the machine load, cost control, resource consumption and other factors influence, so this paper puts forward a kind of improved genetic algorithm based on multi-objective optimization, to minimize the maximum completion time, minimize the machine load and minimize resource consumption three objective function optimization, combined with the improved Pareto multi-objective optimization method, the shortest processing time variation method and the neighborhood variation method, the optimization ability of the algorithm is improved. Finally, the experimental results show that the proposed algorithm is suitable for solving multi-objective flexible job-shop scheduling problem.

A variable neighborhood bee colony algorithm based on crossover and selection strategy for permutation flow-shop scheduling problem

QI Xiangbo, WANG Hongwei, MA Zhiqiang

2023, (5): 179-187. doi: 10.19287/j.mtmt.1005-2402.2023.05.026

[Abstract] FullText HTML PDF(1549KB)

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According to the characteristic of permutation flow-shop scheduling problem, a variable neighborhood bee colony algorithm based on crossover and selection strategy is designed. Firstly, the NEH heuristic algorithm is added in the initial population stage to improve the quality of initial solution. At the start of the algorithm iteration, for the purpose of improving the diversity of solution, differential evolution operator is added to crossover and selection. In the local search stage, two variable neighborhood operations of swap and inverse are added to 50% optimal individuals to enhance the search ability of the algorithm. Selecting appropriate parameters through orthogonal experiments, and conducting simulation experiments on Car, Rec and Taillard standard test sets, the results show that the proposed algorithm is superior to other swarm intelligence algorithms compared with it. Finally, the job scheduling problem on the tire production line of a company is solved with the optimization objective of minimizing the makespan. The results are better than the compared algorithm, which further verify the feasibility of the proposed algorithm in solving PFSP.

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