制造技术与机床

Rolling bearing fault diagnosis based on depth feature extraction and domain-adversarial training of neural networks

CHEN Kai, ZHANG Lihua, ZHAO Heng, CHEN Jingming

2023, (1): 9-15. doi: 10.19287/j.mtmt.1005-2402.2023.01.001

[Abstract] FullText HTML PDF(1743KB)

Abstract:
Intelligent diagnosis of bearings is the key to the intelligent diagnosis of rotating equipment. Actual bearing fault diagnosis is exposed to problems such as incomplete feature extraction and low efficiency of traditional diagnosis methods under variable working conditions. To solve these problems, a combination method is hereby proposed, and deep-level features of the original vibration signal are extracted using a deep feature extraction network combining a convolutional neural network with a wide convolution kernel and a long-term and short-term memory network. Besides, the knowledge transfer between the source domain and the target domain is realized by a domain-adversarial training of the neural network, which solves the problem of the unfavorable cross-domain diagnosis ability under variable conditions. The hereby proposed method is correspondingly verified, and the experimental results show that the proposed method can effectively extract the bearing vibration signals and identify the bearing fault types under variable working conditions, and improve the cross-domain diagnosis ability.

Feature extraction and diagnosis of bearing fault signals based on LE and DBN algorithms

YU Zhen, HE Liujie, WANG Feng

2023, (1): 16-20. doi: 10.19287/j.mtmt.1005-2402.2023.01.002

[Abstract] FullText HTML PDF(1215KB)

Abstract:
In order to improve the operation stability of mechanical transmission system, a fault signal feature extraction method based on LE and DBN algorithm was proposed. LE algorithm was selected to extract manifold parameters of high-dimensional vibration signals. The manifold learning data was input into DBN to realize the secondary mining process of feature data and complete the classification of different faults. The results show that the le-DBN model used in this paper achieves better performance than other models. LE algorithm can significantly shorten the computation time of LE-DBN combined model. The recognition accuracy of training set samples is almost 100%, indicating that the model can play a good fitting effect on training data. Compared with PCA and KPCA, LE algorithm has better feature extraction performance and can achieve nearly 100% accuracy when appropriate parameters are set. When the number of label samples is between 60 and 120, DBN network shows better classification performance than CNN network. The LE-DBN model achieves the ideal classification accuracy and fast recognition requirements for different bearing fault diagnosis.

Fault detection method of machine tool bearing based on empirical modal analysis

LIU Bin, LIU Jia, ZHANG Haipeng

2023, (1): 21-28. doi: 10.19287/j.mtmt.1005-2402.2023.01.003

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Abstract:
In order to solve the problem of fault detection of the outer ring for the motor spindle bearing using in the mainstream machine, a non-contact fault diagnosis method using the stator current signal of the machine tool spindle motor was proposed. The empirical mode decomposition (EMD) was used to analyze the non-stationary stator current signal of the machine tool motor, and the eigenmode function (IMF) of the stator current signal was extracted by the empirical mode decomposition method and applied to the Wigner -Ville distribution (WVD) to obtain the fault signal. Finally, the artificial neural network was used for pattern recognition of fault samples, which can effectively detect defects in the outer ring of machine tool spindle bearings. The test results show that the stator current monitoring with Wigner distribution based on empirical mode decomposition has the advantages of high accuracy, small amount of calculation and low detection cost. It has certain engineering practical and popularization value.

Design and performance analysis of ultrasonic generator for giant magnetostrictive transducer

WEI Zechuan, LI Jun, FENG Feng, ZHA Huiting, XU Chao, MA Yuan, ZHAO Xueqi, FENG Pingfa

2023, (1): 29-35. doi: 10.19287/j.mtmt.1005-2402.2023.01.004

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Abstract:
The ultrasonic generator for giant magnetostrictive transducer (GMT) is different from the traditional ones for piezoelectric transducers. However, there are few relevant reports of generators for GMT. In this investigation, the equivalent circuit model of GMT with contactless energy transfer was established, and an ultrasonic generator for GMT was designed. The frequency source circuit was based on direct digital synthesis (DDS), and a full-bridge switching circuit was used for power amplification. The frequency tracking strategy was implemented based on the phase sampling and RMS calculation modules, so that the ultrasonic generator could output signals with fixed frequencies and realize frequency tracking. Finally, the performance of the generator was tested and analyzed. The results showed that, the generator could output ultrasonic signals within a range of 15-50 kHz under the open-loop fixed function and could stably drive GMT to work at the working frequency for a long duration under the closed-loop frequency tracking function. Besides, this investigation also upgraded ultrasonic generator for GMT, and it was verified that upgraded generator could output more than 1 kW power by experiments.

Temperature simulation of ultrasonic assisted cutting of three-dimensional SiCp/Al composites

LIN Jieqiong, YAN Dong, LU Mingming, LI Jiacheng, GAO Xin

2023, (1): 36-43. doi: 10.19287/j.mtmt.1005-2402.2023.01.005

[Abstract] FullText HTML PDF(1911KB)

Abstract:
Aluminum-based silicon carbide (SiCp/Al) composites have been widely used in aerospace, automobile production and other fields because of their excellent properties. In order to deeply understand the cutting mechanism of ultrasonic vibration-assisted turning SiCp/Al, a three-dimensional simulation model of ultrasonic vibration-assisted turning SiCp/Al was established by using finite element simulation software ABAQUS, and the particle, matrix and cohesion models were defined respectively. According to the established three-dimensional model simulation, the SiCp/Al cutting temperatures with different cutting speeds, cutting depths, tool amplitudes and tool vibration frequencies are analyzed respectively. From the simulation results, it can be seen that when cutting SiCp/Al by ultrasonic vibration, the temperature of SiC particles is generally lower than that of Al matrix, and the temperature of workpiece is directly proportional to cutting speed, cutting depth and amplitude of cutter, but the temperature will decrease with the increase of cutter vibration frequency, and the cutting temperature in shear band is the highest.

Experimental study on ultrasonic assisted cutting of TB9 titanium alloy

LIU Le, ZHANG Yalong, GUAN Yue, JIN Hong, LIU Qianfeng, LIU Hai

2023, (1): 44-48. doi: 10.19287/j.mtmt.1005-2402.2023.01.006

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Abstract:
Titanium alloy is the main raw material of aviation fasteners, and its processing performance directly determines the service performance of aviation fasteners, which in turn affects the reliability of aviation equipment. Improving the machinability of titanium alloys is an effective way to improve aerospace fasteners. The research takes TB9 high-strength titanium alloy as the research object, and mainly compares the differences in main cutting force, surface machining morphology and tool wear characteristics between conventional cutting and ultrasonic cutting. The results show that compared with conventional cutting, ultrasonic cutting effectively reduces the cutting fluctuation and cutting force during the cutting processd; In addition, the mechanical scratch depth caused by ultrasonic cutting is reduced by 61.34 %. With the increase of ultrasonic amplitude, the surface processing quality of the TB9 titanium alloy sample is significantly improved. Moreover, the degree of oxidation wear of cemented carbide tools is reduced.

Optimization of CFRP milling tool

HE Ai, YUAN Xinman, CHEN Baolin, HU Zhiqin

2023, (1): 49-54. doi: 10.19287/j.mtmt.1005-2402.2023.01.007

[Abstract] FullText HTML PDF(2214KB)

Abstract:
Carbon fiber reinforced plastics has been widely used in the high level equipment of aerospace area. During edge milling, the tool wear is fast, and it is easy to form burr, delamination, edge collapse and other defects. Burrs on the edge are the uppermost imperfect, causing lots of manual work. Researching the means of burr inhibition is important for the enterprises therefor. Through analyzing the mechanism of burr formation in milling of CFRP, a new cutter is designed with optimized structure. The new cutter has four group of cutting areas, they are pineapple right helix cutting edges, normal right helix cutting edges, pineapple left helix cutting edges and normal left helix cutting edges. The trimming tests of CFRP are performed by the new cutter,the pineapple milling cutter and the cross-flute cutter. The results show that the edge burrs are suppressed effectively by the new cutter.

Study on the influence of elliptical vibration assisted cutting vibration parameters on machining SiCp/Al cutting force

LU Mingming, ZHOU Ruiqi, DU Yongsheng, GAO Qiang, YANG Yakun

2023, (1): 55-60. doi: 10.19287/j.mtmt.1005-2402.2023.01.008

[Abstract] FullText HTML PDF(1911KB)

Abstract:
In order to study the material removal mechanism of elliptical vibration-assisted cutting SiCp/Al composite materials and the influence of different vibration parameters on cutting forces, the finite element analysis software ABAQUS was used to establish a two-dimensional plane SiCp/Al composite cutting model, and the experimental data measured at different cutting depths of the predecessors were compared to verify the correctness of the model, and the simulation of elliptical vibration assisted cutting was carried out. Simulation results show that the average main cutting force and eating resistance are the smallest when the phase difference is π/2. With the increase of vibration frequency, the average main cutting force and knife resistance have a tendency to decrease. The amplitude of the X direction has a significant impact on the main cutting force and the eating force, and the amplitude in the X direction increases and the cutting force decreases. The amplitude in the Y direction increases, the main cutting force decreases but the eating resistance increases slightly.

Simulation and experimental study of deep hole drilling of oxygen-free copper

HAN Xiaolan, HOU Jie, ZHENG Huan, ZHANG Xukang

2023, (1): 61-66. doi: 10.19287/j.mtmt.1005-2402.2023.01.009

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Abstract:
In view of the difficulties of chip breaking and easy bond in the process of oxygen-free copper deep hole drilling, the chip morphology changes in the process of oxygen-free copper deep hole drilling were studied by combining simulation analysis and experimental research. Based on ABAQUS software, the process of anaerobic copper deep hole drilling was simulated, and the effect of the combination of feed rate and speed on chip morphology was analyzed, and the experimental study was carried out. The results show that when the speed is 255 r/min and the feed is 0.07 mm/r, short chip can be obtained and smooth chip removal can be achieved. The research of this paper provides a certain reference for the selection of machining parameters for deep hole drilling of easy cutting and hard chip cutting materials.

Research on dedicated CNC system for flexible bending machining center based on EtherCAT communication and dual-CPU bus type

WU Fenghe, WANG Shuaiqi, SUN Yingbing, ZHANG Huilong, WANG Yu, LIAN Hui, CHAI Haining

2023, (1): 67-73. doi: 10.19287/j.mtmt.1005-2402.2023.01.010

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Abstract:
Allowing for the low cost, convenience, functional integration and customization, this paper designs and develops a dedicated CNC system for flexible bending machining center based on EtherACT communication and dual-CPU bus type. Firstly, by analyzing the forming principle of the 10 axis flexible bending machining center, a control mode of "PC + motion controller" based on the EtherCAT communication and dual CPU bus type is proposed, and the hardware of the CNC system is determined; Then, based on C# programming language, the software of the dedicated CNC system is completed, and the key problems such as positioning accuracy of sheet metal, bending control with springback and human-computer interface optimization are mainly solved; Finally, the machining test and experimental verification are carried out. The results show that the machining angle error range of the special CNC system developed in this paper is less than $ \pm 45'$, and straightness gap error is less than 0.3 mm, which meets GB/T 33644-2017 standard of sheet metal industry. Moreover, the human-computer interaction is friendly, the function integration is high, and the operation is stable, which can well meet the actual production needs.

Develop and integrate special machining functions for GNC62 CNC systems

GENG Wenjian

2023, (1): 74-77. doi: 10.19287/j.mtmt.1005-2402.2023.01.011

[Abstract] FullText HTML PDF(1337KB)

Abstract:
NC machining is widely used for workpieces with complex processes, this requires highly technical ability and experience of programmers, in order to reduce labor costs, we can use the secondary development function of open CNC system to package complex processes and huge NC codes into special functions of CNC system, using this function for processing programming and operation, there are guided prompts and graphical instructions, which greatly reduce the requirements of technical experience and skills for programming and operating operators. Meanwhile, programming efficiency and operation accuracy also can be improved. Maximize the advantages and the values of open CNC systems.

Research on automatic coordinate system compensation of Huazhong NC system horizontal four-axis machine tool

YANG Kai, HU Xingping, FENG Changxi, ZHANG Ning, WU Fei, ZHAO Zhihu

2023, (1): 78-82. doi: 10.19287/j.mtmt.1005-2402.2023.01.012

[Abstract] FullText HTML PDF(1162KB)

Abstract:
Horizontal four axis machine tool, the author of this paper under the condition of no point point follow function, unable to realize the problem of automatic compensation in any position to coordinate system, through the analysis of the tip point follow the principle of combination of machine tool structure and arbitrary point coordinate transformation after the machine tool coordinate and machine coordinate system transformation relations, coordinate system automatically compensate macro program,For development research, based on NX post-processing in NX programming platform in the form of event driven post-processing, complete coordinate system automatically compensate macro program automatically output, realize Hua zhong NC system horizontal four axis machine tool coordinate system automatic compensation, product processing in the machine table any position, improve the applicability of the four axis nc machine tools.

Research on kinematic parameters optimization of robot arm based on random forest Bayesian optimization

LIU Chenhui, ZHANG Weimin, XUE Feng

2023, (1): 83-90. doi: 10.19287/j.mtmt.1005-2402.2023.01.013

[Abstract] FullText HTML PDF(1232KB)

Abstract:
As one of the essential logistics equipment in the production system, the robot arm is required to find the optimal configuration for its unknown loading and unloading trajectory and its kinematic parameters before the new product is put into production to find the optimal logistics parameter configuration scheme for the production. However, there are still some problems in optimizing the kinematic parameters of the robot arm, such as high optimization time cost and poor optimization effect. This paper is aimed at the working scenario of installing the fuel cell plate on the ABB IRB 1410 robot arm. The integrated normalized value of the motion stationarity, absolute positioning accuracy, and logistics efficiency of the robot arm is taken as the optimization objective. The Bayesian optimization based on the random forest probability surrogate model is adopted to optimize the critical kinematic parameters. The optimal experimental results are compared with Bayesian optimization based on the Gaussian process surrogate model under the same conditions. The experimental results show that, compared with Gaussian process Bayesian optimization, the comprehensive effect of random forest Bayesian optimization is improved by 15% in optimizing robot arm kinematic parameters.

Research on integrated clamping system of bench vice

YANG Xi, YIN Tiantian, GAI Lei

2023, (1): 91-96. doi: 10.19287/j.mtmt.1005-2402.2023.01.014

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Abstract:
Aiming at the problems of low working efficiency, small clamping force, and high labor intensity of the commonly used screw rod booster vise, a new clamping system is proposed, integrating screw pressure, two-speed plunger pump pressure, hydraulic cylinder-driven clamping, and embracing support. In this paper, the research progress of bench vise is analyzed. Then, the working principle, structural characteristics and calculation method of relevant parameters of the integrated clamping system are discussed. Finally, the working parameters of two hydraulic bench vise clamping systems are obtained through design calculation. The results show that the new vise clamping system has a more compact structure, larger pressurization ratio, less manual force, and fewer handle turns, making the clamping of the workpiece have enough clamping force, stable and reliable. Manual pushing the movable clamp body part for rapid movement, work efficiency is much higher than the screw drive. It is especially suitable for occasions with a large workpiece size range and frequent replacement of large and small workpieces.

A novel reaching law sliding mode speed controller design for PMSM

TAN Shudan, MA Jiaqing

2023, (1): 97-101. doi: 10.19287/j.mtmt.1005-2402.2023.01.015

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Abstract:
In the vector control system of a permanent magnet synchronous motor (PMSM), a speed controller based on sliding mode control (SMC) is designed for the problems of large d-q axis current ripple and unstable system performance due to the sampling time delay of the speed and current loops caused by the carrier period. Meanwhile, a novel reaching law is also proposed based on the power reaching law, and the speed controller designed according to the reaching law can better reduce the current ripple and chattering, and improve the system performance. The d-q axis current and motor speed waveforms in the motor experiments are analyzed from a microscopic perspective by plotting the phase diagram. Numerical simulations and experiments have demonstrated that the speed stability and response of the system can be improved by this control method compared with the conventional SMC controller.

Based on falling mechanism chaotic sparrow algorithm of AGV path planning

LI Yiming, WANG Gencheng

2023, (1): 102-108. doi: 10.19287/j.mtmt.1005-2402.2023.01.016

[Abstract] FullText HTML PDF(1501KB)

Abstract:
To address the drawbacks of slow convergence speed and poor finding accuracy of sparrow search algorithm (SSA) in AGV path planning, a chaotic sparrow algorithm based on the falling mechanism(SSA-CD) is proposed to solve the AGV path planning algorithm. Firstly, Sinusoidal chaos mapping and variable scale chaos strategy are introduced to initialize the population and improve the population diversity so that the algorithm has the ability to jump out of the local optimal solution. Finally, the optimal solution is further optimized by hermite interpolation to obtain shorter and smoother path paths. The effectiveness, feasibility and robustness of the improved algorithm are demonstrated by simulation experiments with raster maps.

Study on tracking precision characteristics of ball screw feed system under different set-trajectory conditions

LEI Meirong, SU Fang, WANG Shuwei, WANG Chensheng

2023, (1): 109-113. doi: 10.19287/j.mtmt.1005-2402.2023.01.017

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Abstract:
Ball screw feed system is an important part of high-grade numerical control machine tool, and its motion accuracy determines the processing accuracy of multi-axis machining machine tool. In the high-speed and high-precision ball screw feed system, its set-trajectory parameter is an important factor affecting the motion accuracy. In this paper, a semi-physical electromechanical coupling simulation model of ball screw feed system was built based on Simulink and Simscape, and motion accuracy simulation and analysis were carried out considering different command trajectory parameters. The results show that the position, velocity, and acceleration of the command trajectory have an important impact on the motion accuracy of the ball screw feed system. Therefore, in the multi-axis linkage machining machine tool, reasonable planning of the feed system trajectory parameters is of great significance to improve its motion accuracy.

A part machining process ranking method incorporating imperial competition and genetic algorithm

LI Shuhan, ZHOU Xueliang, LENG Jiewu

2023, (1): 114-120. doi: 10.19287/j.mtmt.1005-2402.2023.01.018

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Abstract:
Aiming at the problem of part machining process ordering in computer-aided process planning, with the optimization goal of minimizing the number of machine tools, clamping, and tool changes, a mathematical model of process order was constructed, and an optimization solution method integrating imperial competition and the genetic algorithm was proposed. The optimal processing sequence output by the imperial competition algorithm is used as the initial population of the genetic algorithm, and the solving performance of the algorithm is improved by integrating the characteristics of the imperial competition algorithm that are not affected by the initial population and the rapid convergence ability of the genetic algorithm. The experimental results show that the effect of the hybrid algorithm to find the optimal solution is better than that of the single algorithm, and the convergence speed is faster.

Multi-direction linkage loading forming process for steering nut

LIU Dan, LIU Guanghui, WANG Tao, LIU Hua

2023, (1): 121-125. doi: 10.19287/j.mtmt.1005-2402.2023.01.019

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Abstract:
The steering nut is a complex special-shaped non-circular toothed part on the automobile, which has complex structure and shape. It needs to be deformed in multiple directions and the deformation of each part is different, so the forming is difficult. The multi-directional linkage loading forming process for steering nut is proposed, on the basis of analyzing its structural shape characteristics and forming difficulties. In the process of forming, in order to improve the filling property of the material and reduce the forming force, the loading sequence, speed and stroke of each punch are interconnected controlled according to the material flow and filling situation, so as to control the material to actively flow and fill where it is needed. The metal flow law, material filling state, stress distribution and forming force in the forming process were simulated and analyzed by finite element software. The forming force of steering nut under multi-direction linkage loading is reduced by 28% compared with that under sequential loading. The experiment of the multi-direction linkage loading forming process is conducted, the formed steering nut is full filled, the dimensions meet the requirements of the drawing, and no forging defects are found. The small batch of the steering nuts were produced by using experimental dies. The experimental results show that the process is feasible and practical.

Spur gear pitch deviation detection based on machine vision

LU Haibin, ZHANG Dan, LI Changan, SUI Wentao, DOU Yaping, ZHANG Yufan

2023, (1): 126-131. doi: 10.19287/j.mtmt.1005-2402.2023.01.020

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Abstract:
Aiming at the current situation of high difficulty and low accuracy in measuring the spur gear pitch deviation, this paper detects the spur gear pitch deviation based on machine vision technology. The gear image is acquired by the machine vision system, and the improved Zernike moment sub-pixel edge detection algorithm is used to detect the gear edge; The geometric center of the gear is obtained by the center of gravity method, the number of teeth is obtained by the statistical connected region method, the radius of the tooth crest circle is calculated by the convex hull method, and the radius of the tooth root circle is calculated. The modulus is calculated by the formula of the tooth crest circle, and the radius of the indexing circle is calculated by the formula of the indexing circle; According to the measurement results, the measurement method of gear pitch deviation is given. Through the comparison and analysis between the measurement results and the actual size of spur gears, the rationality of the algorithm in this paper is proved, and the effective detection of gear pitch deviation can be realized.

Research on spinning quality of thin-walled parts based on regular polygon section

WANG Baichao, ZHANG Xinlong, GAO Jianjun, ZHANG Litong, ZHANG Hongming, WANG Huidong

2023, (1): 132-138. doi: 10.19287/j.mtmt.1005-2402.2023.01.022

[Abstract] FullText HTML PDF(1781KB)

Abstract:
Based on the new non-circular spinning forming method, the forming trajectory equation of the contour of the spinning wheel pair of polygonal parts was discussed. Taking the spinning of equilateral triangle section and regular pentagonal section as an example, the influence of three technological parameters, namely, spindle speed, feed ratio of spinning wheel and passes, on the wall thickness difference of spinning parts with regular polygon section in the spinning process of the new non-circular spinning forming method was studied. The finite element software is used for simulation analysis. According to the simulation results, the wall thickness distribution of the regular polygon spinning parts was analyzed, that is, the wall thickness of the regular polygon spinning parts was distributed periodically, and the maximum wall thickness occurs to the corner of the regular polygon spinning parts. The Box-Behnken experimental design method was used to design the simulation experiment. The variance analysis of the wall thickness difference between in the parts was carried out according to the simulation data, and the prediction model of the wall thickness difference was established and optimized. Finally, multiple groups of simulation study are carried out to verify the accuracy of the model. The results show that the spindle speed, the feed ratio of the spinning wheel and the pass have significant effects on the wall thickness difference of the regular polygon parts. The spindle speed was positively related to the wall thickness difference, while the feed ratio was negatively related to the wall thickness difference. The effect of the pass on the wall thickness difference decreases first and then increases.

Research and implementation of roughness data processing based on GPS profile method

PAN Lili

2023, (1): 139-144. doi: 10.19287/j.mtmt.1005-2402.2023.01.023

[Abstract] FullText HTML PDF(1608KB)

Abstract:
According to the GPS specification, a feasible solution for roughness data processing of profile method is proposed and the algorithm is realized by programming through the following steps: the nominal form in the measured data is eliminated by the best fitting least squares method; the Gaussian filter output function is discretized to realize the digital filter, and this Gaussian filter is used to filter out the noise, and the primary profile, roughness profile and waviness profile are derived by filtering.

A multi-objective green flexible job shop scheduling method based on improved NSGA-II algorithm

ZHENG Jincan, SHAO Lizhen, LEI Xuemei

2023, (1): 145-152. doi: 10.19287/j.mtmt.1005-2402.2023.01.024

[Abstract] FullText HTML PDF(1693KB)

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For the multi-objective green flexible job shop scheduling problem, a multi-objective optimization model with minimizing the maximum completion time, total load and total energy consumption as objectives is established, and an improved NSGA-II multi-objective optimization algorithm with adaptive crossover mutation operator and learning mechanism is proposed. In this algorithm, the initial population is obtained by the non-dominated sorting selection strategy based on global, local and random selection through a two-level coding mechanism of machine and process. Hybrid crossover mutation strategy with adaptive operator is adopted to improve the global search performance of the algorithm. A distribution function is introduced to improve the elite preserving strategy and the diversity of population. Neighborhood search is carried out by learning mechanism to improve the local search capability of the algorithm. Finally, Brandimarte and Kacem data sets are used to test the algorithm. The results show that the improved NSGA-II algorithm for solving multi-objective green flexible job-shop scheduling problems has the advantages of high precision, fast convergence and good diversity of solution sets, which can guide the practical production decisions.

Design and implementation of drawing number apply system based on machine learning

LUO Ruixu, ZHANG Hui, ZHANG Shengwen, LI Kun, FANG Xifeng

2023, (1): 153-159. doi: 10.19287/j.mtmt.1005-2402.2023.01.025

[Abstract] FullText HTML PDF(1626KB)

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For the current situation of low efficiency of drawing number apply in enterprises, a drawing number apply system based on machine learning was developed. First, the dataset is obtained by remove serial number and remove duplicates processing of the existing historical drawing number apply records in the enterprise PDM database. Secondly, the K-means++ algorithm is used to divide the dataset and the parts that need to apply for drawing numbers into several clusters, traverse the new parts in each cluster and use the KNN algorithm to get their attribute drawing numbers. For the “same name and different number” parts, the MVCNN-based 3D model retrieval technology is used to obtain the attribute drawing number. Finally, assign the latest serial number to the attribute drawing number to obtain the complete drawing number. Taking a batch of refrigerated trucks in an enterprise as an example, the correct rate of system drawing number apply is over 95%, and the efficiency is increased by 5~6 times.

Flexible job-shop rescheduling decision with hidden disturbance

SONG Lijun, XU Zhipeng, LI Fei

2023, (1): 160-167. doi: 10.19287/j.mtmt.1005-2402.2023.01.026

[Abstract] FullText HTML PDF(1626KB)

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Aiming at the rescheduling problem of flexible job shop with hidden disturbance accumulation, the determination of rescheduling time point and the selection of rescheduling mode are studied. Under the condition that the delivery time of each work piece does not exceed, by analyzing the dynamic correlation between processes, the allowable delay completion limit of each process is calculated as the time point triggered by rescheduling. Three rescheduling methods (right-shift rescheduling, partial rescheduling and complete rescheduling) are designed by genetic algorithm, and a mathematical model is established to select the rescheduling methods. Finally, the accuracy of rescheduling point and rescheduling mode selection are proved by simulation.

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