Table of Content

25 July 2020, Volume 31 Issue 14

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Modeling and Reliability Evaluation for Electromechanical Systems Based on Probabilistic Behavior Trees

YANG Peilin, LIU Qing, FAN Juanni, HOU Yi

2020, 31(14):  1639-1646.  DOI: 10.3969/j.issn.1004-132X.2020.14.001

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Modeling systems directly using formal language provided by model checker were non-intuitive and difficult. Therefore, probabilistic behavior trees were introduced to model the electromechanical systems and evaluate their reliability through probabilistic model checking herein. States and transitions of function carriers in the function execution of electromechanical systems were studied. Based on the syntax and semantics of probabilistic behavior trees, an approach was proposed to model the state transition of electromechanical systems by probabilistic behavior trees. A support tool for probabilistic behavior tree modeling was developed, which could establish the model of electromechanical systems with probabilistic behavior trees and translate the model into the formal model based on PRISM codes. Based on the potential faults in electromechanical systems, continuous stochastic logic formulas were employed to specify the reliability evaluation indices formally. With the probabilistic behavior tree model and formal specification of reliability evaluation indices, reliability evaluation was implemented using probabilistic model checker PRISM. Compared with the modeling method using formal language directly, the method presented herein is more intuitive, easier to understand and use.

A Novel Forward Position Kinematics Modelling Principle for Mechanisms Based on Ordered Solutions for SOC Units and Its Two Solving Methods

SHEN Huiping, XU Ke, YANG Tingli

2020, 31(14):  1647-1658.  DOI: 10.3969/j.issn.1004-132X.2020.14.002

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A novel modeling principle for solving the position forward solution of any mechanism was presented based on ordered SOC units. Firstly, the mechanisms were decomposed into a series of SOC units with different constraint degrees based on the principle of mechanism composition. Then, according to the principle that the sum of all constraint degrees was equal to zero, a series of SOC units were grouped into several basic kinematic chains(BKC_i) with zero degree-of-freedom and the value of coupling degree was κ_i. Position equations for each BKC_i with the minimum number of variables were obtained. In addition, two methods, i.e., numerical solution and closed-form solution were given. The numerical method was relatively simple, and the position equation of the mechanisms was solved directly by κ-dimensional search method. However, the closed-form solution, nonlinear position equations with higher order were firstly derived from the position equation of the mechanisms with κ virtual variables by using the symbolic processing of Mathematica, and then the higher order equation was solved by using the conventional method. Four examples were illustrated in details. The solving processes of the kinematics modeling principle that considers the ordered topological decomposition and SOC unit solution and its two methods are clear, and the solving method for forward solution of parallel mechanisms may be simplified and its calculation amounts are greatly reduced. The kinematics modelling principle is suitable for solving the position forward solution of any complex planar and spatial parallel mechanisms.

Suspension Control Applications of Magnetorheological Damper Magic Formula Model

ZHANG Lixia, PANG Qiqi, PAN Fuquan, GE Xiaohan, LIN Binqin, HE Yichao, WEI Yintao, DU Yongchang

2020, 31(14):  1659-1665.  DOI: 10.3969/j.issn.1004-132X.2020.14.003

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The parameters of the magnetorheological damper magic formula model were identified based on the experimental data of a certain magnetorheological damper. The errors of the model were within 8%. Under the conditions of simplifying the magic formula of magnetorheological dampers, the reverse model of the magnetorheological damper magic formula was obtained by direct inverse thrust. In the simulations, when the magnetorheological damper magic formula positive and inverse models realized the expected damping forces of the ADD control strategy, the average errors are 3.67%. In the bench test, the applications of the inverse model of the magnetorheological damper magic formula reduces the body acceleration of 6.27% and realize the control effectiveness of the new control strategy. Finally, the magnetorheological damper magic formula model was successfully applied to the semi-active control suspension system simulation and bench test. The research on magnetorheological semi-active suspension control system has strong practical significance.

Assisted Driving Method of Network-connected Vehicle in Out-of-sight Roads

ZHANG Hongchang, GUO Jun, ZHAO Wei, MI Xinglin, ZENG Juan

2020, 31(14):  1666-1671.  DOI: 10.3969/j.issn.1004-132X.2020.14.004

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A assisted driving method of network-connected vehicle was proposed for solving the problems that out-of-sight road conditions in front of vehicles which were not easy to predict, and the drivers were prone to dangerous accidents such as misoperation of vehicles due to unclear road conditions. A assisted driving system of network-connected vehicle was designed based on real-time communication technology of vehicle networking. The system was mainly composed of cloud service, shared stations and vehicle-mounted units. The methods of road condition information identification was studied based on moving vehicles, including road adhesion coefficient identification, road curvature calculation and pavement slope measurement. Then the fusion and correction method of road condition information was studied based on multi-vehicle measurement data, and a calculation model of the safe driving speed on a bend was established based on three-degree-of-freedom vehicle model. The real vehicleing test results show that the proposed method may accurately measure the road condition information of the roads out of sight, and may enable the driver to obtain the out-of-sight road traffic informations in advance and accurately, especially the road condition information of the bend.

Tool Reliability Analysis for Wear Degradation Data under Competitive Failure Conditions

WANG Xingang, ZHANG Xinyao, YANG Lujie, MA Ruimin

2020, 31(14):  1672-1677,1746.  DOI: 10.3969/j.issn.1004-132X.2020.14.005

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The reliability of turning tools in the competitive failure mode was studied. The Weibull distribution was introduced to describe the reliability model of catastrophic failures. The Gamma process was used to describe the cutting tool performance degradation processes. The cutting tool failure was evaluated from the perspective of the amount of degradations, and the reliability model of the competition failure was established by considering the conditional probability of hard failure based on the degradation value. The least square method was used to estimate the parameters in the model. Based on the wear degradation of the VBMT090208 external turning tool as the data, the reliability both of the catastrophic failures and the degraded failures in the competitive mode was established respectively. The results show that if the catastrophic failure is ignored, only the degradation failure modeling of the tools is performed, or the competitive failure reliability models of catastrophic failures and degradation failures are constructed under independent conditions, the reliability of the tools will be overestimated.

Factors Influencing Rotation Accuracy of Four-point Contact Ball Bearings for Robots

CHEN Yue, QIU Ming, DU Hui, YANG Xu

2020, 31(14):  1678-1685,1692.  DOI: 10.3969/j.issn.1004-132X.2020.14.006

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In order to overcome the difficulties in predicting and controlling the rotation accuracy of the four-point contact ball bearings for robots, a numerical method for calculating the rotation errors of the bearings was proposed considering the roundness errors of inner and outer raceways. Firstly, according to the kinematics and geometry relationship of the internal components of the bearings, a numerical calculation model of the rotation errors of the bearings was established. Then, the program for calculating the rotation errors of the bearings was written using MATLAB. the effects of the magnitude and order of the roundness errors of the outer raceway, the magnitude and order of the roundness errors of the inner raceway, the diameter deviation and the number of the steel balls on the rotation accuracy of the bearings were obtained. Finally, experiments on rotation accuracy of the bearings were carried out to verify the correctness of the simulation results. The rotation accuracy of the bearings involves many indicators. The rotation accuracy of four-point contact ball bearings studied herein refers to the radial runout of outer ring of the bearings. The results show that the radial runout of outer ring of the bearings increases smoothly first and then rapidly with the increase of the magnitude of the roundness errors of the inner and outer raceways, changes periodically with the increase of the order of the roundness errors of the inner and outer raceways, decreases linearly with the increase of the diameter deviations of the steel balls and decreases exponentially with the increase of the number of the steel balls. The problem in getting the rotation accuracy of the four-point contact ball bearings theoretically is solved with the model. The rotation accuracy of the bearings may be predicted accurately and a theoretical basis may be provided for the accuracy design of the four-point contact ball bearings.

Wafer Manufacturing Data Anomaly Detection Based on Error Attention

YU Shilong, BAO Jinsong, LI Jie, ZHANG Qihua

2020, 31(14):  1686-1692.  DOI: 10.3969/j.issn.1004-132X.2020.14.007

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In wafer manufacturing processes, it was difficult and inefficient to extract abnormal data in the anomaly detection. Therefore, an anomaly detection method was proposed based on error attention mechanism. Firstly, the wafer manufacturing data was converted into grayscale images while keeping the data distribution unchanged. Then, based on the errors with the normal sample, a position-based flexible attention map was generated for the grayscale images. The dominant expressions of the error features were developed while the redundant features areomitted. In addition, deep learning neural network model LeNet-5 was used to perform convolution training to obtain an optimal model for anomaly detection. Finally, the wafer fabrication data set was used to compare the performance between the proposed method and the existing methods. The proposed method reduces the time consuming by 160% and increases the F2-Score by 3%, which verifies the effectiveness of the method.

Data Communication Technology and Applicationins for Intelligent Manufacturing Workshops Based on OPC UA

SONG Tingxin, LI Ke

2020, 31(14):  1693-1699.  DOI: 10.3969/j.issn.1004-132X.2020.14.008

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In order to realize data communication and unified information management with various devices, a data communication technology of intelligent manufacturing workshops was proposed based on OPC UA architecture herein. The communication principles and network architecture were discussed. An integration scheme of OPC UA and industrial ROS and sensor embedded system was proposed. The data communication programming method was discussed in case study based on Python language, and the MES(manufacturing executive system) robot monitoring module was developed based on OPC UA. The practical applications show that the data communication technology based on OPC UA has high versatility and compatibility, and may effectively realize data integration and unified management of equipment information in intelligent workshops.

Multi-dimensional Analysis Method of Industrial Big Data Based on JSON Document Structure

LI Minbo, XU Xinxing, LI Qiang, HAN Le

2020, 31(14):  1700-1707,1716.  DOI: 10.3969/j.issn.1004-132X.2020.14.009

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The growing industrial big data made data analysis and mining extremely complicated since they had complex correlations and multi-source heterogeneous characteristics in the intelligent manufacturing processes. However, the traditional industrial big data analysis approach based on the relational database or data warehouse was not flexible to deal with multi-source heterogeneous data and was less efficient to do search and analysis operations. An OLAP model architecture of industrial big data was presented based on JSON document structure, which might use Key-Value data to flexibly define diverse industrial data structure. The table structure in the dimensional information was converted into a JSON-based document structure, and the dimensional information contained in the fact table was stored by nested document. Then constructing a document tree and the analysis target was the root node, and used Elasticsearch to store the document structure tree and built an inverted index, which might improve the efficiency of the data analysis query. The query and analysis operations were transformed into the traversal and query operations in the document contents. An intelligent parsing engine which might design custom search conditions and query statements was realized to generate intelligent visualization chart related to multidimensional industrial data.

Automatic Extraction Method for Corresponding Relationship among Endpoint-to-location of Cable Wiring under Coordinate System Guidance

WANG Falin, GUO Xuepeng, LI Zhinong, SONG Likang

2020, 31(14):  1708-1716.  DOI: 10.3969/j.issn.1004-132X.2020.14.010

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To solve the problems of the low efficiency and error-prone of manual search for the corresponding relationship of endpoint-to-location among cable endpoints and electrical connector's wiring positions in complex mechatronic products, an automatic extraction method of corresponding relationship among endpoint-to-location of cable wiring was proposed based on coordinate system guidance. Firstly, a cable information model and electrical connector information model were established based on cable wiring process planning, and the cable information and the electrical connector information were extracted by the feature extraction technology. Then the endpoint coordinate system of cable and the point coordinate system of electrical connectors were established, the relationships were analyzed after transform the two coordinate systems into the assembly coordinate system by coordinate transformation, thus the corresponding relationship of endpoint-to-location among the cables and the electrical connectors were automatically extracted based on coordinate system guidance. Finally, the method was applied to the automatic extraction of corresponding relationship among endpoint-to-location of cable wiring of phased array radar. The examples prove that the corresponding relationship of endpoint-to-location among the cable endpoints and the electrical connector's wiring positions are extracted quickly and accurately by the proposed method.

Discrete Element Simulation for Effects of Roller's Vibrations on Powder Spreading Quality

ZHANG Jiangtao, TAN Yuanqiang, BAO Tao, XU Yangli, JIANG Shengqiang

2020, 31(14):  1717-1723.  DOI: 10.3969/j.issn.1004-132X.2020.14.011

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Al₂O₃ ceramic powder was selected as research object, and a DEM model of Al₂O₃ ceramic powder flow was established. Aiming at the effects of roller's vibrations on powder-bed quality in additive manufacturing powder spreading processes, the effects of roller's vibration directions, amplitudes and frequencies on the compactness, uniformity and flatness of powder-beds were simulated. The simulation results show that the roller's axial vibrations may improve the compactness and uniformity of powder-beds, while will cause powder-bed flatness to deteriorate. The roller's radial vibrations may lead to poor powder-bed flatness. When the vibration amplitude is greater than 8 μm, powder-bed quality is significantly worse due to compression and rebound effect of particles. The roller' tangential vibrations may improve the compactness and uniformity of the powder-beds, and have little effects on the flatness of the powder-beds. However, it is easy to cause powder splash when the frequencies of tangential vibrations are too high. This study shows that applying low-frequency vibrations to rollers in the tangential directions may improve the powder-bed quality effectively in additive manufacturing processes.

Energy Efficiency Modeling, Process Parameter Optimization and Sequencing Modeling Optimization of Cold Rolling Continuous Annealing Units Based on Energy Consumptions

YANG Jie, HU Qi, XIAO Ting, ZHANG Wenying, ZHANG Chaoyong

2020, 31(14):  1724-1732.  DOI: 10.3969/j.issn.1004-132X.2020.14.012

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The furnace area with concentrated energy consumption of cold rolling continuous annealing units was studied. The theory of energy flow and thermodynamics was used to establish a mapping model between energy consumption and main process parameters. Combining MATLAB and an improved quantum genetic algorithm, the energy efficiency model was optimized to obtain a process parameter combinations with the highest energy efficiency under the premise of quality assurance. The minimum energy consumption of auxiliary equipment, the smooth transition of production specifications and the satisfaction of delivery time were used as optimization targets. The multi-objective optimization model of production scheduling for cold rolling continuous annealing lines was established and solved by NSGA-Ⅱ, and then the optimal sorting was presented. The results show that the model and the algorithm have a certain guiding effectiveness on production.

Multi-depot Half Open Vehicle Routing Problem with Time Windows

GU Yong, YUAN Yuanyi, ZHANG Lie, DUAN Jingjing

2020, 31(14):  1733-1740.  DOI: 10.3969/j.issn.1004-132X.2020.14.013

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Aiming at the vehicle routing problem under multi-depot collaborative distribution, a minimization model of total costs was established. The model satisfied the characteristics of multi-depot, multi-demand points and half-open. Considering the complexity of the problem, a three-stage solution algorithm was designed. K-mediods clustering algorithm was used to decompose the original data. The original large-scale multi-depot VRP was transformed into multiple single distribution center routing problems. Then, an improved multi-ant colony algorithm was designed to solve the single distribution center routing problem, and the initial scheme was obtained. In the adjustment stages, the initial scheme was optimized by using the saving mileage method. At last, the simulation results were compared with ones of the other methods. The results show that the proposed algorithm is better than GA-ACO algorithm, wolf pack algorithm and ant colony algorithm. The optimal path is optimized by 32.16%, 8.99% and 24.76% respectively, and the total cost is optimized by 30.42%, 8.99% and 3.40% separately, which verifies the rationality of the model and the effectiveness of the multi-stage algorithm design.

Experiments on ESD-Heating Remelting, Rolling Dressing

XU Anyang, WANG Xiaoming, ZHAO Yang, ZHU Sheng, HAN Guofeng

2020, 31(14):  1741-1746.  DOI: 10.3969/j.issn.1004-132X.2020.14.014

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Aiming at the defects such as pores, microcracks, loose surface structure, poor continuity and poor surface quality in the ESD layer, a machining method of “ESD-remelting and rolling” was proposed herein. Taking the conventional ESD as a comparison,experiments were carried out using the new method. The deposited layers were analyzed. The results show that during the remelting and rolling processes, the electrode has a large extrusion and rolling effects on the deposition surfaces. Remelting and rolling dressing may effectively eliminate defects such as pores, microcracks and loose tissue inside the sediment layer. In addition, such process may refine the grain and improve the continuity and integrity of the layers. It is believed that the rotating electrode has a significant grinding coating effectiveness on the surfaces of the deposited layers. The defects such as surface micropores and cracks are basically eliminated, experimental results show that the roughness values of the remelting and rolling coating is 76.3% of the conventional ESD coating, which indicate the surface quality of the deposited layers is improved.

Improved Parking Detecting Algorithm Based on Ultrasonic Radar

QIU Xu, ZHU Hao, DENG Yuanwang

2020, 31(14):  1747-1753.  DOI: 10.3969/j.issn.1004-132X.2020.14.015

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Aiming at the problems of insufficient detection accuracy caused by the difficulty of capturing distance jumps and determining the attitude of parking spaces in traditional parking space detection algorithms, an improved parking space detection algorithm was proposed based on fitted feature line segments. First, an energy gain compensation scheme was designed for the ultrasonic radar amplitude attenuation; then, the characteristic line segment representing the outline of the obstacles was fitted based on the real-time vehicle poses and ultrasonic distance data, and the fitting accuracy of the characteristic line segments was evaluated with the help of lidar, and further detection processes of fusion parking space preliminary detection, parking space re-judgment, parking space constraint judgment and parking space attitude calculation were designed. Finally, the proposed algorithm was experimentally verified based on the real vehicle platforms. The experimental results show that the proposed algorithm may obtain an average detection accuracy of 92.5%, and provide accurate and reliable target parking space informations for the intelligent car parking systems.

Research on Complicated Impact Loads and Equivalent Test Method of Thin-walled Casings

OUYANG Zhigao, LI Jian, WU Liqiang, AI Xing, ZHANG Di

2020, 31(14):  1754-1761.  DOI: 10.3969/j.issn.1004-132X.2020.14.016

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Aeroengine casings were typical thin-walled frame structure, aiming at complicated impact loads due to axial and circum-torsional impacts by turbine rotors caused by shaft breaks, the numerical simulation models were established involving key components of turbine rotors and exhaust casings. On the basis of the complicated impact loads and energy dissipations of the exhaust casings in the simulation results, the dynamic responses of complicated impact loads and energy dissipations in the processes of complicated impacts were obtained. It is pointed out that the initial rotation velocity has little influences on impact loads and energy dissipations under the conditions of certain axial forces in the term of the complex movements of turbine rotors. Furthermore, the relative motion relation between the turbine rotor and the exhaust casing was converted. The analysis results show that the impact load and energy dissipation results after conversion remain highly similar to those before conversion. In the subsequent equivalent test methods, these conclusions might be used as a reference for simplifying the structural design of test bed.