Table of Content

25 March 2020, Volume 31 Issue 06

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Automatic Calibration Method for PHEB Control Parameters Based on Driving Cycles

GAO Jianping;SUN Jiahui;XU Zhenhai;XI Jianguo

2020, 31(06):  631-637. 

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In order to solve the problems of lack of scientific selection of calibration parameters and low efficiency of manual real-time calibration in simulation calibration processes of the control parameters of PHEBs under driving cycles, an automatic calibration method of control parameters was proposed in any driving cycles. Based on the actual bus driving cycles, an orthogonal experiment was designed to analyze the fuel consumption impact of control strategy parameters, and five control parameters with greater impacts were selected as calibration parameters. An optimization model of control parameters was constructed by using self-optimizing characteristics of optimization algorithm instead of manual analysis results and adjusting parameters. Real-time simulation platform for automatic calibration of control parameters was developed using Cruise, MicroAutoBox, Isight and other tools. Simulation results show that under the same calibration times, the time of automatic calibration is shortened by 75.51% compared with that of manual calibration. The fluctuation of supercapacitor SOC is reduced due to the reasonable torque distribution, and the fuel consumption of control strategy is reduced by 12.30% after automatic calibration. These results verify the feasibility of the calibration method herein.

Test Methods of Ultra-high Pressure and Large Flow Proportional Cartridge Valves

YAO Jing1,2,3;KOU Chenghao1;YIN Yuxin1;KONG Xiangdong1,2;SUN Ruihui4;LI Hao5

2020, 31(06):  638-646. 

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Aiming at the shortage of testing technology for ultra-high pressure and large flow proportional cartridge valves, taking the DN130 displacement follow-up ultra-high pressure and large flow two-way proportional cartridge valve as object, special work requirements for 70MPa ultra-high pressure and 8000L/min large flow were considered. Ultra-high pressure test bench and high-pressure large-flow test bench were designed. Test methods for pressure-resistance characteristics and dynamic and static characteristics were formulated based on the industrial test standard. The model-based simulation prediction method was adopted when the test bench flow could not be reached. The test results show that the valve has good pressure-resistance characteristics flow gain characteristics, hysteresis characteristics, linearity characteristics, repeatability characteristics and dynamic characteristics, which provides a practical basis for the design and test of ultra-high pressure and high flow proportional cartridge valves.

Experimental Study and EDEM Numerical Simulation of Ultrasonic Vibration Finishing

ZOU YilanWEN DonghuiWANG YangyuXIAO YutingZOU Lei

2020, 31(06):  647-654,661. 

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Numerical simulations were carried out on ordinary passivation finishing experiments and ultrasonic vibration assisted finishing experiments using EDEM discrete element analysis software. Simulation results provide basis for the proposed ultrasonic vibration finishing system. Using ultrasonic vibration finishing equipment to perform passivation experiments on flat end mill, a large number of experimental studies were carried out by changing the passivation conditions. The surface morphology and the radius of the blunt circle of the milling cutter before and after passivation were observed by scanning electron microscope, the influences of ultrasonic vibration on the passivation efficiency and finishing effectiveness were analyzed. Experimental results show that the passivation efficiency with ultrasonic vibration increases about 26% and the surface topography is greatly improved.

Influences of Cutting Parameters on Shaving Cutting Forces and Tooth Profile Concave Errors

CAI Anjiang;LIU Libo;LIU Lei;LI Wenbo

2020, 31(06):  655-661. 

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The experimental formula of radial shaving forces was introduced into the theoretical formula of metal cutting forces, and the shaving cutting force model was constructed. Based on the principle of single variable, the influences of different cutting parameters on shaving forces were analyzed quantitatively. Meanwhile, the mechanism of tooth profile concave errors was shown based on cutting parameters. The validity of the model was confirmed by the finite element method and experiments. The results show that the shaving cutting forces are positively correlated with the radial feeds or the axial feeds, while is inversely related to the spindle rotation speeds. The radial feeds have the greatest influences on the shaving cutting forces. The shaving cutting forces reaches the peak value near the pitch circle, indicating that the excessive shaving happens at the positions. And the tooth profile concave errors are easily caused with error reflection.

Cobalt-based Alloy Material Removing Method under Photocatalytic Conditions

XI Fengfei;ZENG Xi;JI Shiming;CHEN Guoda

2020, 31(06):  662-669. 

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Cobalt-based alloy materials were widely used in laser cladding and the difficult processing problems were exhibited. Based on the analyses of the physical properties and chemical reaction characteristics of cobalt and its compounds, combined ultraviolet(UV) photocatalysis and chemical corrosion, a method for cobalt-based alloy removing materials under photocatalytic conditions was proposed. The mechanism model of material removal method under photocatalytic conditions was established, and the reaction principle of cobalt-based alloys in combination with UV photocatalysis and chemical corrosion solution was described. The corrosion solution configuration test was designed and basic yellow 40+TiO2 corrosion solution was determined through multiple sets of comparative tests. On the basis of the results of corrosion solution configuration test, a cobalt-based alloy machining tests were established based on a pneumatic grinding wheel test platform. The processing examples prove that the combination of UV photocatalysis and basic yellow 40+TiO2 chemical corrosion pretreatment may significantly increase the mechanical material removal rate of cobalt-based alloy materials, and effectively reduce the surface roughness and reduce the surface defects. At the same time, the mechanical material removal rate of the cobalt-based alloy coatins may be increased by 2 to 3 times after 30 minutes of pretreatment. Processing efficiency may be increased by more than 40% while avoiding excessive material removal. It is anticipated that the experiments verify the rationality and effectiveness of the method.

Two-tube Conduction Zero Vector Direct Torque Control of Brushless DC Motors

SHI Peicheng;WANG Suo;ZHANG Rongyun;XIAO Ping

2020, 31(06):  670-678. 

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In view of the difficulty in torque calculations in the existing direct torque control of the brushless DC motors and the large torque ripples caused by the zero voltage vector defined by the traditional all-zero digital, further studies were made on the motor torque calculation and zero vector selections on the basis of the non-magnetic chain observation direct torque control systems. In the terms of torque calculations, the cumbersome back-electromotive force calculation method was abandoned, and the torque calculation was made combining three-phase current and Hall signals. In the terms of space voltage vector optimization, a two-tube conduction zero vector and space voltage selection table were proposed, and the control effectiveness was compared with the zero voltage vector defined by the traditional all-zero digital theoretically. The simulation model of the torque control systems was built in MATLAB/Simulink for simulation verification. A hardware experimental platform was set up using DSP2812 as the main control board for experimental verification. Both simulation analysis and experimental verification show that the proposed control method may further simplify the torque observation and effectively suppress the electromagnetic torque fluctuations in both of static and dynamic states.

Grinding Force Model and Experimental Study of Tapered Roller Ball Base Surfaces

ZHU Wenbo1;LI Kangshun1;ZHU Huanhuan2;CHI Yulun1

2020, 31(06):  679-687. 

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In order to realize the high-quality and high-efficiency grinding of tapered roller ball base surfaces, based on the principle of roller ball base surface grinding, a mathematical model of the grinding force of tapered roller ball base surfaces was established, a method was proposed to verify normal and tangential grinding forces based on static stiffness and power. The influence factors of grinding forces were systematically analyzed, which included speed difference of guide wheel of clamping tapered rollers, the rotation speed of the tapered rollers and the linear speed of the grinding wheel. Meanwhile the grinding process parameters were optimized based on the mathematical model of ball base surface grinding forces. The results show that the calculated values of the proposed grinding force model are consistent with the experimental ones. The reduction of the rotation speed difference of the guide wheel, the reduction of linear speed of tapered roller and the increase of linear speed of grinding wheel will decrease the grinding forces. The optimized grinding process parameters may effectively reduce the radius deviation of the tapered roller ball base surfaces, thus verifying the correctness of the ball base surface grinding force model again.

Influences of Rotation Speed and Feed Speed in Shaft Riveting on Properties of Hub Bearings

SHU Weicai1;QIU Baoxiang2;YANG Jianguo1;GAO Zengliang1

2020, 31(06):  688-694. 

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The shaft riveting forming process of hub bearings was studied by using elastic-plastic finite element method. The motion law of plum blossom shape of punches in shaft riveting was analyzed, and the punch was treated as a rigid body to achieve axial translational motion and plane plum blossom motion simultaneously. This method improves calculation accuracy, and improves computational efficiency. The properties of flange shafts and inner rings were tested, and the elastic-plastic constitutive relation of hub shaft materials was determined. The influences of rotation speed and feed speed on the performance of wheel bearings were studied, and the stress-strain analysis of shaft riveting forming with plum blossom shape loading trajectory was carried out. The results show that with the increase of the rotation speed of punches, the clamping force of hub bearing increases first and then remain stable. When the rotation speed of punch increases to 516 r/min, the radial variation of inner ring reaches peak value. When feed speed changes within a certain range, clamping force and inner ring radial deformation appear peak and valley values. Increasing rotation speed or reducing feed speed may reduce clinching forces, and reduce the vibration of riveting machines and improve forming quality.

Evolutionary Game Model of Knowledge Transfer Incentive in Cloud Manufacturing Supply Chains

HE Zheng;ZHANG Zhizhao;LI Bo

2020, 31(06):  695-705. 

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In the operations of cloud manufacturing supply chains, the knowledge transfer between cloud manufacturing enterprise and customer might improve the operation performance of the supply chains. However, due to information asymmetry and limited rationality, both of enterprises would not actively transfer knowledge, which might reduce the overall operation performances of the supply chains. In order to improve the operation performances of the supply chains, the strategic tendency of knowledge transfer and the change of the evolution path were studied. According to the motivation of the customer to acquire knowledge, an evolutionary game model of knowledge transfer between cloud manufacturing enterprise and customer was established by evolutionary game theory, and the model was solved and analyzed. The corresponding research conclusions were obtained. The correctness of the conclusions was verified by numerical simulation. The study results show that the higher the knowledge amount, the knowledge transfer willingness, the knowledge transfer ability, the knowledge absorption ability, the knowledge transferability, and the mutual trust degree of the cloud manufacturing enterprise and customer, the more likely they are to adopt knowledge transfer strategies; the higher the knowledge transfer costs and speculative gains of the cloud manufacturing enterprise and customer, the more likely they are not to adopt knowledge transfer strategies. Finally, considering the above factors, some countermeasures and suggestions were put forward to promote the knowledge transfer between cloud manufacturing enterprise and customer.

Error Analysis and Compensation for Clearances among Kinematic Pairs of 2-RPaRSS Parallel Manipulators

KONG Juncheng;LI Ju;SHEN Huiping

2020, 31(06):  706-713. 

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A trajectory correction method was proposed based on AHPSO algorithm for a new 3T1R parallel manipulator 2-RPaRSS, which possessed the clearances among moving pairs causing positioning deviations and the misfit between real trajectory and theoretical trajectory. The clearance errors of kinematic pairs were established, and the clearance errors of the kinematic pairs was equivalent to the rod length errors. According to the inverse kinematics equation, the position and attitude error models of 2-RPaRSS were established, the differential relation between input and output was obtained, and the input angle compensation of driving rod was introduced. The particle swarm optimization (PSO) algorithm was used to optimize the compensation, and the gap error compensation problem was transformed into the minimum fitness problem. Finally, the PSO algorithm was improved by means of hybrid weight adaptive adjustment, learning factor adaptive adjustment and chaotic disturbance adaptive adjustment strategy, and AHPSO was obtained. The simulation results show that the performance of the AHPSO algorithm has better convergence and the stability is excellent. It is an effective method to compensate the clearance errors of the motion pairs of the parallel manipulators, and the positioning accuracy is obviously improved after compensation.

A Battery Dynamic Grouping Equalization Method Based on Adaptive Topology

LIU Zhengyu1,2;WEI Zihong1;XU Yajuan1;YANG Kun1

2020, 31(06):  714-721. 

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When traditional grouping equalization methods used to reduce battery inconsistency, there were inefficient energy consumption problems in the grouping mode. Therefore, a battery grouping equalization method was proposed based on adaptive circuit topology. A novel adaptive topology for grouping equalization was designed with the characteristics of the Buck-Boost circuit and several switches. Based on the analysis of the shortages of initial cluster centers and the membership matrix should be given for the fuzzy C-means(FCM) clustering algorithm, a new density-based fuzzy C-means (DBFCM) clustering algorithm was proposed from a software perspective for implementing batteries grouping. In each equalization period, DBFCM clustering algorithm was used to group the individual battery into several battery clusters. Based on the proposed adaptive circuit, the clustered batteries were balanced among the groups. The experimental results show that the scheme may effectively improve the overall energy efficiency of the battery pack, reducing equalization time and reducing the inconsistency among single batterys.

A Calibration Method for Parallel Robot Based on Eye in Hand Vision

LI Yongquan1,2;WANG Haochen2,3;ZHANG Yang1,2;ZHANG Yan1,2;ZHANG Lijie2,3

2020, 31(06):  722-730,755. 

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A calibration method of parallel robots was proposed based on eye in hand vision. Firstly, based on the loop increment method, the kinematics errors and calibration model of a planar 2-DOF redundant actuated parallel robot were established. Secondly, a target plate was designed for the calibration experiments, and the target image was captured by the camera and processed by the segmentation, recognition and rotation compensation, and then the pixel error values of the end positions and the actual positions of the mechanisms were obtained. Thirdly, limited by the structures of the mechanisms, using the boundary curve to identify the feature corner points, a method was proposed to determine the rotation angles of the detection point based on the feature corner points. On the basis of compensating the rotation angles of the camera, using a simplified model of the camera pinhole, the error values of the pixel errors were converted to the true position error values of the ends of the mechanisms. Finally, the calibration model and the error values obtained through the visual system were used for kinematics calibration. After 4 iterations, the errors of the mechanisms are decreased to 1/3, which verifies the feasibility of the robots. The proposed method has the advantages of short time of calibrations, small amount of data and low cost of experiments.

Cross Process Coordinated Scheduling Problem Based on Hybrid Discrete Bat Algorithm

LU Jiansha1,2;LI Jinqing1;TANG Hongtao1

2020, 31(06):  731-739. 

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Aiming at the problem of collaborative scheduling of production and distribution across processes, a collaborative scheduling model of single-machine batch processing in former process and order-by-order processing in latter process was constructed, and AGV circular distribution was adopted among the processes. A hybrid discrete bat algorithm, which is combined with simulated annealing algorithm and modified unstring and string algorithm, was designed to minimize the maximum completion time and waiting time before subsequent process. Compared with the improved discrete particle swarm optimization and Ullrich genetic algorithm, the proposed algorithm may reduce queue waiting time and production cycle of products.

Research on Fatigue Life of Welding Spot Defects Considering Corrected Average Equivalent Stress Intensity Factor

HU Jinhua1;SONG Kai2;XIONG Liming3

2020, 31(06):  740-745. 

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A fatigue life prediction method for welding spot defects was proposed based on ultrasonic echo, where the damage coefficient was obtained based on ultrasonic echo characteristics and fuzzy mathematics theory. Then the effects of normal stress, shear stress and initial defects were taken into account，and the corrected average equivalent stress intensity factor through the defect propagation paths was calculated as the evaluation parameters of fatigue life. Through shear fatigue tests for the qualified spot welding joints，small nugget spot welding joints and over burning spot welding joints for the high strength steel-DP600GI, the fatigue life of different welding spot joint defects were compared, and a curve between the corrected average equivalent stress intensity factor and the fatigue life was obtained as the fatigue life prediction curve for welding spot defects. The results show that the curve may effectively predict the fatigue life of the spot welding joints with initial defects, and the proposed method helps to design defect tolerance of resistance spot welding.

Multi Objective Parameter Decoupling Optimization Method of Two-speed EVs

HUANG Kang1，2;LIU Zelian1;QIU Mingming1，3;ZHANG Yiran1;WANG Qiang1;RU Yan4

2020, 31(06):  746-755. 

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A decoupling optimization algorithm with layered method was proposed. Multi-objective particle swarm optimization was used to optimize the parameters of vehicle's power components at outer layer. Meanwhile, efficiency optimizations of the battery and inverter were introduced to extract and transfer the different optimization fruits to inner layer. Bellman dynamic programming algorithm was used at inner layer. The optimal shifting strategy was established by solving the parameters of power component from outer layer optimizations. Based on this, the gear shifting optimization results of dynamic planning were extracted by GRNN, and an adaptive driver model and a vehicle forward simulation model were established by using the gear shifting strategy obtained. Aiming at the power and economy, the layered optimization results were further selected by the vehicle forward simulation analysis. The results show that the optimization algorithm realizes the decoupling of shifting control strategy and the parameters of the power components, effectively improves the efficiency of the optimization, and at the same time, the global optimization results may be obtained, which means that the vehicle economy improves significantly.