Table of Content

25 March 2021, Volume 49 Issue 3

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Contents



2021, 49(3):  0. 

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Mechanical Engineering

Calculation Method for Rigid Mode and Displacement Control of Powertrain-Subframe Mounting System



SHANGGUAN Wenbin, FANG Zhiyuan, LI Liping, et al

2021, 49(3):  1-7.  doi:10.12141/j.issn.1000-565X.200391

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A new 12 DOFs ( Degrees of Freedom) calculation model for the powertrain-subframe mounting system was established by reducing the mount into three-dimension springs with the nonlinear force and displacement relation． Then the rigid mode and energy distribution，the displacements of the powertrain's CG，the displacements of the subframe's CG，and the displacements and loads of the mounts in the powertrain-subframe mounting system of an electrical vehicle under the ultimate load were calculated． The theoretical calculation model was verified by ADAMS model． The calculation model provides methods for rigid mode optimization and the design of mounting force-displacement control in powertrain-subframe mounting system．

Blind Restoration of Motion Blur Label Image Based on L₀ Sparse Priors



LIU Ning, ZHAO Huanming, LI Deping, et al

2021, 49(3):  8-16.  doi:10.12141/j.issn.1000-565X.200431

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Label image sharpness is the key point that influences the effectiveness of visual inspection during the label qualify inspection of household appliances with machine vision． To solve the motion blurring problem of tag image captured by camera fixed on the moving robot，a regularization model based on L0 norm was proposed． The general methods of deblurring algorithms have considered and implemented much of image priors for blurred images，which can obtain the well-done visual overall effect． However，these general algorithms does not take the characteristic of identification tag into consideration，and this is an important prior to deblurring． To this point，a specific model consisting of image gradient prior regularization and sparse regularization was proposed to analyze pixel distribution and gradient distribution features of label image． The experimental results show that，as compared with other deblurring algorithms，the proposed method can effectively suppress the ringing effect at the edge of the label image while restoring label image sharpness on synthetic images and real images，and the real computation speed is increased by 80. 52% ．

Identification and Location Algorithm of Connectors for Automatic Wiring System



HU Guanghua, HUANG Junfeng, WANG Ning, et al

2021, 49(3):  17-24,33.  doi:10.12141/j.issn.1000-565X.200449

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In order to realize automated wire-socket assembly，an automatic robot wiring system based on machine vision was designed． And，to avoid the interference caused by the change of imaging angle and the clutter background，a connector identification method based on cumulative quantization gradient orient feature was proposed to improve the stability of target connector identification． On this basis，a multi-socket positioning algorithm based on scan line histogram characteristics was proposed to solve the problem of multi-sockets' center positioning caused by the dense arrangement of sockets． Experimental results show that the designed algorithm can stably identify the target connector and meet the accuracy requirements of socket positioning．

Intelligent Control Method for Pump-Valve Parallel Electro-Hydraulic Position Servo System



WANG Chengwen, GUO Xinping, ZHANG Zhenyang, et al

2021, 49(3):  25-33.  doi:10.12141/j.issn.1000-565X.200296

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In light of the valve control system's advantages of fast response and high energy efficiency，a pumpvalve parallel electro-hydraulic position servo system was proposed，and its intelligent control method is studied． Firstly，a single neuron PID controller，which can realize the self-adaptive adjustment of the weight，is designed for the pump-controlled subsystem of the pump-valve parallel system． Secondly，a RBF ( Radial Basis Function) neural network-based sliding mode controller was designed for the valve-controlled subsystem of the pump-valve parallel system． The Lyapunov function was designed to prove the stability of the closed-loop system． Finally，the co-simulation was conducted by using Matlab /Simulink and AMESim． The co-simulation results show that the single neuron PID controller of the pump-controlled subsystem has better speed tracking control performance than the traditional PID controller． The RBF neural network-based sliding mode controller of the valve-controlled subsystem has better position tracking accuracy and stronger anti-interference ability than the traditional PID controller． The proposed intelligent control method can significantly improve the control performance of the pump-valve parallel system.

Research and Application Progress of 4D Printing Technology



ZHAO Xianfeng, TANG Pengfei, SHI Hongyan, et al

2021, 49(3):  34-46,54.  doi:10.12141/j.issn.1000-565X.200503

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4D printing，also called variable-property rapid prototyping，is a technology that combines material， mathematics，and additive manufacturing． The materials used in 4D printing are smart materials，and the printed structure，shape，attributes，or function can change over time under environmental stimuli． With its characteristics of self-assembly，self-adaptation and self-repairing，flexible，personalized and intelligent structures can be designed． This article firstly introduced 4D printing technology，including the characteristics of 4D printing，molding methods，materials used and deformation forms，and then explained the application progress of 4D printing． Finally，it discussed the key issues and the future development direction of 4D printing．

Interval Analysis of Structural Static Response Based on Univariate Function Decomposition



WEI Tonghui, MENG Guangwei, ZUO Wenjie, et al

2021, 49(3):  47-54.  doi:10.12141/j.issn.1000-565X.200291

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An interval finite element method based on univariate function decomposition was proposed to deal with the problem of the static response with unknown-but-bounded uncertainties． Firstly，the displacement function of interval finite element was expanded by higher-order Taylor series at the single variable points，and the interval expression of univariate function decomposition is derived． An n-dimension displacement function is approximately expressed as the sum function of n one-dimension functions by using the univariate interval function decomposition． Each one-dimension function has only one interval parameter，and the rest of the interval parameters are replaced by their interval midpoint． Thus，the problem of solving the upper and lower bounds of n-dimension function can be converted to solving that of one-dimension functions，which reduces the computational cost and is easy to implement． Compared with the existing interval perturbation finite element method，the proposed method does not need to calculate the sensitivity of the response to the uncertain variables and the inverse of the structural stiffness matrix， and is suitable for solving the strongly nonlinear response function． The numerical results show that this method is effective and feasible．

Research on Surface Properties of Nd: YAG Crystal Modified by Plasma Jet



CAO Faxiang, KONG Jinxing, DU Dongxing

2021, 49(3):  55-61.  doi:10.12141/j.issn.1000-565X.200241

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The surface wettability and mechanical properties of Nd: YAG crystals were investigated to study the influence of plasma jet on Nd: YAG crystals by using self-developed plasma equipment at room temperature． The results show that the plasma has significant effects on surface properties of Nd: YAG crystals，and the wettability of Nd: YAG crystals with three different roughness is improved after plasma modification． Especially，the smooth surface changes from hydrophobic to super-hydrophilic，and the good state of hydrophilicity lasts 30 hours． The improvement of wettability of Nd: YAG surface mainly lies in the increase of oxygen-containing functional groups on the surface of the modified Nd: YAG crystals． The microhardness remains unchanged within 0 to 11h，decreases first and then increases within 11 to 22h，and remains stable within 22 to 35h after the modification． Especially，a minimal microhardness occurs between 11 to 22 h after the modification． Under the peak load of 15. 0，30. 0 and 70. 0mN，the average microhardness decreases by 56. 2%， 45. 0% and 31. 6%，respectively． And the morphology of some indentations shows features of“ladder”and“shadow” due to the rapid increase of plasticity on Nd: YAG surface 11 hours after the modification．

Food Science & Technology

Effects of Structural Evolution of Starch Materials with Different Gelatinization Degrees on Materials' Printability of Hot-Extrusion 3D Printing



CHEN Ling, DU Anlin, TANG Yukuo, et al

2021, 49(3):  62-70,87.  doi:10.12141/j.issn.1000-565X.200596

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3D printing is a new food processing technology with important application prospects，and is also a research hotspot in the field of food science． Based on the acquisition of starch gelatinization materials with different gelatinization degrees，this paper investigated the evolution behavior of multi-scale structure of rice，wheat and potato starch materials in the gelatinization control system and the influence of structural evolution on the molding properties of 3D printing through modern structural analysis technology． The results show that with the increase of gelatinization degree from 30% to 70% ，the layered structure of starch granules is destroyed gradually and the compactness of nano aggregates decreases significantly; relative crystallinity decreases continuously; the content of double helix and single helix decreases significantly and the proportion of amorphous structure increases significantly． Meanwhile，with the increase of starch gelatinization degree，the thread width of 3D printing decreases first and then increases，while the number of printing layers increases first and then decreases． The ideal printing molding properties can be achieved when the gelatinization degree of rice，wheat and potato starch materials is 50% ，40% and 30% ，respectively． The research results provide a certain data basis for the precise design and quality control of starch gelatinous materials and starch food．

Study on Biological Characteristics of Lactobacillus delbrueckii DMLD-H1 and Optimization of Fermentation Medium



LIU Dongmei, YU Jiajia, PENG Xin, et al

2021, 49(3):  71-79.  doi:10.12141/j.issn.1000-565X.200332

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A strain of Lactobacillus was isolated from the homemade yogurt in Inner Mongolia． Through physiological，biochemical and morphological identifications and 16S rDNA homology analysis，the strain was known to be Lactobacillus delbrueckii DMLD-H1． The biological characteristics of the strain were studied to clarify its gastrointestinal tolerance，antibacterial effect and probiotic characteristics． The safety of the strain was evaluated through hemolytic experiment and acute toxicity test． The fermentation medium of the strain was optimized by response surface methodology． The results show that Lactobacillus delbrueckii DMLD-H1 grow rapidly at the optimum temperature of 37 ℃ and pH value ranging from 3. 0 ～ 7. 0． The blood agar plate study shows that the strain has no hemolytic activity． The acute toxicity test indicates that Lactobacillus delbrueckii DMLD-H1 has no acute oral toxicity to mice． Thus the strain has the characteristics of edible bacteria． After incubation for 3 h in artificial gastric and intestinal juice whose pH value is 3. 0 ～ 4. 0，the survival rate of the strain is above 85% ，with good tolerance． Its fermentation products have inhibitory effects on both Escherichia coli and Staphylococcus aureus，indicating that Lactobacillus delbrueckii DMLD-H1 has potential probiotic properties． When the best components of the fermentation medium are optimized as follows: oligo-fructose content 20. 2g /L，bacteriological peptone content 19. 7g /L and magnesium sulfate content 0. 596 g /L，the concentration of viable bacteria of Lactobacillus delbrueckii DMLD-H1 is 1. 32 ×109 CFU/mL． Under this condition，the fitting rate between the above-mentioned concentration and the measured value is 98. 48% ，indicating that after the optimization of the medium，the model can well predict the bacteria's growth characteristics．

Multi-Physical Field Simulation and Experiment of Plate-Type Continuous Treatment Chamber



ZENG Xinan, YAN Peng, CAI Jinlin, et al

2021, 49(3):  80-87.  doi:10.12141/j.issn.1000-565X.200145

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COMSOL multiphysics software was used to simulate the electric field，flow field and temperature field of the plate type continuous treatment chamber． The experimental results show that the distribution of the electric field is not uniform，and the structure of the treatment chamber has little effect on the sterilization effect when the inlet velocity is 5 cm /s． The sterilization experiment was performed on acetic acid bacteria using this processing chamber． By controlling the input energy，the effects of applied voltage，pulse width，and frequency on the sterilization effect were explored． The experimental results show that the effect of voltage on the sterilization effect is more significant than that of pulse width and frequency．

Antioxidant Activity of Lactobacillus rhamnosus LR ZB1107-01 in Vitro



XU Xilin, ZHOU Xiaoli, ZHENG Liuqing, et al

2021, 49(3):  88-94.  doi:10.12141/j.issn.1000-565X.200290

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The antioxidant capacities of Lactobacillus rhamnosus ZB1107-01 ( LR ZB1107-01) and Lactobacillus rhamnosus GG ( LGG) in vitro were compared． Taking free radical scavenging activity of DPPH clearance，hydroxyl clearance and superoxide anion as the indexes and establishing the oxidative damage model of Caco-2 cells，this study investigated the effects of LR ZB1107-01 on oxidative stress of Caco-2 cells by measuring the activities of SOD and GSH-Px． The results show that the higher the concentration of bacteria，the stronger the ability of scavenging the three free radicals． The scavenging capacity of LR ZB1107-01 fermentation liquor on DPPH is significantly higher than that of LGG，the scavenging capacity of supernatant on hydroxyl radical is slightly higher than that of LGG，and the scavenging capacity of cell lysate on superoxide anion free radical is significantly higher than that of LGG． In the model of oxidative damage of Caco-2 cells，the measurement of the enzymatic activity of SOD and GSH-Px shows that LR ZB1107-01 can reduce the oxidative stress damage of Caco-2 cells and increase its antioxidant function under oxidative stress．

Effect of Fermented Polygonatum sibiricum Polysaccharides on Intestinal Flora in Obese Mice



ZHANG Zhi, BAO Zhiying, SUN Jiajia, et al

2021, 49(3):  95-105,113.  doi:10.12141/j.issn.1000-565X.200219

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The aim of this paper is to investigate the effect of microbiological method extraction of fermented Polygonatum sibiricum polysaccharides on the improvement of blood lipid levels and intestinal flora in mice with high-fat diet． Firstly，the cholesterol and cholate sorption experiments were carried out to evaluate the in vitro lipid-lowering capacity of Polygonatum sibiricum extracted by hot water extraction and microbiological method，and fermented Polygonatum sibiricum polysaccharides ( FPSP) extracted with the microbiological method which has better in vitro lipid-lowering capacity was used for animal experiments． The results of in vivo studies show that FPSP can significantly reduce the body weight，fat index，liver index，serum TC，TG，LDL-C levels，increase HDL-C levels，and significantly inhibit TNF-α and IL-6 release ( P ＜ 0. 05) ． High-throughput sequencing technology analysis finds that，after the intervention of FPSP，the total relative abundance of Firmicutes and Bacteroidetes in mouse feces increased in the phylum level; at the genus level，the relative abundance of probiotics such as Lactobacillus and Barnesiella relatively increased，and the relative abundance of pathogenic bacteria such as Clostridium XIVa，Helicobacter，Streptococcus，and Alistipes decreased． The above results show that Polygonatum sibiricum polysaccharides can improve the blood lipid level of high-fat diet mice and regulate the intestinal flora disorders．

Experimental Study on Decalcification of Brown Sugar Solution by Sodium Alginate



HUANG Lixin, WANG Zhanquan, YIN Shouwei, et al

2021, 49(3):  106-113.  doi:10.12141/j.issn.1000-565X.200166

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Traditional brown sugar production uses lime to clean cane juice，and the product contains a large amount of calcium and residual flocculants． Sodium alginate ( SA) contains a large number of carboxyl which has a strong chelation on calcium ions． This article explored SA's application to decalcification of brown sugar solution， and examined the effects of SA dosage，brown sugar solution's content，reaction temperature，and pH value on the calcium removal rate and reaction efficiency of SA． The results show that: the SA flocculent precipitate ( main body) of the brown sugar solution is calcium alginate; the unit mole ratio of Ca∶SA is the most important influencing factor of the calcium removal rate and the reaction efficiency of SA． The larger the dosage of SA is，the higher the removal rate and the lower the reaction efficiency of SA are． When the unit molar ratio of Ca∶SA is about 2. 5， the suitable mass fraction of brown sugar solution is 50% ～ 60% ，and the reaction efficiency of SA is about 90% ． Temperature also has a certain effect on the calcium removal rate and reaction efficiency of SA． The calcium removal rate is the highest when temperature is 50 ～ 60 ℃，and this temperature range is also good for dissolving operation． The removal effect is similar in the pH range of 5. 1 ～ 9. 0，so sugar solution can be obtained by directly using water-soluble commercial brown sugar without adjusting the pH value． It is safe and feasible to remove some calcium ions from the brown sugar solution by SA and to use the product as a flocculant．

Traffic & Transportation Engineering

Time-Varying LQR Control of Four-Wheel Steer /Drive Vehicle Based on Genetic Algorithm 



LUO Yutao, ZHOU Tianyang, XU Xiaotong

2021, 49(3):  114-122.  doi:10.12141/j.issn.1000-565X.200131

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As compared with traditional vehicles，four-wheel steer/drive vehicles have very good active dynamics control performance，ensuring that the four-wheel steering /torque is independently controllable． This article proposed a time-varying LQR control system based on genetic algorithm for the coordinated control of the steering angle-torque of four-wheel steer/drive vehicles． Different from the traditional linearized tire reference model，it established a linear time-varying system considering the variable stiffness characteristics of the tire，and the control weight matrix of the state quantity was optimized with the genetic algorithm． The simulation results show that under a given corner step input，the time-varying LQR control considering the non-linear characteristics of the tire is better than the linearized model control system in zeroing the center of mass sideslip angle，and the tracking accuracy of the yaw rate with ideal value is improved by 3. 01% ． The simulation of the double line change under high speed and low road conditions shows that the time-varying LQR control system based on genetic algorithm ensures a better trajectory tracking ability of the vehicle，and the maximum lateral displacement error control effect is improved by 44% ，compared with that of front-wheel steering vehicles．

An Efficient Computation Method for Real-Time Hybrid Testing of Vehicle-Track-Bridge Coupling System of High-Speed Railway



GU Quan, ZHANG Deyu, GUO Wei, et al

2021, 49(3):  123-130.  doi:10.12141/j.issn.1000-565X.200322

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Since the train runs fast，it is necessary to build a long enough bridge and to adopt a sufficiently refined vehicle-track-bridge coupling mode in real-time hybrid testing of high-speed railway system． Therefore，high accuracy and efficiency of numerical computation is essential． At the same time，the real-time hybrid testing requires high instantaneity，and each step needs to be completed in a short time，which further increases the difficulty of the problem． To this end，a new computation method，named the moving load integration method，was proposed． The data needed for the numerical substructure computation of the bridge was stored before the testing． In the actual computation，the corresponding data of each time step was extracted and computed to obtain the displacement response of the current time step． The method was extended to the local nonlinear condition by means of the elastoplastic numerical substructure method，and then the feasibility and reliability of the method were systematically verified by the real-time hybrid testing of the scaled-down high speed railway shaking table．

Driver's Visual Information Processing Mode in Foggy Highway Cooperative Vehicle-Infrastructure System Environment Based on Simulated Driving



LI Xuewei, ZHAO Xiaohua, LI Zhenlong, et al

2021, 49(3):  131-138,148.  doi:10.12141/j.issn.1000-565X.200094

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The aim of this paper is to explore the influence of the cooperative vehicle-infrastructure system in foggy highway on the driver's visual information processing mode． Firstly，based on the driving simulation platform，a cooperative vehicle-infrastructure system in foggy highway ( CVIS-HF) was designed to obtain the driver's visual behavior parameters． Next，the road ahead was defined as area of interest，and the driver's fixation，saccade and other explicit visual behavior indexes at the global level and area of interest were extracted and analyzed． Finally，three common factors，information extraction factor，perceptual density factor and information search，were obtained by using factor analysis method to characterize the driver's visual information processing mode under the effect of CVIS-HF． The results show that the application of CVIS-HF significantly affects the driver's scanning behavior and the allocation of visual resources for the road ahead． The original information distribution is changed by the intervention of cooperative vehicle-infrastructure system information，which improves the efficiency of information extraction and information search，but reduces the perceptual information density． The research results can provide theoretical reference and technical support for the design and safety application of human machine interface ( HMI) in cooperative vehicle-infrastructure system．

Effects of Navigation Broadcast Wording Complexity on Driving Behaviors



YANG Liping, BIAN Yang, ZHAO Xiaohua, et al

2021, 49(3):  139-148.  doi:10.12141/j.issn.1000-565X.200195

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To explore the effects of navigation broadcast wording complexity on driving behaviors, this paper took ordinary intersections as an example, divided wording complexity into levels: I, II, III and IV , obtained experiment data through driving simulation method, constructed a multi-dimensional indicator system considering the spatiotemporal and comprehensive driving performance of drivers, and explored the temporal and spatial characteristics of driver behaviors under different navigation broadcast wordings using variance analysis and nonparametric test methods, excavated the change rule of comprehensive driving performance. The results showed that drivers start to slow down from 200m upstream of the intersection; the effects of the four broadcast wordings are obviously different beteween100m upstream to 100m downstream in the intersection; under the guidance of Level I and II broadcast wording, the stability of vehicle operation is poor; compared with Level I wording, the comprehensive behavior of the driver under the guidance of Level II, III and IV broadcast wording improves by 15%, 20% and 40% respectively.