Table of Content

25 July 2024, Volume 35 Issue 07

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Robust Control of High-pressure Pneumatic Pressure Servo Systems

ZHANG Dijia1, 2, GAO Luping2, ZHOU Shaoliang2, GAO Longlong2, LI Baoren2

2024, 35(07):  1141-1150.  DOI: 10.3969/j.issn.1004-132X.2024.07.001

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Parameter uncertainty and unmodeled dynamics of HPPS restricted the improvement of the control accuracy. An adaptive robust control method was proposed and applied to control the HPPS based on RISE. This paper considered the influencs of HESV control performance on the high-precision control of HPPS, and a cross-comparison test was designed. The results show that the HESV position control method may avoid sinusoidal signal distortions and reduce steady-state pressure jitter, and the HPPS pressure control method may improve the response speed and dynamic tracking capability of the systems.

Friction Reduction Mechanism of MoSe2/Graphene-Stainless Steel Self-lubricating Materials

YAN Songshan1, XIAO Zhengli1, MAO Ya1, HU Rui2

2024, 35(07):  1151-1155.  DOI: 10.3969/j.issn.1004-132X.2024.07.002

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In order to overcome the shortcomings of high friction coefficient and easy wear of stainless steel friction pair parts， based on the through-hole characteristics of powder metallurgy stainless steel porous matrix and the super sliding effect of heterojunction nano lubricants, a two-step preparation process of vacuum impregnation and hydrothermal synthesis were used to preduce MoSe2/graphene-stainless steel self-lubricating materials. The tribological properties and friction reduction mechanism of the composites were studied. The results indicate that the MoSe2/graphene lubricants in the matrix pores form a uniform lubricating film on the friction surfaces under the dragging effect during the friction processes, and significantly reduce the friction coefficient and wear rate of the friction pairs. At room temperature, load of 40 N, and speed of 100 r/min, the friction coefficient drops to 0.106, and the wear rate drops to 6.45×10-5 m3/(N·m). Compared with the stainless steel matrix, the friction coefficient and wear rate are reduced by 86% and 93% respectively. 

Geometric Design and Performance Analysis of Multi-closed-loop Deployable Honeycomb Mechanisms with Thick Panels

CHANG Boyan1, 2, GUAN Xin1, JIN Guoguang1, 2, LIANG Dong1, 2

2024, 35(07):  1156-1167.  DOI: 10.3969/j.issn.1004-132X.2024.07.003

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A new type of space mechanisms with single-closed-loop was proposed according to thick-panel origami teory, and the mobility was analyzed by using screw theory. The degree of freedom of mechanism was reduced to 1 by the introduction of Myard constraint and Sarrus constraint, and the corresponding deployable units were obtained with the names of Myard deployable honeycomb unit and Sarrus deployable honeycomb unit. M-type honeycomb mechanism and S-type honeycomb mechanism were proposed based on kinematic analysis and planar mosaic array of deployable honeycomb units. The influence regularity of various factors on folding ratio was analyzed, and the deployable honeycomb units  were optimized with the rising of folding ratio index. The results show that M-type honeycomb mechanism may achieve flat surface, and S-type honeycomb mechanism may achieve higher folding ratio index.

Research on Robot Parameter Calibration Based on Configuration Similarity Clustering

GAO Wenbin1, 2, ZHAN Qingyuan1, 2

2024, 35(07):  1168-1177，1187.  DOI: 10.3969/j.issn.1004-132X.2024.07.004

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Based on the similarity mapping between positioning errors caused by non-geometric parameter errors and robot configurations, the robot parameter calibration configuration space was divided into multiple subspaces by clustering algorithm, then the parameter calibration was completed in each subspace. The configurations to be compensated were classified into the corresponding subspaces by similarity relation, then the robot motions were controlled according to the parameter calibration results of the subspaces, and the positioning errors caused by non-geometric parameter errors were compensated effectively. An UR5 robot was used as the calibration object for the experiments. Compared with the ordinary calibration compensation method, the maximum and average of the positioning error mode of the proposed method are reduced by 60.24% and 66.62% respectively after calibration compensation.

Lubrication Characteristics of Gear End Face Friction Pairs of Aviation High-speed Gear Pumps

CHEN Yuan1, XIONG Dianfeng1, LI Yuntang1, GAO Yongcao2, LI Chuancang2, WANG Bingqing1, JIN Jie1

2024, 35(07):  1178-1187.  DOI: 10.3969/j.issn.1004-132X.2024.07.005

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Aiming at the serious wear problems of gear end face friction pairs of aviation external gear pumps, a new compound texture combining Tesla valve groove type and elliptical shape was opened on the gear end faces to improve lubrication performance. Based on hydrodynamic lubrication theory and finite element simulation calculation method, a theoretical analysis model of gear textured end face friction pair lubrication was established. Pressure distribution and velocity distribution of fluid within the end face liquid films were simulated and analyzed under conditions with and without texture, and the effects of operating and structural parameters on the openness and sealing performance of gear end faces were studied. The results show that the hydrodynamic pressure generated by the texture may make the gear end face friction pairs run non-contact, which has a positive effect on reducing friction and increasing efficiency. With the comprehensive consideration of the openness and leakage control performance of gear end face friction pairs, groove depth is as 7~9 μm, height difference is as 5~6 μm, inclination angle is as 0°~10°, and shape factor is as 0.4~0.5 are the optimal structural parameters for the texture structure.

Temperature Modeling and Verification of High-voltage Micro-arc with a Tungsten Electrode

LI Ruijun, ZHAO Liang, YAO Pan, WANG Yongjun, YANG Xiaoting, XIA Guo, CHENG Zhenyin

2024, 35(07):  1188-1193，1204.  DOI: 10.3969/j.issn.1004-132X.2024.07.006

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In order to improve the success rate of the preparation of monolithic micro tungsten ball tips, the high-voltage micro-arc was studied during the preparation processes. A multi-physics field coupled simulation model of tungsten-pole high-voltage micro-arc was established to calculate the arc temperature distribution at electrode spacing of 0.5~2.0 mm and voltage of 1~12 kV. The simulation results were then subjected to least-squares fitting, and a mathematical model between the arc temperature and the discharge parameters was obtained. Finally, the mathematical model was validated by building a spectral temperature measurement system based on the Boltzmann graphing method. The results show that the arc is elliptically distributed, and there is a high temperature barrier in the near-anode region, and the anode temperature is much lower than that of the cathode temperature. The arc temperature has a parabolic relationship with the voltage and electrode spacing. The average relative error between the model calculation results and the experimental results is as 3.3%. The model may be used to calculate the arc temperature for controlled preparation of the tungsten ball tips. 

A Multiaxial Fatigue Life Prediction Model for Notched Parts Considering Additional Damage and Notch Effect

CHENG Qin1, GAO Jianxiong1, YUAN Yiping1, ZHU Pengnian2

2024, 35(07):  1194-1204.  DOI: 10.3969/j.issn.1004-132X.2024.07.007

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To address the issue of significant errors in predicting the multiaxial fatigue life of notched components with local stress-strain method, a method for predicting the fatigue life of notched components under multiaxial loading was proposed based on the critical plane theory which toke the stress gradient and size of the notchs and influences of additional strengthening effects into account. The model was validated by experimental data from three different materials of notched specimens, and the prediction results of the proposed model were compared with those of two classic models. The results show that the prediction accuracy of the proposed model is higher than that of the other two models, and the prediction results are almost all within the double life error band.

Analysis of Lubricating Efficiency Enhancement of Line Contact Pairs under Micro-oil Supply

LI Shuyi1, 2, GUO Feng1, WONG Pat Lam2, JIN Wei1, LIANG Peng1

2024, 35(07):  1205-1211.  DOI: 10.3969/j.issn.1004-132X.2024.07.008

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It was found that the surfaces of interlaced wettability could improve the effective lubrication film formation performance under micro-oil supply. Based on this, a lubrication model of finite length roller pairs was established. The influences of the parameters such as interlaced wettability and working condition on the functional surface in micro-oil supply were analyzed. The results show that under certain working conditions, the interval oil supply mode of trace lubricating oil may play a role in enhancing lubrication efficiency. Due to the existence state of alternating oil supply, the lubrication performance in contact zones is unstable. The effectiveness of lubrication enhancement is affected by hydrophilic/hydrophobic bandwidth of the functional surfaces and the entrainment speed. 

Visual Loop Detection Method with Sensitivity Analysis of Network Weight Parameters

SHEN Yehu1, LI Huan1, ZHANG Daqing1, MIAO Yang1, ZHAO Chong2, JIANG Quansheng1

2024, 35(07):  1212-1221.  DOI: 10.3969/j.issn.1004-132X.2024.07.009

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In visual-based simultaneous localization and mapping, the loop-closure detection might determine whether the robot reached the previous positions, so that the accumulated errors caused by pose estimation might be effectively eliminated. With the increase of data volume, the generalization performance of network model will be reduced by the existing methods. In order to realize sustainable loopback detection, a visual loop detection method was proposed herein based on sensitivity analysis of network weight parameters. A lightweight feature extraction network was constructed by combining residual neural network and generalized mean pooling. The variable similarity sensing areas were designed, and the variable sliding windows were combined with the similarity matrix to extract three samples. The proposed sensitivity analysis method of network weight parameters reduced the catastrophic forgetting of network models. Compared with the typical method MAC, the recall rate of the proposed method in Nordland and other data sets is improved by about 42%.

A Grinding Trajectory Accurate Calculation Method for Circular-arc End Mill Flanks Based on Contact Area Adaptive Adjustment

LIU Zhe1, YANG Decun1, 2, YANG Zhihui1, JIANG Lei1

2024, 35(07):  1222-1231，1240.  DOI: 10.3969/j.issn.1004-132X.2024.07.010

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In order to ensure the machining accuracy of circular-arc end mill flanks, a grinding trajectory accurate calculation method for circular-arc end mill flanks was proposed based on contact area adaptive adjustment. Firstly, the mathematical model of the flank was constructed through structural feature decomposition of the circular-arc end mill. Then, by calculating the grinding contact area between the grinding wheel and the flank, the grinding wheel posture was adaptively corrected to avoid grinding interference, which realized the accuracy and consistency of flank geometric parameter control and ensured the smooth connection of the curved surfaces. Finally, based on the implement of VC++ platform algorithm module, the effectiveness of the proposed algorithm was verified by machining simulation and grinding experiments.

Flow Channel Wall Erosion Characteristics and Impacts on Performance in Radial Turbines

MA Chao1, 2, ZHANG Jianjian2, 3, WANG Ningning2, 3, GUO Shanshan1, 2

2024, 35(07):  1232-1240.  DOI: 10.3969/j.issn.1004-132X.2024.07.011

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Carbon particles, as inherent products of internal combustion engine combustion, might cause erosion on channel walls of turbines when carried by the mainstream and affect performance after prolonged operations. The erosion characteristics of the walls of a certain radial flow turbine were calculated by means of two-phase flow numerical simulation, and the effects of various key parameters on the erosion rate density and performance deterioration of the turbine were investigated. The results show that the distribution characteristics of wall erosion are impacted by particle sizes and the effects on performance exhibite a non-linear changing pattern. Particle emission margin and expansion ratio presented a linear relationship with the change rate of the performance. The variations in turbine speed show a linear relationship with the efficiency change rate and exhibit a rapidly increasing and then continuously decreasing relationship with the change rate of the mass flow parameter(MFP). Particle sizes and turbine operating conditions are significant factors affecting the change rate of turbine performances, which are 5~7 times and 19~24 times greater than the effects of particle emission margin and expansion ratio on the change rate in efficiency and MFP, respectively. 

Potential and Challenges for GPT Robots

ZHANG Fan , TAN Yuegang

2024, 35(07):  1241-1252.  DOI: 10.3969/j.issn.1004-132X.2024.07.012

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The fusion of robots and ChatGPT might create “silicon intelligence entity” with human-like intelligence and advantages, defined as “GPT-R”. The characteristics, technological trends, and applications of GPT-R were explored in industrial and human life domains, with a focus on the integration of ChatGPT and robot intelligence. The challenges of GPT-R in physical abilities, intelligence, and coexistence with humans were analyzed, and the corresponding strategies from robotic body and intelligence of GPT-R, law and security issue, and social rules were proposed. The GPT-R, which integrated ChatGPT and robotics technology, will be expected to have increasingly broad applications and market potential, and will become one of the crucial directions in the future development of the integration of artificial intelligence and robotics.

Automated Grinding System and Method for Robotic Weld Seams Based on Point Cloud

GE Jimin1, DENG Zhaohui2, WANG Shuixian1, ZHUO Rongjin1, LIU Wei1, Chen Xi3

2024, 35(07):  1253-1262，1268.  DOI: 10.3969/j.issn.1004-132X.2024.07.013

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Service life and dynamic performance of structural components were affected by the accuracy and surface consistency of weld grinding. Currently, weld grinding mainly relied on manual or trajectory teaching methods, which had problems such as poor uniformity, low efficiency and high cost. So, a point cloud-based automated grinding system for robotic weld seams was proposed. A quadratic streamlining method for weld seam point cloud was proposed to obtain the global information of the weld seam surfaces accurately, and the weld seam width, height, and centerline features were extracted based on the distances between sampling points and neighborhood center of gravity points. The errors of height and width of the extracted weld seams are as 0.09 mm and 0.2 mm respectively, and the minimum residual height of the weld seams after grinding is as 0.17 mm, and the vlaue of surface roughness Ra is up to 0.498 μm.

Three-dimensional Measurement Point Processing and Accurate Calculation of Throat Area for Aircraft Turbine Nozzles

WANG Dongfang1, JIANG Cheng1, GONG Boyue2, LI Wenlong1

2024, 35(07):  1263-1268.  DOI: 10.3969/j.issn.1004-132X.2024.07.014

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Turbine nozzles were crucial components in aircraft engines, and the throat area was a key parameter that directly affected the engines power performance. In response to the issues of low efficiency and inaccurate estimation in existing measurement methods for the throat area, a new method for three-dimensional measurement point processing and accurate calculation of the throat area for aircraft turbine nozzles was proposed. Comparative experiments between the proposed method and the CMM method were conducted on a multi-blade turbine nozzle sample. The experimental results show that the throat areas obtained by the proposed method are more accurate, and the results of multiple measurements and calculations have high consistency.

Multi-objective Scheduling Optimization for Hybrid Flow Shops with Limited Waiting Time and High Energy Consumption

CHANG Daliang1, 2, 3, SHI Haibo1, 2, LIU Chang1, 2

2024, 35(07):  1269-1278.  DOI: 10.3969/j.issn.1004-132X.2024.07.015

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In order to solve the hybrid flow shop scheduling problems with tight time and high energy consumption process characteristics, a hybrid flow shop scheduling model was established with the objectives of optimizing product exposure time, maximum completion time, and energy consumption. An improved multi-objective particle swarm optimization algorithm was proposed to optimize the hybrid flow shop scheduling problems effectively. Firstly, based on ISDE indicator and a local neighborhood search strategy the archive maintenance strategy was constructed to assist the algorithm to jump out of local extreme values and reduce production congestion. Then, based on fuzzy theory a decision analysis method was proposed to select the optimal scheduling. Finally, by simulation experiments, the feasibility and superiority of the proposed multi-objective scheduling model and optimization algorithm were verified. 

Thin Wall Metal Material Laser Cutting Process Optimization Based on Orthogonal Experiments

ZHAI Zhaoyang1, LI Xinxin1, ZHANG Yanchao1, LIU Zhongming2, DU Chunhua1, ZHANG Huaming3

2024, 35(07):  1279-1289.  DOI: 10.3969/j.issn.1004-132X.2024.07.016

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After laser cutting, the material substrates of thin wall metal components and the support plates below were prone to adhesion, which seriously affected the cutting quality. Fiber laser cutting experiments were conducted on 304 stainless steel and GH605 high temperature alloy thin plates, and the formation mechanism of the adhesion in laser cutting of different materials was analyzed. The single factor experimental method was used to analyze the influences of laser cutting process parameters on the HAZ and burr accumulation. The processing results show that with the addition of a micro-connection process, when the laser power is as 165 W, the cutting speed is as 5 m/min, and the auxiliary gas pressure is as 1.2 MPa, the cut edges are smooth and without deformation and residual adhesion.

Effects of Ni Interlayers on Mechanical Properties and Microstructure of Resistance Spot Welding Joints of 6061T6 Aluminum Alloy Plates/08Al Dissimilar Metal

PENG Yuxin1, 2, 3, LIU Sheng1, 2, 3, HU Xinbin1, 2, 3

2024, 35(07):  1290-1298.  DOI: 10.3969/j.issn.1004-132X.2024.07.017

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By adding Ni interlayers to steel plates, the reliable connections between 6061T6 aluminum alloy plates and 08Al steel plates were successfully realized, and the mechanical properties of aluminum/steel spot welding joints were significantly improved. The results show that the thickness and distribution of Ni intermediate layers on steel plates may be controlled by using the prefabricated Ni intermediate layer processes, and the formation of Al-Fe brittle intermetallic compounds may be reduced. Compared with adding Ni foil intermediate layers directly, the prefabricated Ni intermediate layer processes may effectively increase the nugget diameter. The maximum tensile sheer force of aluminum/steel resistance spot welding joints with laser cladding Ni layer on steel plates is 35.5% higher than that without intermediate layers.

Fatigue Life Prediction of Multiple Unit Axle Considering Wheel Polygon

2024, 35(07):  1299-1307.  DOI: 10.3969/j.issn.1004-132X.2024.07.018

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Taking the axle of a certain type of high-speed locomotive set as research object and the measured polygonal abrasion as input, the effects of polygonal abrasion on the fatigue damage of axle were analyzed at the speed of 300 km/h, which was based on the rigid-flexible coupling dynamics model of vehicle track considering wheel-rail flexibility, the finite element model of wheelset, and the multiaxial fatigue model. The results show that under the influences of polygonal wear, the loaded condition of the wheelset fluctuates drastically and has significant periodicity, and the load fluctuation is related to the orders of polygonal wear. Under the influences of 18 orders of polygonal wear, the service life of the axle of high-speed locomotives is reduced to 22 years, which is less than the design life of axle as stipulated in Regulations on the Operation and Maintenance of Railway Locomotives.

Dynamics Analysis and Engineering Applications of Multi-tagline Anti-swing System for Marine Cranes

SUN Maokai, WANG Shenghai, HAN Guangdong, CHEN Haiquan, SUN Yuqing

2024, 35(07):  1308-1317.  DOI: 10.3969/j.issn.1004-132X.2024.07.019

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Aiming at the problems such as low working efficiency, high risk, and low positioning accuracy of marine cranes under rough sea conditions, a multi-tagline anti-swing system for marine cranes was proposed. The multi-tagline anti-swing system was simplified into a constrained pendulum model excited by ship motions and wind loads. MATLAB/Simulink was used to simulate the dynamics characteristics of the multi-tagline anti-swing systems, and the multi-tagline anti-swing system of marine cranes was verified on the experimental prototype. The experimental results show that the average wobble reduction ratio of the system may reach 78%, which proves the effectiveness of the multi-tagline anti-swing systems. 

Self-positioning Cutting Control Methods and Experimental Research for Coal Mine Roadheaders

LIU Songyong1, WU Hongzhuang2, CHENG Cheng2, SONG Mingjiang1, 3, CUI Yuming4

2024, 35(07):  1318-1329.  DOI: 10.3969/j.issn.1004-132X.2024.07.020

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A self-positioning cutting control methods were proposed, and the experimental studies of roadheaders were conducted herein. An self-positioning cutting control strategy was proposed. The monocular vision and deep learning based six degrees of freedom pose detection method for roadheader body and the double-layer fuzzy adaptive backstepping control method with prescribed performance were utilized to achieve the self-positioning cutting of roadheaders. The tracking control of cutting head was realized at arbitrary body poses of the roadheaders. The cutting head tracking control experiments were carried out under two different body poses of the roadheaders. The experimental results illustrate that the maximum contour errors are within 48 mm and 52 mm(about 2.14% and 2.32%) respectively, which verifies the effectiveness of the proposed self-positioning cutting control method for the roadheaders.