Table of Content

25 February 2024, Volume 35 Issue 02

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Analysis for Aero -elastic Characteristics of Prop-Rotor in Hover with a Swept Tip

HUANG Wei, CHI Cheng

2024, 35(02):  191-200.  DOI: 10.3969/j.issn.1004-132X.2024.02.001

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The issues of significant stress and strain concentration within the prop-rotor blades caused by large negative twist and swept tips were addressed herein. By 3D structural dynamics model, rotor aerodynamics model, and rotor trim methods, a comprehensive model of composite prop-rotor was developed, and the aeroelastic loads of composite prop-rotor were analyzed, and the accuracy of the synthesis model was validated through hover experiments. The analysis of aero-elastic characteristics was performed for rotor blades with zero twist, large negative twist, and large negative twist with swept tips. The results indicate that the large negative twist enlarges the stress concentration area, while the swept tip makes the stress concentration at the swept transition area larger and the degree of concentration worsens. 

Experimental Study of Surface Morphology of Polycarbonate Ultra-low Temperature Cooling Turning

BAO Rui, LIU Kuo, ZHANG Jie, HAN Lingsheng, LI Jianming, ZUO Yueshuai, LIU Haibo, WANG Yongqing

2024, 35(02):  201-207.  DOI: 10.3969/j.issn.1004-132X.2024.02.002

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Aiming at the problems of poor heat resistance, deformation, and swelling, a turning test of polycarbonate was carried out under dry cutting, water cooling, ultra-low temperature cooling, and the shape of the surface was analyzed. The morphological differences of machined surfaces were explained from the perspective of relaxation time of molecular chains, crazing generation, and brittle-toughness transition. It is found that, on polycarbonate surfaces, dry cutting produces a large number of strong crazing, water-cooled cutting produced a large number of fine crazing, while the ultra-low temperature cooling cutting produces less crazing. Therefore, ultra-low temperature cooling has a positive effect on improving the processing quality of polycarbonates.

Coating Technology and Mechanism of Modified Diamond Powder by Surface Coating of WC Powders

XU Zuolin, HUANG Chuanzhen, LIU Huanlian, LIU Dun

2024, 35(02):  208-214.  DOI: 10.3969/j.issn.1004-132X.2024.02.003

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The powder surface coating technology might endow the powder with new physical and chemical properties. By electrophoretic deposition technology, diamond powder was modified on the surface coating of WC powders. The core-shell structure of diamond and the coating between diamond powder and WC powder were analyzed by different characterization methods. The influences of diamond powder content on coating effectiveness were studied, and the bonding strength among powders was compared under different coating processes. The results show that when the mass ratio of WC powder to diamond powder is as 6∶1, the coating effectiveness is the best. The strong bonding force among the modified powders comes from the chemisorption formed by covalent bonds such as COO-W and C-O-W and the physical adsorption formed by van der Waals force.

Accelerated Editing of Automotive Component Load Spectrum Based on S-transform Dual Threshold Method

YAO Lingyun, LIN Yongjie, LI Li,

2024, 35(02):  215-220.  DOI: 10.3969/j.issn.1004-132X.2024.02.004

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 Based on S-transform a dual threshold editing method was proposed to address the issues of poor acceleration of editing performance in S-transform editing. Firstly, this method performed an S-transform on the load spectrum to obtain the maximum amplitude spectrum. Then the method retained the corresponding load spectrum segments based on the amplitude spectrum segments which were recognized and retained by the dual threshold method to assemble the accelerated load spectrum. Finally, the statistical parameters, power spectral density, breakdown count, and fatigue simulation results of the acceleration spectra edited by the S-transform dual threshold editing method and the S-transform editing method were compared and analyzed. The results indicate that the S-transform dual threshold editing method may significantly compress the original load time, and the compression efficiency is higher than that of S-transform editing method. The fatigue damage and life analysis errors of the steering joint are smaller, which verifies the proposed method is suitable for accelerated editing research of automotive component load spectra.

Contact Fatigue Performance of PEEK under Oil-injected Lubrication

WU Ruo, WEI Peitang, XIE Huaijie, BIAN Jiang, LU Zehua, LIU Huaiju

2024, 35(02):  221-228.  DOI: 10.3969/j.issn.1004-132X.2024.02.005

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PEEK was a high-strength, heat-resistant engineering polymer, but the absence of basic data of PEEK contact fatigue restricted the reliable and long-life applications under heavy-duty conditions. PEEK rolling contact fatigue tests and gear contact fatigue tests under oil injection lubrication were conducted herein, and the S-N curves were obtained. It is found that the PEEK rolling contact fatigue limit is 14% higher than gear contact fatigue limit, and the rolling contact fatigue life of rollers under the contact pressure of 135 MPa is 58% higher than gear fatigue life. And then, the conversion formula of PEEK roller-gear contact fatigue life was further proposed.

Design of Experimental Device for Sealing Performance of Hydraulic Pump Plungers

LUO Longjun, HE Xiaofeng, LIU Xun, ZHANG Qiaxuan, HUANG Hewen

2024, 35(02):  229-235.  DOI: 10.3969/j.issn.1004-132X.2024.02.006

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In order to solve the sealing reliability and selective design problems of the plungers and cylinder liners of oil-water separated plunger pump, a plunger sealing performance experimental device and the loading system were developed to simulate the actual operating conditions of the hydraulic plunger pump, and the dynamic balance design of the experimental device was carried out. The simulation model of the loading system for the experimental device was established, and then a reasonable loading method was determined through simulation and comparison. The loading test and stability test of the experimental device show that the operation of the experimental device is stable and reliable, and the volumetric efficiency is within a reasonable range.

Contrastive Experiments on Up and Down Grinding of Unidirectional Ceramic Matrix Composite C/SiC with Variable Angle

ZHANG Lifeng, WANG Zixu, ZHANG Wangtong, DENG Yunfei, SUI He, GUO Zhiyong

2024, 35(02):  235-243.  DOI: 10.3969/j.issn.1004-132X.2024.02.007

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This paper investigated the impact mechanism of grinding forces and machined surface quality on unidirectional C/SiC by a regular dodecagon-based grinding track method. Comparative analysis reveal that up grinding reduces tangential forces by 10%~25%, normal forces by 30%~50%, and surface roughness by 25%~65%, compared to down grinding. Moreover, the fiber grinding angle has a pronounced impact on the grinding characteristics. When the fiber grinding angle is as 0°~90°， the magnitude ranking of grinding force from large to small is as 60°, 30°, 90°, 0°. When the fiber grinding angle is as 90°~180°， the magnitude ranking of grinding force from large to small is as 120°, 90°, 150°, 180°. The order of surface roughness Sa on the machined surface aligns with the grinding force magnitude ranking as 0°, 150°, 120°, 30°, 60°, 90°. A pronounced material deformation rebound effectiveness is observed in C/SiC grinding. A comparative analysis of surface microstructures at diverse fiber grinding angles, and a grinding material removal model was introduced.

On-line Identification of Narrow Gap P-GMAW Sidewall Fusion States Based on Arc Acoustic Signals

YUE Jianfeng, LONG Xinyu, HUANG Yunlong, GUO Jialong, LIU Wenji

2024, 35(02):  244-250，259.  DOI: 10.3969/j.issn.1004-132X.2024.02.008

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 To grasp the internal welding status of welds in real time during welding processes, an on-line acquisition system of arc sound signals was constructed. The correlation analysis between arc sound signal characteristics and sidewall fusion states was carried out under the conditions that the torch swing center were in different positions. Arc acoustic features with strong correlation to side wall fusion state were extracted from time domain and frequency domain respectively. In order to further improve the effectiveness of the fusion state prediction, a support vector regression model for sidewall fusion state recognition was constructed by arc acoustic feature parameters. To reduce the impacts of non-features and improve the prediction accuracy of the model, genetic algorithm was used to optimize the model parameter. After parameter optimization, the recognition rate of the model is  as 93.33%, which realizes the effective recognition of the fusion states of the narrow gap sidewalls.

Research on Flow Field Characteristics of Composite Spiral Abrasive Flows

YUAN Qiaoling, DING Jie, KONG Fanzhi, WEN Donghui, QI Huan

2024, 35(02):  251-259.  DOI: 10.3969/j.issn.1004-132X.2024.02.009

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 In response to the precision machining of frictionless aluminum alloy cylinder with anodized oxide films, a composite spiral abrasive flow polishing method was proposed. A simulation model was established to analyze the collision between particles and the wall in polishing processes, and the influences of particle velocity in different directions on polishing were investigated. The processing mechanism of the composite spiral abrasive flow polishing was revealed. The simulation results show that the composite spiral motion changes the trajectory of the abrasive particles, and the addition of rotational velocity enhances the effective stress of the abrasive. The effective plastic deformation of the wall increases with the spiral groove speed. Particle image velocimetry observation experimental results demonstrate that the composite spiral motion increases the rotational velocity of the abrasives and enhances the vorticity of the flow field. The experimental results show that the composite spiral abrasive flow polishing not only causes less damages to the aluminum alloy anodized film, and effectively improves the surface quality of the workpieces.

Scheduling in SAT in Multi-operation Mode Based on Artificial Hummingbird Algorithm with Twin Population

WANG Hong, WU Lihui, CHEN Da, ZHANG Jie

2024, 35(02):  260-267，279.  DOI: 10.3969/j.issn.1004-132X.2024.02.010

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 In order to solve the scheduling problem of SAT in multi-operation mode, an artificial hummingbird algorithm with twin population was proposed with the goal of minimizing the maximum completion time. The twin population mechanism was designed to improve the solution accuracy. By double decoding, twin population generation and cooperation methods, the searching space for solutions was expanded, the quality of the initial population solution was improved, and the diversity of population solutions was increased in optimization processes. By the bidirectional-guiding foraging strategy, the relationship between algorithm diversity and convergence was balanced, and algorithm stability was enhanced. By the strategy of four-variable neighbor searching, the local optimization ability of the algorithm was enhanced. The test results show that the proposed method may effectively shorten the maximum completion time of the SAT.

SLAM-based Underwater Image Enhanced Visual 3D Reconstruction Method

MEI Jie, QIN Jiarui, CHEN Dingfang, CHEN Kun,

2024, 35(02):  268-279.  DOI: 10.3969/j.issn.1004-132X.2024.02.011

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Regarding with problems of low quality of underwater images and difficulty of underwater autonomous localization faced by bionic robotic fish in underwater operations, an enhanced underwater image algorithm with color equalization and a priori fusion of G-B channels was proposed. The algorithm was combined with visual SLAM construction methods to enhance visual 3D reconstruction of underwater images. Underwater image processing experiments, underwater environment visual 3D reconstruction experiments, and motion trajectory tracking experiments were carried out in different water environments. The results show that the method effectively improves the comprehensive quality of underwater images. The feature matching efficiency is improved by 16.03%, and the error between the real trajectory and the estimated trajectory is about 7.99 mm on average.

A Real-time Tool Path Smoothing Algorithm Considering Joint Jerk Constraints

DU Xu, CHANG Zexin, ZHENG Junqiang, REN Pengfei

2024, 35(02):  280-286.  DOI: 10.3969/j.issn.1004-132X.2024.02.012

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Aiming at the problems of joint jerk exceeding constraints in robot machining, a tool path smoothing algorithm was proposed considering joint jerk constraints. The FIR filter interpolation was used to smooth the five-axis tool paths. Path smoothing and speed planning were achieved in one step. The relationship of velocity, acceleration, and jerk between joint and tool was established, and the joint jerk did not exceed the constraint by adjusting the time constant. Time constant calculated by the proposed method was smaller than considering the acceleration constraints of robot joint. Simulation and experimental results show that the proposed algorithm may reduce the tracking error of the joint and improve the stability of the robot joint in machining.

Assembly Array Tractile State Sensing Technology of Micro Flexible Flat Cables

LIN Jie, HU Zhikai, LIU Siyuan, TANG Weiwei, CHU Zhongyi

2024, 35(02):  287-292，304.  DOI: 10.3969/j.issn.1004-132X.2024.02.013

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For the problems of small device size and visual occlusion during the micro flexible flat cable assembly operations, an assembly state sensing technology of micro flexible flat cables was proposed based on capacitive array tactile sensors herein. Firstly, the mechanism of capacitive three-dimensional tactile sensing was analyzed, and a highly sensitive array tactile sensor based on vertical topological mesh dielectric layer was designed to realize highly sensitive sensing of the assembly state of the micro flexible flat cables. Secondly, in order to overcome the limitation of wiring complexity and array scanning cycle, based on the expansion of capacitive digital chip, the highly dynamic three-dimensional array information scanning system was designed and the highly dynamic sensing for assembly states of micro flexible flat cables was realized, and the miniaturized capacitive array tactile sensors were fabricated integrally. Finally, the robot micro flexible flat cable assembly operating system was built and the array tactile information features were collected and analyzed in real time during the assembly processes, so as to verify the accuracy and effectiveness of the proposed technology.

Inverse Kinematics Solution of Robots Based on IQPSO Algorithm

CHEN Zhuofan, ZHOU Kun, QIN Feifei, WANG Binrui

2024, 35(02):  293-304.  DOI: 10.3969/j.issn.1004-132X.2024.02.014

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Aiming at the problems of singular pose, non-unique solution and low solution precision in the inverse kinematics solution processes of general robots, an improved quantum particle swarm optimization algorithm was proposed. Firstly, the robot kinematics model was established by using the D-H parameter method, and the minimum pose errors at the end of the manipulators were the main optimization goal, and the constraints of the minimum joint angle changes before and after the movement and the smooth and continuous stroke were added, and the objective function was designed. Secondly, an IQPSO algorithm was designed by using the Levy flight strategy to improve the particle update method, nonlinear dynamic adjust the shrinkage and expansion factors, and using the variable weight method to calculate the optimal average position. Then, the simulation and comparison experiments of three algorithms（IQPSO,APSO,QPSO） were carried out by simulating two different solutions of single point pose and continuous trajectory. The results show that the IQPSO algorithm has the advantages of fast convergence speed and high solution accuracy; finally, the IQPSO algorithm was used in the body of the robot arm for physical verification. The results show that the trajectory composed of interpolation points obtained by the IQPSO algorithm is continuous and smooth, which further proves the stability and feasibility of the algorithm in practical motion control.

A Multi Index Comprehensive Optimal Anti Impact Trajectory Planning Method

RONG Yu, CHEN Gang, DOU Tianci,

2024, 35(02):  305-316.  DOI: 10.3969/j.issn.1004-132X.2024.02.015

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A comprehensive optimal trajectory planning method was proposed to improve the efficiency and impact resistance of robotic arms. Firstly, by establishing a 3-5-3 polynomial curve mathematical model, a joint motion trajectory with controllable endpoint motion parameters was constructed. Secondly, considering constraints such as joint position, velocity, and acceleration, the objective function was defined using the weighted coefficient method to achieve a comprehensive optimization of the action time, impact, and dexterity of the robotic arm. The dynamic weighting method was used in the design of the objective function to address the contradiction between joint velocity and impact. Finally, for the standard particle swarm optimization algorithm, the Latin hypercube sampling function was used to homogenize the population, and a random inertia weight update strategy was proposed to obtain an improved particle swarm algorithm. This algorithm was used to optimize the objective function and obtain the comprehensive optimal motion trajectory. Simulation and prototype experiments were conducted, and the experimental results demonstrate the feasibility of the proposed method.

Intelligent Layout for Pipeline Supports of Nuclear Power Plant under Complex Load

SUN Yuxiang, CHEN Li, LONG Bo, WANG Yanping, LIU Shihua, JIA Kun

2024, 35(02):  317-323，336.  DOI: 10.3969/j.issn.1004-132X.2024.02.016

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 Nowadays, the arrangement of pipeline supports for nuclear power plants is achieved by iterative manual calculations, which had many drawbacks such as high labour intensity, long design cycles, and high costs. An intelligent layout method for three-dimensional nuclear power pipeline supports was proposed based on particle swarm optimization-genetic algorithm hybrid algorithm and finite element mechanics analysis. The examples of intelligent arrangement of pipeline supports for typical nuclear pipelines show that the proposed method may automatically arrange multiple supports of different types in the global space of the pipeline to meet the Design and Construction Rules for Mechanical Equipment of Nuclear Island of Nuclear Power Plants, and greatly reduce workload.

Design and Research of Heavy-duty Posture-adjusting Assembly Robots in Narrow Space

LIU Yi, YI Wangmin, YAO Jiantao, WANG Xingda, YU Peng, ZHAO Yongshen

2024, 35(02):  324-336.  DOI: 10.3969/j.issn.1004-132X.2024.02.017

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In response to the issues of a wide variety of equipment, large batches, heavy payloads, limited space, complex assembly paths, and high assembly risks inside the cabin, a heavy-duty positioning and assembly robot was designed. Based on the study of the robot kinematics, an error model was established. With the radius of minimum bounding sphere as the constraint condition, the identification results of error parameters by genetic algorithm were compensated into the robot control system. Taking cabinet assembly as an example, a working path was planned based on spatial constraint conditions. By a dynamic constraint energy consumption function model, multi-objective optimal trajectories were obtained with time, impact, and energy consumption as optimization objectives. Prototype testing verified the effectiveness of the error parameter identification, which reduces the absolute positioning errors of the robot. Moreover, the multi-objective optimal trajectory has a small total joint impact and smooth motion, achieving efficient, smooth, and reliable installation of cabinet-type equipment.

Regulation for Magnetic Field Distribution of Sheet Metal Electromagnetic Forming with Track Coil

TANG Tianyu, HUANG Liang, XU Jiahui, SUN Yiran, ZHOU Wei,

2024, 35(02):  337-346.  DOI: 10.3969/j.issn.1004-132X.2024.02.018

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 In order to effectively regulating the deformation behavior of aluminum alloy sheet in electromagnetic forming processes of track coil, the influences of the relative position of the sheet metal and the coil assembly on the electromagnetic force, current density, deformation velocity and forming height were revealed by experimental-simulation and theoretical calculation. An engineering calculation model of the magnetic induction intensity in central plane of the coil was derived. With the increase of the offset in sheet assembly, the maximum height difference of the deformation zone of the electromagnetic forming specimen gradually decreases, and the specimen changes from “low inside and high outside” to “high outside and low inside”. The peak electromagnetic force density moves from the inside of the sheet metal to the center. When the offset amount is as 2.5~3.0 mm, there is a minimum value for the height difference between the two sides. When the offset is as 3.0 mm, the lateral deformation speed of the sheet metal tends to be 0, and the electromagnetic force is axisymmetrically distributed along the center of the sheet. Based on the engineering model of the magnetic induction intensity of the track coils, the relationship among the position of the symmetrical center region of magnetic inductance and the half length of the straight section of the coil, the turn spacing, the center distance the sheet assembly clearance was deduced, and the optimal offset is as 2.2~3.9 mm. This results are consistent with the simulation experimental ones and confirm the reliability of the model.

Comprehensive Thickness Control Technology of 1180 MPa Grade Ultra-high Strength Steels in Cold Tandem Rolling

ZHANG Wenjun, WANG Wenqi, ZHANG Xiaodong, LIN Wei, ZHANG Yandong, BAI Zhenhua,

2024, 35(02):  347-353，370.  DOI: 10.3969/j.issn.1004-132X.2024.02.019

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To resolve the issues of thickness variation and thickness deviation at head and tail for ultra-high strength steels in continuous cold tandem rolling, a thickness deviation prediction model and a roll gap adjustment estimation model were established based on the metal mass flow equation firstly. In addition, a thickness control system was exploited, and optimal roll gap adjustment model was established. Finally, an optimization model for rolling speed and tension in the head and tail rolling processes of the strip steels was built. The first stand of continues cold tandem rolling unit was taken as the technical application objects to test the two typical ultra-high strength steels. The results demonstrate that the length of thickness deviation for the ultra-high strength steel AR4146E1 and DU6220A1 decreased from 70.3 m and 36.89 m to 16.85 m and 16.33 m respectively.

Mode Transition and Gear Shifting Control Strategy for Parallel Hybrid Commercial Vehicles Based on Optimal Drive System Efficiency

YAN Zhengfeng, JIANG Guangzong, YAO Mingyao

2024, 35(02):  354-363.  DOI: 10.3969/j.issn.1004-132X.2024.02.020

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To enhance the fuel economy of parallel hybrid commercial vehicles equipped with automatic transmissions and optimize the efficiency of the drive system, a new method for dividing driving mode boundaries and gear boundaries was proposed. A control strategy for mode switching and gear shifting was developed based on optimal efficiency and simulated under the driving conditions of Chinese heavy commercial vehicles. The results demonstrate that the proposed strategy maintains the balance of the battery state of charge, and achieves a 11.2% reduction in fuel consumption per 100 kilometers compared to the electric assist control strategy, which improves the fuel economy.

Roller Pose Compensation in Automotive Body Roll-hemming Forming Process with Adhesive for Dimensional Deviation

LI Mozhi, ZHU Wenfeng, WANG Shunchao

2024, 35(02):  364-370.  DOI: 10.3969/j.issn.1004-132X.2024.02.021

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In order to meet the stricter requirements for appearance accuracy of aluminum alloy automotive bodies, a roller pose compensation method was proposed for the dimensional deviation of automotive bodies. The dimensional deviation matrix was obtained by equidistant discretization of the dimensional deviation interval and the die edge. Based on the Frenet scale frame and Cartesian coordinate transformation, the dimensional deviation was mapped to the roller pose, and the deviation matrix of roller pose was obtained. The roller pose compensation amount was converted into the adjustment amount of the row number of the deviation matrix of roller pose, and the compensated roller pose was obtained. Among them, the deviation matrix of roller pose was determined by the surface/curve equation of die, the roller angle and the quantization model of dimensional deviation and the value of tool center point-robot target point(TCP-RTP). The quantization model of dimensional deviation and the value of TCP-RTP was obtained by finite element simulation of finite element method-smoothed particle hydrodynamics. The results show that the average value of the dimensional deviation is reduced from 0.32mm to 0.14mm after the roller pose compensation.

Mechanism of Rock Breaking by Convex Non-planar PDC Cutter and Its Applications in Gravel-bearing Formation

CHEN Lian, WEI Xiaohu, CAO Qiang, ZHOU Yan, YANG Yingxin, HU Chuan, ZHAO Zhijie, WU Bin

2024, 35(02):  371-379.  DOI: 10.3969/j.issn.1004-132X.2024.02.022

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A study of convex non-planar PDC cutter was conducted to improve the impact resistance of PDC bits in gravel-bearing, soft-hard interlaced, and other inhomogeneous formations. By comparing simulation and laboratory experiments, the mechanism of rock breaking between convex non-planar cutter and conventional planar cutter was investigated. Compared to planar cutter, the contact stress generated by cutting rock with convex non-planar cutter is more uniform on the cutter, the load fluctuation during the cutting processes is significantly smaller, and the cutting stability is higher. The special non-planar structure of the cutter changes the interaction mode between the cutting cutter and the rock, and is successfully applied in heterogeneous formations.