Table of Content

25 January 2022, Volume 33 Issue 02

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Research on Virtual Grinding Wheel  Modeling Based on Convex Polyhedron Collision Detection

CHEN Hao, ZHAO Ji, XU Xiuling, YU Tianbiao

2022, 33(02):  127-133.  DOI: 10.3969/j.issn.1004-132X.2022.02.001

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 The bounding sphere was usually used to detect the collision of grinding grains in the virtual grinding wheel modeling methods. When the bounding spheres were in contact， there was still a large gap between the abrasive grains， which resulted in a big difference between the virtual and actual grinding wheel surfaces. To solve this problem， a virtual grinding wheel modeling method was proposed based on convex polyhedron collision detection. The mathematical model of the random positions of abrasive grains on the grinding wheel surface was derived in detail. The interferences of grains were judged based on the convex polyhedron collision detection method， and the virtual grinding wheel was finally generated. The virtual grinding wheel surfaces generated by convex polyhedron and bounding sphere collision detections were compared. The improved method may generate virtual grinding wheel with 60% volume fraction of abrasive grains， while the original method may not generate virtual grinding wheel with more than 50% volume fraction of abrasive grains. The results indicate that the improved method may generate a virtual grinding wheel with a higher abrasive volume fraction and more randomness surface. Finally， the virtual grinding wheel surfaces were compared with the actual grinding wheel surfaces， and results show that the virtual grinding wheel surface has the characteristics of actual grinding wheel surface. 

Hybrid Control of Electromagnetic Active Suspensions Based on Nonlinear Actuators#br#

HU Yiming, LI Yinong, ZHENG Ling

2022, 33(02):  134-142.  DOI: 10.3969/j.issn.1004-132X.2022.02.002

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In response to the problems that the nonlinear characteristics of the electromagnetic active suspension linear actuators affected the performance of the control system， a nonlinear mathematical model of input current and electromagnetic actuation force was established based on the theory of magnetic field harmonics. A nonlinear dynamics model of electromagnetic active suspension was established by combining with the suspension systems， and the influences of nonlinear characteristics on active suspension performance were analyzed. In order to eliminate the influences of nonlinear characteristics， a MOPSOH2/H∞ robust controller was designed based on filter-x recursive least squares adaptive filter compensation. Simulation results show that the proposed hybrid controller may restrain the control force in the unsaturated interval and compensate the fluctuations of the control force effectively， which improves the vehicle dynamics performance and the control efficiency of the active suspensions， and significantly eliminates the influences of the nonlinear characteristics of the actuator on the active suspensions. 

Braking Energy Recovery Control Strategy for PHEVs Considering Coupling Influence of Driving Cycle and Driving Style

QIU Mingming, YU Wei, ZHAO Han, LIU Hao, CAO Longkai

2022, 33(02):  143-152.  DOI: 10.3969/j.issn.1004-132X.2022.02.003

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The influences of driving cycles and driving styles on braking energy recovery were analyzed, and a method of braking energy recovery was proposed by considering the coupling effects of driving cycles and driving styles. The pedal signals and velocity signals were collected by the driver-in-loop experimental platform. The driving cycle correction factor α and driving style correction factor β of the braking forces were defined, and their ranges were determined by using normal distribution and t distribution methods respectively, and then, the braking energy recovery strategy was established. The collected data of driving cycles and driving styles were used to train the recognition models of driving cycles and driving styles through learning vector quantization neural network. Finally, a simulation model was established and the braking energy recovery strategy was verified. The results show that the energy recovery efficiency of the braking energy recovery strategy proposed herein is higher, which considers the coupling influences of driving cycles and driving styles, and the economy of the vehicles is improved.

Study on Damage Mechanism of High-volume Fraction Silicon Aluminum Alloy Milled with Diamond Coated Cutting Tools

ZHAO Guolong, XIN Lianjia, LI Liang, WANG Min, HAO Xiuqing, HE Ning

2022, 33(02):  153-159.  DOI: 10.3969/j.issn.1004-132X.2022.02.004

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Due to the large amount of silicon particles，the machinability of the high-volume fraction silicon aluminum alloys was poor.Severe tool wear and deteriorated machined surfaces with defects were major problems in cutting high-volume fraction silicon aluminum materials.To further explore the machining damages，the milling experiments of 70% Si/Al（mass fraction is 70%）alloy were carried out，where the tools were prepared by chemical vapor deposition（CVD）method.Milling force，tool wear and mechanism of machining damages were investigated.As a comparison，milling tools with TiN coating were also utilized under identical cutting parameters.The results show that the main tool wear modes of the diamond coated tools are coating peeling and abrasive wear，which are due to the impact and scratching of hard silicon particles in milling processes.In the normal wear stages of the diamond coated tools，the milling force is stable in the range of 4357～4895 N，while the milling force of TiN coated tools is higher and the tool life is shorter.The damages on machined surfaces are mainly pits，scratches and ruptured particle.Under the premise of ensuring the strength of cutting-edge radius，machining damage may be obviously reduced by reducing the radius of tool cutting-edge.The surface roughness value（Sa=23 μm）machined with a cutting-edge radius of 12 μm is lower than that with a radius of 156 μm（Sa=67 μm）.

Topological Design and Dynamics Modeling of a Spatial 2T1R Parallel Mechanism with Partially Motion Decoupling and Symbolic Forward Kinematics

HUANG Kaiwei, SHEN Huiping, LI Ju, ZHU Zhongqi, YANG Tingli

2022, 33(02):  160-169.  DOI: 10.3969/j.issn.1004-132X.2022.02.005

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According to the theory and method of topological design for parallel mechanisms（PM） based on the position and orientation characteristic（POC） equations， a spatial two-translation and one revolution（2T1R） PM with zero coupling degree and partial motion decoupling was designed， which consisted of fully revolute pairs and a redundant actuated chain（RRR）. And the topological structure of the PM was analyzed. By the kinematics modeling principles based on topological characteristics， the symbolic forward kinematics was given. At the same time， the inverse kinematics was derived to obtain the Jacobian matrix of the moving platform， where the speed and acceleration of each link were derived. Finally， the ordered-single-open chain method was used for the inverse dynamic modeling and analysis of the PM based on the principle of virtual work proposed by the author team. The driving torques of the PM and the action forces of the kinematic pair were solved， which was then verified by ADAMS dynamics simulation. The study provides a technical basis for the design of the parallel pipe benders required for the tube bending machining. 

Research on Multi-point Measurement of Pneumatic Multi-dimensional Forces under Combined Support Mode

REN Zongjin, LI Yang, XU Tianguo, LYU Jiangshan, HONG Ji

2022, 33(02):  170-175,186.  DOI: 10.3969/j.issn.1004-132X.2022.02.006

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An aircraft design  was usually based on the pneumatic loads obtained by the model in wind tunnel tests. For aircraft models with large dimensions and large aspect ratios， the test space was limited， and it was difficult to meet the size and dynamic characteristics requirements of wind tunnel tests based on conventional support devices and measurement methods. To solve the problems， with piezoelectric sensors as the core test elements， a combined support mode was proposed with combining tension support and tail support， and a pneumatic multi-dimensional force test system integrated with support devices and test elements was developed. The balance relationship between the pneumatic forces and the supporting reaction forces of the model was analyzed， and the mechanics model of the pneumatic multi-dimensional forces acting on the model and the output of the force measurement units was established. The static calibration on the required force measurement units was performed to obtain the input and output performances of each force measurement unit. The calibration experiments were carried out on the whole system. The static calibration experimental results show that the nonlinearity and repeatability errors of the test system are both lower than 1%， and the maximum cross interference is as 2.04%； The dynamic pulse excitation experimental results show that the first-order natural frequencies of the three directions of the test system are as 195 Hz， 136 Hz and 273 Hz respectively， and the dynamic characteristics of the test system are improved significantly. 

Reverse Reasoning Technology for Product Key Design Quality Characteristics Based on Fault Feedback

2022, 33(02):  176-186.  DOI: 10.3969/j.issn.1004-132X.2022.02.007

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In order to reduce the subjectivity of identifying the key design quality characteristics of products and ensure the scientific sequencing, a method of identifying and sequencing key design quality characteristics of products by reverse reasoning from the perspective of fault feedback was proposed. Firstly, in order to reduce the fuzziness and redundancy of information in fault analysis, product element faults were extracted based on extension operation. Taking the meta-fault, the fault cause and the key design quality characteristics as the basic correlation elements in the reverse reasoning processes, the extended correlation model of key design quality characteristics was established by analyzing the vertical correlation between different levels of “meta fault-failure cause-key design quality characteristics” and the horizontal correlation between same level. Based on this model, a quantitative expression model and algorithm for the influence breadth and influence depth of key design quality characteristics were established, and a quantitative ranking of key design quality characteristics was realized through directed graph and failure mode and impact analysis. Finally, the effectiveness of the proposed method was verified by a case of crane hoisting mechanism.

Fault Diagnosis Method of Rolling Bearings Based on Improved Multi-linear Principal Component Analysis Network 

GUO Jiaxin, CHENG Junsheng, YANG Yu,

2022, 33(02):  187-193,201.  DOI: 10.3969/j.issn.1004-132X.2022.02.008

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The measured rolling bearing vibration signals were usually interfered by noises and had nonlinear and non-stationary characteristics， while multi-linear principle component analysis network（MPCAnet）had poor nonlinear fitting ability and poor feature clustering ability when dealing with complex non-stationary data. An improved multi-linear principal component analysis network was proposed by introducing kernel transformation， which increased the degree of difference among the training samples， further enhanced the generalization ability and classification accuracy when dealing with non-linear data. It is proved that this method has high robustness in different fault diagnosis data sets of rolling bearings and may accurately identify various faults of rolling bearings. 

Large-field and High-precision Dynamic Positioning Method of Indoor Mobile Robots

TIAN Mingrui, , YANG Hao, HU Yongbiao

2022, 33(02):  194-201.  DOI: 10.3969/j.issn.1004-132X.2022.02.009

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High-precision indoor positioning process was the basis and prerequisite for mobile robots to fulfill tasks such as autonomous navigation, motion control, and cooperative operation. a large-field and absolute positioning method was proposed for indoor mobile robots based on the principle of monocular vision positioning. This method was suitable for the synchronous dynamic positioning of indoor multi-mobile robots, the problems of multi-camera nonlinear calibration and field fusion in the large-field environment were solved, and the camera calibration accuracy was improved by 52.6%. A high-speed positioning algorithm was designed based on optical beacons to improve the dynamic positioning accuracy of the mobile robots, where the image processing speed of the positioning system was improved. Then the dynamic errors of the positioning system were predicted and compensated. The experimental verification of each algorithm shows that the proposed method may perform high-precision dynamic positioning of multiple indoor high-speed mobile robots. When the robot moving speed is less than 3.2 m/s, the average dynamic positioning errors of the system position are less than 5 cm, and the average dynamic positioning errors of the system attitude angle are less than 0.6°.

Calibration Method for Cable-driven Continuum Robots

LI Famin, ZHENG Tianjiang, SHEN Wenjun, WANG Huixiao, FANG Zaojun, LIANG Dongtai

2022, 33(02):  202-208.  DOI: 10.3969/j.issn.1004-132X.2022.02.010

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In order to improve the positioning accuracy of the cable-driven continuum robots, an error calibration and compensation method was proposed for the cable-driven continuum robot modules(CDCRMs). The product-of-exponential(POE) formula was employed to develop the kinematics model for the CDCRMs. The kinematics error transfer model was derived through the kinematics model, which was used to identify the kinematics errors by using the least-squared algorithm. Identified errors were used to compensate the kinematics model, thus the accuracy of the CDCRMs was improved. A prototype of a CDCRM with a flexible backbone was made to verify the calibration algorithm by simulation and experiments. The results show that the position accuracy of the CDCRMs is improved by 32.23% and the orientation accuracy is improved by 81.64%, which prove the effectiveness of the calibration algorithm.

Research on Flat CWR Mill for Precision-forming of Hard-to-deform Materials

SHI Mingjie, CHENG Ming, ZHANG Shihong, VLADIMIR Petrenko, GRAZHINA Valerievna Kozhevnikova

2022, 33(02):  209-216.  DOI: 10.3969/j.issn.1004-132X.2022.02.011

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In order to meet the needs of CWR technology research and to promote the applications and development of the flat CWR mill in China， a high precision flat CWR mill（IM500） was developed by the cooperation of Institute of Metal Research， Chinese Academy of Sciences（IMR， CAS） and Physical-Technical Institute of the National Academy of Sciences of Belarus（PhTI NAS B）. IM500 was designed with horizontal structure. Single movable plate was drive by hydraulic. Three sections including the body structure， hydraulic station and electric control subsystem were integrated in IM500 mill. The finite element simulation method was used simultaneously to check and optimize during design of the body structure. The billets of 45 steel， GH4169 and TC11 were used for CWR experiments with IM500 mill. The experimental results show that the high dimensional accuracy of rolled parts may be manufactured by the mill. It may be operated and repaired easily and more automation technologies may be used widely. 

Precision GHP Mold Manufacturing for Dual Aspherical Chalcogenide GlassLens with Small Aperture

TANG Kun, SHU Yong, LI Dianyu, KONG Minghui, LUO Hong, YU Jianwu, ZHANG Mingjun, MAO Cong

2022, 33(02):  217-225.  DOI: 10.3969/j.issn.1004-132X.2022.02.012

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In order to improve the preparation efficiency and accuracy of GHP mold and meet the demands of high-precision batch manufacturing of the lens, the FEA method was combined with mold contouring prediction and compensation for precision GHP of dual aspherical chalcogenide glass lens with small aperture. According to the analysis of heat transfer, viscoelasticity, stress relaxation behavior, and structural relaxation characteristics for the chalcogenide glass in the processes of GHP, the glass thermodynamic performance parameters under high temperature were obtained, and FEA model for GHP was also established. The RBF(radial basis function) was adopted to fit the simulated aspherical curves of the lens, and the contour deviation of the mold cavity was compensated. According to compensated mold aspherical parameters, GHP mold was machined and tested precisely. The dual aspherical chalcogenide glass lens with small aperture were pressed on a multi-station GHP machine by using the prepared mold, and the testing data of the lens were also analyzed. The results show that the simulated values of the contour deviation h of lens aspheric surfaces ASP1 and ASP2 are both less than 0.25 μm after three compensations. The roughness RMS values of mold ASP1 and ASP2 are as 3.5 nm and 5.6 nm respectively, and their form error PV values are 31.5 nm and 50.4 nm respectively. The measured values of pressed lens ASP1 and ASP2 basically meet the requirements of error PV ≤ 0.2 μm，Ra ≤ 0.04 μm and h ≤ 1 μm. 
Key words: aspheric chalcogenide glass len; precision glass hot pressing(GHP); mold 


Numerical Simulation and Experimental Verification of High-power Ultrasonic Welding of Al/Steel Joints

LI Huan, HUANG Chaowang, ZHOU Kang, ZHANG Changxin, ZENG Caiyou

2022, 33(02):  226-233.  DOI: 10.3969/j.issn.1004-132X.2022.02.013

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 To reveal the mechanism of high-power ultrasonic welding， a three-dimensional thermal-mechanics coupling finite element model of high-power ultrasonic welding was established for predicting the interface temperature and materials plastic deformation in high-power ultrasonic welding 6061-T6 aluminum alloy to DC04 mild steel. The welding heat inputs were related to the ultrasonic power， while the materials ultrasonic softening was related to the welting vibration amplitude and frequency. The simulation results show that the rate of ultrasonic electric power converted into welding heats increases exponentially and then stabilizes. The maximum welding temperature is as 566 ℃， which reaches its 87% of the melting point of aluminum alloys. At the steel/aluminum interfaces， the materials plastically flow from the outside to the central area beneath the sonotrode， and accumulate around at the welding zones. This promotes the formation of welds， resulting in the area of the welded area being larger than that of the sonotrode. In addition， in the initial stage， the sonotrode penetrates into top surfaces of the steels. Subsequently， under the action of ultrasonic softening and high temperature， the speed of the anvil tips penetration into the aluminum alloy surfaces is accelerated. The penetrations depth of workpieces reaches maximum at the end of welding. 

Multi-objective Optimization of Commercial Vehicle Power Cabins Based on Flow Field Modulation

TANG Rongjiang, ZUO Yingxiang, LI Shenfang, LU Zengjun, XU Enyong, BI Daokun

2022, 33(02):  234-242.  DOI: 10.3969/j.issn.1004-132X.2022.02.014

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Aiming at the problems of dust， heat dissipation， and poor driving thermal comfort in the power cabins of commercial vehicles， a power cabin flow field modulate optimization method was proposed based on CFD numerical simulation and superposition optimization. The simulation analyses of the flow field in the power cabins of the original commercial vehicles revealed that reducing the airflow resistance and increasing the air intake may improve the performance of the power cabins. The performance modulation optimization of the flow field of the power cabins were realized by the superimpose optimization design of the radiator， cooling fan， and air guide hood. The results show that after optimization， the intake air volume is increased by 70.9%， the cooling K-value is reduced to 49.5 ℃， the intake air temperature increment and the number of dust particles are reduced by 19.8 ℃ and 94.0% respectively compared with the original commercial vehicles. The performance of the power cabins is significantly improved. The optimized commercial vehicle test results are in good agreement with the simulation ones. 

Influence Laws of Blade Gradient Angle on Natural Frequency of Compressor Impellers

LI Song, YANG Xinle, LI Weikang, TANG Meiling

2022, 33(02):  243-251.  DOI: 10.3969/j.issn.1004-132X.2022.02.015

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The natural frequency analysis of the turbocharger impeller played a vital role in predicting the reliability life. In order to obtain the influences of the geometry of the compressor impellers on the natural frequency， the blade gradient angle related to the thickness and blade cantilever length was defined. Concepts NREC software was used to design serial impellers， then ANSYS finite element analysis software was used to simulate impeller natural frequency and strength. Moreover， 8 representative size milling impellers were selected for vibration test experiments by the impeller modal test system. The results show that blade thickness has a greater influence on the blade gradient angle than that of the blade cantilever length. The ratio of the blade gradient angle and the first-order natural frequency always show a monotonous increasing linear relationship， and the same with the ratio of the blade gradient angle and the first-order frequency multiplication ratio. The maximum stress at the blade roots of the compressor first decrease with the increase of the blade gradient angle， and then increase with the increase of the blade gradient angle. When the value range of blade gradient angle is as 3.258°， the maximum equivalent stress of the impellers is smallest. The errors between the experimental results and the simulation calculations are 2. 13%～4. 92%， indicating that the calculation results are reliable. When the compressor impeller rotates， the pre-stress of centrifugal force increases the stiffness of the impellers， thereby increasing the modal frequency of the impellers.