Table of Content

10 November 2020, Volume 31 Issue 21

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Stability Investigation of Car-trailer Combinations Considering Steering System Parameters

ZHANG Ning;LI Tian;YIN Guodong;WU Jianhua;ZHAO Ziqian

2020, 31(21):  2521-2528.  DOI: 10.3969/j.issn.1004-132X.2020.21.001

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Body sway was a complicated dynamic instability phenomenon in car-trailer combinations. It was often manifested as Jackknifing, sideslip, rolling etc., which brought great hidden troubles to road traffic safety. Aiming at this problem, a 6-DOFs system model of car-trailer combinations was established considering steering system of the towing car and applying the Lagrange equation herein. The influences of steering system inertial parameters, steering system stiffness and steering system damping on the stability of system were studied through the nonlinear analysis method. The results show that the influences of different steering system characteristics on the system stability are not the same. Reasonable selection of steering system characteristics may effectively improve the dynamic stability of car-trailer combinations.

Reliable Design of PMSs

LIU Chunmei1;HUANG Dehui1;ZHENG Cheng2;CHEN Xiaokai2;ZHANG Kai1

2020, 31(21):  2529-2534.  DOI: 10.3969/j.issn.1004-132X.2020.21.002

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As the influence of uncertainty factors such as manufacturing error of suspension stiffness on PMSs, a reliable design flow was proposed to perform reliable design of PMS. Variations  of reliability were analyzed under different design states. Analysis results of deterministic design was used to show necessity of enhancing reliability of systems. A three-step flow, including performing, choosing and decision was proposed to perform reliable design of a PMS. Finally, this flow was used to perform reliable design of one PMS. Results indicate that a reasonable decision contributes to commonly enhance system reliability. In some cases, a continuously stable region may be found in feasible field at multiple levels of uncertainties, this is an ideal result and it also shows effectiveness of the proposed design flow.

Design of Shaper Cutter for Precision Machining Internal Beveloid Gears

HU Rui;DU Xuesong;ZHU Caichao

2020, 31(21):  2535-2541.  DOI: 10.3969/j.issn.1004-132X.2020.21.003

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It was difficult to achieve high-precision machining of internal beveloid gears with standard shaper cutters by inclining the shaper-arbor with respect to the gear axis or slotting angle optimization method. A design method of special gear shaper cutters was proposed for precision machining internal beveloid gears. The tooth profile equation of the gear shaper cutters included both of geometric parameters of the cutters and the slotting angles. The tool profile equations were derived based on the meshing principle, the mathematical models of the gear shapers were established, and the parameter optimization processes of the shaper cutters were given. The profile errors of different machining methods were compared and analyzed, and the influences of design parameter changes on profile errors were studied. The results show that the proposed method may effectively reduce the tooth profile errors under various design parameters, and the designed cutters may achieve the precision machining of internal beveloid gears by linear slotting according to the optimal slotting angle, without the needs to transform the machine tool, which is easy to promote.

Experimental Study on Ultrasonic Vibration Lens Assisted Laser Drilling

SHEN Cheng;ZOU Ping;KANG Di;WANG Wenjie

2020, 31(21):  2542-2546.  DOI: 10.3969/j.issn.1004-132X.2020.21.004

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In order to study the effects of ultrasonic vibration lens assisted on the quality and efficiency of laser drilling, the YLR-1000 continuous laser and the self-designed ultrasonic vibration lens auxiliary device were used to study 304 stainless steel sheets, respectively, with different defocusing amounts, laser power, drilling time, and ultrasonic amplitude were compared with or without ultrasonic vibration assisted laser drilling. In the experiments, the VHX-1000E super depth of field microscopy system was used to detect the workpiece, and the experimental results were analyzed with the aperture, heat affected zone radius, hole taper, hole depth and splash height as the main indicators. The results show that the ultrasonic vibration lens assisted improves the processing quality and efficiency of laser drilling in general.

Screw Theory Based Modeling Methodology of Horizontal Machining Center Volumetric Errors and Its Quantitative Validation

HU Teng1,3;WANG Wenkuan1;YIN Guofu2;YANG Suixian2

2020, 31(21):  2547-2556.  DOI: 10.3969/j.issn.1004-132X.2020.21.005

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Aiming at solving the problems that the current modeling approach of machine tool volumetric errors was complex and non-uniform, and that the present validating strategies were incapable to be quantitative, a complete methodology of modeling and validating systems were presented for the horizontal machining center volumetric errors. Combining with the topological analysis of machine tool kinematic chains, screw theory and serial mechanism kinematics were employed as the theoretical fundamentals to build the kinematic model of horizontal machining centers. The issue of singular matrix that was potentially generated due to matrix transformation in the traditional modeling approaches might be eliminated by the proposed kinematic modeling method which was also believed to be helpful for simplifying the mechanism kinematics analysis. The effects of the kinematic error definitions on kinematic model referring to different coordinates were systematically studied, based on which the approaches and the principles for confirming the relationship between nominal kinematic matrix and kinematic error matrix were proposed. The volumetric error model of the horizontal machining center was then established accordingly. In order to validate the volumetric error model quantitatively, the validating strategy and technique were proposed based on the concept of Euclidean norm of a volumetric vector. According to the comparisons, the predicted Euclidean norm deviations agree with the experimental results with a maximum relative error of 15.79%. It indicates that the proposed volumetric error modeling methodology is feasible and correct. It is also proved that the proposed quantitative validating strategy is direct and efficient.

Configuration Synthesis of Planetary Shifting Mechanisms Based on Analysis of Topology Characteristics Variation

FU Shengping1;HUANG Hanlin2;MING Wei2

2020, 31(21):  2557-2565.  DOI: 10.3969/j.issn.1004-132X.2020.21.006

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The feasible schedules of planetary shifting mechanisms were various, which consisted of several planetary gear sets and operation elements to meet the demands of the default gear number and each transmission ratio. Aiming at this problem, a configuration synthesis method of planetary shifting mechanisms was proposed based on the analysis of topology characteristics variation. According to the composition principles of planetary shifting mechanisms, the design criteria of planetary group and clutch group models were established. In the sense of relative speed, components and correlation functions adjacency matrixes of planetary shifting mechanisms were both defined. The mathematical models of configuration evolution were deduced. It was realized to recognize the topological characteristics of some special configurations automatically. And the component group models which met the requirements of predetermined gear number was constructed. The topological evolution characteristics of different configuration states were revealed. And a method of calculating the characteristic parameters of planetary shifting mechanisms and distinguishing the component attributes was proposed to realize the configuration synthesis of planetary shifting mechanisms. Eventually, a design example was given to verify the effectiveness and accuracy of the proposed method.

Motion Characteristics Analysis of 4-DOF Hybrid Antenna Mechanisms

ZHANG Guoxing1;HOU Yulei1;ZENG Daxing1;DOU Yuchao2;DUAN Yanbin2

2020, 31(21):  2566-2572.  DOI: 10.3969/j.issn.1004-132X.2020.21.007

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The design of antenna configuration and the  motion characteristics analysis were the prerequisite for the realization of the tracking task of the antenna systems. A 3-R(RRR)R+R hybrid antenna mechanisms was constructed based on the 3RSR parallel mechanism, and the structure of the hybrid antenna mechanism was described. The number and properties of the DOF of the hybrid antenna mechanisms were analyzed by the screw theory. Using the exponential product formula to express the positions and orientations of each link of the hybrid antenna mechanisms, the kinematic models of the hybrid antenna mechanisms were established, and the twist matrix of each link of the hybrid antenna mechanisms was obtained. The azimuth and pitch trajectories of the hybrid antenna mechanisms were obtained by MATLAB software simulation, and the kinematics parameters of the hybrid antenna mechanisms were verified by ADAMS software simulation. Finally, based on the prototype of hybrid antenna mechanisms, the experiments of motion characteristics were carried out.

QAREDNN for State Trend Prediction of Rotating Machinery

LI Feng1;CHENG Yangyang1,2;CHEN Yong1;TANG Baoping3

2020, 31(21):  2573-2582.  DOI: 10.3969/j.issn.1004-132X.2020.21.008

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A state trend prediction method for rotating machinery was proposed based on QAREDNN herein. In the proposed QAREDNN, the attention mechanism was used to simultaneously reconstruct encoder and decoder of QAREDNN, so that QAREDNN might fully excavate and pay attention to important informations but suppress the interference of redundant informations to obtain better nonlinear approximation capacity. The quantum neuron was used to construct a new quantum gated recurrent unit (QGRU) in which activation values and weights were represented by quantum rotation matrices. The QGRU might traverse the solution space more finely and had a lot of multiple attractors, so it might replace the traditional recurrent units of the encoder and decoder and enhance the generalization ability and response speed of QAREDNN. The Levenberg-Marquardt algorithms were introduced to improve the update speeds of the rotation angles for quantum rotation matrices and the attention parameters of QAREDNN. The effectiveness of the proposed method was verified by the examples of state trend prediction of rolling bearings.

Characteristics and Modeling of Roadway Surface Topography under  Influences of Cutting Head Geometry

LIU Zhixiang1;WANG Shuai1;XIE Miao1;CHEN Hongyue1;MIAO Chong1;XIE Chunxue2

2020, 31(21):  2583-2591.  DOI: 10.3969/j.issn.1004-132X.2020.21.009

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Considering the movement track of the cutting head of the longitudinal roadheader directly affected the shape characteristics of the formed surfaces of the roadway, this paper analyzed the formation mechanism of the outer contours of the roadway obtained by the cutting head cutting the roadway, determined the coordinates of the cutting head of the roadheader in the spatial coordinate system of the roadway, and constructed the mathematical model of the cutting head cutting the outer contours of the roadway.Through numerical calculation, the influences of feed rate, cutting angle, cutting head shape, cutting head radius and cutting head cone angle on the cutting surface topography were analyzed. The results show that the surfaces of the tunnel are the most uneven when they are cut by the ball crown +cylinder type cutting head, and the tunnel surfaces are the most flat when they are cut by the ball crown +cone +cylinder type cutting head. With the decrease of cutting angle, the decrease of cutting feed, the increase of ball crown radius of cutting head and the increase of cone angle of cutting head, the flatness of roadway obtained by cutting is higher. The larger the cutting angle is, the more necessary the roadway flatness controls accurately.

Design and Tests of Mechanical-pneumatic Combined Peanut Precision Seed-metering Devices

ZHU Tong1;CONG Jinling1,2;QI Beibei1;WU Mengchen1;PENG Xinyi1;WANG Yisu1

2020, 31(21):  2592-2600.  DOI: 10.3969/j.issn.1004-132X.2020.21.010

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Aiming at the problems of low adsorption rate and high wind pressure when sowing large-diameter seeds such as peanuts with air-suction type metering device, a mechanical-pneumatic combined peanut precision seed-metering device was designed by using pneumatic and mechanical cooperative seed picking, gas blocking and seed unloading, and mechanical carrying seed.In filling stage, bumps were used to disturb, positioning and hold seeds. Seeds collection were coordinated with negative pressure of the hole.These may effectively improve the filling performance.After the simulation analyses of seed disturbance performance with different structure seed-metering discs, results show that the best seed disturbance performance comes from the one using ring groove double V-shaped bump.Taking shapes of seeds, rotational speeds of seed-metering disc and working negative pressure as factors,seed-metering performance tests with double V-shaped bump were conducted. Results show that the spherical seeds have the best seed-metering performance. The optimal parameter combination of the seed-metering devices was determined through multi-objective parameter optimization.Field test results show that the seed-metering device may meet the requirements of peanut precision seeding.

Data-driven Energy Consumption Prediction Method of  CNC Turning Based on Meta-action

LI Congbo;YIN Yuxian;XIAO Qinge;LONG Yun;ZHAO Xikun

2020, 31(21):  2601-2611.  DOI: 10.3969/j.issn.1004-132X.2020.21.011

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Aiming at the problems of low accuracy and poor generalization of conventional energy consumption prediction model, a data-driven energy consumption prediction method of CNC turning was proposed based on meta-action. The effects of meta-action on energy consumption were explored under each period of turning via analyzing the energy consumption characteristics of CND turning. A data collection method of meta-action and energy consumption was proposed and the states of turning were judged by the meta-action data. Then, based on the data collected in the processes of CNC machining, energy consumption prediction model was built using Gaussian process regression, which was used to predict dynamic energy consumption of CNC turning. Finally, the superiority of the proposed model was verified by comparing three fitting methods, taking the machining of an axial workpiece as an example, a case study was conducted to validate the practicality of the proposed energy consumption prediction method through comparison with theoretical model.

Review of Product Modular Design from Perspective of Green Manufacturing

CHENG Xianfu1;ZHOU Jian1;XIAO Renbin2;LIU Junjie1;YOU Minhua1

2020, 31(21):  2612-2625.  DOI: 10.3969/j.issn.1004-132X.2020.21.012

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The implication of green product life cycle was expounded, and the characteristics related to environmental attributes of each stage and the association relationship in green product life cycle were analyzed. A classified summing-up was carried out for currently existing multi-methods of green modular design. According to the different emphases of each stage in green product life cycle, the green manufacturing modular design were divided into several aspects: modular design for product life cycle, modular design for green design, modular design for environmental conscious, modular design for remanufacturing, modular design for disassembly, modular design for maintenance, modular design for recycling, modular design for reuse, and other modular designs. Then, its corresponding modular design methods were reviewed and analyzed. Finally, the challenges for further research efforts were prosected.

Energy Consumption Model of Hobbing Machine Tools Based on Workpiece Material Removal Rate

LI Junliang;WANG Shilong;WANG Sibao;XIA Changjiu

2020, 31(21):  2626-2631.  DOI: 10.3969/j.issn.1004-132X.2020.21.013

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A research of energy consumption modeling and parameter analysis of hobbing machine tools was carried out. Based on the analysis of the geometric parameters and spatial motions of hobs and workpieces, numerical calculation of undeformed chips was performed to calculate the material removal rate during gear hobbing, and energy consumption prediction models of hobbing machine tools were established. It was verified by orthogonal tests, and the average prediction accuracy exceeds 95%. Based on the experimental results and the proposed numerical model, the effects of feed rate, hob rotation speed and depth of cut on the specific energy consumption representing the energy utilization efficiency were analyzed. The results show that the proposed model may accurately predict the energy consumption of the machine tools in gear hobbing processes.

Research on Te-Cr-Cu Electrode Life for Aluminum Alloy RSW

ZHENG Lihao1,2;ZHANG Chaoqun1,2;ZHANG Qingxin1,2;ZHANG Guotao1,2;LI Yongbing1,2

2020, 31(21):  2632-2637.  DOI: 10.3969/j.issn.1004-132X.2020.21.014

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In order to solve the pitting phenomenon of aluminum alloy RSW electrode, which led to low efficiency and unstable weld quality, a new RSW copper electrode made of Te-Cr-Cu alloy was successfully developed. The changes of weld nugget diameter, tensile shear strength and contact resistance obtained with the times of welding were studied by comparing the traditional Cr-Zr-Cu electrodes and Te-Cr-Cu electrodes. The life of the copper electrodes was characterized by using confocal laser scanning microscope. It is proved that Te-Cr-Cu electrodes have longer electrode life than that of traditional Cr-Zr-Cu electrodes. The reasons for the prolonged electrode life were revealed from the point of retarding the growth of Al-Cu intermetallic compounds.

Research on Milling Subsurface Layer Damages of  DD5 Ni-based Single Crystal Superalloy

LI Qiang;GUO Chenguang;DING Guangshuo;LENG Yuefeng;YUE Haitao

2020, 31(21):  2638-2645.  DOI: 10.3969/j.issn.1004-132X.2020.21.015

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In order to research the milling subsurface layer damages of DD5 Ni-based single crystal superalloy, based on the directional cutting method and slot milling experiments, this paper discussed the DD5 deformation layer characteristics and recrystallization behaviors though the massive DD5 longitudinal sections micro-metallographic structures and micro-hardness tests under different milling parameters before and after heat treatments. Then the control approaches for inhibiting the deformation layer generation and development were proposed. The research results demonstrate that milling parameters，cooling methods and crystal direction conditions all influence the DD5 hardening rate largely, the hardness of the machined surface along the normal direction show the “hardening-softening-hardening”trend, which illustrate that the main reason for metamorphic layer formation is work hardening under the competition mechanism between the thermal softening and strain hardening, and the metallographic structure in this area is transformed, which improve the corrosion resistance of DD5 machined surfaces. The reasonable milling trajectory along the ［110］ crystal direction scheme and the water based minimum quantity lubrication adoption of cooling methods are beneficial for the inhibition of deformation layer formation. In addition, under the machining conditions designed herein, the milling processes may not provide sufficient stored energy to activate material recrystallization under the traditional and vacuum high temperature conditions to 1300℃.