Table of Content

25 April 2017, Volume 28 Issue 08

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High Speed Cutting of TC4 Titanium Alloy under Cryogenic CO2 Cooling Conditions

XIAO Hu, LI Liang

2017, 28(08):  883-887. 

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Rapid tool wear and poor chip breaking performance appeared on high speed cutting of TC4 alloy, while quality of the machined surfaces might not be guaranteed. By high-pressure liquid CO2 supply system, TC4 titanium alloy was tested with high speed cutting processes under condition of CO2 snow coolant. Cutting temperaturs, cutting force, tool wear, surface roughness and chip breakings of TC4 cutting were analyzed on high speed TC4 under enhanced cooling of cryogenic CO2. Difference between suppress CO2 snow cooling condition and dry cutting condition were compared with multi-parameters. Experimental results show that cutting temperatures, cutting forces, chip breakings, tool wears and quality of the machined surfaces are improved by the suppress CO2 snow coolant.


Energy Transfer of Nonlinear Vibration Absorber under Colored Noise Excitation

LIU Lilan, REN Bolin, LI Shuchao, ZHANG Xiaojing

2017, 28(08):  888-894. 

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Bistable oscillator was adopted as nonlinear vibration absorber herein. Mechanics model of main system with a nonlinear vibration absorber system was established. Nondimensional governing equation of the main system with the nonlinear vibration absorber system was obtained under colored noise excitation. Effect laws of structural parameters on vibration energy of the nonlinear vibration absorber and the main system were obtained by means of simulations, such as initial condition, tuning frequency ratio, mass ratio and damping coefficient. Optimal parameter configuration conditions of the nonlinear vibration absorber with maximum vibration energy of vibration absorber and main system withminimum vibration energy were obtained by means of gradual selection of the optimal parameters.

Tool Path Planning Method Oriented Feature Library of Integral Impeller

XU Shaokun, YIN Yanchao, JI Changjie, NIU Hongwei

2017, 28(08):  894-898. 

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In complex machining surfaces of integral impeller, changes of curvature were big, and flow channel cavities were special, a feature oriented tool path planning method was proposed herein. Characteristics of integral impeller machining surfaces and processing difficulties were analyzed. A feature library composed of different tool paths for surfaces of blade, flow channel, inlet and outlet, blade root was established. Matching rules between the impeller surfaces and the feature tool path library were designed. Furthermore, the tool path planning system of integral impeller processing surface features was developed. Case study shows that the presented method may reduce the number of tool paths for machining impeller surfaces effectively, and improve blade machining quality and efficiency of the free surfaces of integral impeller.

Design and Parametric Analyses of a Wheel-track Robot with Self-adaptive Ability

LI Fan, ZHANG Minglu, LYU Xiaoling, TIAN Ying, BAI Feng

2017, 28(08):  899-904. 

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Concept of a wheel-track robot was proposed with passive self-adaptive ability. When confronted with constraints like stairs or trenches, the robot could autonomously switch its locomotion mode by transforming track configuration. Thus, obstacles higher than the robot could be climbed. The wheel-track robot was driven by two separate servo systems to adapt with different terrains. Having built a model of the robot, the parametric analysis and optimization were conducted. At last, the simulation was performed and it shows that the results accord with the designing purposes.

Adaptive Motion Tracking Control of a Micro-manipulation Stage

HU Junfeng, ZHENG Changhu, CAI Jianyang

2017, 28(08):  905-911,916. 

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Considering hysteresis nonlinearity and time variation of micro-manipulation stage, a single neuron PID control strategy was proposed for motion tracking control to improve motion accuracy and response of the stage. Gradient informations of the micro-manipulation stage might be obtained online by RBF neural network identifier, and learning algorithm of single neuron network was applied to achieve online self-tuning of PID parameters to achieve the adaptive motion tracking control of the micro-manipulation stage. In order to illustrate the feasibility of the proposed control method, experimental comparative analyses with ordinary PID control were carried out. Experimental results show that, displacement error ranges of the single neuron PID are as -0.5~0.5μm, and the adjustment time of that is as 0.1s, while displacement error ranges of ordinary PID control are as  -2.5~2.5μm, and the adjustment time of that is as 0.4s. It shows that the proposed control method has better control accuracy, response speed, and stronger adaptability.

Research on Wellbore Security Equipment and Performance of Offshore Heavy Oil Thermal Recovery Wells

YU Yanqun, CHANG Zongyu, QI Yaoguang, XUE Xin

2017, 28(08):  912-916. 

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A wellbore security device with sealed tubing and annulus was designed in response to spatial changes of wellbores in rod pumping systems. Setting and unseting processes of the rubber sleeves were analyzed based on principle of volume invariance. Mechanics models of the rubber sleeves were established, and the well startup and shut-in forces under different pressures were studied. A new equipment of sealed rods was developed to solve the wellbore security problems in thermal recovery and rod lifting of offshore heavy oil.

Granular Extrusion Experimental Researches Based on Multi-hole Devices

JIANG Qinghai, WU Kai, SUN Yu, YANG Dong

2017, 28(08):  917-923. 

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According to analyses of pelleting processes of rotated roll forming, demands of simulation devices were discussed, and the shortcomings of single pellet unit were analyzed. Ａ multi-hole device was designed to simulate granular extrusion processes, and a series of experiments were carried out. Change rules of compressing forces F were analyzed, and forming mechanism of granular extrusion was discussed. Mathematical models for the relationship among compressing forces F and some basic parameters such as length-diameter ratios L, moisture contents W and temperatures θ were established. Production tests were designed to verify the proposed model. A multi-hole device was proved to be practical in comparison with the results of production tests.

Cloud Manufacturing Task Decomposition Method Based on HTN

LIU Mingzhou, WANG Qiang, LING Lin

2017, 28(08):  924-930. 

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A cloud manufacturing task decomposition algorithm was proposed herein on the basis of sequential task decomposition. Firstly, a descriptive model of manufacturing tasks and the related definitions of task constraint structures were provided were carried out. Then the researches of manufacturing task granularity analysis method, cohesion measurement method were carried out, and correlation measuring method. Then, recursive decomposition algorithm was adopted to carry out the tasks of optimization decomposition consistently, considering the task resource matching problem during the decomposition processes. Finally, feasibility and effectiveness of the proposed method was verified by an example of a gearbox test-manufacturing task decomposition.

Control Chart Pattern Recognition Based on Fusion Feature Reduction and SVM

ZHAO Chunhua, WANG Chengkang, HUA Lu, ZHENG Siyu, LIANG Zhipeng

2017, 28(08):  930-935. 

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In order to improve the intelligence of quality monitoring in machining processes, the paper proposed a control chart classification method based on fusion feature reduction and KPCA-SVM, on the basis of quality fluctuation which was described by control chart. Firstly, the Monte Carlo method was applied to generate the control chart data sets, statistical features and shape features were extracted to fuse with original features, then kernel principal component analysis was applied to reduce dimensionality of high dimensional fusion feature sets. Finally, genetic algorithm was used to optimize parameters of SVM. Recognition accuracy were compared through the simulation experiments with the applications of dimensionality reduction and different classification models, the results demonstrate that the higher recognition accuracy may be achieved by using the proposed method.

Noise Cancellation Algorithm Method Combinated Priori Probability with Curve Probability Threshold Segmentation

ZHANG Yucun, XU Fei, FU Xianbin

2017, 28(08):  936-940,945. 

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The original point cloud data acquired from two dimensional laser scanner had noises, and the noises affected measurement accuracy. For this problem, a noise cancellation algorithm method combinated priori probability with curve probability threshold segmentation was proposed. Two dimensional laser scanner scaned the profiled annular section, and was used as experimental object, then acquired original point cloud data .The proposed de-noising method dealt with the original point cloud data and got noise cancellation data. The original point cloud data and noise cancellation data were used to calculate the heights of the ring steps. Comparisons of calculated values and real values show that the calculated values for data de-noising are closer to the true values of the ring. The experimental results prove that the noise cancellation method may effectively improve measurement accuracy.

Transformation Method from Parametric Modeling to Direct Modeling

LU Peng, YAN Chongjing, GU Qiushi

2017, 28(08):  941-945. 

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Currently, parametric modeling and direct modeling were two main methods of 3D geometric modeling, these methods had strong complementary on the functions. In view of how to realize the conversion between them, to reflect designers' intentions better, and to improve design efficiency, a method was proposed herein based on surface reconstruction. In order to restructure the parameterized model, the method needed to do a Delaunay triangulation by the points from parameterized model surface, and the direct modeling operation was realized by tracking tag and data update of the triangular mesh elements which contained feature informations. Finally, experimental results show that the proposed method is suitable for most feature models with a high conversion efficiency.

Experimental Research of Electrostatic Spray Jet Behavior with Gas Focusing

LIU Haiyan, PAN Yinbo, JIANG Jiaxin, ZHANG Kai, ZHENG Gaofeng, LIU Juan

2017, 28(08):  946-952. 

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Electrostatic spray spinneret with gas focusing was designed herein, which improved the stability of electrostatic spray jet and the efficiency of micro thin film deposition. Distributions of space electric field and flow field of gas were simulated, regularity of the spray was analyzed, and effects of processing parameters on the deposition areas of the film and diameters of nanoparticles were discussed. Experimental results show that, the jet injection velocity is increased by loading of auxiliary flow, and continuous stretching of auxiliary flow will lead to decrease the diameters of nanoparticles and to improve the nanopartides homogeneity.

Dynamics Model and Anti-disturbance L2 Gain Robust Backstepping Control for Space Manipulators with Fully Flexible Links

ZHANG Lijiao, CHEN Li

2017, 28(08):  952-957. 

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Dynamics model and anti-disturbance L2 gain robust backstepping control for space manipulators with fully flexible links were discussed. A dynamic model of the system was successively derived by combining with Lagrange equations, the system linear momentum and assumed mode method. Based on singular perturbation method, the system was decomposed into a slow subsystem which was described joint rigid trajectory tracking, and a fast subsystem which was described the vibrations of flexible links. A robust backstepping controller which made the external bounded disturbances had the performance of the L2 gain of the output system is less than the given value. And the controller also might suppress external bounded interferences. Vibrations of the flexible links were suppressed by optimal control theory of linear systems for the fast subsystem. Numerical simulations show the feasibility and effectiveness of the hybrid control.

Error Analysis and Kinematics Calibration of 3-UPS/S Parallel Stabilizing Platform in Full Load Conditions

LI Yukun, LI Yongquan, SHE Yazhong, ZHANG Lijie,

2017, 28(08):  958-965. 

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Compared to geometric errors, output accuracy of moving platform influenced by deformation errors might not be ignored when the loads of any parallel mechanism reached a certain values. Geometric and deformation error models were established based on parallel mechanism， which were studied for an electro-hydraulic 3-UPS/S stabilized paltform, and a total error transfer model was established by linear superposition of geometric and deformation errors. Based on the geometric error model, a kinematics calibration model of the stabilized platform was established. Kinematics calibration experiments were completed in full load conditions, positions of the reference points on moving platform were measured. Posture errors δH0 of the moving platform were calculated, geometric errors δH were obtained by separating the deformation errors δH1, and then the calibrations of geometric error parameters were completed based on least-square method.

Path-tracking of APS Based on ADRC

ZHAO Linfeng, XU Lei, CHEN Wuwei

2017, 28(08):  966-973. 

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A dynamics model of APS was established herein based on EPS. Consideration of car dynamics constraint and avoidance of collision was taken. Path-planning of two arcs and arctangent function were used, which improved the route fitting. A non-time reference path tracking control strategy was used and ADRC was proposed to track the target angle and the HIL test was conducted. The simulation and test results show that the arctangent function path planning and the non-time reference path tracking all have good control effects, ADRC has a more precise and quick path-tracking ability than that of PID controller.

Calculation of Cutting Parameters of Cutters of PDC Bit under Wear Conditions

MA Yachao, HUANG Zhiqiang, LI Qin, PENG Shijin, XIE Dou

2017, 28(08):  973-978. 

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For the problems of cutting parameters calculation and cutter layout design under wearing conditions might not meet the requirements of equal wear principles very well, a geometric model of waring cutters was built. Zero point traversing method used to calculate the cutting parameters was proposed. Then, cutting arc length, cutting area and cutting volume were calculated by zero point traversing method based on MATLAB software. The results reveal that zero point traversing method may be used to calculate the cutting parameters of wearing cutters and unworn cutters, and the calculation error is less than 2%. Combined with the force model and the wearing model, the wear tendency of the cutters in PDC bit may be predicted.

Steady Speed Control of On-board Hydraulic Generators under Moving Conditions

LI Hao, YANG Yuqiang

2017, 28(08):  979-982,990. 

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On-board hydraulic generators might ensure high steadiness under parking conditions, but under moving conditions, stability of generator speed was poor for running load disturbances. The paper studied steady speed control of the hydraulic generators under moving conditions. A mathematical model of pump-motor closed system was constructed, and motor output speed fluctuation mechanism was revealed. Motor speed control strategy of pump controled motor system was proposed, aiming at the motor output speed fluctuation mechanism. Simulation and test results show that feed forward compensation with speed feedback has good control precision and robustness, and power quality satisfies stand and of military Ⅱ spontaneous power station.

Size Effects of Deformation Behaviour and Ductile Fractures in Meso-scale Thin Sheet Metal of Phosphor Bronze

WANG Lei, HU Daochun

2017, 28(08):  983-990. 

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Size effects of mechanics properties and ductile fractures for ultra thin sheet metal of phosphor bronze sheet were studied by uniaxial micro tensile test. Experimental results show that yield strength has second order size effeets with metal thickness t and grain size d， and has first order size with t/d. Fracture surface shows that the fracture mechanism is composed of transitions from dimple-microvoids accumulation fractures to slip separation with the material thicknesses decrease, and dimple morphology becomes larger and deeper with the increases of grain sizes, but when t/d＜1, initiation of micro cracks is geminated, and fracturs are occurred immediately. At last, a hybrid constitutive equation was established based on surface layer model.

Internal Stress and Tension Optimization Technology of Steel Roll in Uncoiling Processes

BAI Zhenhua, LI Qilin, LIU Yaxing, CUI Yaya, GUO Zhensheng, SONG Zhangfeng

2017, 28(08):  991-995. 

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With reference to problems of coil relaxation and interlayer slip in steel roll uncoiling processes, this paper fully considered mechanical and technological characteristics of uncoiling unit by a large number of theoretical researches and field tests, established a set of internal stress distribution models of steel roll uncoiling, and achieved prediction of internal stress distribution in uncoiling processes. Based on generation mechanism analyses of coil relaxation and interlayer slip, a new concept of “uncoiling layer sliding factor” was proposed to describe the degree of coil relaxation and interlayer slip quantitatively. With combination of internal stress distribution models, a set of uncoiling tension comprehensive optimization technology was developed to prevent and control the defects of coil relaxation and interlayer slip.


Optimization Design of TRB Car Doors Based on 6σ Robustness

ZHU Maotao, ZHU Caifan, GUO Jiahuan, QIAN Yang

2017, 28(08):  996-1001. 

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For car door structure optimization studies, most of them did not consider the car door uncertainty factors. In order to improve robustness of structure optimized car door's performance, a new type manufacturing process of TRB was applied in car doors, and influences of sheet thicknesses and material performance parameter's volatility on the robustness of each constraint were considered. Combined with Latin hypercube design and RBF model, using dual cycle optimization strategy of combining Monte Carlo simulation with improved non-dominated sorting genetic algorithm, a TRB car door lightweight design was proposed based on 6σ robustness. This method may obtain an optimal solution, and may improve reliability of design variables and robustness of objective function.

Investigation of Tire Wear Particle Paths Based on Analytical Method

XUAN Shanshan, HUANG Haibo, LIU Jinpeng, LIU Qingguo, LU Xuan

2017, 28(08):  1002-1007. 

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Wear particle scattering paths possessed an important significance on grasping and gathering tire wear particles. Differential equation of wear particles was established based on Lagrangian principle. Influences of tire velocities and particle sizes on patch were investigated. The model was verified by conducted experiments. The results show that collision location variation is great for wear particles of about 100μm size, but is gentle for wear particles of smaller, about 10μm, and bigger size, about 500μm. The scattering collision location for wear particles(<100μm) is about from 150mm to 250mm in height on the covering parts.