Table of Content

10 October 2015, Volume 26 Issue 19

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Analyses of Launch & Recovery System of Seafloor Drill under Different Launching and Recovering Velocities

Jin Yongping, Wan Buyan, Liu Deshun, Peng Youduo

2015, 26(19):  2557-2563. 

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A launch & recovery system of a seafloor drill was chosen as the study object, and the dynamics model was established herein,that considered the influences of the seawater resistance for launch & recovery system of seafloor drill. The dynamic characteristic of launch & recovery system of seafloor drill was analyzed under different launching and recovering velocities. The research results show that there are significant differences in the pendulum angles of the seafloor drill and the tension of the umbilical cable for different stages. The seawater resistance has obvious inhibition effects on reducing the erratic fluctuation of the pendulum angles of the seafloor drill and the tension of the umbilical cable. At the same time, the pendulum angles of the seafloor drill and the tension of the umbilical cable are decreased along with the increase of the launching velocity. As the increasing of recovering velocity, the pendulum angles of the seafloor drill will decrease, while the maximum value of the tension of the umbilical cable will increase.

Generalized Demodulation Method Based on ASTFA Method and Its Applications

Li Baoqing, Cheng Junsheng, Peng Yanfeng, Yang Yu

2015, 26(19):  2564-2570. 

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Combining with the advantages of the ASTFA and the generalized demodulation, a generalized demodulation method was proposed based on the ASTFA. Firstly, the original signals were decomposed via ASTFA,and the component and its corresponding phase function were obtained. Secondly, the demodulation phase function was formatted by extracting the secondary and higher order terms of the phase function. Then, the generalized demodulation method was applied to the component using the demodulation phase demodulation function. Finally, the frequency domain analyses were applied to the demodulated component to extract feature information. Simulation and experimental analyses show that the method is very suitable for processing multi-component frequency modulated signals, and can effectively extract the damage characteristic informations of the rolling bearing damages in shifting conditions.

VMTPD and Its Performance of Wideband Vibration Reduction

Zhao Yanqing, Xia Jingjing, Gao Qiang, Song Weizhi, Han Ning

2015, 26(19):  2571-2574,2580. 

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In order to extend the effective frequency band of a conventional TPD with fixed system parameters, a novel VMTPD was proposed herein. Dynamics properties of the new VMTPD were studied via simulations and experiments, and the relationship between the volume of water in container and the optimal frequency of vibration reduction was established by using data fitting method. The results show that the optimal frequency of vibration reduction of the proposed VMTPD can be adjusted by changing the volume of water, and a wideband VMTPD can be obtained.

Research on Dynamic Electromechanical Coupling Characteristics of Dielectric Elastomer Actuator

Chen Juan, Liu Kun

2015, 26(19):  2575-2580. 

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The mechanical behavior theory of DE material was analyzed herein. The electromechanical coupling constitutive model of DE drive was built based on the common strain energy function, such as Mooney-Rivlin model, Ogden model, and Yeoh model. Through the drive experiments, the experimental data was compared with ones from three kinds of electromechanical coupling model. Then the important factors that affected the electromechanical stability of the DE were obtained, and the most suitable model of electromechanical coupling performance behavior used for DE material was determined.

Study on  Function Cutting Paths of Patent Design Around for Mechanical Products

Li Hui, Liu Limeng, Zhao Shaokui, Yu Fei, Tan Runhua

2015, 26(19):  2581-2589. 

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With patents being the most important competitive factors in intellectual property strategy, more enterprises with core patents blocked latecomers by using patent barriers. Therefore, it was necessary to break though patent barriers to carry on the innovation design according to patent technology.  To protect the effective and non-infringe existing patents of the new innovation design, firstly, the scope of patent rights was established based on patent system constraints and function model by considering the fusion between the function cutting and patent infringe principle. Secondly, the function of cutting road was studied according to different principles of patent design around.  Finally, a complete innovation design process for patent design around was put forward by front-end design principles of patent design around, and the effectiveness of the design process was validated by using of pipeline robot.

A Novel Motion Synthesis Approach with Enlargeable Error Space Allowance for Planar Linkages

Zhu Lihong, Zhang Liang, Zhao Han, Zhao Ping

2015, 26(19):  2590-2594,2600. 

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Using kinematic mapping theory in Clifford algebra, a new motion synthesis approach with enlargeable error space for planar linkages was proposed herein. This paper mainly focused on the situation when the given task yielded no exact solutions or the practical requirements that could not be realized by the mathematical optimal approximated solutions. By increasing error tolerance, the error space could be enlarged according to the requirements, thus more choices of approximated solutions could be introduced. After that, the optimal dyads may be selected to form a four-bar linkage or planar parallel linkages so as to realize the given task motion.

Identification of Reliability Life Distribution of Hydraulic Pump Based on KPCA and FSVM

Jing Tao, Cao Keqiang, Hu Liangmou, Gao Bin

2015, 26(19):  2595-2600. 

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Aiming at identifying the reliability life distribution model of the hydraulic pump accurately and efficiently, an algorithm of KPCA and FSVM was brought forward. The recognition model of the reliability life distribution model was designed by making full use of advantages of the KPCA nonlinear feature extraction and the FSVM classification capacity, and might be used for identifying the reliability life distribution model of the hydraulic pump. The simulation results show that, the proposed method can reduce computation complexity, has good ability for generalization, and identify the life distribution type of life on time between failures of hydraulic pump accurately.

Design of an Omnidirectional Mobile Robot Based on Decoupled Powered Caster Wheels

Qu Naiheng, Yang Guilin, Zheng Tianjiang

2015, 26(19):  2601-2605. 

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A novel decoupled powered caster wheel was designed herein, so that the wheel's steering and rolling motions could be independently controlled. Based on the new wheel design, an omnidirectional mobile robot was developed for indoor applications. Kinematic model of this robot was formulated and verified through the computer by MATLAB. Simulation results show that the omnidirectional mobile robot is able to perform the side-way and spinning motions.

Extraction of Unit Pulse Response Function Based on Sparse RBF Network Applyed in Rail Anchor Screw

Yang Dan, Zhou Yu, Ye Qingwei, Wang Xiaodong

2015, 26(19):  2606-2612. 

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Light rail anchoring screw is a key force component for connecting rail girder and piers.The extraction of the impulse response function is the key premise and the core technology to the screw anchor's health monitoring.Sparse optimization solution was introduced to replace the RBF network's classical least square method.The sparse RBF network with input and output calculation scheme was constructed.Two-dimensional DCT-basis was introduced to represent the weight and the orthogonal matching pursuit(OMP) algorithm was used to get sparser network weights training value.A unit excitation signal was taken as the network's input and the output of the network was the unit impulse response function of the system.The experiments show that optimization solution of the RBF network in the paper can accurately extract the impulse response function.The work herein has reference value in engineering applications.

Fault Diagnosis Method for Bearings Based on MEMD Cross Approximate Entropy and FCM Clustering

Zhang Shuqing, Hu Yongtao, Li Pan, Bao Hongyan, Jiang Wanlu, Qian Lei

2015, 26(19):  2613-2618. 

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A new fault diagnosis method for rolling bearings was presented  based on MEMD cApEn and FCM clustering herein. The MEMD method could restrain mode mixing of EMD effectively and the cApEn was the improvement of approximate entropy, which could express the more irregularity and complexity. Signals were decomposed by MEMD to obtain a set of stationary intrinsic mode function (IMF), and some IMF components that were most relevant to the original signals were sifted out by the energy analysis criterion. The cApEn values of every IMF components were calculated as fault feature vectors that could represent the operating conditions of equipment more intuitively. FCM algorithm was introduced to fault recognition, which could achieve well effect of clustering with easier calculation. The experiments and engineering analyses demonstrate the superiority of this method.

Gearbox Fault Diagnosis Technology Based on Mixed Interference

Jiang Chunlei, Han Jiaming

2015, 26(19):  2619-2624. 

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Through the applications of laser SMI in the detection of gearbox, a new fault detection sensor for gearbox was proposed herein. A planetary gearbox fault SMI detection system was built by semiconductor laser self-mixing sensor QL65D5SA and planetary gearbox of hollow cup motor Faulhaber 2342l012CR. And the system was applied to do the wheel breaking tooth fault experiments for the planet Z1. Through the analyses of the time-domain waveform, 12 shock points were found at the rated frequency. Through the analyses of the Fourier spectrum of gearbox fault signals, it can be found that there are sidebands around the meshing frequency of the fault gear, which is an integer multiple of the characteristic frequency of the fault gear and the planetary frame transfer frequency. Amplitude of the wave at the meshing frequency is obviously increased, which is in accordance with the theoretical vibration model of gear pair.

Tactile Display System of Mechanical Dot Matrix

Chen Yikang, Liu Junbiao, Li Bo, Guo Shaopeng, Huo Rongling

2015, 26(19):  2625-2628. 

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This paper proposed a tactile display system of mechanical dot matrix for the blind's electronic reading. The statuses of dots were kept by claws latching the different positions of the display pins, and the raise status of display pins were controlled by one Z axis actuator cooperating with XY mobile stage. Then all the display pins would be reset by the reset actuator, so that the statuses of dots might be interchanged automatically. The experimental results show that 54 dots can be automatically interchanged in 1 minute between upward and downward positions by using a Z axis actuator.

Research on Tool Axis Vector Optimization Based on Graph

Liu Hongjun, Cao Ningjiang, Zhao Jibin

2015, 26(19):  2629-2632. 

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According to the five axis NC machining of ball end milling, this paper presented a new method to optimize tool axis vector based on graph. Based on the characteristics of the cutter axis vector data, the minimum optimization model and algorithm of the cutter axis vector directed graph were proposed. This method can get global minimum cutter axis vector variation of cutter axis vector sequence and improve the computational efficiency of the algorithm by using the boundary of the feasible region of cutter axis vector joining in the directed graph calculation. Simulation and data analyses show that the proposed method improves the continuity and smoothness of cutter axis vector in a certain extent, and also has certain applicability in its optimal tool posture along the boundary of the feasible region.

Analysis of Nonlinear Dynamics of Rotor System Supported by Finite Long Bearing

Hei Di, Lü Yanjun, Zhang Yongfang

2015, 26(19):  2633-2640. 

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Based on the assumption of π oil film, an approximation expression of nonlinear oil film force of finite hydrodynamic bearing was obtained by variational constraint principal and the separation of variables. The results calculated by the proposed method are in good agreement with the oil film forces by the finite element method, and the computing cost is reduced greatly. Based on the nonlinear oil film force, the speed of rotor, eccentricity of disk and stiffness of shaft were taken as control parameters, nonlinear dynamic behaviors of bearing-rotor system were analyzed by Newmark method. Numerical results reveal periodic, double-periodic, quasi-periodic, 6-periodic, 10-periodic of rich and complex nonlinear behaviors of the system.

Numerical Simulation of Atomization Performance for Double-spout Nozzle Used in MQL Grinding

Mao Cong, Zhou Xin, Tan Yang, Sun Xiaoli

2015, 26(19):  2640-2645. 

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In order to reduce the impacts of gas barrier, a double-spout nozzle was proposed. The atomization mechanism of MQL was analyzed, and the mathematical model was established by two-stage atomization model. The atomization process of the double-spout nozzle was simulated to analyses the atomization properties, and experiments were carried out to verify the simulation. The results show that the structure of the double-spout can effectively decrease the diameter of droplets and improve the atomization performance. The droplets sprayed by the assistant jet can break the air barrier layer and reduce the effect of the gas barrier layer on droplet flow. Therefore, the droplets from the main jet can enter the grinding zone easily.

Analysis and Verification of Hybrid Sliding Mode Flux Observer of Induction Motors

Li Mengqiu, Zhou Zhikang, Liao Wu, Peng Jing

2015, 26(19):  2646-2651. 

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In DTC of induction motors, flux linkage observation is an important part of precise control of motor. The analyses from two aspects of convergence and parameter sensitivity were carried out herein in view of two kinds of speed sensorless sliding mode observer. The advantages and disadvantages of two kinds of speed sensorless sliding mode observer were compared. A hybrid flux observer algorithm combined with the actual needs of engineering was proposed. The initial flux errors might be eliminated in the control of the new hybrid flux observer with good robustness. The correctness and effectiveness of the proposed method were verified by simulations and experiments.

Frequency Response Prediction of Deep Hole Internal Grinder Spindle Endpoint Based on Receptance Coupling Substructure Analysis

Li Xiaoru, Zhu Jianmin, Zhang Tongchao, Wang Jian

2015, 26(19):  2652-2661. 

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Based on RCSA, this paper predicted the frequency response function of the endpoint of a deep hole internal grinder spindle. At first, the method separated the model of grinder spindle into several subsections to calculate their free-state frequency response function (FRF) matrices, then rigidly coupled the FRF matrices of each substructure sequentially, revised the FRF matrices of the coupled substructure with structural modification method at the support points of bearings, coupled till to the last substructure, then the FRF of the endpoint of grinder spindle was calculated．With a deep hole internal grinder spindle system as the research object, the paper predicted the FRF of the spindle endpoint through proposed method and finite element method, meanwhile a group of FRF data were collected by experiments．Experimental results indicate that this method, with higher prediction precision and faster calculation speed, is better in the structure optimization of the deep hole internal grinder spindle system.

Modeling and Simulation of Servo-driven BHF Control System

Yang Li, Wang Guozuo, Zou Fenggang, Qin Siji

2015, 26(19):  2661-2666. 

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Servo-driven control technology of BHF is more effective and can improve the forming effect in deep drawing process. BHF control system driven by servo motor was composed of the mechanical system and CNC system. The parameters of components in BHF system had a greater influence on the dynamic performance of the system, so it could have effects on accuracy and efficiency in BHF control. Firstly linearization of the input and output equations was made for the six-bar linkage and the double-slider mechanism. And mathematical models of mechanical system and CNC control system were obtained respectively. Then performance of the system was simulated and analyzed and the PID parameters of the position loop were adjusted. Finally, the parameters in the experiments of the BHF control system were given based on simulation results. The experimental results show that it can meet the requirements of the BHF control to adjust slightly the values of the parameters of the control components based on the modeling and simulation results, so the debug time of system control parameters can be shorten greatly.

Fault Diagnosis of Wind Turbine Gearbox Based on Kernel Fuzzy C-means Clustering and Gravitational Search

Li Zhuang, Ma Zhiyong, Hu Liang, Liu Yibing

2015, 26(19):  2667-2671,2676. 

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In order to diagnose known faults and unknown faults of wind turbine gearbox, a method was proposed based on kernel fuzzy c-means clustering and gravitational search. Firstly, the clustering model was built based on wrong classification rate of training samples. The training samples were classified by kernel fuzzy c-means clustering. Then the gravitational search method was introduced for solving the clustering model. The class centers of optimal clustering result were acquired. Finally, the similarity parameters in kernel space between new data samples and the class centers were calculated for diagnosing whether the new data sample belonged to the known faults. The results show that the proposed method has higher precision, which can be applied to diagnose fault of wind turbine gearbox.

Analyses of Interior Temperature Field Distribution for Hot Axial Forgings with Void

Zhang Yucun, Zhang Leiqiang, Fu Xianbin

2015, 26(19):  2672-2676. 

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For hot axial void forgings, interior temperature field distribution plays a key role in the detection of inner void defect. Aiming at the issue, a two-dimensional unsteady heat transfer model of the forgings with void was established based on the heat transfer theory. Firstly, interior boundary conditions of the model were obtained by using lumped parameter method. Secondly, the initial temperature conditions of the model were collected by the thermal infrared imager. The interior temperature field distribution of forgings with void was acquired by separation variable method. Finally, interior temperature field distribution characteristics of forgings under different void size conditions were analyzed according to the experimental results.

Simplified Rolling Force Model for Temper Rolling Mill Based on Non Circular Arc Theory

Wang Dongcheng, Wang Yunhong

2015, 26(19):  2677-2681. 

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In view of the disadvantages of the rolling force model for temper rolling mill, considering the strip's elastic and plastic deformation, a simplified rolling force model for cold temper rolling mill was put forward based on a lot of calculation results of non circular arc theory. The simplified rolling force model could be used to mill designing and developing procedures for both dry and wet temper rolling mill. The results of 4 typical examples show that the simplified rolling force model is in well agreement with the non circular arc theory. Finally, the simplified model's correctness was verified by the measured rolling force of 2 temper rolling mills.

Study on Modeling Method for Failure of a Warren Structure under Whirligig Impact Load

Shi Tongcheng, Chai Xianghai, Hong Weirong

2015, 26(19):  2682-2687. 

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A modeling method to simulate the failure of a superplastic forming/diffusion bonding titanium Warren girder structure under whirligig impact load was investigated herein. In the proposed model, the effects of local stress concentration and local defect distribution at the girder areas were considered by defining effective tensile and shear strengths. The diffusion bond was incorporated into the finite element model through tie-break contact algorithm. Then，the calibrated bond strength was implemented in the numerical model, of which the result was further compared with whirligig impact tests to validate the rationality of the modeling method. The results show that the proposed method can effectively simulate the failure of the Warren girder structure under whirligig impact load.

Car-body Design Based on Regional Sensitivity Analysis and Space-multi-layer Topography

Hu Zhaohui, Yu Wanyuan, Chen Shaowei, Zeng Tuwei, Li Guangyao, Yuan Zhijun

2015, 26(19):  2687-2692. 

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This paper put forward the method of regional sensitivity analysis, by setting thickness-variables of the key regions as variables instead of single component thickness. And the paper also put forward the optimization technique of the space-multi-layer topography that was based on the reconstruction of the optimization space and the screening mechanism of sensitivity, which validly solved the optimizations problem of reinforcing plate to bulge from two normal sides of the plate. The two methods were applied to the lightweight of body in white(BIW) at the same time. The example indicates that the analysis method can analyze and solve the problem of regional sensitivity analysis successfully, and greatly shortenes vehicle's development period.

Cornering-time Optimal Algorithm for Intelligent Scaled Vehicle Based on Kalman Filter

Sun Tao, Xu Zhengjin, You Lin, Huang Xu, Zheng Songlin, Zhang Zhendong,

2015, 26(19):  2693-2697. 

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Vehicle optimal cornering-time is one of the most significant aspects in the field of lap time optimization. An optimal cornering-time algorithm was proposed herein based on the Kalman filter and optimal control theory. The Kalman algorithm was used to estimate the motion state of the vehicle，and the optimal trajectories were computed by the optimal control algorithm. A scaled vehicle with Freescale controller was developed subsequently according to the Buckingham Pi theorem based on dynamics similarity to validate the effectiveness of the control algorithm. The experimental results indicate that the scaled vehicle reduces the vehicle cornering-time effectively without sacrificing the vehicle stability.