Table of Content

25 August 2016, Volume 27 Issue 16

Previous Issue    Next Issue

Applications of Split Unbiased Estimation Algorithm in Thermal Error Modeling of CNC Machining Center

Miao Enming, Liu Yi, Yang Sixuan, Chen Weikang

2016, 27(16):  2131-2136. 

Asbtract ( )   PDF (511KB) ( )  

References | Related Articles | Metrics

Considering the distortion problems of estimated model parameters when dealing with the modeling of multi-collinear thermal error data of CNC machine by the multiple linear regression without offset estimation algorithm, a split unbiased estimation algorithm used for dealing with collinear data was proposed herein. The algorithm divided the modeling process into several steps, and in each step only one independent variable was regressed so as to avoid the collinear problem. In addition, taking Leaderway-V450 machining center as the experimental object, according to batches of idling experimental data which were measured on different seasons, the accuracy and robustness of SUE algorithm were compared with that of MLR algorithm. The results show that, the accuracy and robustness of SUE model is much better than that of MLR model, especially for forecasting these data on different seasons, the advantages of this algorithm is more obvious.

Free-hand Sketch Query Interface for Retrieving Mechanical Parts Using Normal Vector Distribution Feature

Wang Jiale

2016, 27(16):  2136-2140. 

Asbtract ( )   PDF (500KB) ( )  

References | Related Articles | Metrics

A sketch query interface was proposed for retrieving 3D models of mechanical parts. The maximum normal distribution of a 3D model was computed to assist the principal component analysis（PCA） to normalize the orientation of the 3D model, and then the projected views of the 3D model could be coordinated with the free-hand sketches submitted by users. To retrieve the 3D models similar with the user sketches, an image similarity assessment algorithm was employed to compare the shape similarity between user sketches and the views of the model. Experiments demonstrate that users can express their query intentions through the proposed query interface rapidly with satisfactory retrieval performance.

Investigation on Temperature Properties of Elevator Magnetorheological Brake

Zheng Xiangpan, Chen Kaifeng, Chen Shumei

2016, 27(16):  2141-2147,2154. 

Asbtract ( )   PDF (848KB) ( )  

References | Related Articles | Metrics

A new MR brake(MRB) was designed for traction elevator because of the shortcomings of the existing traction elevators with machine-electric brake—high operating impacts and high noise. The device had a dual-coil structure, which also designed channels for the circulation of coolant liquid for integral heat radiating, satisfying elevator braking with large braking torque and good heat dissipation. Based on mathematical model in heat transfer, the numerical simulation analysis was performed for thermal field of MRB in no-load operation conditions and in typical emergency braking situation with finite element software. The work improved heat dissipation by using water cooling, revealing the temperature changing regularities under typical condition of key parts. The reasonable working temperature range was verified with test methods. Simulation and experimental results show that temperature has a greater impact on braking mechanics performance; however, the device can satisfy the requirements of the elevator operating with the effective cooling conditions.

Normal Contact Model of Rough Surfaces Based on True Stress-Strain Relationship

Wang Shijun, Yang Chao, Wang Shiyi, Yang Huixin, Zhao Jinjuan, Li Shujuan, Li Pengyang

2016, 27(16):  2148-2154. 

Asbtract ( )   PDF (628KB) ( )  

References | Related Articles | Metrics

A modeling method for normal elastic-plastic contact of rough surfaces was presented. Based on elastic-plastic finite element contact model of asperity, normal contact characteristics between asperities of 40Cr, 45, Q235 and rigid plane were studied respectively. In finite element model, the true stress-strain relationships of the three materials were used and the influences of the different hardening behaviors on contact characteristics of asperity were investigated. As a result, unified function expressions of contact variables of asperity were built in three stages: elastic, elastic-plastic, plastic deformation. Based on the contact analysis of asperity, a normal elastic-plastic contact model of rough surfaces was built by probabilistic statistics method. By the presented method, the changes of contact variables of asperity in the contact model depended entirely on results of elastic-plastic finite element and it was unnecessary to divide the deformation process of asperity into different deformation stages, which avoided non-continuity and non-smoothness of contact variables between different stages and arbitrariness of choice of interpolation function in elastic-plastic deformation stage. Compared with other contact models, the calculated results of the model are confirmed.

Design of a Conjugate Concave-Convex Non-circular Gear Mechanism

Yu Gaohong, Yu Jiaping, Tong Junhua, Ye Bingliang, Zheng Shiyong,

2016, 27(16):  2155-2159,2165. 

Asbtract ( )   PDF (574KB) ( )  

References | Related Articles | Metrics

In order to design a concave-convex non-circular gear mechanism with two-unequal-amplitude transmission ratio function, the driving gear tooth profile was designed by using the software of self-developed, while the curve of the concave part was optimized by using CAD software. A new method of tooth profile generation was proposed. Pro/E software was utilized imitating generating method to generate tooth profile, using the driving gear as tool gear and the driven gear as gear blank. Virtual simulations were carried out, and the theoretical value of gear transmission ratio was extracted. The tests of gear transmission were completed. The experimental value of gear transmission ratio was measured by using high-speed digital video camera. The results show that the values of the two groups are basically the same. The correctness of the concave-convex non-circular gear in meshing and transmission, and the feasibility of this kind of special non-circular gear mechanism are verified.

Pressure Angle Analysis of a Double Generating Wave Swing Rod Movable Tooth Drive

Yi Yali, Shao Cang, Jin Herong

2016, 27(16):  2160-2165. 

Asbtract ( )   PDF (638KB) ( )  

References | Related Articles | Metrics

The pressure angle was used as the evaluation index of force transmission characteristics to guide the design parameters of double generating wave swing rod movable tooth drive. A tooth profile equation was established by complex vector method based on the meshing theory of movable tooth drive. Taking two typical transmission types as the research objects, the calculation formulae of pressure angle were deduced. The changing laws of each pressure angle were analyzed to ascertain influences of oscillation amplitude coefficient, teeth number of central wheel, radius of base circle, length of swing rod and center distance on pressure angles. By employing the orthogonal experiment, the scheme design was carried out based on experimental table with 4 factors and 3 levels to obtain the influence weights of each design parameter on pressure angle.

Coupled Heat Transfer and Experiments of Waist Tube Radiator

Zhao Jin, Ma Xiuqin, Li Meijun, Zhang Bingkun, Guo Song

2016, 27(16):  2166-2171. 

Asbtract ( )   PDF (620KB) ( )  

References | Related Articles | Metrics

A 3-D model of waist tube radiator was established on the basis of effects of waist tube on the cooling performance, and the coupled heat transfer principle was employed to simulate the heat transfer process. The pressure drops, heat transfer coefficients and heat transfer flux were obtained at different air speeds. And the effects of the waist tube on the structure and distribution of the air flow were summarized herein. Then the performance differences among various radiators were comparatively analyzed  though the wind tunnel tests. The results show that the tube radiator has better thermal performance and meets the cooling needs of various engine cooling systems.

Virtualization Descriptions and Integrated Intelligent Service Model of Cloud Manufacturing Resources

Tang Huamao, Guo Gang

2016, 27(16):  2172-2178. 

Asbtract ( )   PDF (796KB) ( )  

References | Related Articles | Metrics

According to the service model of cloud manufacturing resources and the features, the cloud manufacturing resource and its granularity model were formally defined. A semantic-based distributed description model of manufacturing resources was constructed. This model shielded the differences of all kinds of manufacturing resource granules in the basic data structures. It realized the virtualization description of the manufacturing resource granules at a higher level in the information representation. A virtual model of cloud manufacturing resource was constructed based on ontology. So the manufacturing resources in all kinds of network might be conducted unified management, semantic query and reasoning in logic. An intelligent service model of cloud manufacturing resources was also built. This model makes the manufacturing enterprise alliance more efficient and convenient in resource searching, resource matching, resource utilization and resource synergy.

Effects of Amorphous Alloy Stator on Performance of Remanufacturing Motor

Song Shouxu, Tan Hao, Wang Zhanchun, Wang Shuwang

2016, 27(16):  2179-2185. 

Asbtract ( )   PDF (761KB) ( )  

References | Related Articles | Metrics

In order to improve performance of the remanufacturing electric vehicles with permanent magnet synchronous motor, the waste motor silicon stator was replaced by the low iron loss amorphous stator. Based on 2D FEM analysis, performance of the same dimensional amorphous alloy and silicon stator motor, with load and without load, was compared in rated speed. The results show that the amorphous motor efficiency is 1.8% higher than waste motor, but 6% rated load torque is reduced. To recovery the rated load torque, the design of amorphous stator slot and winding was optimized. The results show that the optimized amorphous alloy stator remanufacturing motor rated load torque is recovery, meanwhile the motor efficiency is improved by 1.9% compared with waste motor. The FEM analysis results was validated by remanufacturing motor experiments.


Research on Multi-fault Diagnosis of Rotor Based on Approximate Entropy and EEMD

Han Zhonghe, Xu Bochao, Zhu Xiaoxun, Jiao Hongchao

2016, 27(16):  2186-2189,2248. 

Asbtract ( )   PDF (498KB) ( )  

References | Related Articles | Metrics

For the purpose of accurate identification of the turbine rotor multi-fault states, a diagnosis method was put forward based on the EEMD, approximate entropy and SVM. Firstly, the fault signals were decomposed to a number of intrinsic mode functions (IMFs) by EEMD method, then calculating entropy of IMFs as the feature vector to construct samples for binary tree SVM for multi-state classification. This paper compared with approximate entropy, fuzzy entropy and energy method. The experimental results verify the correctness of quantifying the nonlinear characteristics of fault signals with EEMD and entropy theory. They also indicate that the feature vectors based on approximate entropy are farthest from each other in European space, and the classification accuracy is the highest.

Target Recognition of Tower Crane Safety Pre-warning Based on Ultrasound Timing Sequence Neural Network

Li Xiping, Gu Lichen, Kou Xueqin

2016, 27(16):  2190-2195. 

Asbtract ( )   PDF (587KB) ( )  

References | Related Articles | Metrics

Aiming at tower crane safety pre-warning of instability and collision prevention, to improve the passive security model of tower crane which lacked low cost, initiative, flexibility, rapidity and simultaneity, the relationships among the target characteristics， ultrasound timing sequence relevent characteristics and distance characteristics were analyzed. Combined with Elman and SOM network, a system of target recognition of tower crane safety pre-warning was developed based on ultrasound timing sequence neural network. The functions such as sampling, data fusion, initiative pre-warning of twist angles and obstacles were achieved. Experimental results verify that the system can satisfy the tower crane working requirements with low cost, high speed and high precision.

Optimization Design of Human Machine Interaction Interface Based on Visual Perception

Zhang Bao, Ding Min, Li Yanjie

2016, 27(16):  2196-2202. 

Asbtract ( )   PDF (690KB) ( )  

References | Related Articles | Metrics

In order to improve the visual comfort and efficiency of HMI interface, an optimized method of HMI interface was proposed based on visual perception. Firstly, according to sensing intensity of cone cells, the partition model of HMI interface was established. Secondly, the priority grading method was scientifically used to measure the visual perceptional gradation. Finally, based on the sensing intensity of HMI interface and the importance index of perceptional elements, the optimal layout model of HMI interface was established on the basis of visual perception, and this model was solved by genetic algorithm. The examples of tool compensation interface show that this method is suitable for the optimal layout design of HMI interface.

Fault Diagnosis of Rolling Bearings Based on Unsupervised Discriminant Projection

Jiang Li, Guo Shunsheng

2016, 27(16):  2202-2206. 

Asbtract ( )   PDF (492KB) ( )  

References | Related Articles | Metrics

Aiming at the imbalanced fault samples and redundant fault features of rolling bearings, a rolling bearing fault diagnosis method was proposed based on UDP. The method firstly extracted several feature parameters from time domain and time-frequency domain. Thus, the raw high-dimensional feature set was constructed. Subsequently, the most sensitive low-dimensional manifold features were extracted from the feature set by employing UDP algorithm. Finally, K-nearest neighbor classifier was utilized to recognize the operating conditions of rolling bearings. The method was applied to the identification of bearing fault categories and inner fault severities separately. Compared with the traditional methods, the feasibility and superiority were validated.

A Piezoelectric Harvester Excited by Malposed Rotary Magnets

Kan Junwu, Zhang Xiaoyi, Wang Shuyun, Wang Bin, Yu Jie, Zhang Zhonghua, He Hengqian

2016, 27(16):  2207-2210. 

Asbtract ( )   PDF (528KB) ( )  

References | Related Articles | Metrics

To avoid the mutual impacts between the exciting magnet and that on the end of piezo-cantilever, a piezoelectric harvester excited by malposed rotary magnets was presented. Simulation and analysis of the magnetic coupling characteristics of the malposed magnets were carried out. The influences of rotary-speed/exciting-distance/proof-mass on energy generation performance were tested. The results show that the piezoelectric harvester excited by malposition magnets is feasible. There are multiple optimal rotary speeds for the generated voltage to achieve peak. Radial exciting distance exerts no influence on the optimal speeds, but great influence on the peak voltage. There are different positive/negative exciting distances for output voltages to achieve peak. The proof mass and the number of exciting magnets have great influences on the performance of the energy harvester. With the increasing of proof mass, the optimal rotary speeds of each order decrease, and the relative peak voltage increases. The orders of optimal speeds, the values of the optimal speeds, and the relative peak voltage decrease with the increasing of the number of exciting magnets.

Investigation and Application on Image Hierarchical Matching Algorithm Based on Global Feature and Local Feature

Zhu Qiguang, , Wang Ziwei , Chen Ying

2016, 27(16):  2211-2217. 

Asbtract ( )   PDF (640KB) ( )  

References | Related Articles | Metrics

Aiming at the problems that the image feature extraction and match algorithm should have high accuracy, good performance in real-time and robustness when the mobile robot navigated based on topological map, the paper proposed a new image hierarchical matching algorithm based on the global feature and local fusion. First, the improved shape context algorithm was applied to the input images to be matched to extract the global features which were matched roughly with the images in the database, obtaining 3 images that had the highest similarity to the current image which constituted a temporary image database. Then, the improved SIFT algorithm were used to extract local feature of the input images which were matched accurately with the local feature of the 3 images in the temporary image database, finally obtaining the image with highest similarity as the match results. The image hierarchical matching algorithm based on the global feature and local feature combined the improved shape context algorithm based on global features and the improved SIFT algorithm based on local features, so as to achieve the purpose of complementary advantages. The experimental results show that this algorithm can effectively improve the matching efficiency and reduce the running time when the mobile robots navigate based on topological map. 

Adaptive Parameterless Empirical Wavelet Transform(EWT) and Its Applications to Fault Diagnosis of Rotor System

Zheng Jinde, Pan Haiyang, Pan Ziwei, Luo Jiesi

2016, 27(16):  2218-2224. 

Asbtract ( )   PDF (775KB) ( )  

References | Related Articles | Metrics

To fulfill an adaptive separation of Fourier spectrum in EWT, an adaptive parameterless EWT(APEWT) method was proposed herein. To overcome the shortcomings of Hilbert transform and estimate more accurate time-frequency distribution of a given signal, an improved normalized Hilbert transform(INHT) was put forward. The proposed APEWT and INHT were compared with empirical mode decomposition(EMD), ensemble EMD(EEMD) and local characteristic-scale decomposition(LCD) methods and the analysis results demonstrate the effectiveness of the proposed method. Finally, APEWT and INHT based time-frequency analysis method were applied to local rubbing fault diagnosis of a rotor system, and the analysis results of experimental data indicate that the proposed method may fulfill rotor rubbing fault diagnosis effectively and have better effectiveness than that of EMD and EEMD methods.

Design of Supervisory Control Platform for Composite Hydraulic Speed Control System with Variable Frequency and Displacement

Tian Qingqing, Gu Lichen

2016, 27(16):  2225-2229,2266. 

Asbtract ( )   PDF (725KB) ( )  

References | Related Articles | Metrics

The supervisory control system for a pump-control-motor composite hydraulic volumetric speed control system with variable frequency and displacement was researched. Based on the full introduction to the working principles about the experimental system and the supervisory control system's structure, the supervisory control platform was implemented with LabVIEW technology. The results indicate that the supervisory control system realizes the acquisition, preservation and processing of the data, including analog data, serial data and so on. At the same time, the control for the speed of hydraulic system was realized by adjusting frequency or variable displacement，and the electro-hydraulic load simulation was achieved by adjusting the proportional relief valve. The supervisory control platform with friendly man-machine interface has a good openness and extensibility,and performs reliably, which is able to meet the needs of dynamic parameter monitoring and automatic control for the hydraulic system better.

Contour Error Analysis and Compensation for Camshaft CNC Grinding

Yang Shouzhi, Deng Zhaohui, Liu Wei, Li Jian, Peng Keli

2016, 27(16):  2230-2235. 

Asbtract ( )   PDF (597KB) ( )  

References | Related Articles | Metrics

Based on the current situations of grinding error analysis and compensation, a new contour error analysis and compensation method was proposed for camshaft CNC grinding in X-C axis linkage, to improve the accuracy of cam grinding. According to the camshaft grinding motion model in X-C axis linkage, the mathematical model was derived for cam lifting to grinding offset. It pointed out that the variation trends of cam lifting errors and contour errors were basically the same. Then a stable and repeatable cam lifting errors could be predicted with series fitting of cam lifting errors from multiple grinding experiments, using least square method. By inverse superposition of predicted lifting errors to theoretical lifting table in a certain proportion, the virtual lifting table could be obtained after the smoothing using least square method. Finally, the camshaft grinding experiments were applied according to the virtual table. The experimental results indicated that: the speed and acceleration of grinding carriage are basically in the response range of grinder servo, the maximum cam lifting error and the maximum adjacent error are decreased, the surface roughness satisfies with the processing requirements. It is proved that the error analysis and compensation methods are correct and feasible.

Creep Effects on Interferences of Extrusion Container with Consideration of Working Conditions

Li Yihong, Luo Yuanxin, Ma Ling, Song Zongtao, Wang Yongqin

2016, 27(16):  2236-2241. 

Asbtract ( )   PDF (594KB) ( )  

References | Related Articles | Metrics

An analytical method, also called direction displacement method (DDM), was proposed based on the Lamé equation to predict the stress/strain evolution in extrusion container. Then, the experiments for evaluating the creep effects of H13 steel at the temperature of 500℃ were conducted, and the creep behavior was modelled by using Norton's law. Finally, a case study was investigated to analyze the relationship between material creep effects and interferences. It is found that the creep strain of each layer in the interface is different, caused the radial deformation is different, thus the interferences are reduced.

Liquid Phase Migration and Freeze-form Extrusion Fabrication of Aqueous Ceramic Paste

Yan Cunfu, Li Shujuan, Yang Leipeng, He Longfei, Yang Zhenchao

2016, 27(16):  2242-2248. 

Asbtract ( )   PDF (701KB) ( )  

References | Related Articles | Metrics

During the aqueous ceramic paste freeze-form extrusion fabrication process, liquid phase migration had important effects on extrusion proces and the part performances. The extrusion process was divided into 3 stages, i.e.compaction stage, transition stage and stable extrusion stage. The extrusion pressure equation which included the shear forces between the barrel inner wall and the extrusion paste was derived based on Benbow-Bridgwater model. The influences of extrusion speed, interval time and nozzle diameter on liquid phase migration were studied attentively through single factor experiments. The results show that the longer interval time, the more serious the liquid phase migration, the higher extrusion speed and the bigger diameter of extrusion nozzle may reduce liquid phase migration and improve the forming efficiency.

Temperature Field Analysis Model of Shaft Forgings with Cracks during Forging

Fu Xianbin, Zhang Yucun, Dong Zhiming, Zhang Leiqiang

2016, 27(16):  2249-2253. 

Asbtract ( )   PDF (519KB) ( )  

References | Related Articles | Metrics

Based on the unsteady heat conduction theory, a temperature field analysis model of shaft forgings with symmetric and asymmetric cracks was proposed. The shaft forgings with cracks were considered as composite media. According to lumped parameter method, the temperature field function of crack was obtained through solving governing equation of forgings with symmetric cracks. Then the temperature field function of asymmetric cracks was obtained by introducing correction factors. Moreover, the temperature field function of symmetric crack was regarded as the boundary conditions of heat conduction equation for shaft forgings with symmetric cracks. The temperature field function of asymmetric cracks was regarded as the boundary conditions of heat conduction equation for shaft forgings with asymmetric cracks. Therefore, combining with the corresponding boundary conditions, the temperature field analysis model of shaft forgings with cracks was established. The feasibility of this model was verified according to experimental results.

Study on P91 Alloy Ductile Fracture Behavior Based on Compressing Experiment

Liu Yutong, Yuan Chaolong, Wu Rendong, Jiao Wei, Qiang Hao

2016, 27(16):  2254-2258. 

Asbtract ( )   PDF (564KB) ( )  

References | Related Articles | Metrics

Ductile fracture was the main fracture form in plastic processing of metal, and obtained material's critical damage value was the key to numerical simulation of plastic processing, which involved fracture behaviors. Compressing experiments were employed and the complex stress integration in upsetting process was calculated with numerical simulation herein. Under normalized C-L criteria, the critical damage value of P91, a kind of heat resisting & high tensile alloy, was obtained. Based on the calculation results, bottom-cutting process, a preforming process used in seamless steel tube production was simulated. The simulation results agree with the real engineering ones.

Analyses of Occupant Injury Affected by Combination of Autonomous Emergency Braking and Reversible Pretensioner Seatbelts

Cao Libo, Ouyang Zhigao, Jia Yuci, Xu Zhe, Zhang Guanjun

2016, 27(16):  2259-2266. 

Asbtract ( )   PDF (806KB) ( )  

References | Related Articles | Metrics

Aiming at the occupant seat posture aggravated by AEB, the effectiveness of RPS in improving occupant OOP seating posture was investigated. A numerical simulation approach was utilized to establish a driver-side restraint system model involving AEB, RPS and active human model(AHM). On the basis of volunteer tests which were conducted to obtain the key parameters induced by restrained occupants with different seat postures in the pre-crash phase, the tension force and increased length of seatbelts of RPS were set. The influences imposed by AEB and RPS on the occupants movement in the pre-crash phase were interpretted, as well as the injury risk during in-crash phase. The results indicate that AEB increases occupants injury risk in identical impact severity, especially thorax injury. Nevertheless, occupants injury risk decreases significantly with the utilization of RPS through improving occupants OOP seat posture.

Sensitivity Analysis about Design Parameters for Car-body Vertical Bending Vibration Frequencies

Wang Changke, Yang Guangwu, Zhu Tao, Yu Jinpeng

2016, 27(16):  2267-2271. 

Asbtract ( )   PDF (529KB) ( )  

References | Related Articles | Metrics

The sensitivity analysis about key parameters of a car-body was carried out with the stiffness optimization method to find the relationship among design variables and system responses, the gradient of the structure variables (key parameters of car-body) for the target functions (first order vertical bending frequency of car-body) was obtained. First, the first order vertical bending frequency equation was built from Euler-Bernoulli theory with initial and boundary conditions. Then, the frequency equation was corrected with car-body characteristics to get an accurate result, and the results were tested by a finite element result of a subway car-body. Finally, sensitivity analysis was done with 6 key parameters for the bending vibration frequency of car-body. The conclusions show the significance sequence of main car-body parameters for first order vertical bending frequency according to the sensitivity, which may give some advices to designers.