Table of Content

25 November 2012, Volume 23 Issue 22

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Mobility of a New Type Shaft/Radial Telescopic Tire Building Drum

YANG Pan-Dong-1, 2, YANG Yu-Hu-1

2012, 23(22):  2647-2652. 

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Aiming at a new type radial telescopic tire building drum used for radial tire building,based on the principle of superposition,a tire building drum mechanism was decomposed into several kinematic sub-chains which possessed the same mobility.Further structural decomposition of the driving unit,several planar six linkage and three bar four kinematic pair branch chains were gotten.The partial freedom,virtual constraints and common constraints of all the kinematic chains were judged based on screw theory and their degrees of freedom were analysed respectively.According to the principle of substitution of the generalized kinematic pair,mobility of the complex loop mechanism composed by multiple sub-chain was studied.
By structural decomposition of the tire building drum mechanism,the number and property of mobility for the mechanism was obtained.

Influence of Adjacent Grit Trajectory on Grinding Process in 2D Ultrasonic Vibration Grinding

YAN Yan-Yan-1, XU Pei-Lin-1, FENG Ji-Cheng-2, HE Jia-Wei-1

2012, 23(22):  2652-2655. 

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The influences of wheel parameters,processing parameters and ultrasonic vibration parameters on the trajectory of adjacent grits were considered fully in elliptic ultrasonic vibration grinding.The locus equation of adjacent grits in elliptic vibration grinding was formulated.The criterion of the relationship of the trajectory among adjacent grits was given.Simulation and analysis were made to show the influences of adjacent grit distance between the adjacent grits,the radial height difference of the neighboring grits,the workpiece feed rate,the radiual of the wheel and the amplitude of the ultrasonic.

Research on Scheme Decision of Particle Scattered and Conveying System Based on FAHP

TANG Qi-Jing-1, DIAO Tie-Dan-1, DAN Zhong-Pan-1, YU Fei-Hu-1, ZHENG Xiu-Xin-2, WANG Li-Long-2

2012, 23(22):  2656-2660,2666. 

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In order to get small particles similar as finished goods for testing,the chunk of compound fertilizer was made to particles scattered.Comprehensive considering the system's demands and working in strong corrosive and high dust environment,main factors of scattered and conveying system were confirmed,three schemes were put forward.Using FAHP to construct the system's decision-making model,the various factors's weights and the optimal scheme were determined.After the experimental comparison,chunk of compound fertilizer was scattered and conveyed,the particles have the similar particles size distribution as the finished goods.It verifies that the decision-making model and method are correct.

Automatic Defect Inspection of PCB Bare Board Based on Machine Vision

YANG Qiang-Hua-1, CHEN Liang-1, XUN Yi-1, CHEN Wen-Biao-2

2012, 23(22):  2661-2666. 

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An algorithm was proposed for defect inspection of PCB bare board.It was based on comparison between the standard PCB image and the target image and analysed the boundaries of  the different regions in the target image.Multiple images were acquired for the qualified PCB at the same position,and an average was applied as the standard image.Then the target image was compared with it.On the PCB image there symmetrically distributed some vertical mark lines.First,these mark lines were detected rapidly by restricted areas Hough transform and the intersection of the lines were chosen as the feature point.Then the affine registration between the target image and the standard image could be completed.After subtraction,false defects were removed by threshold segmentation and morphological processing in the difference images.The locations of defect areas were obtained.The difference image was in the process of dilation,then the coordinate values of each defect area closed contour points could be obtained by boundary detection.The aligned target image was treated with threshold segmentation.In the processed image,the pixel values of the points whose coordinate values had been get above were obtained.According to the analysis of the pixel values and the judgment of whether the defect was lack of material or not,the type of detects could be quickly determined.The experimental results on 400 PCB images  indicate that the correction rate of detection is of 98.3%.The algorithm can accurately detect conventional defect steadily.

A Compensation Method for Deflection of Ram with Combined Pull and Push Rods

TUN Feng-He, DIAO Feng-Bing

2012, 23(22):  2667-2670,2684. 

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According to structural and loading characteristics of ram of heavy-duty CNC boring and milling machine,a new compensation method for the deflection of the ram with combined pull and push rods was proposed. Based on eccentric compression(or tensile) theory,two group of rods which provided opposite direction forces were installed inside of the ram.One group was the pull rods installed on the top side of the ram,another group was the push rods installed on the bottom side of the ram.Two group of pull and push rods were arranged with up and down,left and right symmetry about the spindle centerline,which form the two-way force groups.The axial pitch of two push rods and two pull rods were equal in size and opposite
in direction,so there were no additional deformation in axial direction.Compared with the traditional compensation method with pull rods,the compensation forces were provided by two tension cylinders and two thrust cylinders,so in the situation of same compensation degree,only a smaller cylinder pressure needed to be provided.The advantages of this compensation method were verified by theoretical analysis and finite element simulation.

On Selection of Texture Image and Surface Craft under Target Form Image

ZHOU Hai-Hai, CHEN Li, HU Wei-Feng

2012, 23(22):  2671-2675. 

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The image space structure of form texture was revealed, and the position of the target image and the material samples was confirmed in the material image space through a method of factor analysis. A concept of the fitness to the target image was presented herein. The fitness to the target object of texture sample was obtained through computing the distance between them, so that the most fitness texture samples to the target form object can be obtained. Then, the regression relationship among the fitness and different surface crafts was obtained by the method of theory of quantificationⅠ.It can be used as the reference during product concept design. The reasonableness and feasibility of the method were certified through applying the product development design case of financial machinery.

Development of Fuzzy Controller for Precision Positioning of Piezo Actuator

ZHANG Jian-Hua, GE Gong-Yu, LI Hong-Qing, TENG Fu-Lin

2012, 23(22):  2676-2680. 

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Aimming to solve problems in accuracy and reality performance of piezo precision positioning system, a fuzzy method was proposed. Hysteresis and step response model of piezo actuator were built with series experiments, Then, fuzzy controller for piezo actuator was suggested, simulated and achieved with a 32-bit embedded microprocessor, S3C2410. System tests on precision positioning indicate that about the step response, the steady state error is less than 0.1μm, the settling time is less than 3ms and the overshoot is less than 20%; about the sinusoidal response, the displacement error is ranged from -0.24μm to 0.2μm.

Numerical Study of Aerostatic Bearings Based on CFX

TAO Mei-Gong-1, ZHANG Heng-Feng-2

2012, 23(22):  2681-2684. 

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Bearing gap internal fluid area of different eccentricities were studied by the CFX fluid dynamics software,Pressure,velocity distribution diagrams were got,the variation of the load capacity of bearing and bearing flow with different eccentricities were also obtained.The analysis results show that with eccentricity
increases,the gas film pressure distribution is no longer symmetrical;the peak velocity and the speed differences of gas film area are getting bigger and bigger;the load capacity of the bearing is non-linear increasing with the increase of eccentricity,and the bearing flow is non-linear decreasing with the increase of eccentricity.It provides the theory foundation for further improving the design of inherent hole restriction aerostatic radial bearings.

Research on Tool Presetting Method for Manufacturing of Pinion Cutter with Convex Curved Rake Face

LI Hua-Guang, ZHANG Shu-Ren, SHI Guo-Quan, SONG Lin-Sen

2012, 23(22):  2685-2688,2738. 

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As for NC machining of convex curved rake face of a pinion cutter,the original position of grinding wheel is very important for the machining precision and tooth profile precision.Herein,tool presetting scheme was designed by using laser sensor,the tool presetting device was designed and manufactured,the original position of grinding wheel could be ascertained by using the device.The tool presetting experiments were done,the results of tool presetting experiments testify  the feasibility of the scheme,gear shaping experiments were done also,and the results of gear shaping show that the tool presetting device can satisfy the demands of the manufacturing of pinion cutter with convex curved rake face.

#br# Research on Ceramic Core Structure Influences on Surface Accuracy of Hollow Turbine Blade Based on Numerical Simulation

YANG Xiao-Ning, BO Hun, LIU Jin-Gang, DONG Yi-Wei, FU Jiang-Wei

2012, 23(22):  2689-2693. 

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In precision casting process,due to the mechanical resistance of solidification shrinkage of ceramic core,and the structure also had an important influence on the blade surface dimensional accuracy.Based on precision casting numerical simulation method,the influences of the ceramic core structure on blade deformation rule were analyzed.Its solidification process was simulated and the deformation displacement field was obtained by using ProCAST software.Three different structures of ceramic core in the displacement field were analyzed by the displacement deformation trend graph comparison method,the influence rule of ceramic cores structure on blade deformation was obtained.It provides a basis for optimal die.

Remanufacturing Supply Chain Decision-making Mechanism Based on Government's Environmental Regulation

CAO Jian, HU Jiang, LOU Ting-Yuan, ZHOU Gen-Gui

2012, 23(22):  2694-2702. 

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For a RSC system including a remanufacturer and a treatment agency under the intervention of government's environmental regulation,a bilevel programming model between the government and the supply chain system was established with game theory.Combined with current situations of China,the incentive contract between the remanufacturer and the treatment agency was designed involving with the remanufacturer's level of participating in DfE activities.The premise for the remanufacturer to participate in DfE was provided,the influences of  the government's financial intervention on the system members' decision-making and expected profits were analyzed,and the effects of various parameters on design of the government's financial policy were discussed.The results indicate that,implementation of  the government's environmental regulation is effective to motivate the remanufacturer's DfE participation,as well as to improve the treatment agency's effort-extent.The conclusions are helpful to the design of the government's environmental policy and the operation of RSC in the early stage of remanufacturing industry's development.

#br# Evaluation and Selection Method for Knowledgeable Manufacturing Mode Based on Fuzzy DEA/AR

WANG Yu-Fang-1, 2, YAN Hong-Sen-1

2012, 23(22):  2702-2707. 

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A fuzzy DEA/AR method was proposed to evaluate the relative validity of manufacturing modes.In the data envelopment analysis model,the knowledgeable manufacturing modes were regarded as decision making units and their complexity were also considered.The input and output variables in the model were expressed by the triangular fuzzy number.The weight assurance region was used to avoid the effects of  the conventional non-Archimedean infinitesimal on the evaluation results.To evaluate the validity of the decision making units,the α cuts were introduced into resolve fuzzy data envelopment analysis model.Based on the calculated upper and lower bound of fuzzy validity,a ranking method was given to provide basis for selecting knowledgeable manufacturing modes.Eventually,an example was employed to demonstrate the feasibility of the proposed method. 

Optimization of Warehouse Items Layout In a Mixed Assembly Workshop

SHU Lin-1, HE Ji-Chang-1, 2, FAN Xiu-Min-1, 2

2012, 23(22):  2708-2714. 

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To solve the warehouse storage assignment problem with multiple materials in a mixed assembly workshop,the concept of labor's average routing path was put forward and a mathematical model was built to minimize the path.The position where the materials should be placed was as decision variable.The warehouse layout and the storage rack capacity were as constraints.Heuristic algorithm based on ant colony system was used.At the same time,in order to reduce the dimension of the solution,the second decoding method was applied.The optimization results give the material storage assignment layout in different storage racks.Heuristic algorithm based on ant colony system is better than the general algorithm.Finally,the feasibility and effectiveness of the method was verified by the example of the picking area in an air-conditioner assembly workshop.

Capacitated Multi-objective Original Equipment Manufacturer Cooperative Production Order Allocation and Application of Hybrid Ant Colony Optimization Algorithm

HAN Jin-Dong, LI Yang-Dun, CHEN Zhi-Xiang

2012, 23(22):  2714-2719. 

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How the brand manufacturer allocates customer orders to different cooperative OEM suppliers with largest profit and highest service level is one of the key manufacturing problems under the circumstances of cooperative production environment of BTO.Based on the characteristics of this problem,this paper established a multiple-objections order allocation model and then found the assignment solution by a novel hybrid ant colony optimization algorithm,which combined simulated annealing and ant colony optimization algorithm.We also made some improvements to the hybrid algorithm and then used numerical examples to show the effectiveness and reasonability. 

Ontology-based Knowledge Modeling of Collaborative Product design for Multi-design Teams

WANG Wei-Yuan, WANG Fa-Lin, LE Cheng-Yi, ZHANG Dan-Beng, ZONG Qi

2012, 23(22):  2720-2725. 

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To solve the problems of the design knowledge sharing and reuse difficulty in the process of collaborative product design, an ontology-based knowledge modeling method of collaborative product design for multi-design teams was proposed. A collaborative product design work model for multi-design teams was established by analyzing the characteristics of collaborative product design firstly, and an ontology construction framework for collaborative product design was also put forward. At the research background of mechanical product collaborative design, the knowledge modeling process of collaborative product design for multi-design teams based on ontology modeling theory was studied by utilizing the classification and description method of thinking, including the design knowledge classification and concepts extraction, the OWL description and the property definition. On this basis, a knowledge ontology model for mechanical product collaborative design was constructed. Finally, an application case was presented to illustrate the feasibility and validity of the knowledge modeling method.

Finite Element Analysis(FEM)  on Thermal Fatigue Failure of  Water-cooling Disc Brake

CA Yun-Di, TANG Wen-Xian, HUANG Qiu-Yun, WANG Ling-Ling

2012, 23(22):  2726-2731. 

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Aiming at the repeated braking conditions of offshore drilling drawworks during the round trip,a three-dimensional FEM of thermo-mechanical coupling analysis of the water-cooling brake disc was established.By using  the FEA software ABAQUS,the repeated braking process was simulated.Distribution characteristics of the surface and inner temperature field and stress field were obtained,based on which,the thermal fatigue failure mechanism of brake disc was analyzed.The results show that,in the repeated braking,
the temperature and stress of brake disc are coupled,and they have the similar variation disciplinarian.Thermal stress in the circular direction is the main stress for causing the initial cracks on the surface of brake disc.These cracks are getting larger under the effect of repeated thermal stress,eventually,inducing the fracture of brake disc.The analysis results are in good agreement with the practical situation,
which prove the validity and feasibility of the analysis method used herein.

#br# Neural Network Adaptive Control Algorithm Modified by PSO

XU Qing-Nan, ZHOU Jie-De, AI Jing-Song, LIU Quan

2012, 23(22):  2732-2738. 

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As in some situations the control objects are nonlinear or variable,the traditional PID control can not meet the requirements and the PID parameters need to be constantly adjusted by empirical knowledge.
A new neural network adaptive control algorithm modified by PSO was proposed herein.It consisted of the traditional PID,BP neural network and the PSO global optimization algorithm which was used to optimize the initial weights of BP neural network.The optimized BP neural network was then used to adjust PID parameters on-line.Variation operation was introduced to the optimization process and the comprehensive influence on PSO and BP introduced by the choice of the activation function gain and the number of hidden layers was considered.The algorithm can improve the problem more effectively that neural network goes easily into the local minimum value and has slow convergence speed.Simulation results show that the proposed method has greatly improved in accuracy and real-time performance.

Stability Analysis of Plow Body of Coal Plow

KANG Xiao-Min, LI Gui-Han

2012, 23(22):  2739-2743. 

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With the increase of coal seam thickness,the height of plow body increases correspondingly.During cutting coal,acting forces of coal made plow body instability.Analyzing the acting force on plow body and the factors influencing on the stability of plow body,the height of plow body and cutting depth were the important factors on stability of plow body.And the change rule of plow body stability influenced by plow body
height and cutting depth was obtained with an example.It provides references for determining the installation height of the support,and provides theoretical basis for further measures to improve the stability of plow body.

#br# Design and Analysis of a Transformable Quadruped with Rolling Mode

HONG Gong-Bei-1, TU Lian-Qiang-2, 3, WANG Yu-Jin-2, WANG Li-Beng-3

2012, 23(22):  2743-2747. 

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To adapt to the unstructured environments where the terrain is irregular and plain alternately,a transformable quadruped robot which has rolling mode was proposed herein.The quadruped structure was designed and the structural parameters were also  obtained by geometric method.In order that the mass center coincided with the centroid,static balance counterweight was made to the quadruped.The roller was
simplified as open chain bow-shaped linkages as the rolling movement was discussed in a straight line.When the linkages were expended as noncircular form,gravitational moment was generated as the mass center departed from the centroid,and the roller was self-propelled by the moment. The mass center expression of noncircular roller during a quasi-static rolling circle was derived using D-H method.The offset of mass center varied in a quasi-static rolling circle was figured out when the structural parameters of circular roller was inputted into the expression.The results verify  the rationality of structural design and counterweight.

#br# #br# Study on Ball Screw Grinding Chatter and Monitoring Method

CHI Yu-Lun, LI Hao-Lin

2012, 23(22):  2748-2751. 

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The ball screw grinding chatter influences seriously to improve the workpiece surface quality and production efficiency.Based on a lot of experimental studies,the paper analyzed and tested the relationship
among workpiece chatter marks and monitoring signals.Then,the information rate was used to monitor grinding chatter phenomenon as variable parameters of acoustic emission signals and acceleration signals.At last,the setted threshold was applied to identificate the ball screw grinding chatter phenomenon automatically,and its validity and feasibility were proved.

Positive and Reverse Design of Screw Rotor Profiles Based on Freeform Curve

HE Xue-Meng, DAI Jin, LIU Hong-Wan

2012, 23(22):  2752-2757. 

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In the traditional screw compressor rotor profile generation method,the process of cockamamie parameters adjustment and confirmatory is complex;the whole design cycle is long and cannot predict the modified results in advance.Based on freeform curve,two rotor profile generation methods were proposed in
order to solve the problems.One method was positive,and the female and male rotor profiles were acquired by every profile segment defined with freeform curve;another one was reverse,and the rotor profiles were derived through the meshing line.The rotor profiles were fitted by freeform curve and the shape of rotor profiles can be adjusted by moving the control points.Finally,the two methods were used to develop a system for designing the rotor profiles quickly.

A New Error Analysis Method for Eddy Current Sensor Measurement Accuracy

TAO Huan-Xin-1, MIAO En-Ming-2, NIU Feng-Cheng-2

2012, 23(22):  2757-2760. 

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Because the random error analysis method for eddy current sensor calibration can expand the range of measurement error estimation and limit its engineering applications,a new error analysis method was used herein to analyze upper and lower limits of multiple batches measurement data.At the same time,a criterion for the measurement times was catched up.This method can obtain the measurement accuracy more precise,and has good engineering application values.

Analysis of Structural-acoustic Coupling of an Enclosure Surrounded by Honeycomb Sandwich Panel

WANG Cheng-Chun-1, 2, DENG Zhao-Xiang-1, WANG Pan-1, CAO You-Jiang-1

2012, 23(22):  2761-2764. 

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The structural-acoustic coupling mechanism,characteristics,effect of system parameters on structural-acoustic coupling degree and on eigenfrequency of the system were analyzed theoretically.The eigenfrequency of the coupled system was estimated.The theoretical model and calculational methods were validated by comparing with available results.The influence of structural parameters of honeycomb sandwich panel on the sound pressure response in cavity was then studied systematically.The analysis results demonstrate that increase in thickness of face sheet and core is propitious to reduction of sound pressure response in cavity under the restriction of total mass and the fundamental frequency of structure.

Dynamic Modeling and Analysis of Vehicle Shimmy System with Consideration of Rack-and-pinion Steering Box Backlash#br# 

LEI Jian-Wei-1, TUN Zhang-Wei-1, TUN Ji-Xiang-1, LIU Meng-Jun-2

2012, 23(22):  2765-2768. 

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Based on nonlinear dynamics theories,a dynamic model of rack-and-pinion movement pair was discussed,and the dynamics model of vehicle shimmy system with consideration of rack-and-pinion movement pair backlash was presented.The dynamics behavior of  the system was analyzed by numerical examples,which provides theoretical basis for better vehicle shimmy control.

Design of an Electronically Controlled Injection Device for Heavy-duty Gas Engine

GE Wen-Qiang-1, 2, LIU LIANG 1, CHANG Sai-Qi-1, SUN Bin-Bin-1

2012, 23(22):  2768-2771. 

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According to the fact that the scavenging effect of heavy-duty gas engine is insufficient,and problem of low control precision of the air-fuel ratio and slow response,an injection device using the moving-coil electromagnetic linear actuator and mushrooms type valve structure was proposed herein.The electronically controlled injection device can achieve multiple-point sequential and intermittent fuel injection.The design and the principles of the main design parameters determination were discussed.The design of injection device was completed and a prototype was developed.The digital controller of the injection device was also developed for characteristic tests.The results show that the technical solution can meet the
 engine's requirements of high flow rate and response.