High frequency group pulse electrochemical machining

In the process of machining ultrathin metal structure parts, the signal composition of high frequency group pulse, the influence of frequency to reverse current, and the design of the cathode in high frequency group pulse electrochemical machining (HGPECM) are discussed. The experiments on process were carried out. Results indicate that HGPECM can greatly improve the characteristics of the inter-electrode gap flow field, reduce electrode passivation, and obtain high machining quality. The machining quality is obviously improved by increasing the main pulse frequency. The dimensional accuracy reaches 30–40 μm and the roughness attained is at 0.30–0.35 μm. High frequency group pulse electrochemical machining can be successfully used in machining micro-parts. __________ Translated from Transactions of Beijing Institute of Technology, 2006, 26(7): 585–588 [译自: 北京理工大学学报]     

Manufacturing system modeling and performance evaluation based on improved stochastic statechart

Stochastic statecharts are widely used in modeling systems. Considering that the comparability between different subsystems can streamline the modeling process, a stochastic statechart is improved by using the abstract sub-system and general system chart to express the comparability and integrity of a stochastic statechart respectively. Per formance data can be obtained by using a continuous-time Markov chain, which is transformed from a manufacturing system model described by the improved stochastic statechart. The case study shows that the improved stochastic statechart can effectively simplify the modeling and performance evaluation process and the results are useful to the configuration and optimization of a manufacturing system. __________ Translated from Journal of Beijing University of Technology, 2006, 32(8): 693–698 [译自: 北京工业大学学报]     

Laser vision sensing based on adaptive welding for aluminum alloy

A laser vision sensing based on the adaptive tungsten inert gas (TIG) welding system for large-scale aluminum alloy components was established to fit various weld groove conditions. A new type of laser vision sensor was used to precisely measure the weld groove. The joint geometry data, such as the bevel angle, the gap, the area, and the mismatch, etc., aided in assembling large-scale aerospace components before welding. They were also applied for automatic seam tracking, such as automatic torch transverse alignment and torch height adjustment in welding. An adaptive welding process was realized by automatically adjusting the wire feeding speed and the welding current according to the groove conditions. The process results in a good weld formation and high welding quality, which meet the requirements of related standards. Translated from Journal of Beijing University of Technology, 2006, 32(8): 714–718 [译自: 北京工业大学学报]     

New kind of subarea-parallel scanning mode for laser metal deposition shaping

A scanning mode is the key technology in a laser metal deposition shaping (LMDS) fabrication process. On the basis of the analysis of existing scanning modes and their influences on the fabrication efficiency and the quality of parts, some disadvantages of them are pointed out. A new kind of subarea-parallel scanning mode for LMDS based on a subdividing profiled outline into monotonous polygon subareas is presented. First, based on the principle of point visibility, inner loops are eliminated, and simple polygons are subdivided into monotonous polygons with the minimal zones. Second, the parallel scanning paths of all monotonous polygon subareas are finished, which diminishes the length of the scanning line. The practical application shows that the scanning mode can enhance the fabrication efficiency and quality. __________ Translated from Chinese Journal of Mechanical Engineering, 2006, 42(10): 170–175 [译自: 机械工程学报]     

Research and implementation of flexible coding system oriented multi-view

On the basis of the requirements of a product data management system (PDM) for the flexible coding system, the principle of the flexible coding system oriented multi-view is analyzed. Generation and utilization of coding should be associated with the context of the object. The architecture of the flexible coding system oriented multi-view is studied and the implementation class diagram of the system is designed. The system can support the establishment of five types of code segments, provide the tools of flexible defining coding rules and drive the automatic generation of object coding in different views (contexts). On the foundation of the characteristics of the system, coding for parts is taken as a sample to validate and elaborate the flexible coding process of the system. __________ Translated from Transactions of Beijing Institute of Technology, 2006, 26(1): 14–18 [译自: 北京理工大学学报]     

Parameter prediction in laser bending of aluminum alloy sheet

Based on the basic platform of BP neural networks, a BP network model is established to predict the bending angle in the laser bending process of an aluminum alloy sheet (1–2 mm in thickness) and to optimize laser bending parameters for bending control. The sample experimental data is used to train the BP network. The nonlinear regularities of sample data are fitted through the trained BP network; the predicted results include laser bending angles and parameters. Experimental results indicate that the prediction allowance is controlled less than 5%–8% and can provide a theoretical and experimental basis for industry purpose. __________ Translated from Optics and Precision Engineering, 2007, 15(6): 915–921 [译自: 光学精密工程     

Intelligent high-speed cutting database system development

In this paper, the components of a high-speed cutting system are analyzed firstly. The component variables of the high-speed cutting system are classified into four types: uncontrolled variables, process variables, control variables, and output variables. The relationships and interactions of these variables are discussed. Then, by analyzing and comparing intelligent reasoning methods frequently used, the hybrid reasoning is employed to build the high-speed cutting database system. Then, the data structures of high-speed cutting case base and databases are determined. Finally, the component parts and working process of the high-speed cutting database system on the basis of hybrid reasoning are presented. __________ Translated from Computer Integrated Manufacturing Systems, 2006, 12(3): 420–427 [译自: 计算机集成制造系统]     

Quality monitoring of resistance spot welding based on electrode displacement characteristics analysis

A new method is developed to monitor joint quality based on the information collection and process in spot welding. First, twelve parameters related to weld quality are mined from electrode displacement signal on the basis of different phases of nugget formation marked by simultaneous dynamic resistance signal. Second, through correlation analysis of the parameters and taking tensile-shear strength of the spot-welded joint as evaluation target, different characteristic parameters are reasonably selected. At the same time, linear regression, nonlinear regression and radial basis function (RBF) neural network models are set up to evaluate weld quality between the selected parameters and tensile-shear strength. Finally, the validity of the proposed models is certified. Results show that all of the models can be used to monitor joint quality. For the RBF neural network model, which is more effective for monitoring weld quality than the others, the average error validated is 2.88% and the maximal error validated is under 10%. __________ Translated from Chinese Journal of Mechanical Engineering, 2006, 42(10): 176–181 [译自: 机械工程学报]     

A novel decoupling approach to an integrated optical-fiber proximity sensor for robots

The structure and the working principle of a self-compensational integrated optical-fiber proximity sensor that detects distance and orientation are introduced in this paper. The corresponding decoupling approach to the sensor is presented on the basis of multiscale characteristics. The decoupling process can be divided into two parts: classifying the information on the basis of the multiscale degree and solving the coupling equation via the computational approximation methods with different precisions. Finally, the principle, the physical meaning, and the implementation process of the approach are discussed. They indicate that the proposed approach is real-time and accurate, and can be applied to other similar circumstances. Translated from Journal of South China University of Technology (Engineering and Technology Edition), 2006 (7): 21–25 [译自: 华南理工大学学报(工程技术版)]     

Analysis of actuating mechanics characteristics for a flexible miniature robot system

Based on the inchworm movement, a miniature endoscope inspection robot system with a flexible structure is designed. The system is actuated by a pneumatic rubber actuator with three degrees of freedom, and it holds its position by air chambers. The actuating mechanics characteristics of the robot are analyzed. An electro-pneumatic pressure system is designed to control the motion of the robot. Results of the calculation and experiments are consistent, and the robot system can move smoothly in a soft tube. __________ Translated from Chinese Journal of Scientific Instrument, 2007, 28(1): 7–11 [译自: 仪器仪表学报]     

A measurement system for thin elastohydrodynamic lubrication films

An elastohydrodynamic lubrication (EHL) film measurement system using multi-beam interferometry is introduced in this paper. The measurement principle and the instrumentation are discussed. A simple and efficient method is suggested to obtain the fringe order of measured points. It is demonstrated that the presented measurement system can provide continuous measurement of lubricating films from nano to micro scales at a nano-level resolution, and can be used to investigate ultra-thin EHL films and tiny variations in EHL films. Translated from Tribology, 2006, 26(2): 150–153 [译自: 摩擦学学报]     

A novel soft-switching twin arc pulse MAG welding inverter

The high-speed double wire pulse metal-gas arc (MAG) welding process possesses advantages of automation and high efficiency and quality. Thus, it attracts much more attention nowadays. To meet the requirements of the double wire pulse MAG welding process, a novel double wire pulse MAG welding inverter integrated with technologies, such as soft-switching, double closed loop control, and synchronic control, is produced. A complete performance test was done for the pulsed MAG welding power supply by using a computer testing platform. The results of the experiment indicate that the novel welding inverter has an excellent performance both in the dynamic and the static characteristics. Also, the synchronic control between the master inverter and the slave inverter is reliable. Translated from Journal of South China University of Technology (Natural Science Edition), 2006, 34(7): 31–34, 59 [译自: 华南理工大学学报 (自然科学版)]     

Basic model study on efficiency evaluation in collaborative design work process

During the efficiency evaluation process of collaborative design work, because of the lack of efficiency evaluation models, a basic analytical model for collaborative design work efficiency evaluation is proposed in this paper. First, the characteristics of the networked collaborative design system work process were studied; then, in accordance with those characteristics, a basic analytical model is created. This model, which is built for centralized collaborative design work, includes an analytical frame, a process view model, a function view model and an information view model. Finally, the application process and steps of this basic analytical model are elaborated when used for efficiency evaluation through an experiment. __________ Translated from Modern Manufacturing Engineering, 2006, (9): 19–22 [译自: 现代制造工程]     

Internet-Based Collaboration System: Press-Die Design Process for Automobile Manufacturer

To survive in a severe competitive environment, manufacturing enterprises must accomplish objectives such as cost reduction, quality improvement and short time-to-market. Also, as the manufacturing environment becomes more globalised and distributed, it is important to manage the workflow harmoniously and to share the information efficiently among geographically dispersed users. In this research, we propose a collaborative design and engineering system, which manages various design processes in an integrated manner and enables the sharing of design information. Because design information is usually very large in its size, it is very difficult to synchronise the individual design data of each designer with the entire design data. As a solution for efficient data sharing among the designers in networks, CORBA can be applied to synchronise the states of the design information. If one user modifies design data on his/her computer, this operation is detected and transmitted to other users who are related with the design modification. A receiver’s computer automatically synchronises its data with the sender’s message. In this paper, an Internet-based collaboration system for a press-die design process for automobile manufacturers is developed with CORBA, Java, Java3D and a relational database system. After modelling a practical press-die design process with the UML language, workflow routing paths are created by the modelling data. Cost and time for design can be estimated by the concurrent quasi-procedural method. The system developed can notify design modification to users when it is required, and enables users to share design models and analysis results. Designers can exchange opinions about common design matters by the conferencing function of the system. ID="A1" Correspondence and offprint requests to: S. H. Kong, Automatic Control Research Centre, Seoul National University, San 56–1, Shin-lim-dong, Kwanak-ku, Seoul 151–742, Korea. E-mail: silkysix@snu-.ac.kr     

Development of meso-scale milling machine tool and its performance analysis

To overcome the shortcomings of current technologies for meso-scale manufacturing such as MEMS and ultra precision machining, this paper focuses on the investigations on the meso milling process with a miniaturized machine tool. First, the related technologies for the process mechanism studies are investigated based on the analysis of the characteristics of the meso milling process. An overview of the key issues is presented and research approaches are also proposed. Then, a mesoscale milling machine tool system is developed. The subsystems and their specifications are described in detail. Finally, some tests are conducted to evaluate the performance of the system. These tests consist of precision measurement of the positioning subsystem, the test for machining precision evaluation, and the experiments for machining mechanical parts with complex features. Through test analysis, the meso milling process with a miniaturized machine tool is proved to be feasible and applicable for meso manufacturing. __________ Translated from Chinese Journal of Mechanical Engineering, 2006, 42(11): 162–167 [译自: 机械工程学报]     

Process Planning Support System for Green Manufacturing and its application

Owing to a lack of practical methods and software tools in the existing researches on green manufacturing (GM), process planning support system for green manufacturing (GMPPSS) was developed to deal with the problems in optimization of environment-benign process planning. The GMPPSS consisted mainly of three function modules and related model repositories including: selection of process elements, optimization of process courses, and evaluation of process projects for GM. The database of the GMPPSS was used to provide plentiful information on resources consumption and environmental impact in manufacturing processes, which consisted of process attribute database, inventory database, machine database, tool database, and the cutting fluid database. Raw materials, secondary material consumption, energy consumption, and environment impacts of process planning were optimized to improve the green attribute of process planning of parts with the supports of the databases and model repositories. The gear processing in the machining tool factory was presented to verify the system’s applicability. __________ Translated from Computer Integrated Manufacturing System, 2005, 11(7): 975–980 [译自: 计算机集成制造系统]     

New method for computer numerical control machine tool calibration: Relay method

Relay measurement method, which uses the kilogram-meter (KGM) measurement system to identify volumetric errors on the planes of computer numerical control (CNC) machine tools, is verified through experimental tests. During the process, all position errors on the entire plane table are measured by the equipment, which is limited to a small field. All errors are obtained first by measuring the error of the basic position near the original point. On the basis of that positional error, the positional errors far away from the original point are measured. Using this analogy, the error information on the positional points on the entire plane can be obtained. The process outlined above is called the relay method. Test results indicate that the accuracy and repeatability are high, and the method can be used to calibrate geometric errors on the plane of CNC machine tools after backlash errors have been well compensated. __________ Translated from Journal Huazhong University of Science and Technology (Nature Science Edition), 2005, 33(11): 60–62 [译自: 华中科技大学学报(自然科学版)]     

Analysis of stability and nonlinear response of rotor system with elliptical sliding bearing supports

Based on the variational constraint approach, the variational form of Reynolds equation in hydrodynamic lubrication is revised continuously to satisfy certain constraints in the cavitation zone of oil film field. According to the physical characteristic of oil film, an eight-node isoparametric finite element method is used to convert the revised variational form of Reynolds equation to a discrete form of finite dimensional algebraic variational equation. By this approach, a perturbance equation can be obtained directly on the finite element equation. Consequently, nonlinear oil film forces and their Jacobian matrices are calculated simultaneously, and compatible accuracy is obtained without increasing the computational costs. A method, which is a combination of predictor-corrector mechanism and Newton-Raphson method, is presented to calculate equilibrium position and critical speed corresponding to Hopf bifurcation point of bearing-rotor system, as by-product dynamic coefficients of bearing are obtained. The timescale, i.e., the unknown whirling period of Hopf bifurcation solution of bearing-rotor system is drawn into the iterative process using Poincaré-Newton-Floquet method. The stability of the Hopf bifurcation solution can be detected when estimating Hopf bifurcation solution and its periods. The nonlinear unbalanced T periodic responses of the system are obtained by using PNF method and path-following technique. The local stability and bifurcation behaviors of T periodic motions are analyzed by Floquet theory. Chaotic motions are analyzed by Lyapunov exponents. The numerical results revealed the rich and complex nonlinear behavior of the system, such as periodic, quasiperiodic, jumped solution, chaos, and coexistence of multisolution, and so on. __________ Translated from Chinese Journal of Mechanical Engineering, 2006, 42(4): 88–95 [译自: 机械工程学报]     

Optimization model for rotor blades of horizontal axis wind turbines

This paper presents an optimization model for rotor blades of horizontal axis wind turbines. The model refers to the wind speed distribution function on the specific wind site, with an objective to satisfy the maximum annual energy output. To speed up the search process and guarantee a global optimal result, the extended compact genetic algorithm (ECGA) is used to carry out the search process. Compared with the simple genetic algorithm, ECGA runs much faster and can get more accurate results with a much smaller population size and fewer function evaluations. Using the developed optimization program, blades of a 1.3 MW stall-regulated wind turbine are designed. Compared with the existing blades, the designed blades have obviously better aerodynamic performance. __________ Translated from Journal of Shantou University (Natural Science), 2006, 21(1): 44–49 [译自: 汕头大学学报 (自然科学版)]