Mechatronic means for machine accuracy improvement

The paper deals with the mechatronic means for the accuracy improvement of metal cutting machines, co-ordinate measuring machines, robots, etc. The mechatronic correction means of raster scales, encoders errors and final 3-D position correction of a cutting instrument or touch probe are presented. The technical solutions are given with the application of active materials for smart probes and piezoactuators. A case of calculations for piezoactive raster plates is described together with volumetric control diagrams and the examples of practical implementation.     

复杂装备通信系统数据传输终端机检测系统设计

针对复杂装备通信系统数据传输终端机结构复杂,技术先进,部队技术保障难度大,缺乏维修保障设备的问题,设计了基于PCI总线结构,包含A/D、D/A、DI、DO接口模块,数字信号和模拟信号调理模块的数据传输终端机检测系统。该系统能够对数据传输终端机主要通信接口信号采集与处理,实现了2FSK信号和并行数字通信信号等数据传输终端机主要通信信号的检测。该检测系统为复杂装备通信系统数据传输机技术保障提供了实用的方法,对装备维修自动化水平的提高具有重要的意义。     

Evaluation of performance criteria of CNC machine tool drive system

The stability, steady-state error analysis, damping factor, and setting time of discrete data drives for computer numerical control (CNC) machine tools are analyzed to obtain the necessary information for the design of a practical system. The stability of the drive is reviewed using Jury's test and the Mitrovic criterion. The variation of damping factor and settling time with respect to system parameters are presented based on the Mitrovic criterion     

Quality-reliability chain modeling for system-reliability analysis of complex manufacturing processes

System reliability of a manufacturing process should address effects of both the manufacturing system (MS) component reliability, and the product quality. In a multi-station manufacturing process (MMP), the degradation of MS components at an upstream station can cause the deterioration of the downstream product quality. At the same time, the system component reliability can be affected by the deterioration of the incoming product quality of upstream stations. This kind of quality & reliability interaction characteristics can be observed in many manufacturing processes such as machining, assembly, and stamping. However, there is no available model to describe this complex relationship between product quality, and MS component reliability. This paper, considering the unique complex characteristics of MMP, proposes a new concept of quality & reliability chain (QR-Chain) effect to describe the complex propagation relationship of the interaction between MS component reliability, and product quality across all stations. Based on this, a general QR-chain model for MMP is proposed to integrate the product quality with the MS component reliability information for system reliability analysis. For evaluation of system reliability, both the exact analytic solution, and a simpler upper bound solution are provided. The upper bound is proved to be equal to the exact solution if the product quality does not have self-improvement, which is generally true in many MMP. Therefore, the developed QR-chain model, and its upper bound solution can be applied to many MMP.     

Mechatronic approach to the feeding system of an overlock sewing machine

This paper describes the initial study of the research program being carried out on the feeding system of an industrial overlock sewing machine. The results obtained from the displacement and compression force, together with the graphic kinematic analysis, which includes the velocity and acceleration taken from the displacement–time curves of the presser foot bar, led to further understanding of the feeding system dynamics. This study is expected to provide the basis for the development of a redesigned and optimised fabric feeding system, in which the role of an actuator integrated in the presser foot bar will also be discussed as a major contribution to achieving a desired dynamic behaviour at high sewing speeds.     

Economic analysis and optimization of tool portfolio in semiconductor manufacturing

The tool portfolio of a plant refers to the makeup, in quantity and type, of processing machines in the plant. It is determined by taking into consideration the future trends of process and machine technologies and the forecasts of product evolution and product demands. Portfolio planning is also a multicriteria decision-making task involving tradeoffs among, investment cost, throughput, cycle time, and risk. Tool portfolio planning is a complex task that has strong bearing on manufacturing efficiency. In the first part of this paper, a multicriteria economic decision model is presented for optimal configuration. of the portfolio and to determine the optimal factory loading. The second and third parts of the paper contain applications of the model. If plants are closely located or have a twin-plant design, portfolio planning at multiple plants can be integrated to enhance the overall effectiveness of portfolios. In the second part, a novel methodology for arbitrating capacity backup between plants is described. Because the economic model is constructed upon a valuation of both cycle time and throughput, it is a suitable method for the evaluation of cycle time reduction projects. The application procedure is outlined in the third part.     

A tool for the quantitative spatial analysis of complex cellular systems.

Spatial events largely determine the biology of cells, tissues, and organs. In this paper, we present a tool for the quantitative spatial analysis of heterogeneous cell populations, and we show experimental validation of this tool using both artificial and real (mammary gland tissue) data, in two and three dimensions. We present the refined relative neighborhood graph as a means to establish neighborhood between cells in an image while modeling the topology of the tissue. Then, we introduce the M function as a method to quantitatively evaluate the existence of spatial patterns within one cell population or the relationship between the spatial distributions of multiple cell populations. Finally, we show a number of examples that demonstrate the feasibility of our approach.     

基于振动信号处理技术的传动链误差分析

以某数控机床传动系统为研究对象,分析了该数控机床传动系统的动态特性。为进一步提高数控系统的可靠性,文章对机床轴系振动信号进行处理分析,研究了该数控机床的多轴同步性、动态传动链误差的测量、分析与溯源。     

AM光纤传输系统性能分析

1　ＶＳＢ -ＳＣＭ -ＡＭ光纤系统的噪声特性ＶＳＢ -ＳＣＭ -ＡＭ光纤传输中的主要噪声源如图 1所示。图 1　ＡＭ光纤传输中的主要噪声源分析整个系统的噪声特性 ,首先从ＰＤ的灵敏度和信噪比入手。当入射一个光子时 ,理想情况是它的能量ｈｆ能使一个电子跃迁入导带而成为载流子。但实际情况并非如此 ,产生电子数和入射的光子数的比例就是量子效率 ,用 η表示 ,则ＰＤ的输出电流可由下式给出 :Ｉ0 =ｅηｐｈｆ (1)(1)式还没有考虑到光被调制的情况 ,如果用调制度为ｍ的正弦波对光的功率进行调制时 ,信号电流的有效值由下式给定 :Ｉ=ｍｅｐ…     

Human-in-the-Loop Camera Control for a Mechatronic Broadcast Boom

Platforms like gantries, booms, aircrafts, and submersibles are often used in the broadcasting industry. To avoid collisions and occlusions, such mechatronic platforms often possess redundant degrees-of-freedom (DOFs). As a result, manual manipulating of such platforms demands much skill. This paper describes the implementation of several controllers that, by using computer vision, attempts to reduce the number of manually manipulated DOFs. Experiments were performed to assess the performance of each controller. A model for such a system was developed and validated. To determine how the visual servoing can improve the tracking, a novice operator and an expert were asked to manually track a moving target with the assistance of visual servoing. The results of these tests were analyzed and compared     

A method for analysis of complex transmission coefficients of symmetric matched two-ports

A method for generalized analysis of the transmission coefficients of symmetric matched two-ports is proposed. The method allows fast determination of the values of active and reactive components of input admittances of intrinsic one-ports for even-and odd-mode excitation of the two-port’s ports. The concept of an intrinsic coefficient of a symmetric two-port is introduced. The variation intervals of this coefficient are determined for dissipative, reactive, and dissipative-reactive two-ports.     

基于上限分析的机器学习系统最佳优化决策选择

本文的重点是使用上限分析法解决在机器学习系统开发中无法判断哪部分最值得优化的问题,以便于做出最佳的优化决策.以一个简单的图像文字识别系统为实例,对其的文字侦测、字符分割、字符识别三个部分使用上限分析法进行模拟,得出各个部分的潜在上升空间,然后比较对3个部分分别进行优化对最终预测结果的影响,从而了解该系统中已经达到"最高水平"的部分,做出最佳的优化决策,避免开发中资源的浪费.     

Performance optimization of a fast tool servo for single-pointdiamond turning machines

This paper describes a new, fast tool servo system designed for fabrication of nonrotationally symmetric components using single-point diamond turning machines. A prototype device, designed for flexible interfacing to typical machine tool controllers, is described, along with performance testing data of tilted flat and off-axis conic sections. Techniques for controlling the piezoelectric actuator to less than 1% error are discussed. The performance of a standard integral controller shows a significant error due to hysteresis in the actuator. The effects of the hysteresis were reduced by implementing two control schemes, an optimized PID controller and a technique that utilizes a dynamic compensator module in conjunction with the linear controller. The compensator samples the hysteretic voltage/displacement relationship in real time and modifies the effective gain accordingly. Experimental implementation results in an 80% reduction in the motion error caused by hysteresis, but peak-to-valley errors are limited by side effects from the compensation     

Mechatronic Design Quotient as the Basis of a New Multicriteria Mechatronic Design Methodology

A concurrent, integrated, and multicriteria methodology is presented for the conceptual design of mechatronic systems. It uses an evaluation model called mechatronic design quotient (MDQ) to facilitate decision-making in the design process. A nonlinear fuzzy integral is used for the aggregation of criteria in MDQ, thereby accommodating possible correlations among them. The performance of the developed methodology is validated by applying it to an industrial fish cutting machine called Iron Butcher-an electromechanical system that falls into the class of mixed or multidomain systems     

An approximate protocol analysis with performance optimization for WDM networks

In this study, our main goal is to investigate the performance optimization conditions for WDM networks. We introduce a network architecture of passive star topology that uses a Multi-channel Control Architecture (MCA) to avoid both the data channels and the receiver collisions. Especially, we propose a synchronous access scheme that exploits the propagation delay parameter in order to assign the data channels to the stations for successful data packet transmission. Thus, we achieve effective bandwidth utilization. An approximate analysis based on Poisson statistics is developed in order to explore the performance measures optimization. Finally, extensive comparative study is given for various stations populations and number of MCA channels.     

Detection of tool deflection in milling by a sensory axis slide for machine tools

Previous publications regarding the project Gentelligent Components for Machine Tools of the Collaborative Research Center 653 presented the design of a new sensory z-slide for a 5-axis machining center. Equipped with several strain sensors, the new slide is able to feel the machining process by measuring the process forces and vibrations. Here, a challenge is the detection of mechanical strains in the slide without degrading its high global stiffness. The application of micro strain gages in small notches on the slide represents a promising approach for the improvement of the sensitivity as well as the integration of sensors into the slide. This paper presents the utilization of the sensing axis-slide in a manufacturing environment. For this purpose, a first prototype of the slide is build and integrated into a milling center DMG HSC 55 linear. In this test machine, the dynamic characteristics of the integrated slide are identified with frequency response function measurements. Based on force measurements with a dynamometer, force calibration matrices are computed to calculate the forces in the machine coordinate system at the tool center point from the measured strain signals during milling processes. The force sensing with the slide allows furthermore the identification of tool characteristics such as the static tool stiffness. This parameter is estimated from the ratio of the measured contact forces and the set collision distance when moving the tool smoothly into the work piece. The known tool stiffness enables the detection of the static tool deflection from the force signals during a milling process. To compare the detected tool deflection with the real tool deflection, reference measurements on the work piece are performed using a perthometer. For further monitoring applications of the tool deflection in more complex 2.5D milling an approach to transform the measured forces from the stationary machine coordinate system into the moving tool coordinate system is presented.     

卧式数控机床对刀间隙自动检测系统设计

为了克服人工操作检测系统对刀间隙检测精度低的弊端,设计新的卧式数控机床对刀间隙自动检测系统。系统核心由光源、CMOS图像采集模块与自动检测模块构成,使用红色环形光源照射工件与刀具的间隙部位,CMOS图像采集模块通过CMOS摄像机采集间隙图像,并通过USB接口传输至自动检测模块,自动检测模块通过基于Hough变换的对刀间隙自动检测算法,对得到的间隙图像进行计算,获取刀具和工件的间隙值。经验证,所设计系统能够有效检测对刀间隙,且检测精度与检测鲁棒性优于同类检测系统,应用价值可观。     

基于虚拟现实技术的车床教学训练系统的研究

本文提出了一种针对机床虚拟仿真教学训练系统的开发方案,并介绍了该系统的结构设计和实现途径;利用UG建立了机床的三维实体几何模型,经格式转换和镜像修正解决了实体模型读入的问题;利用Quest3D三维引擎开发平台对场景进行实时驱动和人机交互控制,实现了虚拟场景交互操作;提出了通过建立简单包围模型来参与碰撞检测的方法.与以往类似系统相比,本系统开发方案对硬件要求低,开发周期短,具有潜在应用价值.     

Single-wafer cluster tool performance: an analysis of throughput

Cluster tools gained greater acceptance over the past several years, although concerns still exist over the throughput these tools can achieve. This paper presents an analysis of the relationship between process times, transport times, and maximum throughput in an individual cluster tool. Theoretical models which quantify the time required to process both an individual wafer and a lot in a cluster tool are developed. Three techniques for increasing throughput, based on these models, are also presented. These modifications require minimal modification of many existing designs and can yield significant increases in performance