高可靠性增量式光电编码器接口电路设计

针对目前增量式光电编码器辨向计数电路脉冲或抖动干扰抑制能力差的问题,提出了一种基于有限状态机的编码器接口电路设计方案,并给出了硬件实现。首先将光电编码器输出的A、B两路信号在每个脉冲周期内的电平变化细分为4个子段,总结出正、反向旋转时A、B信号电平的正常变化规律,并引入有限状态机方法进行描述;再利用状态机机制,检测出光电编码器输出的信号的各种有效、错误和无效状态,同时正确输出转速计数脉冲、旋转方向、出错报警3路信号,以满足高准确度和高容错性计数的要求,增强角位置测量系统的可靠性;最后介绍了采用EPROM完成状态机时序电路实现的具体方法。     

基于FPGA的增量式光栅信号采集系统设计

针对步进光刻机工作台对高精度定位信息的高速实时采集要求,利用高精度增量式光栅尺实现工作台位置测量,设计基于FPGA的增量式光栅信号采集系统整体结构。介绍光栅尺A、B脉冲信号的相位鉴定及脉冲计数方法,提出基于双模光纤介质的高速实时串行传输机制,介绍光纤通信内核的控制结构及其FPGA实现方法,实现信号采集卡与上位机控制卡的高速实时通信。增量式编码器数据采集实验结果表明,该系统具有高速、稳定可靠等优点。     

基于FPGA的旋转编码器抗抖动四倍频电路设计

本文分析了旋转编码器工作原理,设计了一种高精度抗抖动四倍频电路。它主要由鉴相电路、脉冲加减计数电路、抗干扰电路、抗抖动电路和四倍频电路组成。电路采用Altera公司生产的FPGA,利用VHDL语言设计,具有计数频率高、可同时对多个编码器信号进行记数的优点。QuartusⅡ7.2的仿真结果表明,该电路准确可靠,定位精度明显提高,能有效地消除抖动的影响。     

基于单片机和光电开关的通用计数器设计

目前光电开关在工业自动化设备中的运用越来越广泛,介绍的通用计数器使用红外光电开关作为检测元件,当有工件通过时,红外光被遮挡,光电开关会产生相应的脉冲信号,通过对脉冲信号进行计数,可以实现对工件的自动计数;该设计方法采用模块化设计方法,分为电源模块、光电转换模块、光耦隔离电路模块、断电保护模块、矩阵键盘模块、计数模块及显示模块;主要采用51单片机对各个模块进行控制,用keilC51软件进行程序设计,用Proteus软件对其进行仿真,最后通过实际搭建电路,实现准确地计数,证实该设计方案是可行的。     

基于单片机的光电编码器位置检测系统设计

为了实现对机床设备运行状态的实时监测,设计了一种基于单片机的光电编码器位置检测系统;系统采用高性能的AVR单片机对编码器的两相位置信号进行鉴相及四倍频处理,然后通过MCS-52单片机的T2计数器进行硬件计数,同时使用MCS-52单片机的串行端口将位置数据传送至上位PC机中;采用VB6.0软件设计上位机的监控界面,实时动态显示各种编码器的位置数据;试运行结果表明,该设计不仪电路简单,且计数精度高、响应速度快,达到150kHz,适用于各种位置及角度检测场合.     

基于Atmegal6单片机的重物提升控制系统设计

为了实现对重物提升的精确控制,设计中选择了以Atmegal6单片机为核心的控制系统。根据控制要求,提出了实施以单片机主、从结构的控制方式。重点介绍了用光电编码器作为传感器、对传感器输出的脉冲信号进行整形、鉴相后送入单片机计数的硬件电路和单片机对计数脉冲、设定位移量进行计算处理的软件程序,根据计算结果完成相应的智能化控制。     

基于Atmega16单片机的重物提升控制系统设计

为了实现对重物提升的精确控制,设计中选择了以Atmegal6单片机为核心的控制系统。根据控制要求,提出了实施以单片机主、从结构的控制方式。重点介绍了用光电编码器作为传感器、对传感器输出的脉冲信号进行整形、鉴相后送入单片机计数的硬件电路和单片机对计数脉冲、设定位移量进行计算处理的软件程序,根据计算结果完成相应的智能化控制。     

一种光电编码器用可编程计数电路的设计

设计了光电编码器用可编程计数电路，它主要由方向判别电路，双脉冲加减计数电路，输出缓冲电路，预置锁存电路，译码控制电路，F／V转换电路等组成，能输出光电编码器位置的16位数字量，旋转速度模拟量和旋转方向指示电平，具有目标位置设定，当前状态指示等功能，易于与微机的I／O数据采集卡相连接而实现可编程控制，实际应用结果表明，该可编程计数电路抗干扰能力强、工作稳定可靠，控制方便，具有很高的实用价值。     

基于ARM-Linux的旋转编码器接口与驱动程序的设计

针对ARM-Linux平台下对旋转编码器脉冲计数研究较少的问题,完成了在AT91 RM9200处理器和Linux2.6内核下旋转编码器的脉冲计数电路接口和驱动程序的开发.根据旋转编码器的基本工作原理,用AT91RM9200处理器的PIO中实现了脉冲辨向及加减计数电路,利用Linux字符设备驱动编写的基本方法在CE9200-3开发平台上进行了驱动和应用程序的设计.实验结果表明,方案切实可行,稳定性、实时性好,功能丰富,实现了ARM-Linux下的对旋转编码器支持,并已应用在材料冲击试验机嵌入式控制系统中.     

基于Fuzzy—PID嵌入式平台调平控制器设计

为提高惯性平台调平精度、缩短调平时间,采用FPGA嵌入式技术,运用Fuzzy-PID控制算法,设计完成了平台调平控制器设计;通过电压—频率转换电路将平台加速度计输出的误差电压信号转换为成比例的脉冲串,FPGA对脉冲进行计数,通过内部的Fuzzy-PID控制逻辑,输出占空比可调的PWM波控制作用于陀螺力矩的脉冲电流,实现平台精确调平;实验结果表明该调平控制器能够实现平台全工作角度范围内(—60°~60°)调平,且调平精度小于2角分,调平时间小于10s,相较现有武器系统,调平精度提高10%,调平时间缩短30%。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.