基于PLC的位置控制系统的设计

设计的位置控制系统是由步进电机、旋转编码器、同步带、同步轮、标尺、指针及西门子S7-200CPU224组成。旋转编码器采集同步带的实际位置,以脉冲信号形式送给PLC,PLC利用高速计数器指令对脉冲进行计数,将所计的数值转换成实际位置并与给定位置相比较,用PID运算的结果输出给步进电机驱动器,控制步进电机转向和转速,带动同步带和指针移动,实现位置控制。多次试验证明,系统运行稳定可靠,其位置控制稳态精度≤±2mm。以57BYG250C型步进电机为例,文中给出了步进电机详细的硬件接线图及控制步进电机运行的梯形图。     

一种光电编码器精度自动检测系统

随着光电编码器的广泛应用,市场对其需求也逐渐增大。利用自准直仪－金属多面棱体对光电编码器精度检测的传 统手动检测方法具有检测效率低的缺点,严重制约了光电编码器生产效率的提高。针对上述问题,设计了一种光电编码器精度自动检测系统,MATLAB程序控制电机带动待测光电编码器同步旋转,通过对比待测光电编码器及电机运动角度的数据计算待测光电编码器的精度,实现光电编码器精度自动检测。系统采用沿面检测算法减小测量结果的分辨率误差,采用傅里叶谐波分析方法对电机转角误差进行修正,进而提高了检测精度,使用该系统对某型号的 16位光电编码器进行检测.实验结果显示该系统检测精度不大于±２″,该系统具有结构简单,检测精度高的优点,可提高光电编码器的生产和检测效率。     

电动执行机构中光电编码器脉冲波形问题的研究

介绍电动执行机构中光电编码器的结构、工作原理,以及如何实现光电编码器输出脉冲方波信号,论述光电编码器对电动执行机构产生的影响。     

步进电机控制系统的设计

系统由单片机产生数字脉冲信号,通过ULN2003驱动芯片控制电机的运行。由于脉冲信号的频率决定电机的转动速度,所以要改变转速就需要改变脉冲频率。系统采用定时中断的方法改变脉冲频率,而按键次数主要控制外部中断用以改变存储区中的速度值,步进电机的输出脉冲频率就发生相应的改变,最终达到改变转速的效果。     

基于光电传感器的风轮转速测定

介绍了一种利用光电传感器和STC89C52单片机快速测定风力发电系统风轮转速的方法.该测速系统的硬件主要包括单片机控制模块、传感器模块、显示模块和串口通信模块.光电传感器用于检测风轮叶片的存在与否,并输出相应的电平信号.单片机则对传感器的输出脉冲信号进行计数,然后推算出风力发电系统风轮的真实转速,并将结果输出至LCD.实验结果表明,该测速系统结构简单,成本低,测量准确,适用于尚未嵌入旋转编码器的风力发电系统.     

步进电机控制系统的设计及应用

基于DSP的步进电机控制系统采用了闭环控制方式,同时以光电编码器反馈检测信号以及专用大功率驱动芯片THB6064H的应用不仅简化了系统外围硬件电路结构,而且增强了系统的可靠性和抗干扰能力,并根据工程实际中出现的问题进行分析并且提出了具体解决措施。对系统的软硬件方案设计及部分外围电路进行了简要介绍,通过对步进电机位移的实时控制实现了数控机床中刀具进给的快速跟踪定位,对DSP在步进电机控制系统中的进一步开发应用提供了借鉴。     

基于DSP的四相步进电机控制系统设计

本系统拟采用DSP控制四相步进电机的设计。首先,系统主要控制器为TMS320F28335,采用DSP输出PWM脉冲波经过脉冲分配电路、光电隔离电路和功率放大电路来对步进电机进行驱动;其次,通过电流采样电路、A/D转换器和过电流保护电路控制步进电机,从而增强步进电机的稳定性、系统的可靠性和抗干扰能力;最后,无线控制模块控制步进电机的运行状态。对DSP 在步进电机控制系统中的进一步应用提供了借鉴。     

基于光电编码器的永磁球形电动机转子方位测量系统

设计了基于光电编码器的三自由度永磁球形电动机转子方位测量系统。介绍了永磁球形电动机的结构和球体方位描述方法。通过分析微分运动,推导出测量系统的误差矩阵,并对系统性能进行了分析。系统中,光电编码器的输出脉冲经硬件电路倍频、鉴相、可逆计数和存储后,由单片机进行计算,测得的转子方位由液晶显示器(LCD)实时显示并经串口发送到电机闭环控制系统中。实验验证表明:设计的测量系统的有效性。     

步进电动机原理及其驱动电路研究

步进电机是一种纯粹的数字控制电动机,又称为阶跃电机或脉冲电机。是一种受电脉冲信号控制的无刷式直流电动机,也可以看作是在一定频率范围内转速与控制脉冲频率同步的同步电动机。它能将输入电脉冲信号转换成机械的运动量加以输出。每一个主令脉冲都可以使步进电机的转轴前进一个步距角,并依靠它特有的定位转矩将转轴准确地锁定在空间位置上,在实际工程中有着广泛的应用,文章主要探讨了步进电动机原理及其驱动电路的特点。     

步进电动机原理及其驱动电路研究

步进电机是一种纯粹的数字控制电动机,又称为阶跃电机或脉,中电机。是一种受电脉冲信号控制的无刷式直流电动机．也可以看作是在一定频率范围内转速与控制脉冲频率同步的同步电动机。它能将输入电脉冲信号转换成机械的运动量加以输出。每一个主令脉冲都可以使步进电机的转轴前进一个步距角,并依靠它特有的定位转矩将转轴准确地锁定在空间位置上,在实际工程中有着广泛的应用,文章主要探讨了步进电动机原理及其驱动电路的特点。     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。