基于磁通门的三轴电子罗盘自动误差补偿方法

该方法以自制的小型三轴磁通门航向系统为基础,加入MEMS三轴加速度计,形成了三轴电子罗盘的硬件结构。针对电子罗盘的罗差容易受到环境影响的特点,研究了自动误差补偿方法。首先对加速度计进行校准,其次采用基于椭球拟合的算法进行磁通门罗差的自动补偿,在剩余误差分析的基础上,利用加速度计的输出用递推最小二乘的方法对剩余误差进行了自动补偿。室温下实验结果表明该方法不仅方便有效,而且电子罗盘的误差从15°降低至2°内,在大倾角(60°)情况下也能保持较好精度。     

一种新的电子罗盘校准算法研究

针对复杂磁环境下磁强计误差补偿算法效果不理想而导致电子罗盘精度较低的问题,本文对磁强计的误差来源进行了详细分析与建模,提出了一种基于模拟退火算法(SA)的空间椭球磁强计校正方法,采用模拟退火算法,对磁强计测量数据进行空间椭球拟合,用估计的参数进行刻度系数与软磁干扰、硬磁干扰与零点偏移的整体误差补偿。最后,利用最小二乘法求解出非正交轴的方向余弦,进行非正交误差和安装误差补偿。最终利用设计的算法对某电子罗盘系统进行了航向角误差对比试验,实验结果表明该方法能准确计算出磁强计的误差参数,实测航向角精度从4.5°提高到0.4°,提高了一个数量级。该方法在电子罗盘的校准中具有了一定的工程参考价值。     

三轴电子罗盘的设计与误差校正

介绍了三轴电子罗盘的测量原理.利用各向异性磁阻传感器和加速度传感器研制了带倾斜补偿功能的三轴电子罗盘,并论述了电子罗盘的硬件设计和软件流程.针对电子罗盘传感器的误差特点,采用十二位置标定法实现了罗盘的校正.在罗盘处于不同倾斜的情况下进行圆周测试,经误差校正和倾角补偿后的轨迹是大体重合的圆,有效降低了罗盘误差.在某些具备翻滚条件的应用场合,该校正方法还可有效补偿电子罗盘的罗差.     

电子罗盘水平状态下航向角误差补偿算法的研究

针对电子罗盘测量时存在传感器的零位、灵敏度误差和干扰磁场引起的航向角误差问题,应用一种航向角误差补偿算法进行校正;在分析了电子罗盘航向角测量的工作原理、航向角误差形成原因的基础上,详细阐述了该补偿算法的实现原理,并通过LbVIEW软件仿真验证;同时设计了两种测量方案和测试系统,利用HMC1043芯片的电子罗盘进行多次实测验证并得出结论;实验结果表明:补偿后电子罗盘测量的航向角误差在4.5°以内;该补偿算法补偿效果良好,实现简单。     

无航向基准条件下电子罗盘的误差补偿方法研究

针对HMR3300电子罗盘在实际使用时,航向角测量精度低问题,探讨有效的磁差补偿方法.在分析电子罗盘航向角测量误差产生机理的基础上,建立了无航向基准条件下电子罗盘的误差校正模型,推导了自差补偿系数的计算公式,实验结果表明该补偿方法是正确有效的,可将HMR3300的航向角测量误差控制在0.5°之内.     

基于倾斜补偿和磁补偿的三维电子罗盘研究

将传统的水平电子罗盘通过倾斜补偿算法延伸至空间电子罗盘,再经过椭球拟合校准法对罗盘的硬磁、软磁、比例系数及未对准误差进行补偿,形成完整的电子罗盘使用规范,最后,实物对比实验给出基于HMC5883磁阻传感器与ADXL345捷联的三维电子罗盘精度为1°.     

三轴磁阻电子罗盘的设计和误差补偿

设计了一款具有倾斜补偿功能的三轴磁阻电子罗盘,并对样机系统做了误差补偿。本系统以磁阻传感器HMC1043和MEMS加速度传感器ADXL203为信号采集模块,以MSP430F149单片机为信号处理模块,分别获取、处理磁场和重力加速度信息,并通过液晶显示模块LCM6432ZK显示载体的航向角和姿态角。结合经典的椭圆假设法和傅里叶级数模型,对系统的误差进行补偿。实验结果表明,设计的磁阻电子罗盘实现了集成化和智能化,能实时显示载体的航向角和姿态角,航向误差可稳定在±0.6°以内。     

旋翼飞行机器人磁罗盘误差分析及校准

以旋翼飞行机器人组合导航系统为研究背景,针对电子磁罗盘的误差校准方法进行研究.通过分析其测量原理和误差来源,总结出影响磁罗盘航向解算精度的5个主要误差因素.对于上述误差因素,提出了软件和硬件解决办法.考虑到旋翼飞行机器人平台的特殊性,提出了硬磁罗差和标度因数误差的简化校准实现方法,简化后的磁罗盘校准方法,免去了校准过程中将载体竖起的步骤,且不降低校准精度.实际的磁罗盘校准测试表明,本文提出的方法能避免将大尺寸的载体竖起,降低校磁操作的难度.该方法可以有效地修正原始磁场测量值的椭球分布,从而提高组合导航系统航向解算精度.     

基于RBF神经网络的全姿态磁航向误差建模与补偿

对磁罗盘系统误差和目前多数文献所提出的全姿态磁航向误差补偿方法的不足进行了分析.针对具有一定俯仰角或横滚角的磁罗盘系统磁航向误差建模和补偿问题,提出了基于径向基函数(RBF)神经网络的修正方法,并与BP神经网络方法进行了比较.在分析算法原理的基础上进行了实验仿真,结果表明:采用RBF神经网络在明显提高网络收敛速度的基础上,大大减小了全姿态磁航向误差,校正效果优于BP神经网络.     

基于遗传算法的数字罗盘误差补偿方法研究

提高地磁导航精度的关键在于地磁罗盘的误差补偿,本文通过分析数字罗盘误差产生的原因,提出一种基于遗传算法的误差补偿方法,通过遗传算法的交叉、变异、选择等过程,对罗盘误差补偿参数进行优化,算法克服了传统方法的局部最优问题,达到一种全局最优化。实验结果表明:该算法可以有效修正环境磁场误差,将平均误差由补偿前的10.81°降低到0.53°,补偿后的罗盘可以为地磁导航提供更为精确的航向信息。     

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.