一种MEMS陀螺仪的标定方法研究

微机电系统(MEMS)陀螺仪的测量误差是影响微惯性导航系统精度的重要因素.为了提高微惯性导航系统的精度,提出了一种利用三轴转台完成MEMS陀螺仪的标定方法.根据MEMS陀螺仪的误差模型,设计了标定试验方案和误差模型参数的辨识方法,并通过小波阈值去噪的方法对陀螺的输出数据进行去噪处理.试验与仿真对比分析结果表明:经误差补偿和去噪后MEMS陀螺仪的测量精度提高1～2个数量级,同时验证了该标定方法的正确性、有效性.     

一种微惯性测量单元标定补偿方法

在介绍微惯性测量单元组成与结构的基础上,根据MEMS惯性器件的输出特性,建立了微惯性测量单元中加速度计和陀螺仪的数学标定模型,提出并推导了一种适用于微惯性测量单元的标定方法,该方法可以得到微惯性测量单元中惯性传感器的零位、标度因数、安装误差系数及g值敏感项等33个参数;然后,具体介绍了通过加速度计重力场静态翻滚试验和陀螺仪恒角速率试验对MIMU中参数标定的方法和步骤,并对实验室自研的MIMU进行了标定;最后利用得到的标定参数对测试结果进行了误差分析与补偿;实验结果表明,该方法使MIMU的测量精度提高了1～2个数量级,能够满足姿态解算及导航计算的精度要求。     

基于双轴转位机构的光纤陀螺标定方法研究

针对调制型捷联系统中光纤陀螺误差系数随时间变化的问题,提出一种利用双轴转位机构实现陀螺六位置静态标定方法.根据光纤陀螺仪误差模型,利用转位机构设计六位置标定路径,激励出陀螺仪标度因数、安装误差和零位,标定新方案避免了陀螺仪误差系数的耦合.分析了转位机构的转位误差对标定精度的影响,并利用调制型捷联系统导航实验对六位置标定方案进行原理性验证.结果表明,六位置标定方法所引起的系统定位精度优于传统标定方法.     

MEMS陀螺仪大失准角解耦测试方法的研究

针对传统陀螺仪测试方法不适用于MEMS陀螺仪测试的现状,分析了MEMS陀螺仪标度因数和输入轴失准角测试特点,在此基础上,提出了一种新的解耦测试方法;同时,设计了解耦测试夹具,并给出了解耦测试试验流程;最后采用MEMS陀螺仪典型试验参数进行了仿真.仿真表明,该方法实现了测试参数的解耦,提高了测量精度,适用于大输人轴失准角的MEMS陀螺仪.     

激光陀螺捷联惯导系统的误差参数标定方法

为降低激光陀螺捷联惯导系统误差参数标定对高精度转台的要求,在不精确对北和调平的情况下,综合分析北向基准误差、水平基准误差、转台轴正交度误差、角位置误差以及标定时间等诸多因素,考虑对称位置和整周期旋转等编排原则,改进了速率标定方案,标定出陀螺仪的标度因数和安装误差,同时提出了一种十二位置连续转动标定方法,标定出陀螺仪的零偏以及加速度计的误差参数项.实验结果表明,与传统方法相比,标定精度相当,降低了对标定转台的要求,减少了标定时间,有较高的工程应用价值.     

双轴旋转光纤捷联惯导八位置标定方法

针对双轴旋转捷联惯导系统长期工作时光纤陀螺误差参数随时间变化问题,提出一种姿态未知条件下的八位置标定方法.该方法利用双轴旋转机构可提供惯性测量单元(LMU)相对载体固定角位置特性,结合光纤陀螺简化误差模型,设计出八位置标定路径并激励出光纤陀螺误差参数.新的标定方法既避免了陀螺误差参数的耦合影响,又可以解算出载体航向信息.转台实验结果表明,八位置标定方法可在载体姿态未知条件下完成对光纤陀螺误差参数的标定工作.     

MEMS三轴数字陀螺仪标定方法研究

MEMS陀螺仪作为低成本惯性测量单元在物体姿态监测与导航控制中有着广泛应用.根据三轴数字陀螺仪的数学模型,设计了三轴数字陀螺仪的标定实验,介绍了数学模型中陀螺仪标度因数、安装误差系数以及零偏移值的计算与处理方法.理论分析与实验结果表明:该标定方法原理简单、易于实现,且标定结果精度高,标定后的解算矩阵可为后续姿态解算和导航控制提供较为准确的量测数据,同时,该标定过程和数据处理方法对MEMS三轴数字陀螺仪的标定具有一定的参考价值.     

四旋翼飞行器航姿参考系统的误差补偿方法研究

航姿参考系统是四旋翼飞行器姿态控制和惯性测量的关键,基于MEMS的惯性导航系统长期稳定性较差,陀螺仪传感器和加速度计存在明显的零漂现象,因此在使用前必须对陀螺仪传感器和加速度计的误差系数进行标定;论文首先以航姿参考系统的陀螺仪和加速度计实时数据的采集与处理,并通过对陀螺仪和加速度计的误差产生原理的分析,提出了陀螺仪和加速度计的新型误差补偿模型,并推导了基于高斯牛顿法的误差补偿与标定方法,由此简化了标定过程,得到了标定结果; 实验结果表明了在不提高成本和降低精度的情况下该基于高斯牛顿法的误差补偿与标定方法的有效性。     

改进的IMU传感器安装误差正交补偿方法

针对传统的正交补偿方法难以保证惯性测量单元具有较高的正交补偿精度的问题,提出了一种改进的适用于大角度和小角度安装误差角情形的正交补偿方法,该方法分别建立三轴加速度计和三轴光纤陀螺传感器的安装误差方程,对惯性测量单元进行速率标定和多位置静态标定,并利用最小二乘法求解惯性测量单元的安装误差方程参数.仿真和实验结果表明:该方法较传统的正交补偿方法具有较高的正交补偿精度和传感器标定精度,且回避了静态标定时在较大安装误差角下利用转位机构获得零偏存在较大误差的问题,大大地提高了标定效率.     

基于GUI的大量程MEMS陀螺仪快速标定设计

针对MEMS大量程陀螺仪量程较大,一般的标定设备达不到需要的转速,因此不适合用三轴位置速率转台标定。设计了一种新的标定设备,提出了一种适用于大量程微机电陀螺仪的标定方法,并设计了GUI操作界面。根据微机电陀螺仪的输出数学模型,推导了如何得到MEMS陀螺仪的零点和标定因数等参数。通过实验数据分析可知,大量程微机电陀螺仪标定设备可以标定20 r/s的大量程陀螺仪。该设备原理简单且易于实现,具有较高的应用价值。     

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.