基于精密离心机的三轴硅微谐振加速度计标定方法

为更准确辨识三轴硅微谐振加速度计的误差系数,提高加速度计在飞行器上的加速度矢量测量精度,设计基于精密离心机的加速度计标定方法。分析硅微谐振加速度计的工作原理及误差项,在考虑离心机主要误差源的基础上建立包含零位偏移、标度因数、非正交安装误差、二次项误差与横向灵敏度的硅微谐振加速度计误差模型;设计离心机匀角加速度旋转的三姿态标定方法,在径向轴高g输入的同时,增加角加速度激励,可以更好标定加速度计横向灵敏度;对所提出的标定方法进行仿真,通过最小二乘法完成模型参数辨识。仿真结果表明,参数辨识相对误差可控制在2%以内,二次项系数与横向灵敏度辨识精度均小于1μg。     

基于谐波分析的捷联惯导系统加速度计组件标定技术

惯性器件误差是影响捷联惯性导航系统(SINS)精度的主要原因之一,任何由加速度计和陀螺构建的SINS在使用之前都须进行精确标校,以建立起惯性器件静态误差补偿模型。首先根据三轴加速度计组件的输出建立起加速度计输出模型;然后利用三角谐波的正交特性,设计了1 g重力场下的多位置转台翻滚试验,分离出加速度计组件的各项静态误差系数的解析表达式;最后,分析了由基准误差引入的参数标定误差。利用双轴位置转台对标定方法进行验证,结果证明此方法能够有效标定出三轴加速度计组件的刻度因数、交叉耦合系数和零位偏置,满足系统设计指标要求。     

基于双轴转台的加速度计自动测试方法设计与实现

为了降低加速度计测试成本,简化标定方法,对加速度计在双轴转台上的测试标定方法进行了研究,组建了一个双轴转台测试系统,系统使用NI USB-9239进行模拟数据采集,依据上述系统提出了一套测试标定新方法,并且设计了一套能进行自动化测试的软件;系统能测试出加速度计的标度因数、三阶非线性模型的各项系数、零偏、零偏稳定性和零偏重复性等参数;选用一种MEMS加速度计进行了测试,对提出的测试标定方法和软件自动测试功能进行了验证,试验过程和测得的参数数值表明软件测试自动化程度较高、测试标定方法实用可靠。     

一种基于改进型自适应遗传算法的MEMS三轴加速度计标定方法

针对目前加速度计标定存在依赖于昂贵的转台设备或标定算法复杂、标定参数不完全的问题,研究了一种基于改进型自适应遗传算法的加速度计标定方法。首先,对加速计误差模型进行了分析,构建了基于模标定原理的目标函数。其次,利用优化搜索区间和采用改进型遗传算子的自适应遗传算法对目标函数进行寻优,以提高标定参数寻优的速度和精度。最后,24位置仿真实验表明:标定参数的相对误差对比经典牛顿法略小,实际MEMS加速度计标定实验结果表明:本文方法与经典牛顿法相比,模值RMSE降低了22.2%,模值误差波动范围0.46mgn。     

微机电加速度计的六位置标定

加速度计是惯性导航系统测量载体加速度和影响惯性导航系统精度的主要元器件.为提高惯性导航系统的精度,在使用加速度计以前需要进行加速度计的标定测试[1].主要介绍了微机电(Micro Electro Mechanical Systems,简称MEMS)加速度计的六位置标定法,以便从MEMS加速度计的误差模型中分离出MEMS加速度计的各项标定参数.这些参数包括MEMS加速度计的标度因数、零位漂移以及安装误差系数.并且在得到MEMS加速度计的各项标定参数后将其封装在C函数中进行了验证实验.实验结果表明MEMS加速度计的六位置标定法的原理简单并且在工程应用中容易实现,所得到的MEMS加速度计的输出不但反映了MEMS加速度计的实际输出,而且使MEMS加速度计的线性度得到改善.     

基于多元回归模型的捷联惯性测量组件标定技术

应用多元统计分析方法,对捷联惯性测量组件(SIMU)的系统标定技术进行了研究.在考虑加速度计横向灵敏度影响的情况下,将SIMU加速度计组件视为一个整体,提出了SIMU加速度计组件的多元回归模型,并且给出了模型参数的估计公式.多位置标定及静态测试实验结果表明,采用多元回归分析可有效地标定出加速度计组件的刻度系数矩阵、等效安装误差矩阵和等效零位偏置向量.     

基于递推最小二乘法加速度计信息辅助的磁力计标定方法

由于MEMS磁力计自标定过程无法实现与MEMS加速度计间未对准误差的估计,提出一种利用加速度计矢量作为辅助信息,对磁力计的误差参数及磁力计与惯性单元间的未对准误差参数的一步估计方法。首先.对加速度计进行标定处理;然后,利用加速度计和磁力计间点积不变的性质,构造误差参数模型;最后通过递推最小二乘法完成对误差参数的迭代求解。通过仿真与实验对本文提出方法进行了验证,结果表明,本文提出方法估计出的磁力计误差参数的误差在10-4量级,标定后的磁力计与加速度计所在的惯性单元间的旋转角稳定在苏州磁倾角47.5°附近,完成了误差参数的一步估计。且迭代计算效率较高,相比于最小二乘法计算速度,在5秒钟左右就完成了对误差参数的估计,更适用于现场标定。     

基于LabVIEW的加速度计模型参数辨识模块设计

加速度计的模型参数辨识对研究加速度计动态特性具有重要作用.针对加速度计动态特性测试系统中加速度计模型参数辨识模块的设计,利用LabVIEW图形化编程的特点,以最小二乘原理为基础,通过对加速度计频域响应函数的拟合实现了加速度计模型参数的辨识,并构建了可视化软面板.实验测试表明:所设计模块能够实现加速度计模型参数辨识,有较高的参数辨识精度,并具有良好的人机交互,所辨识出的模型能够描述加速度计的动态特性.     

石英加速度计零偏非线性集成预测

基于小波变换(WT)的多尺度分析能力和径向基函数(RBF)神经网络良好的非线性预测与集成能力,研究了一种非线性集成预测方法.针对贮存期石英挠性加速度计零偏漂移抑制的问题,提出了基于WT和RBF神经网络的一种石英挠性加速度计零偏非线性集成预测方法.为验证所提方法的有效性,设计了一种加速度计参数的重力场标定实验,并针对某型号石英挠性加速度计进行了为期2年的标定实验.分别利用所提WT-RBF集成模型和RBF模型对零偏标定序列进行了预测分析,仿真结果显示:WT-RBF集成模型具有更好的预测性能.     

MEMS数字倾角仪的标定补偿方法研究

在介绍MEMS数字倾角仪组成结构的基础上,根据数字倾角仪内部MEMS加速度计的输出特性,对MEMS加速度计的敏感单元建立数学标定模型,提出并推导了一种适用于MEMS数字倾角仪的标定方法;该方法可以得到双轴MEMS数字倾角仪中加速度计的零位电压、标度因数矩阵、安装误差系数等敏感项参数;通过重力场静态翻转实验对实验室研制的数字倾角仪进行标定;最后使用MATLAB拟合计算得到所求标定参数,并对测试结果进行了误差分析和补偿对比;实验结果表明,该方法能使MEMS数字倾角仪的测量精度提高到±0.05°,可以满足高精度的角度测量需求。     

Reusing specifications in OO applications

Work on the ESPRIT Ithaca project has produced a model and environment for reusing specifications. Central to the environment is Recast, a tool to retrieve reusable specifications from a repository of development knowledge. Developers can also use Recast to tailor existing specifications to suit the current application. The tool, Recast (Requirement Composition and Specification Tool), supports developers in composing reusable specifications from the repository. The examples in this article are taken from the office application     

Verifying task-based specifications in conceptual graphs

A conceptual model is a model of real world concepts and application domains as perceived by users and developers. It helps developers investigate and represent the semantics of the problem domain, as well as communicate among themselves and with users. In this paper, we propose the use of task-based specifications in conceptual graphs (TBCG) to construct and verify a conceptual model. Task-based specification methodology is used to serve as the mechanism to structure the knowledge captured in the conceptual model; whereas conceptual graphs are adopted as the formalism to express task-based specifications and to provide a reasoning capability for the purpose of verification. Verifying a conceptual model is performed on model specifications of a task through constraints satisfaction and relaxation techniques, and on process specifications of the task based on operators and rules of inference inherited in conceptual graphs.     

异构分布式对象互操作模型研究

分布式对象技术,如EJB(EnterpriseJavaBeans)、CORBA(CommonObjectRequestBrokerArchitecture)、COM(CommonObjectModel),允许运行在一台机器上的对象被不同计算机上的客户端应用程序使用。该文在研究上述三种主流分布式对象标准及其两两互操作技术的基础上,提出了一种三种标准间互操作的模型及总体设计,并实现了桥中当已经得到某种标准的客户调用请求后对另外标准对象的调用。     

Analogical reuse of requirements specifications: A computational model

Specifications of requirements for new software systems can be revised, refined, or completed in reference to specifications of requirements for existing similar systems. Although realized as a form of analogical problem solving, specification by reuse is not adequately supported by available computational models for detecting analogies. This is chiefly due to the following reasons: (1) It is assumed that specifications are expressed according to the same specification model and in a uniform representation scheme. (2) Additional information is needed for the detection of analogies, which is not contained in the specifications. (3) Performance scales poorly with the complexity of specifications. This article presents a computational model for detecting analogies, which addresses these issues to a certain extent. The application of the model in the specification of requirements by analogical reuse is demonstrated through an example, and its sensitivity to the representation of specifications is discussed. Finally, the results of a preliminary empirical evaluation of the model are reported.     

Forming telecommunications software specifications from a service-driven model using enhanced software tools

Increasing diversity and sophistication among telecommunications customers has led to pressure on the telecommunications industry to give customer groups the capability to customize aspects of offered telecommunications services for their own particular needs. To offer such user-customizable services correctly, quickly, and cheaply, the telecommunications industry needs adequate techniques for transforming user requirements into software specifications and for realizing these software specifications with application code. In today's environment, several well-known software development life cycle processes exist for realizing software specifications; however, analogous techniques for transforming user requirements into explicit software specifications do not. This paper proposes a technique for transforming user requirements and then demonstrates its use on a sample telecommunications application. The technique creates a simulation environment that lets simulation users describe their application requirements and then determine the appropriate software specifications needed. The technique builds on aspects of a service-driven specification model and simulation software tools published earlier. Because the simulation environment derives from user requirements and produces software specifications, the proposed technique could represent the first phase of a service-driven software development life cycle process, eventually evolving from the nonservice-driven “requirements analysis” phase commonly used in practice today.     

A protocol modeling and verification approach based on aspecification language and Petri nets

An approach for automated modeling and verification of communication protocols is presented. A language that specifies the input/output behavior of protocol entities is introduced as the starting point of the approach, and verification of the linguistic specifications is discussed. Rules for conversion of the specifications into a Petri net model (based on a timed Petri net) are presented and illustrated by examples. This leads to a second level of verification on the net model. The approach is illustrated by its application to a part of the LAPD protocol     

A formal application model for code and test generation

The considered model is used in manual development of application specifications and is based on the Letichevsky theory of basic protocols and a respective symbolic verification tools. Means to limit the behavioral characteristics of the model still matching the source requirements are discussed. If the model is verified successfully, the executable code of the application and the respective test code are generated from the model. The technique of using the developed model is described.     

Dynamic tape path alternation with novel rotary guider

To enable higher recording density and data access accuracy, controlling lateral tape motion within high precision specifications through calibrated tape tension control is one of many key focuses for extra high density magnetic tape drives. This paper presents a novel rotary actuation mechatronic system which regulates travelling tape tension in a modern tape drive by dynamically alternating its tape path through closed-loop controls. Effectiveness of the system was demonstrated through calibrated laboratory parametric studies from which variation of travelling tape tension was found to be significantly reduced. The work described herein suggests engineering feasibility of using flangeless guiders in modern advanced tape drives as well as tape tension control without regulating tape drive??s driving motors.     

一种基于角色访问控制模型的约束规范描述

传统的访问控制主要有自主型的访问控制DAC(Discretionary Access Control)和强制型的访问控制MAC(Mandatory Access Control)。强制型访问控制是“强加”给访问主体的,即系统强制主体服从访问控制政策。自主型的访问控制是在确认主体身份以及它们所属的组的基础上,对访问进行限定的一种方法。随着企业规模的增大,企业的信息化管理变得越来越重要,企业级访问控制和安全管理设计将是最难解决的问题之一,DAC和MAC已不能满足需要。20世纪90年代