并联6—SPS机器人的影响系数及其应用

本文根据并联机构的特点,对位置反解直接求导,建立了并联6-SPS 机器人的一、二阶影响系数矩阵,解决了速度分析和加速度分析问题.为机器人的误差分析和动力学分析奠定了基础.所得的一、二阶影响系数矩阵的形式简单统一,特别实用于计算机计算.最后给出了实例计算.     

4-RP(RR)R并联机器人运动仿真

该文给出一个新型的少自由度并联机器人机构4-RP（RR）R的动态仿真。文中对此机构进行了反解分析,确立了此机构运动平台的位置输出与移动副输入及各空间顶点位置的关系。在此基础上,利用Matlab软件模拟出实物动态图,并对利用几何分析法做出的速度曲线、加速度曲线与利用虚设影响系数法求出的速度曲线、加速度曲线进行分析比较,进一步说明了机构本身的运动特性,以及虚设影响系数法对少自由度并联机器人机构4-RP（RR）R求解的正确性。     

位置误差条件下多运动站无源跟踪PCRLB

在无源跟踪中通常假设目标运动模型为离散白噪声加速度模型,此时状态协方差矩阵奇异,通用的后验克拉美罗限(PCRLB)求解方法失效。另外,观测站位置误差可能对目标无源跟踪性能带来较大影响。对此,首先将状态变量分成非奇异的位置和速度两部分;然后通过构造中间向量得到PCRLB的通用表达式,进而推导了观测站存在位置误差时的PCRLB;最后以多运动站只测角跟踪为例对PCRLB进行了仿真分析,结果表明,所推导的PCRLB计算式可为算法设计提供理论指导。     

五坐标数控技术的联动原理

本文通过对五坐标数控技术的坐标运动规律进行分析研究,揭示了五坐标数控技术的联 动原理.即建立了从CAD中的理想轨迹的几何特性(包括位置、切矢、曲率)和五坐标联动的 运动动力学特性(包括位移、进给速度、各坐标理想速度和加速度)之间的通用数学模型.从 而可根据被加工零件表面的几何形状和机床的进给速度确定联动过程中各坐标的理想速度 和理想加速度.     

基于螺旋理论的水下机器人矢量推进球面并联机构的运动学建模

为设计结构简单、具备旋转运动传递和空间姿态调整双重功能的水下机器人推进机构,采用构造过约束并联机构的方法设计了一种3自由度球面并联矢量推进机构.基于螺旋理论构建了机构的拓扑结构模型,分析了机构的运动特性,计算了机构的位姿正、逆解.在闭链约束方程的基础上运用矢量代数法推导出了机构的雅可比矩阵.利用特征结构配置的解耦法建立了机构速度和加速度的解析模型,并进行了相应的数值算例分析,计算了机构的运动学正、逆解,得到了可达工作空间,并用仿真软件Adams验证了数值计算方法的正确性.设计的矢量推进机构具有较大的偏转范围.     

战地机器人步行腿机构研究

本文研究一种用作机器人步行腿的闭式运动链八杆机构,讨论了该机构的特点,对各构件尺寸进行了初步优化。在此基础上,用拆杆拆副法进行了该机构末端件的相对轨迹仿真、机器人行走时末端件的绝对轨迹及机器人本体运动轨迹的仿真;并进行了速度、加速度分析。文末附有机构运动简图、相对轨迹。绝对轨迹及速度、加速度线图。研究结果表明;该机构用作机器人步行腿机构是较合适的。根据初步优化尺寸研制的模型经试验证明基本成功。     

用CAD约束和尺寸驱动技术分析平面机构的运动

提出用CAD约束和尺寸驱动技术分析平面机构的运动。采用CAD的几何约束、尺寸约束、尺寸方程和尺寸驱动技术，构造一些典型平面连杆模拟机构。给定输入件的驱动尺寸，确定输出件被驱动尺寸，求出输出杆件运动点的轨迹。利用CAD软件的记录功能，得到机构输出点轨迹数据；再用Excel软件拟合轨迹数据，得到轨迹拟合曲线和拟合方法；最后求解机构输出运动件的速度和加速度方程。计算机模拟结果表明，文中方法不仅具有简单、快捷、直观、求解精度高和重复性好的优点，而且可以完成复杂机构和多自由度机构的运动分析，为机构的运动分析提供更有效的工具。     

基于动力学等价的一种通用控制器的设计

在动力学运动方程的基础上,构建了一种系统状态观测器,该观察器能够精确估计被控对象的位置、速度和加速度而无需知道其数学模型。在此基础上,设计了一种通用控制器,该控制器通过系统运动的位置、速度和加速度的负反馈作用,把原被控对象的输出轨迹引导控制到期望的系统输出轨迹,能提高系统的控制品质和鲁棒性能。分析了PID控制器、内模控制器、状态控制器、预测控制器和鲁棒控制器的算法特性,指出这些控制器与所设计的通用控制器在动力学意义上具有等价性。     

基于螺旋理论的四面体可展机构运动特性与动力学分析

为了解决星载四面体构架式可展开天线运动学和动力学建模分析困难的问题,建立了一种基于螺旋理论的运动学和动力学特性分析方法．首先分析了3RR-3RRR四面体可展机构的构型机理及几何特征,基于螺旋理论绘制了旋量约束拓扑图,计算了机构的自由度,结果表明其只有1个自由度．然后对其进行了运动学分析,通过运动旋量的组合运算分析了各个构件的速度,并推导得到了机构的雅可比矩阵,采用旋量导数表示构件的6维加速度,推导得到了各个花盘和杆件的角加速度与质心线加速度．最后基于牛顿－欧拉方程和虚功原理建立了动力学方程,并进行了数值计算与仿真验证,数值计算结果与仿真结果完全一致,验证了基于螺旋理论的运动学和动力学特性分析方法的正确性．本文的研究方法在分析过程中各参数物理意义明确,分析过程较为程式化,易于编程,适合应用于此类空间可展开机构的分析中．     

共轴双驱型导轨精密定位与同步性的研究

为了满足高精度测量系统对高精密运动导轨的需求,通过结合通用运动自动控制器(UMAC)和直线电机的驱动方式,实现了"PID+速度/;加速度前馈+陷波滤波器"控制算法对共轴双驱型导轨精密定位和同步的精确控制.在实验检测的基础上,验证了导轨的同步性在无摩擦负载和有摩擦负载的情况下,分别可以控制在0.7"和5"以内.     

A two-dimensional simulation method for investigating charge transport behavior in 3-D charge trapping memory用于研究三维电荷俘获存储器电子输运的二维模拟方法

This work presents a self-consistent two-dimensional (2-D) simulation method with unified physical models for different operation regimes of charge trapping memory. The simulation carefully takes into consideration the tunneling process, charge trapping/de-trapping mechanisms, and 2-D drift-diffusion transport within the storage layer. A string of three memory cells has been simulated and evaluated for different gate stack compositions and temperatures. The simulator is able to describe the charge transport behavior along bitline and tunneling directions under different operations. Good agreement has been made with experimental data, which hence validates the implemented physical models and altogether confirms the simulation as a valuable tool for evaluating the characteristics of three-dimensional NAND flash memory.     

时序逻辑电路的Petri网分析方法

本文应用带抑止弧的增广Ｐｅｔｒｉ网，建立了基本门电路和常用触发器的Ｐｅｔｒｉ网模型，讨论了运用该模型描述同步和异步时序逻辑电路，给出了增广Ｐｅｔｒｉ网的矩阵描述和状态转移方程，在此基础上提出了同步和异步时序逻辑电路统一分析的Ｐｅｔｒｉ网方法。     

Towards true linguistic modelling through optimal numerical solutions

This paper is concerned with both the problems of quantitative and qualitative modelling of complex systems by using fuzzy techniques. A unified approach for the identification and subsequent extraction of linguistic knowledge of systems using fuzzy relational models is addressed. This approach deals with the identification problem by means of optimal numerical solutions based on weighted least squares and quadratic programming formulations. The linguistic knowledge is extracted in the form of consistent fuzzy rules that describe linguistically the behaviour of the identified system. A new methodology for the simplification of the extracted rules is derived by using a pruning criterion based on the representability matrix concept introduced in previous work. Several numerical aspects concerning the proposed optimization schemes and a covering discussion about the linguistic interpretation of the resulting models are also included together with illustrative examples in the contexts of pattern classification and dynamic systems identification. The paper also provides an overview of fuzzy modelling techniques that intends to situate the relational models among other fuzzy model architectures typically adopted in the literature, highlighting their main advantages and drawbacks.     

Framework of an intelligent grinding process advisor

This paper describes the fundamental framework of an intelligent grinding process advisory system, which has been developed to help process engineers design new grinding processes. The system incorporates both highly complex, nonlinear analytical grinding process models and knowledge-based linguistic rules, and generates unified fuzzy rules by a novel automatic rule generation procedure. Optimal design of the parameters is performedvia fuzzy logic inference. Several design principles for constructing the system are discussed as well as the over-all architecture of the system. The implementation of the system shows that the system can lead to the optimal design of a grinding process very effectively even with a large number of process parameters.     

非正则精确模型的布尔操作

为了加强造型系统的表达能力,实现对线框模型、曲面模型和实体模型的统一表示和操作,该文采用非正则精确模型作为几何对象表示的数据结构,并给出了相应的布尔操作实现算法,在保证效率和精确性的同时确保鲁棒性是算法的目标.作为一个特征造型系统的几何核心,该算法已经在基于NT平台的特征造型系统GS-CAD98中实现.     

一个雕塑实体的布尔操作算法

给出了一个雕塑实体布尔操作的现实算法,在保证效率和精确性的同时确保鲁棒性是算法的目标,实体模型通过裁剪曲面片和半边数据结构来表达几何和拓扑信息。采用了层次求交和交线跟踪的方法来保证曲面片分割和区域分类的一致性,从而克服实践中常见的退化情况。该算法也可以方便地扩展到非流形模型的布尔操作。作为一个实体造型系统的一部分,该算法已经在ＳＧＩ工作站上实现。     

Chemical Discovery as Belief Revision

In this paper we describe STAHLp, a system that constructs componential models of chemical substances. STAHLp is a descendant of Zytkow and Simon's (1986) STAHL system, and both use chemical reactions and known componential models in order to construct new chemical models. However, STAHLp employs a more unified and effective strategy for recovering from erroneous inferences, based partly on de Kleer's (1984) assumption-based method of belief revision. This involves recording the underlying source beliefs or premises which lead to each inferred reaction or model. Where Zytkow and Simon's system required multiple methods for detecting errors and recovering from them, STAHLp uses a more powerful representation and additional rules which allow a unified method for error detection and recovery. When given the same initial data, the new system constructs the same historically correct models as STAHL, but it has other capabilities as well. In particular, STAHLp can modify data it has been given if this is necessary to achieve consistent models, and then proceed to construct new models based on the revised data.     

Matrix splicing system

The string splicing system was introduced by Tom Head, which stands as an abstract model for the DNA recombination under the influence of restriction enzymes and ligase enzymes. However, it is observed that strings are not very capable of modelling the complex chemical process. Hence, in this article, matrix splicing system is introduced with a new splicing operation among the matrices. It is shown with an illustration that the DNA recombination process can be simulated by the matrix splicing system, which justifies the suitability of the matrices for modelling the complex processes of the molecules. The properties of the components of the system such as cutting rules and the splicing rules are discussed. Besides some properties of the system, it is shown that this system stands as a theoretical model for splicing strings in parallel. The abstraction of the ligase enzymes is explained which is missing in all the splicing models that have come out so far. The ability of the system in generating new patterns is also outlined.     

A fuzzy logic approach to experience‐based reasoning

Experience‐based reasoning (EBR) is a reasoning paradigm that has been used in almost every human activity such as business, military missions, and teaching activities since early human history. However, EBR has not been seriously studied from either a logical or mathematical viewpoint, although case‐based reasoning (CBR) researchers have paid attention to EBR to some extent. This article will attempt to fill this gap by providing a unified fuzzy logic‐based treatment of EBR. More specifically, this article first reviews the logical approach to EBR, in which eight different rules of inference for EBR are discussed. Then the article proposes fuzzy logic‐based models to these eight different rules of inference that constitute the fundamentals for all EBR paradigms from a fuzzy logic viewpoint, and therefore will form a theoretical foundation for EBR. The proposed approach will facilitate research and development of EBR, fuzzy systems, intelligent systems, knowledge management, and experience management. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 867–889, 2007.