卡尔曼滤波
提供了kf,ekf,ukf的详细推导过程,从标量推导开始,进而转入矢量推导,非常详细卡尔曼滤波器简介(阎泓著第一步、时间更新29第二步、测量更新“““““““+““44““““42924特殊情况.30第一种情况、先验误差极小...-.----130第二种情况、先验误差极大.30第三种情况、测量噪声极大.…31第三章、标量EKF画,通通画4“““““+44=“++“““++4“4“+“4“““-“++323.1非线性状态模型.323.2模型线性化33.2.1过程噪声项的线性化.333.2.2测量噪声项的线性化...11-343.2.3过程和测量噪声项同时线性化…35324过程的线性化…0353.25测量的线性化…363.3EKF滤波器…1373.31应用卡尔曼滤波器.3733,2计算先验均方差373.33计算后验均方差373.3.4计算k值4a“44444“;4444454a44“44444=424444441“如44444;44444“44.45“#4444444a444444443833.5k值为最优时的后验均方差3834算法39第一步、时间更新………9第二步、测量更新393.5EKF的缺陷44“==++++4=++44日+“44=“““+440第四章、矢量EKF4141非线性矢量状态模型4142矢量模型线性化单“““·***“““***“““““***“““***4““-***4““*“→“““*→*-““““““*“““*+4““→*“·““·““““*4242.1矢量泛函的泰勒展开42.2过程噪声项的线性化424.2.3测量噪声项的线性化.→“““#+4+“44“““-4+44→“““4“4+-““+43424过程和测量噪声项同时线性化4442.5过程的线性化4“““4““*“4““*→““*+“4“““““““*4“““4“““++4““44“““4“44““““七426测量的线性化“““““·+““““*““““+“““““““+4“““““““+4“““→·“““+“4543矢量EKF滤波器面面面面46画面和面面,43.1应用矢量卡尔曼滤波器44““++“44“““*44“““++444““4+444“+“44““““+444643.2计算先验均方差4643.3计算后验均方差4““+44““““44““““+→4““““+4““““4“44““““.47434计算k值47435k值为最优时的后验均方差4845算法“““+““““*“““““+…““““*“+44““48第一步、时间更新.…49第3页(共77页)卡尔曼滤波器简介(阎泓著第二步、测量更新““4--““44-4494.4特殊情况.““““4444“画画新通画通49第一种情况、先验误差极小.画画,画画画园画画,画画画面请通.50第二种情况、先验误差极大….----50第三种情况、测量噪声极大44“““+44““=++“44“““+444““4+“44““44+50第五章、标量无迹变换UT5251无迹变换的任务5252真值“““““++“++4“4“““+4“++4“““““+““+“““““525.3无迹测试点1101453.1标量的无迹测试点………154532无迹权重系数翻国口道55533统计性质公式…5554测试点的无迹变换.565.4.1从测试点得到后验期待值.画画通通画画山通画画新56542从测试点得到后验方差“““+4“++“4“++““平““上“““4““平中“+““““平“4+“=575.5讨论品aB444a日日+44日4日日“4日a4日+a日本“日日日和本上日和4日““458第六章矢量无迹变换UT4“““4“44“““4++44“““4+““4+2+“++“4“++4=“++“““2++““““++““4+““““++5961矢量微分回顾5961.1计算真值会用到的恒等式1962矢量无迹变换的任务中本““丰二“中““6063真值6163无迹测试点63.1矢量的无迹测试点画面通自品面画画面自自通国画日画面国通画日通山国国画山山面通画山山丽右日日画画画画画山63632无迹权重系数64633UT变换下的对称性64测试点的无迹变换6564.1几个恒等式…65642从测试点得到后验期待值.…---1----66642从测试点得到后验协方差.6765讨论68第七章、无迹滤波器UKF11116971高维非线性问题.069711标量特例画画画画画画新画画画画画画““*#“““““44“…4“““““4““+““→““““44““47072无迹滤波器面,面面面面面面面“面画70721无迹测试点““*4“““““44““+44““““*44“““++444“““4““+“44“““““722无迹权重系数通画画通画画通通画画通山请画画画画画画出画请画画副。723先验估计画画·画‘画4““+44““““44““““+→4““““+““““+“444““““+472724应用卡尔曼滤波器737.2.5计算后验均方差…737.2.6计算k值…444““+44“““*447473算法75第4页(共77页)卡尔曼滤波器简介(阎泓著第零步、初始化..-75第一步、时间更新175第二步、测量更新画画,画画画园画画,画画画面请通176第5页(共77页)卡尔曼滤波器简介(阎泓著第一章、标量线性系统实际工作中的线性系统很少有标量的,但是标量的卡尔曼滤波器的理论推导比较直观、易于理解,因此作为学习的切入点比较合适首先必须清楚地陈述卡尔曼滤波器要解决的问题。1.1卡尔曼问题在离散时间中,一个标量线性系统的状态演化常常可以表述为下面的随机差分方程式:x=ax,+bu其中t为时间。x,是一个标量随机变量,代表t时刻系统的内禀状态。a和b为常标量。u,为t-1时刻的输入,也是一个标量。111信号流程图上面的(1)式也可以用下面的信号流程图表示u-1)X()Ibax(t-1)直线表示信号的传送,箭头代表传送的方向。流程图中的图标有三种,第一种方框图标代表时间延迟,见下图x(t)TX(t-1)第二种方框图标代表乘法(增益),见下图第6页(共77页)卡尔曼滤波器简介(阎泓著aax第三种圆形图标代表加法(混合),见下图a-b+CbG这些图标可以按照有意义的方式组合起来,描述一个差分方程。必须指出,这些图标并不局限于标量情形,而且适用于矢量情形,譬如x为一个矢量,而a和b可以为矩阵。112加入白噪声假设在这个线性过程中有一个噪声项v鬟x2=ax21+bu-1+W1-1则此方程式可以用下面的信号流程图表示w(t=1)u(-1)中+baX(-1)假定这个噪声ν是一个高斯白噪声,它满足3N(9),(Q20)〈ww)=0(≠)3在本文采用物理学中常用的记号,(x)=E(x)表示x的期待值第7页(共77页)卡尔曼滤波器简介(阎泓著此外假定w与u.没有关联,也即113加入可测量假设系统的状态量x是不可以直接测量的。可以测量的是另外一个量z,称为可测量。可测量z依赖于系统的状态量x和一个激励倍数h,见下式。hx. +v(5)在实际工作中h可能会随着时间而变化,但在这里假定为常数,为常标量。此时流程图如下。wt-1)u(t-1)+b±2(ax(t-1)测量过程本身带有一个噪声ν,影响了测量的准确度。同样我们假定ν是一个白噪声(,R)(R≥0)(")≥=0(s≠)此外假定ν与w和u都没有关联,也即()=v)=0(s1)114卡尔曼问题陈述现在要考虑的是如何从可观测量z;的观测数据中得出x的最优估计值,把噪声w和v尽最大可能过滤出去,把它们的影响减到最小。这就是卡尔曼滤波器要解决的问题。1.2标量卡尔曼滤波器卡尔曼对这个问题的解答就是卡尔曼滤波器。下面的流程图可以分成上下两个部分:上半部分就是问题本身,下半部分就是卡尔曼滤波器。第8页(共77页)卡尔曼滤波器简介(阎泓著u(-1)X()bh+(aX(t-1)bb(()2()+ak文-b)+Residual在图中,z1代表实际测量值,x代表过程的真值。此外在卡尔曼滤波器的流程图中出现了几种新的符号,分别是x代表先验估计( A priori estimate),和E代表后验估计(A posteriori estimate)4.对一个随机变量当前值的先验估计是根据前一个时刻以及更早的历史观测信息所作出的估计:后验估计是根据当前时刻以及更早的历史观测信息所作出的估计。x1的先验估计是由上一个时间点的后验估计值和输入信息给出的,x,=ax+ bur-p卡尔曼使用x的先验估计给出可测量E的(先验估计)预测5,而z,的实际测得值与预测值之间的差称为滤波过程的革新( nnovation)或者残余( Residua,即Residual=(10)本文采取通用的符号,以表示对某变量y在t时刻的后验估计,而表示对y的先验估计。在某些文献中y又记作y(|t-1),又记作y(t|t)5对于z,而言后验估计没有意义。z,是可观测量,在后验时刻已经有实际观测值了。第9页(共77页)卡尔曼滤波器简介(阎泓著残余反映了预测值和实际值之间的差别。残余为零的话,估计值和实际值完全吻合。如果残余很小,表明估计值很好,反之就不好。卡尔曼滤波器可以利用残余的这一信息改善对x,的估计,给出后验估计。也就是x=x:+k(Residual)=*+k(z,-hR-其中的k称作卡尔曼增益或卡尔曼混合系数( Blending factor)现在剩下的问题就是如何找到k的值,使得估计为最优。为此需要定义先验均方差和后验均方差。121最优的k值先验误差和后验误差分别定义为(12)它们的方差就是先验均方差和后验均方差P≡varP, =vale(13)最优的k值是使后验均方差为最小的值,就是下式成立时的k值(14)ak122计算先验均方差先验均方差为≡war(15)因为(2)式及(8)试式x,=ax_+ bu+we=ax+bu可得e:=x-x=ax+bu +w_)-(ax +bur=a(xx_1)+W因此第10页(共77页)
- 2020-12-03下载
- 积分:1
MSC.Marc 2013.1理论手册
MSC.MARC是功能齐全的高级非线性有限元软件,具有极强的结构分析能力。可以处理各种线性和非线性结构分析包括:线性/非线性静力分析、模态分析、简谐响应分析、频谱分析、随机振动分析、动力响应分析、自动的静/动力接触、屈曲/失稳、失效和破坏分析等ContentsMarc Volume A: Theory and User InformationrefaceAbout this manual■■■■20Purpose of volume A20Contents of volume a20How to Use this manual211 The Marc SystemMarc Programs............■■23Marc for Analysis23Mentat or patran for gul24Structure of marc24Procedure Library24Material Library24Element Library25Program Function Library25Features and benefits of marc252 Program InitiationMarc Host Systems27Workspace Requirements27Marc Workspace Requirements27File Units30Program Initiation.........32Examples of running marc Jobs■■■■■344 Marc Volume A: Theory and User Information3 Data EntryInput Conventions38Input of List of Items39Examples of lists41Table Driven Input■■41Table Input42Parameters46Model Definition Options46History Definition Options46REZONE Option474 Introduction to mesh definitionDirect Input49Element Connectivity Data49Nodal coordinate data53Activate/Deactivate54User Subroutine Input54MESH2D54Block definition54Merging of Nodes54Block Types55Symmetry, Weighting, and Constraints57Additional Options58Mentat58FXORD Option59Major classes of the fXoRD Option59Recommendations on Use of the FXORD Option63Incremental mesh generators■■■■■63Bandwidth Optimization64Rezoning.....64Substructure65Technical Background66Scaling Element Stiffness67Contents 5BEAM SECT Parameter■■■68Orientation of the Section in Space68Definition of the section68Error Analysis74ocal AdaptivityNumber of Elements Created7474Boundary Conditions75Location of new nodes76Adaptive Criteria77Automatic Global remeshing80Remeshing criteria84Remeshing TechniquesPatran Tetrahedral mesher885 Structural Procedure LibraryLinear Analysis99Accuracy100Error estimates100Adaptive meshing101Fourier Analysis101Nonlinear Analysis104Geometric nonlinearities108Eulerian FormulationArbitrary Eulerian-Lagrangian(AEL) Formulation118Nonlinear Boundary Conditions118Buckling Analysis120Perturbation Analysis121Computational Procedures for Elastic-Plastic Analysis126Creep138Viscoelasticity142Viscoplasticity143Fracture Mechanics144Linear fracture mechanics144Nonlinear fracture mechanics147Numerical Evaluation of the J-integral148Numerical Evaluation of the Energy Release Rate with the VCCT Method150Automatic Crack PropagationDynamic Fracture Methodology1626 Marc Volume A: Theory and User InformationDynamic crack Propagation..162Crack Initiation163Mesh Splitting165Mesh Splitting Along Edges or Faces165Mesh Cutting167Dynamics...168Modal(Eigenvalue) Analysis.168Harmonic Response172Spectrum Response75Transient Analysis179Inertia relief191Rigid Body Mode Evaluation.191Rigid-Plastic Flow195Steady State Analysis95Transient Analysis196Technical background..196Superplasticity197Soil Analysis199Technical formulation200Mechanical Wear.,,,,,,,,203Design Sensitivity Analysis........■■205Theoretical considerations207Design Optimization208Approximation of Response Functions Over the Design Space..209Improvement of the Approximation211The Optimization algorithmMarc User Interface for Sensitivity Analysis and Optimization212Define Initial State with Results from a Previous Analysis215Pre state215Model sections217Steady State Rolling Analysis219Kinematics219lnetⅰaE仟fect...221Rolling Contact221Steady state rolling with marc221ContentsStructural Zooming Analysis.222Element Types Supported223Uncoupled Thermal Stress Analysis223Cure-Thermal-Mechanically Coupled Analysis224Cure Kinetics225Cure Shrinkage Strain228References,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,2296 Nonstructural Procedure LibraryHeat Transfer234Thermal Contact235Convergence Controls235Steady state Analysis236Transient Analysisemperature Effects238Initial Conditions239Boundary Conditions239Surface Energy243Thermochemical Ablation and Surface Energy Balance244Mathematical Presentation244Mechanical Erosion251Mechanical Erosion by Other Actions251pyrolySis251Coking255Monitoring Thermal Degradation258Presentation of the Energy Equation260Ablation262Welding27Radiation278Conrad Gap292Channel293Output294Diffusion295Technical Background296Hydrodynamic Bearing300Technical Background3028 Marc Volume A: Theory and User InformationElectrostatic Analysis304Technical Background305Magnetostatic Analysis308Technical background..309Magnetodynamic Analysis∴∴320Technical Background322Piezoelectric Analysis325Technical Background326Strain Based Piezoelectric Coupling..328Acoustic Analysis328Rigid Cavity Acoustic Analysis328Technical Background329Fluid mechanics330Finite element formulation333Penalty Method335Steady State Analysis336Transient Analysis336Solid Analysis336Solution of Coupled Problems in Fluids..336Degrees of Freedom337Element Types.337Coupled Analyses∴..■量■画■■■,,,,,,,,339Thermal Mechanically Coupled Analysis341Coupled Acoustic-Structural AnalysisFluid/Solid Interaction- Added Mass Approach342346Coupled Electrostatic-Structural Analysis348Coupled Magnetostatic-Structural Analysis350Coupled Thermal-Electrical Analysis (Joule Heating)352Coupled Electrical-Thermal-Mechanical Analysis355Coupled Magnetostatic-Thermal Analysis357Coupled Magnetodynamic-Thermal Analysis358Coupled Magnetodynamic-Thermal-Structural Analysis..359References∴,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,362Contents 97 Material LibraryLinear Elastic Material365Composite Material ......367Layered Materials368Classical Lamination Theory for Multi-Layered Shells371Material Preferred direction372Material Dependent Failure Criteria376Interlaminar Shear for Thick Shell, Beam, Solid shell, and 3-d Composite brick elements394Interlaminar Stresses for continuum composite elements397Progressive Composite Failure397Mixture model399Gasket403Constitutive model403Nonlinear Hypoelastic Material407Thermo-Mechanical Shape Memory Model422Transformation Induced deformation424Constitutive Theory425Phase Transformation strains425Experimental Data Fitting for Thermo-mechanical Shape Memory Alloy427Mechanical Shape Memory Model431Conversion from Thermo-Mechanical to Mechanical SMA oyExperimental Data Fitting for Mechanical Shape Memory alle434435Elastomer436Updated Lagrange formulation for nonlinear elasticity455Time-independent Inelastic Behavior456Yield Conditions458Mohr-Coulomb Material(Hydrostatic Stress Dependence)464Buyukozturk Criterion(Hydrostatic Stress Dependence)465Powder material465Obtaining Crush Curve and Shear Failure Parameters by Curve Fitting in Marc475Work or strain hardening.....,,,479Flow rule485Constitutive Relations486Time-independent Cyclic Plasticity489Time-dependent Inelastic Behavior492Creep(Maxwell Model)翻495Oak Ridge National Laboratory Laws50010 Marc Volume A: Theory and User InformationSwelling.501Viscoplasticity502Time-dependent Cyclic Plasticity502Anand solder model504Viscoelastic Material505Bergstrom-Boyce Model516Narayanaswamy Model518Frequency-dependent Material Behavior522Viscoelastic Material Behavior in the Frequency Domain522Thermo-Rheologically Simple Material Behavior in the Frequency Domain538Deformation Dependent Relaxation in the Frequency Domain539Harmonic Equations of motion541Performing viscoelastic Analysis in the Frequency Domain543Temperature Effects and Coefficient of Thermal Expansion,546Piecewise Linear Representation547Temperature-Dependent Creep548Coefficient of Thermal Expansion549Time-Temperature-Transformation549Low Tension Material552Uniaxial Cracking Data552LoW Tension Cracking552Tension Softening552Crack Closure553Crushing553Analysis554Soil model554Elastic Models554Cam-Clay Model555Evaluation of soil parameters for the critical state soil model557Damage Models565Ductile metals565Elastomers568Cohesive Zone Modeling570Nonstructural materials578Heat transfer analysis579Piezoelectric Analysis579Thermo-Electrical Analysis579Coupled Electrical-Thermal-Mechanical Analysis579Hydrodynamic Bearing AnalysisFluid/ Solid Interaction Analysis- Added Mass approach579.579
- 2020-12-04下载
- 积分:1