guidance, flight mechanics and trajectory optimization

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e achieved by a partially observable system. The analysis through which the optimal control action is determined consists of a rather straightforward application of Dynamic Programming, While it is not difficult to formulate the perfectly inobservable problem using other methods, there appears to be no way of treating the perfectly observable or partially observable case using the Variational Calculus. Hence, the stochastic <strong>optimization</strong> problem is one area where Dynamic Programming is not an alternate procedure, but frequently the only procedure available for conducting the analysis. 131
2.5.3 The Treatment of Terminal Constraints In the preceding section, the optimal control action was developed under the condition that no constraints were placed in the terminal state Xc . In this section, a slightly modified version of the linear- quadratic cost problem will be analyzed in which the expected value of the terminal state is required to satisfy one or more conditions. Specifically, the system is again governed by the state equation 2 = AXtGU+g with e Gaussian white noise satisfying This time, however, the performance index takes &he form (2.5.83) (2.5.84) Note that no measure of the terminal error is included in E(J,\ .; that is, .the performance index is a sub-case of the previous performance index in which the matrix A has been set equal to zero. The reason for this change will become agparent'shortly. Let z+ = ic*4) denote a P vector which is linearly related to the terminal state through +!(lk+) = +, = ffX$ (2.5.86) where fl is a constant PXW matrix <strong>and</strong> where PS*l. Three different types of terminal constraints will be considered. is a scalar In the first case, the symbol W denotes the trace of the.matrixE {2+ Z'), Hence, the sum of the diagonal elements of E Z+ 2:; is required to be less i than or equal In.the'second Case, the individual diagonal elements of (c[z+ $\)iL ,, i = I, P > are required 132 ,
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NASA OI 0 0 P; U 4 cd 4 z . . _ -.
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c FOREWORD This report was prepared
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SECTION PAGE 2.5 Dynamic Programmin
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2.0 STATE OF THE ART 2.1 Developmen
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There are several ways to accomplis
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2.2 Fundamental Concepts and Applic
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II. Although the previous problem w
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I,. Citg B. C optimum cost Path for
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The optimum path can be found by st
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The integral in Equation 2.2.1 can
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2.2.2.1 Shortest Distance Between T
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The cost of the allowable transitio
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In a,completely analogous manner th
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2.2.2.2 Variational Problem with Mo
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Ii _ 6 5 9 3 I 8 I I The cost integ
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2.2.2.3 Simple Guidance Problem As
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This process continues in the same
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The algorithm for solving this prob
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The reader, no doubt, has a reasona
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are applied to Min (fl), the range
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Note that each diagonal corresponds
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The value of X can be found by empl
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The initial condition is: K.&P : P(
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it is seen that (for a two stage pr
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The optimal policy can now be found
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2.3 COMPUTATIONAL CONSIDERATIONS So
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If classical techniques were to be
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2.3.3.1 The Curse of Dimensionalitv
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Next, fl is evaluated for all allow
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% Xl + 5 = 2 (A2 = 2) 5+X2=3 (A2=3.
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that minimizes f. This interchange
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2.3.3.2 Stability and Sensitivity I
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Let the lower limit of integration
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But (2.4.10) since the function on
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Now,. noting that the second MIN op
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where v 'is determined from and wit
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NOW, combining these two expression
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The situation is pictured to the ri
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Hence, the boundary condition OAI f
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The boundary condition to be satisf
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2.4.7. Discussion of the Probltsi o
Page 87 and 88: characteristics associated with Eqs
Page 89 and 90: 2.4.8 The Problem of Bolza The prec
Page 91 and 92: The initial position, velocity and
Page 93 and 94: where I is the moment of inertia, F
Page 95 and 96: or, as . -... .-. . .._-_--- to ind
Page 97 and 98: Since R(t, x(t) ) is the minimum va
Page 99 and 100: 2.4.10 Ljnear Problem with Quadrati
Page 101 and 102: where S(t) is some n x n symmetric
Page 103 and 104: The governing equations for the att
Page 105 and 106: y 2.4.11 Dynamic Programming and th
Page 107 and 108: M Since 3t does not depend on u exp
Page 109 and 110: with The P vector for the system is
Page 111 and 112: where With the control known as a f
Page 113 and 114: with and with the boundary conditio
Page 115 and 116: 2.5 DYNAMIC PROGRAMMING AND THE OPT
Page 117 and 118: 2.5.2 Problem Statement Let the sys
Page 119 and 120: Now, introducing the variables qs2,
Page 121 and 122: Thus, the performance index takes t
Page 123 and 124: #R where tr denotes the trace of th
Page 125 and 126: The minimum value of the performanc
Page 127 and 128: variance characterizing Ilt) can be
Page 129 and 130: The solution takes the form with s
Page 131 and 132: Since V is positive definite for f
Page 133 and 134: where the first the second with exp
Page 135 and 136: Taking the limit and using the expr
Page 137: Since V is positive definite for t
Page 141 and 142: F while Equation (2.5.87B) requires
Page 143 and 144: ._ __. ..- . . - which will equal t
Page 145 and 146: is determined. Let p(z,t') be given
Page 147 and 148: of the p and $ equations (i.e., Eqs
Page 149 and 150: (2.5.I.21) Thus, the control is to
Page 151 and 152: Note, as in.Section (2.5.2.3), the
Page 153 and 154: .6 t -(h.(S~tj~fitr~f-‘~~~~n~) =
Page 155 and 156: 3.0 RECOMMENDED PROCEDURES - ._ .-_
Page 157 and 158: 4 Section 2.5 (2.5.1) (2.5.2) (2.5.
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