Investigation and appreciation of optimal output feedback. Volume 1: A convergent algorithm for the stochastic infinite-time discrete optimal output feedback problem
01 Aug 1984-
TL;DR: In this article, the stochastic, infinite time, discrete output feedback problem for time invariant linear systems is examined and two sets of sufficient conditions for the existence of a stable, globally optimal solution are presented.
Abstract: The stochastic, infinite time, discrete output feedback problem for time invariant linear systems is examined. Two sets of sufficient conditions for the existence of a stable, globally optimal solution are presented. An expression for the total change in the cost function due to a change in the feedback gain is obtained. This expression is used to show that a sequence of gains can be obtained by an algorithm, so that the corresponding cost sequence is monotonically decreasing and the corresponding sequence of the cost gradient converges to zero. The algorithm is guaranteed to obtain a critical point of the cost function. The computational steps necessary to implement the algorithm on a computer are presented. The results are applied to a digital outer loop flight control problem. The numerical results for this 13th order problem indicate a rate of convergence considerably faster than two other algorithms used for comparison.
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TL;DR: In this article, a variable-gain, optimal, discrete, output feedback design approach that is applied in a non-linear flight regime is described, where the flight regime covers a wide angle-of-attack a range that includes the stall region.
Abstract: This paper describes a recently developed variable-gain, optimal, discrete, output feedback design approach that is applied in a nonlinear flight regime. The flight regime covers a wide angle-of-attack a range that includes the stall region. The paper contains brief descriptions of the variable-gain formulation, the discrete-control structure and flight equations used to apply the design approach, and the high-performance airplane model used in the application. Both linear and nonlinear analyses are shown for a longitudinal four-model integrated design case with a = 5, 15, 35, and 60 deg and two flight control modes. Nonlinear simulations show good time response for both a longitudinal pitch-up and pitch-down maneuver and a regulation within 5 deg from the nominal angle during a high-ex lateral maneuver.
28 citations
01 Feb 1976
TL;DR: In this article, the control of a continuous linear plant disturbed by white plant noise was considered, and the control was constrained to be a piecewise constant function of time, where the cost function is the integral of quadratic error terms in the state and control, thus penalizing errors at every instant of time.
Abstract: This paper considers the control of a continuous linear plant disturbed by white plant noise when the control is constrained to be a piecewise constant function of time: i.e. a stochastic sampled-data system. The cost function is the integral of quadratic error terms in the state and control, thus penalizing errors at every instant of time while the plant noise disturbs the system continuously. The problem is solved by reducing the constrained continuous problem to an unconstrained discrete one. It is shown that the separation principle for estimation and control still holds for this problem when the plant disturbance and measurement noise are Gaussian.
26 citations
01 Sep 1991
TL;DR: The research process being used to develop control law design methodologies and guidelines in the NASA High-Alpha Technology Program are discussed and a status report is provided on designs being developed for each of these elements.
Abstract: The research process being used to develop control law design methodologies and guidelines in the NASA High-Alpha Technology Program are discussed. This step-by-step process consists of four basic elements: (1) control law architecture definition and linear synthesis, (2) nonlinear batch simulation, (3) piloted simulation evaluation, and (4) flight test validation. This paper discusses the research tools being used in this effort and provides a status report on design methodologies and guidelines being developed for each of these elements.
13 citations
01 Jan 1989
TL;DR: In this article, a variable-gain, optimal, discrete, output feedback design approach that is applied to a nonlinear flight regime is described, and linear and nonlinear analysis are shown for a longitudinal four-model design case with angles of attack of 5, 15, 35, and 60 deg.
Abstract: A variable-gain, optimal, discrete, output feedback design approach that is applied to a nonlinear flight regime is described. The flight regime covers a wide angle-of-attack range that includes stall and post stall. The paper includes brief descriptions of the variable-gain formulation, the discrete-control structure and flight equations used to apply the design approach, and the high performance airplane model used in the application. Both linear and nonlinear analysis are shown for a longitudinal four-model design case with angles of attack of 5, 15, 35, and 60 deg. Linear and nonlinear simulations are compared for a single-point longitudinal design at 60 deg angle of attack. Nonlinear simulations for the four-model, multi-mode, variable-gain design include a longitudinal pitch-up and pitch-down maneuver and high angle-of-attack regulation during a lateral maneuver.
10 citations
01 Dec 1981
TL;DR: Feedforward control theory is used to determine new numerical approaches to eigenvalue eigenvector assignment using output feedback using input feedback.
Abstract: Feedforward control theory is used to determine new numerical approaches to eigenvalue eigenvector assignment using output feedback.
1 citations
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