Minimum fuel control of linear stochastic systems with applications to midcourse guidance
Minimum fuel control for discrete time Gaussian processes, applying results to spacecraft midcourse guidance for earth-Mars mission
Deyst, J. J.↗
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Results for “time discretization”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Nonlinear recursive estimation for systems with quantized data
State estimation for nonlinear discrete time systems with quantized measurements, obtaining recursive algorithm through boundary value problem linearization
Clements, K. A.↗
Empirical Bayes estimation of observation error variances in linear systems
Kalman filter set for state vector and observation error variance estimation in discrete- time linear system, using empirical Bayes techniques
Born, G. H.↗
Recursive formulas for the evaluation of certain complex integrals
Recursive formulas for stability tests and quadratic loss functions evaluation for linear discrete time dynamical systems
Astroem, K. J.↗
Adaptive stochastic control for linear systems. I - Solution method
Linear discrete time stochastic system with unknown gain parameters, interpreting open loop feedback optimal control identifier and controller equations
Athans, M.↗
On the minimax reachability of target sets and target tubes
Closed-loop control of discrete time systems with uncertainty, discussing minimax reachability of target sets and tubes
Bertsekas, D. P.↗
On the identification of nonlinear dynamical systems
Independent noise driven nonlinear dynamic systems identification, performing linear discrete-time scalar measurements
De Figueiredo, R. J. P.↗
Analytic design of digital flight controllers to realize aircraft flying quality specifications
Discrete time digital flight control systems design resulting in closed loop aircraft response characteristics approximation to prescribed flying quality specifications
Montgomery, R. C.↗
Constant directions of the Riccati equation
A constant direction of the Riccati equation associated with a class of singular discrete-time optimization problems is defined. The set of constant directions is completely characterized using a control viewpoint. Constant directions are used to reduce the computational complexity of the optimal system. Application to optimal filtering in colored noise is given.
Rappaport, D.↗
Smooth empirical Bayes estimation of observation error variances in linear systems
A smooth empirical Bayes estimator was developed for estimating the unknown random scale component of each of a set of observation error variances. It is shown that the estimator possesses a smaller average squared error loss than other estimators for a discrete time linear system.
Martz, H. F., Jr.↗
Adaptive control of stochastic linear systems with unknown parameters
The problem of optimal control of linear discrete-time stochastic dynamical system with unknown and, possibly, stochastically varying parameters is considered on the basis of noisy measurements. It is desired to minimize the expected value of a quadratic cost functional. Since the simultaneous estimation of the state and plant parameters is a nonlinear filtering problem, the extended Kalman filter algorithm is used. Several qualitative and asymptotic properties of the open loop feedback optimal control and the enforced separation scheme are discussed. Simulation results via Monte Carlo method show that, in terms of the performance measure, for stable systems the open loop feedback optimal control system is slightly better than the enforced separation scheme, while for unstable systems the latter scheme is far better.
Ku, R. T.↗
Adaptive stochastic control for a class of linear systems.
The problem considered in this paper deals with the control of linear discrete-time stochastic systems with unknown (possibly time-varying and random) gain parameters. The philosophy of control is based on the use of an open-loop feedback optimal (OLFO) control using a quadratic index of performance. It is shown that the OLFO system consists of (1) an identifier that estimates the system state variables and gain parameters and (2) a controller described by an 'adaptive' gain and correction term. Several qualitative properties and asymptotic properties of the OLFO adaptive system are discussed. Simulation results dealing with the control of stable and unstable third-order plants are presented. The key quantitative result is the precise variation of the control system adaptive gains as a function of the future expected uncertainty of the parameters; thus, in this problem the ordinary 'separation theorem' does not hold.
Tse, E.↗
Approximate estimation for systems with quantized data.
Estimation of the state of a nonlinear discrete-time system using quantized data is considered. An exact solution for the maximum likelihood estimate is expressed as the solution of a nonlinear two-point boundary-value problem. Approximate recursive solutions for both the maximum likelihood and the conditional-mean estimates are obtained. The results of Monte-Carlo simulations are presented in which the performance of these two algorithms is compared with that of a Kalman filter in which the quantization error is approximated by white noise.-
Clements, K. A.↗
On the minimax feedback control of uncertain dynamic systems.
In this paper the problem of optimal feedback control of uncertain discrete-time dynamic systems is considered where the uncertain quantities do not have a stochastic description but instead are known to belong to given sets. The problem is converted to a sequential minimax problem and dynamic programming is suggested as a general method for its solution. The notion of a sufficiently informative function, which parallels the notion of a sufficient statistic of stochastic optimal control, is introduced, and conditions under which the optimal controller decomposes into an estimator and an actuator are identified.
Bertsekas, D. P.↗
Stability conditions derived from spectral theory - Discrete systems with periodic feedback.
By use of the spectral theory of linear operators, necessary and sufficient conditions are derived for the stability of a class of discrete time feedback systems with a periodically time-varying feedback gain. These conditions involve a Nyquist plot for an equivalent time-invariant system which may be determined from the frequency response function of the system under consideration. In the special case of a scalar-input scalar-output system, these conditions may be given in a particularly simple form.
Davis, J. H.↗
On the stability of numerical integration routines.
Numerical integration methods for the solution of initial value problems for ordinary vector differential equations may be modelled as discrete time feedback systems. The stability criteria discovered in modern control theory are applied to these systems and criteria involving the routine, the step size and the differential equation are derived. Linear multistep, Runge-Kutta, and predictor-corrector methods are all investigated.
Glover, K.↗
Recent results in convolution feedback systems.
Survey of recent results obtained by the authors concerning certain types of multiinput, multioutput feedback systems. The discrete-time case as well as the continuous-time case are considered. In each case three theorems are shown. These give insight into the nature of the relationship between the open-loop operator and the closed-loop operator of the system, as well as necessary and sufficient conditions for stability of the closed-loop system when 'unstable' poles are present in their open-loop transfer function.
Desoer, C. A.↗
Development of a multikilowatt ion thruster power processor
A feasibility study was made of the application of silicon-controlled, rectifier series, resonant inverter, power conditioning technology to electric propulsion power processing operating from a 200 to 400 Vdc solar array bus. A power system block diagram was generated to meet the electrical requirements of a 20 CM hollow cathode, mercury bombardment, ion engine. The SCR series resonant inverter was developed as a primary means of power switching and conversion, and the analog signal-to-discrete-time-interval converter control system was applied to achieve good regulation. A complete breadboard was designed, fabricated, and tested with a resistive load bank, and critical power processor areas relating to efficiency, weight, and part count were identified.
Schoenfeld, A. D.↗