摘要:

The objective of this investigation is a preliminary design for an aerodynamic entry vehicle autopilot. The design was tested to its upper altitude limit which provides information for blending during control system transition from reaction jet to aerodynamic control. The longitudinal axis design is conventional for the short period mode with the difficulty that phugoid control with attitude feedback is not possible during entry. The lateral.directional axis design problem is dominated by poor co-ordination with an additional problem caused by large angle of attack variations. In all cases these problems are characterized by unconventional behaviour of the transfer function zeros. It is concluded that navigational aids are necessary for phugoid control and that aileron to rudder crossfeed reduces the adverse angle of attack effects and improves co-ordination.

ISSN:0020-7179    

DOI:10.1080/00207177308932354

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Two procedures are presented for the tracking problem whose desired trajectory is given as an output of a known dynamical system. Time-invariant, single-input, single-output, controllable and observable systems are considered. It is shown that the time-invariant overall structure with zero steady-state error can be obtained by choosing an appropriate dynamic controller and an appropriate cost functional.

ISSN:0020-7179    

DOI:10.1080/00207177308932355

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

This paper describes a formal method of designing optimal feedback controllers using the method of dynamic programming. Adopting a quadratic performance criterion, a multi-stage control law is easily programmed for a digital computer thus providing convergent feedback matrices. A visual display system is employed which allows the designer to simulate control of the process for a variety of conditions, enabling him to select the performance function which gives the desired system response.

ISSN:0020-7179    

DOI:10.1080/00207177308932356

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

A sufficient condition for consistent estimates of parametera in linear S.I.S.O. system identification is that the input signal should be ‘ persistently exciting ’, However,. in practice the exact nature of the test signal has a direct bearing upon the identification accuracy. This paper shows howa-prioriknowledge of the approximate system and noise model parameters may be used to design a test signal which will minimize the variance of the parameter estimates. The design procedure is computationally efficient as full advantage is taken of the special structure of linear S.I.S.O. systems. The optimal test signals are shown to result in a significant reduction in the parameter variances. This is of considerable practical importance as either the experiment time may be reduced for the same model accuracy or for fixed experiment time a model of much higher accuracy may be obtained.

ISSN:0020-7179    

DOI:10.1080/00207177308932357

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

This paper presents a systematic method of investigating the existence of limit cycle oscillations in feedback systems with combined integral pulse frequency-pulse width (IPF–P/V) modulation. The method is based on the non-linear discrete equivalence of the continuous feedback system containing the IPF–PW modulator.

ISSN:0020-7179    

DOI:10.1080/00207177308932358

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The object of study is a computer-regulated linear plant in a D.D.C arrangement. The plant is a representation in discrete form of a continuous process and its associated equipment, subject to computer quantization noise and environmental disturbances, all describable by rational transfer functions. It was shown in a previous paper (indberger 1972) that the discrete-time model of the system is a linear, stationary, mixed autoregressive, moving-average (RMA) process in the feedback variable deviation from its mean. After obtaining a large sample of this variable and computing its covariance function, a parameter estimation is performed by fitting the model autocovariance to the sample covariance in a maximum likelihood (L) sense. For a correct model assumption the procedure converges in probability and the estimates have typical ML properties such as consistency and normal distribution. The ML estimate is equivalent to a weighted least squares estimate, obtained by the minimization of certain quadratic forms with respect to the process parameters. The convergence in probability of the latter procedure and the ML properties of the estimates were shown by this author (indberger 1970). The method of identification is by repeated hypothesis trial and test using models of different configurations, under guidance of the results of previous trials. An example is given of a second-order plant subject to two different types of noise sources. Under the restrictions given, and at least for simple configurations of plant and noise sources, a computer-regulated plant can, therefore, be identified without using the standard method of injecting noise of a known spectral density.

ISSN:0020-7179    

DOI:10.1080/00207177308932359

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Geometric arguments are used, to discuss optimal control problems with higher-order state variable inequality constraints. Solutions with boundary arcs as well as with isolated boundary points are treated.

ISSN:0020-7179    

DOI:10.1080/00207177308932360

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

This paper presents a numerical technique which automatically computes the unspecified terminal-time of an optimal control problem as a systematic part of the whole procedure for finding the optimal control inputs.

ISSN:0020-7179    

DOI:10.1080/00207177308932361

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

A direct method for the solution of optimal control problems of linear time-invariant systems with integral quadratic energy constraint is developed with the help of functional analysis. It is based on the representation of the state transition matrix of the adjoint system in terms of an orthonormal set of functions in a finite dimensional sub-space of square integrable Hilbert space and the Fourier expansion of the control vector in the Hilbert space. It is shown that the optimal control vector exists uniquely and is expressed as a linear functional of the orthonormal basis functions of the finite sub-space. The simplicity of the method lies ultimately in reducing the optimal problem to that of solving a finite set of linear algebraic equations

ISSN:0020-7179    

DOI:10.1080/00207177308932362

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

This paper is concerned with the study of controllability of linear systems with delay in the control function. It has been illustrated that many of the techniques which proved to be useful in the study of linear systems with no delay (almanet al.19G2, Kroindlcr and Sarachik 1964) can be generalized when dealing with systems having delay in the control.

ISSN:0020-7179    

DOI:10.1080/00207177308932363

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor