摘要:

An observations-weighted (OW) controller is presented for linear discrete-time stochastic single-input single-output systems. A dual criterion to be minimized includes the usual OW-type cost function, but has in addition the terms of the sensitivity and complementary sensitivity weightings. A stabilizing controller is obtained by using the polynomial equation approach. The dual criterion OW controller proposed here is shown to be a usual OW controller with perturbed weighting functions for the tracking error and control signals. Furthermore, it is asserted that the resulting controller is useful for improving the robustness of the usual OW controller and is very simple to implement. Thus, the controller may be suitable for use in robust self-tuning control systems.

ISSN:0020-7179    

DOI:10.1080/00207179008953581

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The matrix polynomial method of optimization of linear multivariable continuous-time control for unstable plants with stationary stochastic inputs is derived in a constructive manner. New sufficient conditions are included but certain extra conditions imposed previously for continuous-time optimization are shown to be unnecessary. Kučera's second diophantine equation is derived directly from the requirement that the system be stable. As in discrete time, the second equation need not be used in the optimization when a certain coprimeness exists.

ISSN:0020-7179    

DOI:10.1080/00207179008953582

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The discrete-time stationary Kalman filter problem is solved in the z-domain for nth-order systems with>moutputs, where 0 ≤>k≤>mmeasurements are noise-free. The design equations are very similar to the continuous-time cage, and they can be solved by spectral factorization, giving the polynomial matrix D¯∼( z) which parametrizes the reduced-order optimal estimator in the frequency domain. By solving a single linear equation the equivalent time-domain representation for the optimal filter can also be obtained. A simple example demonstrates the filter design in the frequency domain.

ISSN:0020-7179    

DOI:10.1080/00207179008953583

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The old problem of designing reduced-order controllers has been addressed from many different angles. This paper offers an alternative approach to design reduced-order controllers for S1SO systems (the MIMO case is currently under development). The new design technique lies between the two common design methods. The first obtains the controller based on a reduced-order process model. The second obtains the controller by designing a controller for the full-order process model and by then reducing the order of this controller. Unlike those two ‘open-loop’ methods the method presented in this paper works directly with the closed-loop system during the design, thus ensuring that the reduced-order controller achieves a performance similar to that of a full-order controller. Roughly speaking, the proposed procedure computes the reduced-order controller by approximating an equivalent closed-loop state feedback system and then performing an inverse operation.

ISSN:0020-7179    

DOI:10.1080/00207179008953584

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Two practical methods of improving the accuracy of gaussian statistical linearization are compared (Beaman 1981 a, Leithead 1990 a). Both result in an improved estimate for the covariance of the systems. Three examples are used to compare the improved estimates with the gaussian estimate and, where possible, the exact solution. The first example is a scalar odd non-linearity driven by zero mean white noise. The second is a second-order system with odd symmetry and thus zero steady-state mean. The final example is a first-order system which has a bias introduced to produce a non-zero output. It is shown that both methods are an improvement over the gaussian method, but the method of Leithead is computationally easier than that of Beaman. The methods are then applied to the design of a control system for a position servomechanism with a backlash.

ISSN:0020-7179    

DOI:10.1080/00207179008953585

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Global asymptotic stabilization of nominally linear uncertain systems is considered where uncertain elements in the plant are modelled as cone bounded non-linearities. At first, a linear time-invariant state feedback law ensuring global asymptotic closed-loop stability is obtained. The algorithm which calculates such a feedback law is simple and straightforward. It does not involve repeated solutions of a parameter-dependent algebraic Riccati or any such non-linear equations. Any state feedback law thus developed can then be implemented via an observer specially designed to preserve the global asymptotic stability of the closed-loop system.

ISSN:0020-7179    

DOI:10.1080/00207179008953586

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Observers for non-linear uncertain dynamical systems are proposed. The non-linearity and uncertainty in the systems are assumed to be bounded. The bound is however unknown. The observer contains an adaptive scheme designed to accommodate the uncertainty. The design of the observer is only based on certain functional properties of the bound. No statistical information about the uncertainty needs to be assumed or utilized.

ISSN:0020-7179    

DOI:10.1080/00207179008953587

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

In this paper we analyse the problem of continuity of the closed-loop system map as a function of the compensator parameters. Under a suitable parametrization of the compensators we show that a necessary and sufficient condition for the closed-loop systems map to be continuous is given by max (>m, p) ≤ where the plant is a>p×>mplant of degree n. In particular, for single-input single-output plants, the closed-loop systems map is always continuous. The above result is surprising because the inequality is independent of the McMillan degree>qof the compensator. We also analyse the pole placement map and show that it always has points of discontinuity whenever>q> 0.

ISSN:0020-7179    

DOI:10.1080/00207179008953588

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The paper deals with a refined qualitative analysis of the motion of a broad class of continuous, time-varying, non-linear, implicit differential systems. These systems consist of a finite number of first-order implicit differential equations that cannot be set into a normal form. Some novel concepts of stability, boundedness and asymptotic stability, convenient for descriptions of the motion behaviour of the systems, are introduced, discussed and analysed. These concepts employ some nonlinear functions which are not usually in use in stability theory. For the concepts introduced, the general sufficient conditions are derived in terms of the existence of suitable Lyapunov functions. Also, for a subclass of the implicit systems considered, the results developed are specialized to use directly some inherent properties of these systems. The results obtained generalize a number of known results in stability theory, particularly those on the stability of singular (semistate) systems.

ISSN:0020-7179    

DOI:10.1080/00207179008953589

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Frequency-domain design in a quadratic cost setting is treated for a multivariable control system which includes disturbance feedforward, output feedback, and reference-input compensation (i.e. a three-degrees-of-freedom control system). The cost function is taken to account for tracking accuracy, plant saturation and plant sensitivity. The class of all controllers is determined for which the given system is internally asymptotically stable and the quadratic cost function is finite. This controller class is parametrized in terms of arbitrary real rational matrices ZzZuand Zwwhich are strictly proper and analytic in Re s ≥ 0. The optimal solution is obtained by setting the Z matrices to zero.

ISSN:0020-7179    

DOI:10.1080/00207179008953590

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor