摘要:

The paper describes a general approach to state variable feedback pole assignment for linear discrete-time systems. This is based on the definition of a non-minimal state space (NMSS) whose state variables are defined only in terms of the present and past values of the system output and the past values of its input. In more conventional block-diagram terms, it can be interpreted as an extension to a proportional-integral (PI) control system in which linear feedback and forward path digital filters are introduced to ensure the required closed-loop pole assignment, For this reason, we refer to it as a proportional-integral-plus or PIP system. The paper discusses the conditions for pole assignability. Practical examples which illustrate the performance of the PIP system in fixed gain and self tuning/adaptive applications are also discussed.

ISSN:0020-7179    

DOI:10.1080/00207178708934021

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A procedure for designing two-input one-output compensators to achieve asymptotic tracking of a class of reference signals is presented. It is shown that if no mode of the reference signal is a transmission zero of the plant, the design is always possible. The design consists of two steps: stabilization and tracking.

ISSN:0020-7179    

DOI:10.1080/00207178708934022

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An improved recursive least squares algorithm for parameter estimation is presented which includes: on/off criteria to prevent parameter drift during periods of low excitation; a variable forgetting factor which maintains the trace of the covariance matrix at a user-specified value; data preprocessing and normalization to improve numerical accuracy; scaling of the regressor vector to minimize the condition number of the covariance matrix; plus independent estimation of the mean values of the input/output data which can be used to eliminate errors due to d.c. bias or slowly drifting elements in the regressor vector. The algorithm can also include parameter projection to constrain the estimates to apriorispecified regions and retains the formal properties, such as convergence, of a true weighted least squares algorithm. The proposed algorithm is compared with other modifications suggested in the literature, and its advantages are demonstrated by a simulated example.

ISSN:0020-7179    

DOI:10.1080/00207178708934023

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An observer design method for a certain class of non-linear single output systems is introduced. The characteristic feature of this method consists of the fact that it does not require any linearization in the way that the given non-linear system is approximated by a linear one. The present paper deals with the derivation of a transformation of the considered non-linear system into a generalized observer canonical form (GOCF) which enables a systematic observer design similar to the linear one based on the well-known linear observer canonical form. To assign conditions for its existence, the transformation into the GOCF is carried out in two steps via a generalized observability canonical form (GOBCF). In contrast to previous forms used for linear systems, the two non-linear canonical forms presented here also depend on the time derivatives of the input variables. This means that the resulting observer has to be supplied, not only with the input and output variables of the given system, but also with derivatives of the input variables. However, a final example shows that it is possible to eliminate those derivatives in special cases.

ISSN:0020-7179    

DOI:10.1080/00207178708934024

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The paper presents a new method for the analysis of linear singular systems via the single-term Walsh series (STWS) approach. Block pulse and discrete solutions are obtained for any length of time. The method is very simple and direct and can easily be implemented on a digital computer.

ISSN:0020-7179    

DOI:10.1080/00207178708934025

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new method for computing transfer functions of linear time-invariant multi-variable control systems is presented. This method has the following attractive features: (i) it produces analytical expressions for transfer functions, (ii) computations are inherently parallel and can be implemented, for instance, on parallel processors with a fine-grain architecture, (iii) calculations of transfer functions are reduced to two well-studied computational problems: solution of simultaneous linear equations and the fast Fourier transform (FFT), and (iv) state-variable formulations can be avoided. Theoretical conclusions are demonstrated with numerical examples.

ISSN:0020-7179    

DOI:10.1080/00207178708934026

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Based on the explicit algebraic dependences p — g(F) between the vector p of the closed-loop characteristic-polynomial coefficients and the static output feedback matrix F, the well-known problem of arbitrary pole assignability by static output feedback is considered: local pole assignability is possible if and only if the differential g*has full rank. Taking advantage of the known analytical dependences of g*FF on F, new sufficient criteria for global pole assignability are derived. An explicit formula to compute the algebraic submanifold of feedback matrices F for which g*Fdoes not have full rank is also obtained. If the property of local pole assignability holds, then there exists a smooth submanifold of matrices F each point of which ensures the desired pole assignment. An algorithm by which this smooth submanifold can be computed is outlined. Illustrative examples are discussed in some detail.

ISSN:0020-7179    

DOI:10.1080/00207178708934027

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper considers the design of decentralized robust output controls. The system under consideration is composed of interconnected subsystems with time-varying uncertainties. The decentralized control is based on the information of the local output. No communication is allowed among subsystems. The proposed control strategy is a combination of direct and indirect decentralized controls. The salient feature of the controls is that they require only information about the possible bounds of uncertainties.

ISSN:0020-7179    

DOI:10.1080/00207178708934028

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

For many industrial processes, it is of interest to design a decoupling precompensator. The precompensator makes it possible to design controllers based on single-input-single-output models of the process. A model of the process must be known to design the precompensator. This paper shows how the precompensator can be designed adaptively using input-output measurements. The precompensator is first designed for the case when the process is known. The adaptive precompensator is then constructed using the certainty equivalence principle. The convergence properties and the implementation of the adaptive decoupler are discussed. It is shown that the adaptive scheme will converge provided the system is persistently excited and that a suitable model structure is used in the estimation.

ISSN:0020-7179    

DOI:10.1080/00207178708934029

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

It is well known that while the perfect model matching condition (i.e. unstable plant zeros must be zeros of the reference model) is not met, the model reference adaptive control cannot easily be implemented. In adaptive control systems, since the plant is assumed to be unknown previously, it is a difficult task to choose an adequate reference model such that the perfect model matching condition is guaranteed in every adaptive step. In this paper, a new design algorithm for model reference adaptive control systems is proposed to synthesize an adaptive controller such that the error between the reference model output and the plant output can vanish in a deadbeat manner. In this situation, the stringent matching condition can be relaxed in every adaptive step, so our design algorithm is also suitable for unstable or non-minimum phase systems. Several simulation results are presented to illustrate the good behaviour of our design algorithm.

ISSN:0020-7179    

DOI:10.1080/00207178708934030

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor