摘要:

The paper presents a new approach towards unbiased estimation of the transfer functions of continuous-time SISO systems via Markov parameters. A new set of parameters known as Markov-Poisson parameters is introduced to generalise the definition of Markov parameters, thereby lending much flexibility to the estimated model. An effective algorithm giving continuous-time transfer functions through the estimation of such models, and its recursive version are discussed in detail. Numerical examples are included to illustrate the proposed method and its superiority over some existing ones.

DOI:10.1049/ip-d.1993.0001

出版商:IEE    

年代:1993

数据来源: IET

摘要:

Approaches to system identification can involve the estimation of parameters in a number of separate single-input models or the estimation of a single model using multiple-run techniques in which several data sets are combined. Multiple-run identification can be achieved through application of the superposition principle but this approach is restricted to linear systems and requires test records which are all of the same length. Here a multiple-cost approach is proposed which is found to be extremely powerful and useful. A relationship between the results obtained using this approach and those obtained using straightforward individual-run identification is derived, and its accuracy investigated. Using this relationship, it is possible to obtain estimates for multiple-cost identification results on the basis of individual-run results, allowing existing single-run software and techniques to be used unchanged for multiple-cost identification. An example is given of the use of multiple-cost identification with flight data for a Puma helicopter; good results are obtained and some important issues highlighted and discussed.

DOI:10.1049/ip-d.1993.0002

出版商:IEE    

年代:1993

数据来源: IET

摘要:

Compensators can be designed to give zero steady-state error in tracking arbitrary periodic or repetitive reference signals. The previously presented technique for design of the compensator has a limited convergence rate for the decay of tracking errors and a limited region of stability. Several alternative design approaches are presented which yield improvements in high-frequency convergence rate while some designs also improve stability. The design approaches are in two classes, designs based on adding periodic correction to an existing controller and total designs for transient and periodic performance. The approaches include FIR and IIR filter design by pole placement and linear quadratic control design.

DOI:10.1049/ip-d.1993.0003

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The paper presents a top-down methodology for an approach to the systematic design of medium-to-coarse grain multiprocessor systems for real-time computer controllers. The scheme exploits the processing requirements of control applications to simplify software development and maintenance. A design example of a transputer system for the adaptive control of a prototype three degrees of freedom direct drive arm, currently being developed at Oxford University, is given to exhibit the validity of the design philosophy.

DOI:10.1049/ip-d.1993.0004

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The paper presents a new method for model reference adaptive control for nonminimum phase discrete-time systems using approximate inverse systems obtained from the least-squares approximation. We show how unstable pole-zero cancellations can be avoided and how the effect of the disturbances can be decoupled from the plant output. Finally, the results of computer simulation are presented to illustrate the effectiveness of the proposed method.

DOI:10.1049/ip-d.1993.0005

出版商:IEE    

年代:1993

数据来源: IET

摘要:

In the paper a new class of output feedback variable structure controllers and state estimators (observers) for uncertain/nonlinear dynamic systems with bounded uncertainties and/or nonlinearities are proposed. No statistical information about the uncertain elements is assumed. A variable structure systems (VSS) approach together with the geometric approach to the analysis and synthesis of system zeros are employed in the synthesis of the proposed output feedback controllers and state estimators. The role of system zeros in the output feedback stabilisation and state estimation, using the VSS approach, is discussed. Numerical examples included illustrate the feasibility of the proposed stabilisation and state estimation schemes.

DOI:10.1049/ip-d.1993.0006

出版商:IEE    

年代:1993

数据来源: IET

摘要:

A new algorithm which extracts the disturbance model from a minimal model having a different input signal is given. The minimal model is used for adaptive pole placement incorporating the internal model principle. The closed-loop system is shown to reject the disturbances asymptotically. A stability analysis with persistency of excitation conditions towards convergence analysis of the proposed algorithm is also given. A number of simulated examples are given to demonstrate the performance of the algorithm.

DOI:10.1049/ip-d.1993.0007

出版商:IEE    

年代:1993

数据来源: IET

摘要:

Sufficient conditions are obtained for absolute stability of systems that are described by Lurie-type functional differential equations. It is assumed that the uncontrolled systems are unstable. The problem of Lurie consists of finding conditions for the feedback coefficients, and characterising the feedback function which make the trivial solutions of the functional differential equation stable. We assume that the system is completely controllable. The method is based on the use of Lyapunov functionals. A set of ‘easily verifiable’ sufficient conditions on the roots of certain ‘quasi-polynomial’ have been obtained. Systems of this kind are used for modelling a variety of control processes, including processes in biological systems.

DOI:10.1049/ip-d.1993.0008

出版商:IEE    

年代:1993

数据来源: IET