摘要:

An application of recursive covariance lattice algorithms to the adaptive estimation and control of a manipulator with one flexible link is presented. These algorithms are a set of pure order recursive lattice equations, which can in principle identify the effective order and the corresponding parameters of an ARMA prediction model of the manipulator. The reduced-order prediction model represents the significant dynamics of the plant, and is used to generate control sequences by minimising a weighted performance index. In the simulations, the manipulator is modelled by the finite element method and Lagrange's equations. The performance and robustness of the lattice filter and the adaptive controller is demonstrated by numerical results.

DOI:10.1049/ip-d.1992.0031

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A performance index for control systems has been defined as the supremum of the absolute error that occurs over all time and all inputs. The input to the system is known only to the extent that it belongs to a known function space. This paper shows how this performance index is determined for certain sampled data systems with an input space characterised only by a bound on the derivative of the input. An example of a design using this performance index is given.

DOI:10.1049/ip-d.1992.0032

出版商:IEE    

年代:1992

数据来源: IET

摘要:

This paper describes a technique for designing digital regulators when their structure is restricted. A new formula is first derived for computing quadratic performance indices, which indicates that, rather than using iterative algorithms or residue calculus which may be difficult to apply for high-order systems, the problem reduces to solving certain Diophantine equations. Furthermore, gradients of the performance indices, which are needed in any algorithm for updating the controller parameters, can also be easily computed using similar equations. Based on this, we present a minimisation algorithm for tuning the controller parameters. Design of restricted complexity adaptive regulators used in controlling systems subjected to random noise is also given. Because of the importance of PID controllers, we show briefly how the method is applied to their tuning. Several examples for designing the controllers in both the adaptive and nonadaptive cases are given to demonstrate the feasibility of the proposed method and its merits.

DOI:10.1049/ip-d.1992.0033

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A design criterion is developed to achieve the following goals simultaneously: (i) input-output decoupling of multivariable feedback systems; (ii) complete and arbitrary closed-loop pole assignment; (iii) desired zero assignment for reference signal tracking; and (iv) robust stabilisation of multivariable feedback systems subjected to time-varying nonlinear uncertainties. Thus, the requirements of performance as well as stability robustness of a multivariable feedback system will be simultaneously met by employing this design criterion. Moreover, by minimisingH∞-norm of each channel of the closed-loop transfer matrix, we can obtain the robustness optimisation of the system, i.e., we can predict the maximum slope of the sector-bounded nonlinear uncertainties that can be tolerated in each channel of the system. A practical example, the lateral flight control of CCV (control configured vehicle), is given to illustrate the validity of the proposed design algorithm.

DOI:10.1049/ip-d.1992.0034

出版商:IEE    

年代:1992

数据来源: IET

摘要:

An improved procedure is presented for determining a state-space representation of a given time-invariant system whose dynamic behaviour is expressed in a differential operator form. The algorithm is essentially that developed by Wolovich, with the addition of those details and methods necessary to program the procedure, which were not included in his paper. The main modifications are a new method for transforming a polynomial matrix to an equivalent row-reduced matrix and a new technique for reducing the system so that the state equations are strictly proper.

DOI:10.1049/ip-d.1992.0035

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The previously proposed concept of classifying various discrete-time models, such as invariant and mapping models is extended to matched pole-zero models. In the existing matched pole-zero methods, the gain adjustment of the discrete-time model is required and the addition of extra zeros is often suggested in the literature. In the newly proposed method, there is no need for such adjustments. A simple example is provided to show this point and to explain why the existing models need these adjustments.

DOI:10.1049/ip-d.1992.0036

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A connectionist method for autotuning PID controllers is proposed. This technique, which is applicable both in open and in closed loops, employs multilayer perceptrons to approximate the mappings between the identification measures of the plant and the optimal PID values. The neutral network controller is designed to adapt to changing system structures and parameter values online. To achieve this objective, the network weighting coefficients are determined during an offline training phase. Simulation results are presented to illustrate the properties of the controller. One of the important aspects of neural networks is the convergence characteristic of this training phase. In the proposed approach, multilayer perceptrons are employed for nonlinear function approximation. As a consequence, the neurons have a linear activation function in their output layer. It is shown that a new learning criterion can be defined for this class of multilayer perceptrons, which is commonly found in control systems applications. Comparisons of the standard and the reformulated criteria, using different training algorithms, show that the new formulation achieves a significant reduction in the number of iterations needed to converge to a local minimum.

DOI:10.1049/ip-d.1992.0037

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A novel algorithm is presented in this paper for the solution to the continuous-time Lyapunov matrix equation in controllable and/or observable canonical forms by using the dimension-reduced method. The solution evaluation by this method is more accurate and considerably faster than any previously published methods. Numerical examples are given with systems in stable minimal and in unstable non-minimal to demonstrate the computational procedure.

DOI:10.1049/ip-d.1992.0038

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A new method of control system design is developed to simultaneously consider the internal stability, pole assignment, reference signal tracking and control input minimisation. A parametrised design algorithm of the pole-zero assignment control law is derived to achieve the desired goals. The free parameters are used to minimise theL2-norm of the control input signal. Since the requirements of internal stability are satisfied, this design algorithm performs appropriately, even if the plant is unstable and/or is in a nonminimum phase. Examples are given to illustrate the validity of the design algorithm.

DOI:10.1049/ip-d.1992.0039

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The distortion method was introduced by Butterfield and others as a means of verifying a nominal system model, comprising a set of ordinary, nonlinear differential equations, by comparing the model response with a set of experimentally obtained data. The essence of the method is to make the minimum distortions to the model parameters necessary to ensure that the model output exactly matches the measured data. The distortions thus obtained can then be tested againsta prioriknowledge of the parameters, in particular to see if the variance of the distortions is less than the uncertainty in the expected parameter values. In the paper it is shown that, if the nominal model is linear, then, under certain conditions, explicit formulas can be obtained for the distortions, or significant simplifications can be made to the equations, thus removing or reducing the considerable computational overhead inherent in the method. The results of the paper could find application not only in the area of linear modelling (for example in compartmental modelling) but also in model reduction and linearisation, where the method offers a means of testing the validity of the linear or reduced-order model.

DOI:10.1049/ip-d.1992.0040

出版商:IEE    

年代:1992

数据来源: IET