Tracking of perturbed nonlinear plants using robust right coprime factorization approach

Abstract

This paper deals with a plant output tracking design problem of perturbed nonlinear plants by using robust right coprime factorization approach. One of the interesting control system design schemes, which was given by G. Chen and Z. Han, uses robustness of the right coprime factorization for robust stability of the closed-loop system with perturbation. Unfortunately, the robust right coprime factorization cannot easily improve the tracking performance of the control system except for simple cases. I n this paper, nonlinear operatorbased design method for nonlinear plant output to track a reference input is given. Examples are presented to support the theoretical analysis.

Operator-Based Nonlinear Feedback Control Design Using Robust Right Coprime Factorization

“…The space U s is said to be normed if each element x in Us has a norm k x k which can be defined in any way so long as the following three properties are fulfilled: 1) k x k is real, positive number and is different from zero unless x is identically zero. 2) k ax k= jaj k x k. 3 …”

“…Also, the method proposed in [3] is difficult to use for the case in this note, because the method requires the detailed information of 1N.…”

“…Especially, right coprime factorization of nonlinear systems has attracted much attention due to its usefulness in stabilization of nonlinear plants. Recently, robust right coprime factorization of nonlinear plants under perturbations has been studied in [1], and output tracking problem of perturbed nonlinear plants [3] has been considered by extending the design scheme given in [1]. In this case, the nonlinear plant output and reference input share the same space and the Bezout identity is equal to the identity operator, where the perturbation is known.…”

“…Systems in a range of industries are well modeled by bilinear systems, for example, gas-fired furnaces [2], polymerization reactors [3] and papermaking processes [4]. While such a system possesses many similarities to linear systems, the effects of nonlinearity, caused by the multiplicative term involving the product of the control input and system states, are often not negligible.…”

Robust non-linear control and tracking design for multi-input multi-output non-linear perturbed plants

“…Robust control design has been widely investigated using several kinds of effective methods [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Among the above methods, factorisation approach is an interesting one [1-3, 5-8, 10, 16-19].…”