This paper deals with the adaptive control of linearly parameterized discretetime nonlinear system in the presence of bounded disturbances and unmodeled dynamics. A new adaptive law is presented. No a priori knowledge about the bounds on both the plant parameters and unmodeled uncertainty is required to implement the estimation algorithm. The adaptive scheme is free from singularity. This is ac...

In this paper, a nonlinear extension of the Georgiou-Smith system is considered and robustness results are proved for a nonlinear PI controller with respect to fast parasitic first-order dynamics. More specifically, for a perturbed nonlinear system with sector bounded nonlinearity and unknown control direction, sufficient conditions for global boundedness and attractivity have been derived. It ...

The problem of the integral evaluations of the state and control vectors in continuous multi-input-multi-output fuzzy control systems is investigated. The fuzzy controller is assumed to be nonlinearity in a bounded sector and the controlled plant a linear system described by the differential or integral equations. The stability problem is investigated and the problem of how to use the integral ...

In this report we discuss the design of cross-directional controllers which are guaranteed to be robustly stabilizing while incorporating a quadratic programme for steady state performance. The report is loosely based on the technical report of Akkermans (2003) who proposes using the multivariable circle criterion to guarantee closed-loop stability of cross-directional controllers in the presen...

Modern aircraft control systems contain the so-called rate limiter elements which are in fact incorporating the saturation function which is a bounded nonlinearity. In certain critical cases the so-called sector rotation a standard procedure in absolute stability leads to the fact that the sector conditions are broken outside a bounded domain. In order to apply standard results of the absolute ...

A class of Lyapunov functions is proposed for discrete-time linear systems interconnected with a cone bounded nonlinearity. Using these functions, we propose sufficient conditions for the global stability analysis, in terms of linear matrix inequalities (LMI), only taking the bounded sector condition into account. Unlike frameworks based on the Lur’e-type function, the additional assumptions ab...

Abstract— Many nonlinear dynamical systems can be written as Lur’e systems, which are described by a linear time-invariant system interconnected with a diagonal static sector-bounded nonlinearity. Sufficient conditions are derived for the global asymptotic stability analysis of discrete-time Lur’e systems in which the nonlinearities have restricted slope and/or are odd, which is the usual case ...

Tracking of reference signals (assumed bounded with essentially bounded derivative) is considered for a class of single-input, single-output, nonlinear systems, described by a functional differential equation with a hysteresis nonlinearity in the input channel. The first control objective is tracking, by the output, with prescribed accuracy: determine a feedback strategy which ensures that, for...

This paper addresses the control design problem for a certain class of continuous-time nonlinear systems subject to actuator saturations. The system under consideration consists of a system with two nested nonlinearities of different type: saturation nonlinearity and cone-bounded nonlinearity. The control law investigated for stabilization purposes depends on both the state and the cone-bounded...