A Nonparametric Approach to Design Fixed-order Controllers for Systems with Constrained Input

Sofiane Khadraoui, Hazem Nounou

Research output: Contribution to journalArticle


This paper presents an approach for designing fixed-structure controllers for input-constrained linear systems using frequency domain data. In conventional control approaches, a plant model is needed to design a suitable controller that meets some user-specified performance specifications. Mathematical models can be built based on fundamental laws or from a set of measurements. In both cases, it is difficult to find a simple and reliable model that completely describes the system behavior. Hence, errors associated with the plant modeling stage may contribute to the degradation of the desired closed-loop performance. Due to the fact that the modeling stage can be viewed only as an intermediate step introduced for the controller design, the concept of data-based control design has been introduced, where controllers are directly designed from measurements. Most existing data-based control approaches are developed for linear systems, which limit their application to systems with nonlinear phenomena. An important non-smooth nonlinearity observed in practical applications is the input saturation, which usually limits the system performance. Here, we attempt to develop a nonparametric approach to design controllers from frequency-domain data by taking into account input constraints. Two practical applications of the proposed method are presented to demonstrate its efficacy.

Original languageEnglish
JournalInternational Journal of Control, Automation and Systems
Publication statusAccepted/In press - 1 Jan 2018



  • Actuator saturation
  • constrained optimization
  • data-based control
  • energy consumption
  • frequency response
  • safe process operation

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications

Cite this