Predictive LPV control of a liquid-gas separation process

  • Authors:
  • J. V. Salcedo;M. Martínez;C. Ramos;J. M. Herrero

  • Affiliations:
  • Department of Systems Engineering and Control, Universidad Politécnica de Valencia, Camino de Vera S/N, 46022 Valencia, Spain;Department of Systems Engineering and Control, Universidad Politécnica de Valencia, Camino de Vera S/N, 46022 Valencia, Spain;Department of Systems Engineering and Control, Universidad Politécnica de Valencia, Camino de Vera S/N, 46022 Valencia, Spain;Department of Systems Engineering and Control, Universidad Politécnica de Valencia, Camino de Vera S/N, 46022 Valencia, Spain

  • Venue:
  • Advances in Engineering Software
  • Year:
  • 2007

Quantified Score

Hi-index 0.00

Visualization

Abstract

The problem of controlling a liquid-gas separation process is approached by using LPV control techniques. An LPV model is derived from a nonlinear model of the process using differential inclusion techniques. Once an LPV model is available, an LPV controller can be synthesized. The authors present a predictive LPV controller based on the GPC controller [Clarke D, Mohtadi C, Tuffs P. Generalized predictive control - Part I. Automatica 1987;23(2):137-48; Clarke D, Mohtadi C, Tuffs P. Generalized predictive control - Part II. Extensions and interpretations. Automatica 1987;23(2):149-60]. The resulting controller is denoted as GPC-LPV. This one shows the same structure as a general LPV controller [El Gahoui L, Scorletti G. Control of rational systems using linear-fractional representations and linear matrix inequalities. Automatica 1996;32(9):1273-84; Scorletti G, El Ghaoui L. Improved LMI conditions for gain scheduling and related control problems. International Journal of Robust Nonlinear Control 1998;8:845-77; Apkarian P, Tuan HD. Parametrized LMIs in control theory. In: Proceedings of the 37th IEEE conference on decision and control; 1998. p. 152-7; Scherer CW. LPV control and full block multipliers. Automatica 2001;37:361-75], which presents a linear fractional dependence on the process signal measurements. Therefore, this controller has the ability of modifying its dynamics depending on measurements leading to a possibly nonlinear controller. That controller is designed in two steps. First, for a given steady state point is obtained a linear GPC using a linear local model of the nonlinear system around that operating point. And second, using bilinear and linear matrix inequalities (BMIs/LMIs) the remaining matrices of GPC-LPV are selected in order to achieve some closed loop properties: stability in some operation zone, norm bounding of some input/output channels, maximum settling time, maximum overshoot, etc., given some LPV model for the nonlinear system. As an application, a GPC-LPV is designed for the derived LPV model of the liquid-gas separation process. This methodology can be applied to any nonlinear system which can be embedded in an LPV system using differential inclusion techniques.