Brief Ripple-free conditions for lifted multirate control systems

  • Authors:

  • A. K. Tangirala;D. Li;R. S. Patwardhan;S. L. Shah;T. Chen

  • Affiliations:

  • Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada AB T6G 2G6;Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada AB T6G 2G6;Matrikon Consulting Co., Advanced Applications Group, Edmonton, Canada AB T5N 4A3;Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada AB T6G 2G6;Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada AB T6G 2G7

  • Venue:
  • Automatica (Journal of IFAC)
  • Year:
  • 2001

Quantified Score

Hi-index 22.15

Visualization

Abstract

Measurements in chemical processes are often unavailable at a uniform rate due to constraints on the sampling rates of process variables. Situations such as these and others give rise to a set of multirate signals comprising a multirate system. Control of multirate systems is appealing and challenging from a theoretical and practical point of view. Multirate control design in the lifting framework consists of lifting the system and subsequently designing a controller for the single-rate lifted system. In this work, it is shown that under certain conditions, intersample ripples arise in the outputs of closed-loop multirate systems. The process output can be guaranteed to be ripple-free if the controller satisfies certain constraints. Further, it is shown that the presence of an integrator in the plant aids in eliminating these intersample ripples. Experimental evaluations are presented in support of these theoretical results.