Achievable PID performance using sums of squares programming

In addition to process elements like time delay, the PID structure of the controller can pose fundamental limitations on the achievable control performance. A key difficulty in characterizing the limitations due to controller structure is the non-convexity of the resulting optimization problem. In t...

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Bibliographic Details
Main Authors: Sendjaja, Antonius Yudi, Kariwala, Vinay
Other Authors: School of Chemical and Biomedical Engineering
Format: Journal Article
Language:English
Published: 2009
Subjects:
Online Access:https://hdl.handle.net/10356/90997
http://hdl.handle.net/10220/4618
Description
Summary:In addition to process elements like time delay, the PID structure of the controller can pose fundamental limitations on the achievable control performance. A key difficulty in characterizing the limitations due to controller structure is the non-convexity of the resulting optimization problem. In this paper, we present a global lower bound on the achievable PID performance, defined in terms of output variance, by solving a series of convex programs using sums of squares programming. This result is also extended to minimize the weighted sum of the variances of input rate and output. The tightness of the proposed bounds is demonstrated using several benchmark examples drawn from literature.