Multivariable robust optimal PID controller design for a non-minimum phase boiler system using loop transfer recovery technique

Abstract

LQG/Loop Transfer Recovery (LQG/LTR)technique based on Kalman filter as observer, has some difficulties in facing with non-minimum phase systems. The main problem is that the observer becomes unstable when the compensator recovers the target loop asymptotically. In this paper, we propose an optimal robust recoverable target loops for a boiler system. Using asymptotic time-scale eigenstructure assignment ATEA algorithm a stable observer is designed that makes the target loop recovered. Then, the controller is reduced to a PID controller for experimental purposes. Recoverability of target loop under controller reduction has been analyzed. Numerical results of two controllers are given in time and frequency domain. Comparing with a similar work based on loop-shaping approach, LQG/LTR controller shows improvements in energy consumption and time responses.

Design of robust optimal proportional–integral–derivative controller based on new interval polynomial stability criterion and Lyapunov theorem in the multiple parameters' perturbations circumstance

“…In [30], Ying Huang develops a method for design of the robust PID controller that adopts Kharitonov's interval polynomial stability theorem. In paper [31], the loop transfer recovery (LTR) technique is also used to design the robust optimal PID controller.…”

Robust optimal controller design for a non-minimum phase boiler system with a saturable actuator

“…We mentioned that reducing the controller to simpler orders, has the cost of recoverability loss. For example, the estimated PI controller in [19] is not as reasonable as the reduced controller of this paper. Additionally, the controller robustness against an actuators constraint is analytically and numerically checked.…”

“…The designed controller for the current system is reduced to a PID controller in [12,19] with an almost same approach. Furthermore, [19] showed that ignoring high frequency harmonics, the reduced controller can reasonably recover the TLTF.…”

“…Furthermore, [19] showed that ignoring high frequency harmonics, the reduced controller can reasonably recover the TLTF. As another approach, we aim to reduce the controller order such that high and low frequency properties of the controller are more preserved.…”

Nonminimum-phase process control with controllers based on simplified modeling

“…For last several years, a number of different solutions to this problem have been reported in literature. Some of them are based on modification of PID control [22] while others make use of artificial neural networks [23] or fuzzy logic techniques [12]. The advanced control strategies were also applied for control of different nonminimum-phase processes, validated by simulation, e.g.…”