A model reference controller was designed for a unstable second-order system with time delay. The method basically derives the control law so as to make the error dynamics decay as per a third-order model. The resultant feedback control system was that of a lead-lag filter on the measurement y and a conventional Proportional - Integral - Derivative (PID) controller with a lead-lag filter in the forward path. The performance of the control system for both the servo and regulatory problems was better than that of Panda (Chemical Engineering Science, 64, pp. 2807-2816, 2009). The controller is robust for uncertainties in the model parameters such as time delay, time constant or process gain. © 2013 Copyright Indian Institute of Chemical Engineers.

Manickam Chidambaram

Error dynamics

Model parameters

MODEL REFERENCE

model reference control

PID controllers

Second-order systemss

SOPTD WITH A ZERO

Unstable system

Adaptive control systems

Control theory

Proportional control systems

Time delay

Delay control systems

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Model Reference Control of Unstable Second-order Systems with Time Delay

Indian Chemical Engineer

Using the direct synthesis method, a proportional - integral - derivative (PID) controller in series with a lead-lag compensator is designed for control of the open-loop unstable second order plus time delay processes with/without a zero. Set-point weighting is considered for reducing the overshoot. The method has two tuning parameters, and guidelines are provided for selecting the two tuning parameters. The method gives significant improvement in load disturbance rejection performances. The designed controller is also robust for uncertainties in the process parameters. Illustrative examples are considered to show the performances of the proposed method. Significant improvement is obtained when compared to recently reported methods. © 2006 American Chemical Society.

Industrial and Engineering Chemistry Research

Enhanced two-degrees-of-freedom control strategy for second-order unstable processes with time delay

Explicit design formula are derived for feedback controllers by model reference method, synthesis method and internal model control method for an unstable first-order plus time delay system. The performance of the proposed controllers is evaluated for perturbations in time delay, time constant and process gain. The performance is also compared with that of a conventional PI controller. Copyright © 1996 Elsevier Science Ltd. All rights reserved.

Computers and Chemical Engineering

Design of controllers for unstable first-order plus time delay systems

Chemical Engineering Science

Synthesis of PID controller for unstable and integrating processes

AIChE Journal

Design of advanced PID controller for enhanced disturbance rejection of second-order processes with time delay

Journal of Process Control

IMC design for unstable processes with time delays

Journal	Indian Chemical Engineer
ISSN	00194506
Open Access	No