Abstract
A new cascade control program was proposed based on modified internal model control to handle stable, unstable and integrating processes with time delay. The program had totally four controllers of which the secondary loop had two controllers and the primary loop had two controllers. The two secondary loop controllers were designed using IMC technique. They were decoupled completely and could be adjusted independently, which avoided the undesirable influence on performance of the primary controllers. The main controller in the primary loop was devised as a PID using the method of minimum sensitivity, which could guarantee not only the nominal performance but also the robust stability of the system. A setpoint filter was added in the primary loop to improve the tracking performance. All the controllers of the two closed-loops were designed analytically, and could be adjusted and optimized by single parameter respectively. Simulations were carried out on three various processes with time delay, and the results show that the proposed method can provide a better performance of both set-point tracking and disturbance rejection and robustness against parameters perturbation.
Similar content being viewed by others
References
SONG Si-hai, CAI Wen-jian, WANG Ya-gang. Auto-tuning of cascade control systems [J]. ISA Transactions, 2003, 42(1): 63–72.
UTKAL M, SOMANATH M. On-line identification of cascade control systems based on half limit cycle data [J]. ISA Transactions, 2011, 5(3): 473–478.
UMA S, CHIDAMBARAM M, SESHAGIRI R A. Enhanced control of integrating cascade processes with time delays using modified Smith predictor [J]. Chemical Engineering Science, 2010, 65(3): 1065–1075.
TAN K, LEE T H, FERDOUS R. Simultaneous online automatic tuning of cascade control for open loop stable processes [J]. ISA Transactions, 2000, 39(2): 233–242.
ALFARO V M, VILANOVA R, ARRIETA O. Two-degree-offreedom PI/PID tuning approach for smooth control on cascade control systems [C]// 47th IEEE Conference on Decision and Control. Cancun, Mexico, 2008: 9–11.
ALFARO V M, VILANOVA R, ARRIETA O. Robust tuning of two-degree-of-freedom (2-Dof) PI/PID based cascade control systems [J]. Journal of Process Control, 2009, 19(10): 1658–1670.
IBRAHIM K, TAN N, DEREK P A. Improved cascade control structure for enhanced performance [J]. Journal of Process Control, 2007, 17(1): 3–16.
LIU Tao, GU Dan-ying, ZHANG Wei-dong. Decoupling two-degreeof-freedom control strategy for cascade control systems [J]. Journal of Process Control, 2005, 15(2): 159–167.
LIU Tao, ZHANG Wei-dong, GU Dan-ying. Analytical design for a class of open-loop unstable cascade control systems [J]. Journal of Control and Decision, 2004, 19(8): 872–876. (in Chinese)
SARAF V, ZHAO F T, BEQUETTE B W. Relay autotuning of cascade-controlled open-loop unstable reactors [J]. Ind Eng Chem Res, 2003, 42(20): 4488–4494.
LIU Tao, ZHANG Wei-dong, GU Dan-ying. IMC-based control strategy for open-loop unstable cascade processes [J]. Ind Eng Chem Res, 2005, 44(4): 900–909.
LEE Y, SUNGOOL O, SUNWON P. Enhanced control with a general cascade control structure [J]. Ind Eng Chem Res, 2002, 41(11): 2679–2688.
IBRAHIM K, DEREK P A. Use of smith predictor in the outer loop for cascade control of unstable and integrating processes [J]. Ind Eng Chem Res, 2008, 47(6): 1981–1987.
DOLA G P, SOMANATH M. Modified smith predictor based cascade control of unstable time delay processes [J]. ISA Transactions, 2012, 51(1): 95–104.
DOLA G P, SOMANATH M. An improved parallel cascade control structure for processed with time delay [J]. Journal of Process Control, 2012, 49(6): 546–558.
RAO A S, SEETHALADEVI S, CHIDAMBARAM M. Enhancing the performance of parallel cascade control using Smith predictor [J]. ISA Transactions, 2009, 48(2): 220–227.
LEE Y, SKLIAR M, LEE. M Analytical method of PID controller design for parallel cascade control [J]. Journal of Process Control, 2006, 16(8): 809–818.
ZHANG Wei-dong, XU Xiao-ming, SUN You-xian. Quantitative performance design for integrating processes with time delay [J]. Automatica, 1999, 35(4): 719–723.
ZHOU K, DOYLE J C. Essentials of robust control [M]. Upper Saddle River: Pentice Hall, 1998: 129–150.
RICHARD Y C, MICHAEL G S. Robust control toolbox user’ guide [M]. 3rd Edition, Natick, MA: The MathWorks, Inc, 1998: 26–38.
Author information
Authors and Affiliations
Corresponding author
Additional information
Foundation item: Project(J11LG02) supported by the Science and Technology Funds of Education Department of Shandong Province, China
Rights and permissions
About this article
Cite this article
Yin, Cq., Hui, Hz., Yue, Jg. et al. Cascade control based on minimum sensitivity in outer loop for processes with time delay. J. Cent. South Univ. 19, 2689–2696 (2012). https://doi.org/10.1007/s11771-012-1328-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11771-012-1328-3