Enhanced Dynamic Set-point Weighting Design for Two-Input-Two-Output (TITO) Unstable Processes
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Purushottama Rao Dasari
Abstract
Control of unstable systems with time delays usually result in overshoots in the closed loop responses. The intricacy involved in multivariable unstable processes further makes the problem more challenging. In industry, set-point weighting is one of the recommended methods to minimize the overshoot. However, design of the set-point weighting parameters determines the percentage of minimization of the overshoot. In this paper, a method is proposed to design the set-point weighting parameters for unstable multivariable processes which is relatively simple and also reduces the overshoot. Weighting is considered for both proportional (β) and derivative (γ) terms in the PID control law. In the closed loop relation for set-point tracking, the coefficients of ‘s’ and ‘s3’ both in the numerator and denominator are made equal in order to find dynamically β and γ. The obtained expressions for β and γ are simple and dynamically depends on the controller parameters and are applied to TITO systems in present work. Decouplers are used in TITO systems mainly to reduce the interaction between the loops so that they can be viewed as independent loops. Decoupler design suggested by (Hazarika and Chidambaram [1] has been used in this work and two TITO unstable processes with time delays are illustrated here. Comparison with the reported methods available in literature verifies that the proposed method gives improved closed loop performance.
References
[1] Hazarika S, Chidambaram M. Design of proportional integral controllers with decouplers for unstable two input two output systems. Ind Eng Chem Res. 2014;53:6467–76. DOI: 10.1021/ie403791q.Search in Google Scholar
[2] Chen CC, Huang HP, Liaw HJ. Set-point weighted PID controller tuning for time-delayed unstable processes. Ind Eng Chem Res. 2008;47:6983–90. DOI: 10.1021/ie800001m.Search in Google Scholar
[3] Vijayan V, Panda RC. Design of a simple setpoint filter for minimizing overshoot for low order processes. ISA Trans. 2012;51:271–6. DOI: 10.1016/j.isatra.2011.10.006.Search in Google Scholar PubMed
[4] Musmade L, Chidambaram M. Learning automata based set-point weighted parameter for unstable systems. IFAC. 2014;47. doi:10.3182/20140313-3-IN-3024.00162.Search in Google Scholar
[5] Begum KG, Rao AS, Radhakrishnan TK. Maximum sensitivity based analytical tuning rules for PID controllers for unstable dead time processes. Chem Eng Res Des. 2016;109:593–606. DOI: 10.1016/j.cherd.2016.03.003.Search in Google Scholar
[6] Wang Q, Lu C, Pan W. IMC PID controller tuning for stable and unstable processes with time delay. Chem Eng Res Des. 2016;105:120–9. DOI: 10.1016/j.cherd.2015.11.011.Search in Google Scholar
[7] Dasari PR, Kuncham R, Rao AS, Vilanova R Optimal H2 – IMC based simple PID tuning rules for unstable time delay processes. In: 2017 Indian Control Conf. ICC 2017 - Proc., 2017:403–8.10.1109/INDIANCC.2017.7846508Search in Google Scholar
[8] Rao P, Alladi L, Rao AS, Yoo C. Enhanced design of cascade control systems for unstable processes with time delay. J Process Control. 2016;45:43–54. DOI: 10.1016/j.jprocont.2016.06.008.Search in Google Scholar
[9] Begum KG, Rao AS, Radhakrishnan TK. Enhanced IMC based PID controller design for non-minimum phase ( NMP) integrating processes with time delays. ISA Trans. 2017;68:223–34. DOI: 10.1016/j.isatra.2017.03.005.Search in Google Scholar PubMed
[10] Bingi K, Ibrahim R, Karsiti MN, Hassan SM. Fractional-order filter design for set-point weighted PID controlled unstable systems. Int J Mech Mechatron Eng. 2017;17:173–9.Search in Google Scholar
[11] Nasution AA, Jeng JC, Huang HP. Optimal H2 IMC-PID controller with set-point weighting for time-delayed unstable processes. Ind Eng Chem Res. 2011;50:4567–78. DOI: 10.1021/ie1021688.Search in Google Scholar
[12] Georgiou A, Georgakis C, Luyben WL. Control of a multivariable open-loop unstable process. Ind Eng Chem Res. 1989;28:1481–9. DOI: 10.1021/ie00094a008.Search in Google Scholar
[13] Govindhakannan J, Chidambaram M. Multivariable PI control of unstable systems. Process Control Qual. 1997;3:319–29.Search in Google Scholar
[14] Tanttu JT, Lieslehto J. A comparative study of some multivariable PI controller tuning methods. IFAC Proc Vol. 1991;24:357–62.10.1016/B978-0-08-040935-1.50062-4Search in Google Scholar
[15] Besta CS, Chidambaram M. Decentralized PID controllers by synthesis method for multivariable unstable systems. IFAC-PapersOnLine. 2016;49:504–9. DOI: 10.1016/j.ifacol.2016.03.104.Search in Google Scholar
[16] Rajapandiyan C, Chidambaram M. Controller design for MIMO processes based on simple decoupled equivalent transfer functions and simplified decoupler. Ind Eng Chem Res. 2012;51:12398–410. DOI: 10.1021/ie301448c.Search in Google Scholar
[17] Raviteja K, Dasari PR, Rao AS. Improved controller design for two-input-two-output ( TITO) unstable processes. Resour Technol. 2016;2:S76–86. DOI: 10.1016/j.reffit.2016.10.009.Search in Google Scholar
[18] Dasari PR, Raviteja K, Rao AS. Optimal H2 – IMC based PID controller design for multivariable unstable processes. IFAC-PapersOnLine. 2016;49:617–22.10.1016/j.ifacol.2016.03.124Search in Google Scholar
[19] Dasari PR, Chidambaram M, Seshagiri Rao A. Simple method of calculating dynamic set-point weighting parameters for time delayed unstable processes. IFAC-PapersOnLine. 2018;51:395–400.10.1016/j.ifacol.2018.05.058Search in Google Scholar
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Articles in the same Issue
- Editorial
- ICACSE-2019
- Research Articles
- Concentration Enrichment of Fermentation Derived Acetic Acid: Transport Modeling of Forward Osmosis-Nanofiltration Integrated System
- Simulation of a Scaled down 250 MWe CFB Boiler Using Computational Particle Fluid Dynamics Numerical Model
- Effect of Temperature on Effluent Quality in a Biological Wastewater Treatment Process
- Kinetic Modeling and Optimization of the Release Mechanism of Curcumin from Folate Conjugated Hybrid BSA Nanocarrier
- Optimization of Aqueous Two Phase Extraction of Proteins from Litopenaeus Vannamei Waste by Response Surface Methodology Coupled Multi-Objective Genetic Algorithm
- Optimization of the Ratio of ω-6 Linoleic and ω-3 α-Linolenic Fatty Acids of Hemp Seed Oil with Jackknife and Bootstrap Resampling
- Enhanced Dynamic Set-point Weighting Design for Two-Input-Two-Output (TITO) Unstable Processes
- The Hydrodynamics Studies on Loop Seal in CFBC Boiler Using CFD Analysis
- Assessment of Proportional Integral Derivative Control Loops for Large Dominant Time Constant Processes
