This paper studies an improved fractional order parallel control structure (FOPCS) for enhancing the robustness in an industrial control loop having a first order process with dead time along with its tuning aspects. Since inclusion of fractional order calculus also increase the number of parameters to be determined for a particular control loops, tuning becomes an essential task. Four different tuning methods are considered to optimize the gains of parallel control structure (PCS) and FOPCS. Integral of time weighted absolute error for servo and regulatory problems along with overshoot value have been considered for performance evaluation. Extensive simulation studies including change in setpoint and mismatch in processmodel parameters have been carried out. On the basis of these studies, it was observed that FOPCS tuned by backtracking search algorithm, outperformed all other controllers in terms of considered performance measures.
If the inline PDF is not rendering correctly, you can download the PDF file here.
 G. Karunagaran and C. Wenjian, “The Parallel Control Structure for Transparent Online Tuning”, Journal of Process Control, vol. 21, no. 7, pp. 1072–1079, 2011.
 K. J. Åström and T. Hägglund, “The Future of PID Control”, Control Engineering Practice,vol. 9, no. 11, pp. 1163–1175, 2001.
 L. Desborough and R. Miller, “Increasing Customer Value of Industrial Control Performance Monitoring-Honeywell’s Experience”, In AIChE Symposium Series 2002, pp. 169–189, New York, American Institute of Chemical Engineers.
 P. V. Overschee and B. D. Moor, “The End of Heuristic PID Tuning”, IFAC Proceedings, vol. 33, no. 4, pp. 595–600, 2000.
 M. Miccio and B. Cosenza, “Control of a Distillation Column by Type-2 Type-1 Fuzzy Logic PID Controllers”, Journal of Process Control, vol. 24, no. 5, pp. 475–484, 2014.
 P. Mishra, V. Kumar, and K. P. S. Rana, “A Fractional Order Fuzzy PID Controller for Binary Distillation Column Control”, Expert Systems with Applications, vol. 42, no. 22, pp. 8533–8549, 2015.
 Y. Chen, H. Dou, B. M. Vinagre, and C. A. Monje, “A Robust Tuning Method for Fractional Order PI Controllers”, IFAC Proceedings, vol. 39, no. 11, pp. 22–27, 2006.
 A. Oustaloup, F. Levron, B. Mathieu, and F. M. Nanot, “Frequency-Band Complex Noninteger Differentiator: Characterization Synthesis”, IEEE Transactions on Circuits Systems I: Fundamental Theory Applications, vol. 47, no. 1, pp. 25–39, 2000.
 M. Zamani, M. Karimi-Ghartemani, and N. Sadati, “FOPID Controller Design for Robust Performance Using Particle Swarm Optimization”, Fractional Calculus Applied Analysis, vol. 10, no. 2, pp. 169–187, 2007.
 V. Kumar, K. P. S. Rana, J. Kumar, and P. Mishra, “Self-Tuned Robust Fractional Order Fuzzy PD Controller for Uncertain Nonlinear Active Suspension System”, Neural Computing Applications, pp. 1–17, 2016.
 I. Pan and S. Das, “Chaotic Multi-Objective Optimization Based Design of Fractional Order PIλDμ Controller in AVR System”, International Journal of Electrical Power & Energy Systems, vol. 43, no. 1, pp. 393–407, 2012.
 I. Pan and S. Das, “Fractional Order AGC for Distributed Energy Resources Using Robust Optimization”, IEEE Transactions on Smart Grid, vol. 7, no. 5, pp. 2175–2186, 2016.
 I. Pan, S. Das, and A. Gupta, “Tuning of an Optimal Fuzzy PID Controller with Stochastic Algorithms for Networked Control Systems with Random Time Delay”, ISA Transactions, vol. 50, no. 1, pp. 28–36, 2011.
 S. Das, I. Pan, and S. Das, “Performance Comparison of Optimal Fractional Order Hybrid Fuzzy PID Controllers for Handling Oscillatory Fractional Order Processes with Dead Time”, ISA Transactions, vol. 52, no. 4, pp. 550–566, 2013.
 V. Kumar, K. P. S. Rana, and P. Mishra, “Robust Speed Control of Hybrid Electric Vehicle using Fractional Order Fuzzy PD PI Controllers in Cascade Control Loop”, Journal of the Franklin Institute, vol. 353, no. 8, pp. 1713–1741, 2016.
 I. Podlubny, “Fractional-Order Systems Fractional-Order Controllers”, Institute of Experimental Physics, Slovak Academy of Sciences, Košice,, vol. 12, no. 3, pp. 1–18, 1994.
 P. Shah and S. Agashe, “Design Optimization of Fractional PID Controller for Higher Order Control System”, International conference of IEEE ICART, pp. 588–592 (2013).
 V. Feliu-Batlle, R. Rivas-Perez, and F. J. Castillo-Garcia, “Fractional Order Controller Robust to Time Delay Variations forWater Distribution in an Irrigation Main Canal Pool”, Computers electronics in agriculture, vol. 69, no. 2, pp. 185–197, 2009.
 I. Pan, S. Das, and A. Gupta, “Handling Packet Dropouts Random Delays for Unstable Delayed Processes in NCS by Optimal Tuning of Controllers with Evolutionary Algorithms”, ISA transactions, vol. 50, no. 4, pp. 557–572, 2011.
 Y. C. Cheng and C. Hwang, “Stabilization of Unstable First Order Time Delay Systems using Fractional Order PD Controllers”, Journal of the Chinese Institute of Engineers, vol. 29, no. 2, pp. 241–249, 2006.
 S. Manabe, “Early Development of Fractional Order Control”, InASME 2003 International Design Engineering Technical Conferences Computers Information in Engineering Conference 2003, pp. 609–616.
 S. Manabe, “A Suggestion of Fractional-Order Controller for Flexible Spacecraft Attitude Control”, Nonlinear Dynamics, vol. 29, no. 1, pp. 251–268, 2002.
 V. Goyal, P. Mishra, and V. K. Deolia, “A Robust Fractional Order Parallel Control Structure for Flow Control using a Pneumatic Control Valve with Nonlinear Uncertain Dynamics”, Arabian Journal for Science Engineering, pp. 1–15, 2018, DOI:10.1007/s13369-018-3328-6.
 R. Storn and K. Price, “Differential Evolution – Simple Efficient Heuristic for Global Optimization over Continuous Spaces”, Journal of global optimization, vol. 11, no. 4, pp. 341–359, 1997.
 S. Panda, “Differential Evolution Algorithm for SSSC-based Damping Controller Design Considering Time Delay”, Journal of the Franklin Institute, vol. 348, no. 8, pp. 1903–1926, 2011.
 S. Panda, “Robust Coordinated Design of Multiple Multi-Type Damping Controller using Differential Evolution Algorithm”, International Journal of Electrical Power & Energy Systems, vol. 33, no. 4, pp. 1018–1030, 2011.
 P. Civicioglu, “Backtracking Search Optimization Algorithm for Numerical Optimization Problems”, Applied Mathematics Computation, vol. 219, no. 15, pp. 8121–8144, 2013.
 D. Guha, P. K. Roy, and S. Banerjee, “Application of Backtracking Search Algorithm in Load Frequency Control of Multi-Area Interconnected Power System”, Ain Shams Engineering Journal 2016, (in press, available online).
 U. K. Rout, R. K. Sahu, and S. Panda, “Design Analysis of Differential Evolution Algorithm Based Automatic Generation Control for Interconnected Power System”, Ain Shams Engineering Journal, vol. 4, no. 3, pp. 409–421, 2013.
 Y. Sheoran, V. Kumar, K. P. S. Rana, P. Mishra, J. Kumar, and S. S. Nair, “Development of Backtracking Search Optimization Algorithm Toolkit in LabVIEWTM”, Procedia Computer Science, vol. 57, pp. 241–248, 2015.