PSO Based Weight Selection and Fixed Structure Robust Loop Shaping Control for Pneumatic Servo System with 2DOF Controller

Authors: Randeep Kaur, Jyoti Ohri

Abstract:

This paper proposes a new technique to design a fixed-structure robust loop shaping controller for the pneumatic servosystem. In this paper, a new method based on a particle swarm optimization (PSO) algorithm for tuning the weighting function parameters to design an H∞ controller is presented. The PSO algorithm is used to minimize the infinity norm of the transfer function of the nominal closed loop system to obtain the optimal parameters of the weighting functions. The optimal stability margin is used as an objective in PSO for selecting the optimal weighting parameters; it is shown that the proposed method can simplify the design procedure of H∞ control to obtain optimal robust controller for pneumatic servosystem. In addition, the order of the proposed controller is much lower than that of the conventional robust loop shaping controller, making it easy to implement in practical works. Also two-degree-of-freedom (2DOF) control design procedure is proposed to improve tracking performance in the face of noise and disturbance. Result of simulations demonstrates the advantages of the proposed controller in terms of simple structure and robustness against plant perturbations and disturbances.

Keywords: Robust control, Pneumatic Servosystem, PSO, H∞ control, 2DOF.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1337733

References:

[1] S. Kaitwanidvilai and M. Parnichkun, “Genetic Algorithm based Fixed- Structure Robust Η∞ Loop Shaping Control of a Pneumatic Servosystem,” International Journal of Robotics and Mechatronics, Vol. 16, No. 4, pp. 363-372, 2004.
[2] S. Skogestad, and I. Postlethwaite, “Multivariable Feedback Control: Analysis and Design”, John Wiley & Sons, England, Second Edition, 2005.
[3] X. D. Sun, P. G. Scotson and G. Balfour, “A Further Application of Loop Shaping H-infinity Control to Diesel Engine Control-Driven-Idle Speed Control,” SAE World Congress, March 2002.
[4] N. Phurahong, S. Kaitwanidvilai and A. Ngaopitakkul, “Fixed Structure Robust 2DOF H-infinity Loop Shaping Control for ACMC Buck Converter using Genetic Algorithm”, Proceedings of International MultiConference of Engineers and Computer Scientists 2012, IMECS2012,Vol.2, March 2012.
[5] U. Chaiya and S. Kaitwanidvilai, “Fixed-Structure Robust DC Motor Speed Control”, Proceedings of the International MultiConference of Engineers and Computer Scientists, IMECS 2009, Vol. 2, March 2009.
[6] P. Olranthichachat and S. Kaitwanidvilai, “Structure Specified Robust Control of a MIMO Electro-hydraulic Servo System Using Particle Swarm Optimization” Proceedings of the International MultiConference of Engineers and Computer Scientists, IMECS 2011, Vol. 2, March 2011.
[7] W. Tan, H. J. Marquez, T. Chen and R. K. Gooden, “H∞ Control Design for an Industrial Boiler”, Proceedings of the American Control Conference, pp. 2537-2542, June, 2001.
[8] C. D. Yang, H. C. Tai and C. C. Lee, “Systematic Approach to Selecting H∞ Weighting Functions for DC Servos”, Proceedings of 33rd Conference on Decision and Control, IEEE, pp. 1080-1085, December 1994.
[9] Y. Bensalem, L. Sbita and M. N. Abdelkrim, “A Robust Speed and ANN Sensorless Induction Motor Drives”, International Journal of Automation & Systems Engineering, June, Vol. 2, No. 2, p.3., 2008.
[10] Limebeer, D. J. N., Kasenally, E. M., & Perkins, J. D. “On the design of robust two-degree-of-freedom controllers” Automatica, 29(1), pp. 157– 168, 1993.
[11] C. McFarlane, and K. Glover, "A Loop Shaping Design Procedure using H∞ Synthesis," IEEE Transactions on Automatic Control, vol. 37, no. 6, pp. 759-769, June 1992.
[12] McFarlane, D. C. and Glover, K., “Robust Controller Design Using Normalized Coprime Factor Plant Descriptions” Lecture Notes in Control and Information Sciences, Springer, 1989.
[13] Z.L. Gaing, “A Particle Swarm Optimization Approach for Optimum Design of PID Controller in AVR System,” IEEE Transactions on Energy Conversion, Vol.19, no.2, pp. 384- 391, June, 2004.
[14] T. H. Kim, I. Maruta and T. Sugie, “Particle Swarm Optimization Based Robust PID Controller Tuning Scheme,” Proceedings of the 4th IEEE Conference on Decision and Control, pp. 200-205, Dec 2007.
[15] J. Kennedy and R. Eberhart, “Particle swarm optimization,” Proceedings of IEEE International Conference on Neural Networks, pp.1942-1948, 1995.
[16] Araki, M. and Taguchi, H., “Two-Degree-of-Freedom PID Controllers” International Journal of Control, Automation, and Systems, 1(4), pp. 401-411, 2003.
[17] MATLAB Robust Control Toolbox, Mathworks co., Ltd. (online) http://www.mathworks.com.