Abstract
This paper deals with the problem of H ∞ control of linear two-time scale systems. The authors’ attention is focused on the robust regulation of the system based on a new modeling approach under the assumption of norm-boundedness of the fast dynamics. In the proposed approach, the fast dynamics are treated as a norm-bounded disturbance (dynamic uncertainty). In this view, the synthesis is performed only for the certain dynamics of the two-time scale system, whose order is less than that of the original system. It should be noted, however, that this scheme is significantly different from the conventional approaches of order reduction for linear two-time scale systems. Specifically, in the present work, explicitly or implicitly, all the dynamics of the system are taken into consideration. In other words, the portion that is treated as a perturbation is incorporated in the design by its maximum possible gain – in the L 2 sense – over different values of the inputs. One of the advantagesof this approach is that – unlike in the conventional approaches of the order reduction – the reduced-order system still keeps some information of the ‘deleted’ subsystem. Also, we consider the robust stability analysis and stability bound improvement of perturbed parameter (ɛ) in the two-time scale systems by using linear fractional transformations and structured singular values (μ) approach. In this direction, by introducing the parametric uncertainty and dynamic uncertainty in the two-time scale systems, we represent the system as a standard μ-interconnection framework by using linear fractional transformations, and derive a set of new stability conditions for the system in the frequency domain. The exact solution of ɛ-bound is characterized. It is shown that, in spite of the coupling between the dynamic uncertainties and certain dynamics, the designed H ∞ controller stabilizes the overall closed-loop system, in the presence of norm-bounded disturbances. To show the effectiveness of the approach, the modeling of the single-link flexible manipulator and control of the Tip-position of the manipulator by utilizing the mentioned method are presented in the case study.
Similar content being viewed by others
References
Cannon, J.R., Schmitz, E.: Initial experiments on the end-point control of a flexible one-link robot. Int. J. Rob. Res. 3, 62–75 (1984)
Chen, B.S., Lin, C.L.: On the stability bounds of singularly perturbed systems. IEEE Trans. Automat. Contr. 35(11), 1265–1270 (1990)
Chiou, J.S., Kung, F.C., Li, T.H.S.: An infinite ɛ-bound stabilization design for a class of singularly perturbed systems. IEEE Trans. Circuits Syst. 46, 1507–1510 (1999)
Doyle, J.C.: Analysis of feedback systems with structured uncertainties. IEE Proc. 129, Pt.D,
Doyle, J.C., Glover, K., Khargonekar, P.P., Francis, B.A.: State-space solutions to standard H 2 and H ∞ control problems. IEEE Trans. Automat. Contr. 34, 831–847 (1989)
Fraser, A.R., Daniel, R.W.: Perturbation Techniques for Flexible Manipulators. Kluwer (1991)
Fridman, E.: Exact slow–fast decomposition of the nonlinear singularly perturbed optimal control problem. Syst. Control. Lett. 40, 121–131 (2000)
Gajic, Z., Lelic, M.: Singular perturbation analysis of system order reduction via system balancing. Proc. of American Control Conference, pp. 2420–2424, 2000
Gawronski, W.: Computation of H ∞ norm for flexible structures. In: Proc. Ameri. Contr. Conf., June 1993
Green, M., Limebeer, D.J.N.: Linear Robust Control. Prentice Hall (1996)
Karimi, H.R., Yazdanpanah, M.J.: Robust control for a class of uncertain state-delayed singularly perturbed systems. Asian J. Control. 7(2), 202–208 (2005)
Karimi, H.R., Yazdanpanah, M.J.: Robust stability and disturbance attenuation for a class of uncertain singularly perturbed systems. Int. J. Control. Autom. Syst. 3(3), 164–169 (2001)
Karimi, H.R., Yazdanpanah, M.J.: Robust stability analysis of singularly perturbed systems using the structured singular values approach. Int. J. Sci. Technol. (Iranica Scientia) 9(4), 425–432 (2002)
Karimi, H.R., Yazdanpanah, M.J.: Robust stabilization of singularly perturbed systems based on a new modeling approach. Sixth Int. Conf. Contr. Autom. Robot. Visi. (ICARCV), Dec. 2000, Singapore
Khalil, H.K., Chen, F.C.: H ∞ control of two time scale systems. Syst. Control. Lett. 19(1), 35–42 (1992)
Kokotovic, P.V., Khalil, R.E., O’Reilly, J.: Singular Perturbation Methods in Control: Analysis and Design. Academic, New York (1986)
Li, X.P., Chang, B.C.: Properties of H ∞ Riccati solutions. In: Bhattacharyya, S.P., Keel, L.H. (eds.) Control of Uncertain Dynamic Systems, pp. 77–94. CRC, San Antonio Texas (1991)
Pan, Z., Basar, T.: H ∞-optimal control for singularly perturbed systems. Part I. Perfect state measurements. Automatica 29(2), 401–423 (1993)
Pan, Z., Basar, T.: H ∞-optimal control for singularly perturbed systems. Part I. Imperfect State Measurements. IEEE Trans. Automat. Contr. 39, 280–299 (1994)
Saksena, V.R., O’Reilly, J., Kokotovic P.V.: Singular perturbation and two-time-scale methods in control theory: Survey 1976–1983. Automatica 20(2), 273–293 (1984)
Sanchez-Pena, R.S., Sznaier, M.: Robust Systems Theory and Applications. Wiley (1998)
Shahruz, S.M., Behtash, S.: Balanced realization of singularly perturbed systems. Proc. 27th Conf. Decision and Control, pp. 1171–1172, 1988
Shi, P., Dragan, V.: Asymptotic control of singularly perturbed systems with parametric uncertainties. IEEE Trans. Automat. Contr. 44, 1738–1742 (1999)
Sicilano, B., Book, W.J.: A singular perturbation approach to control of lightweight flexible manipulators. Int. J. Rob. Res. 7(4), (Aug. 1988)
Tan, W., Leung, T., Tu, Q.: H ∞ control for singularly perturbed systems. Automatica 34(2), 255–260 (1998)
Tsai, M.C., Tsai, W.I., Sun, Y.Y.: Robustness analysis of singularly perturbed system. IEEE Proc. 30th Conf. Decis. Cont. Brighton, England, pp. 1075–1076, 1991
Tuan, H.D., Hosoe, S.: On a state-space approach in robust control for singularly perturbed systems. Int. J. Control 66(3), 435–462 (1997)
Vian, J.L., Sawan, M.E.: H ∞ control for singularly perturbed systems. Proc. 30th. IEEE Conf. Decision and Control, Brighten, U.K., pp. 1072–1074, 1991
Wang, L.Y., Zhan, W.: Robust disturbance attenuation with stability for linear systems with norm-bounded nonlinear uncertainties. IEEE Trans. Automat. Contr. 41, 886–888 (1996)
Yazdanpanah, M.J., Patel, R.V., Khorasani, K.: Robust regulation of a flexible-link manipulator based on a new modeling approach. Proc. Conf. Dec. Contr., San Diego, California, USA, December 1997
Zhou, K., Khargonekar, P.P.: Robust stabilization of linear systems with norm-bounded time-varying uncertainty. Syst. Control. Lett. 10, 17–20 (1994)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Karimi, H.R., Yazdanpanah, M.J., Patel, R.V. et al. Modeling and Control of Linear Two-time Scale Systems: Applied to Single-Link Flexible Manipulator. J Intell Robot Syst 45, 235–265 (2006). https://doi.org/10.1007/s10846-006-9036-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10846-006-9036-6