Abstract
Linear time-varying (LTV) systems naturally arise when one linearizes nonlinear systems about a trajectory. In contrast the linear time-invariant (LTI) cases which have been thoroughly understood in the analysis and synthesis technologies, many features of the LTV systems are still limited and not clear. This paper addresses the problems of solution and stability of a general unforced LTV differential state space system. Unlike most of the work based on the Lyapunov theory, numerical simulations, or specific constraint systems, the paper proposes the spectral decompositions of the LTV systems by employing extended eigenpairs and with simple mathematical derivation. The spectral decompositions reveal the mechanisms of inherent characterization in general LTV systems, rather than a particular class. Moreover, a novel set of auxiliary equations is developed for guiding and obtaining the extended eigenpairs of its system matrix which completely characterize the LTV systems. The solutions to perform the commutative systems and the second-order systems with companion form are straightforward. The proposed innovative thinking provides a novel guided way to analyze the LTV systems. These findings are easily extended to LTI cases. Examples from the literature demonstrate the effectiveness and the superiority of the proposed approaches when compared with other methods. The proposed results may be of great interest in both for scientific research and application.
Similar content being viewed by others
References
W. J. Rugh, Linear System Theory, Prentice-Hall, New Jersey, 1993.
H. K. Khalil, Nonlinear Systems, Prentice-Hall, New Jersey, 2002.
R. H. Middleton and G. C. Goodwin, “Adaptive control of time-varying linear systems,” IEEE Trans. on Automatic Control, vol. 33, no. 2, pp. 150–155, February 1988. [click]
W. J. Rugh and J. S. Shamma, “Research on gain scheduling,” Automatica, vol. 36, no. 10, pp. 1401–1425, October 2000. [click]
H.-C. Lee and J. W. Choi, “Linear time-varying eigenstructure assignment with flight control application,” IEEE Trans. on Aerospace and Electronic Systems, vol. 40, no. 1, pp. 145–157, January 2004. [click]
B. Lu, H. Choi, G. D. Buckner, and K. Tammi, “Linear parameter-varying techniques for control of a magnetic bearing system,” Control Engineering Practice, vol. 16, no. 10, pp. 1161–1172, October 2008.
W. B. Blair, “Series solution to the general linear time varying system,” IEEE Trans. on Automatic Control, vol. 16, no. 2, pp. 210–211, April 1971.
B. Zhou, G. B. Cai, and G.-R. Duan, “Stabilization of timevarying linear systems via Lyapunov differential equations,” International Journal of Control, vol. 86, no. 2, pp. 332–347, February 2013.
M. Koksal and M. E. Kosal, “Commutativity of linear time-varying differential systems with nonzero initial conditions: A review and some new extensions,” Mathematical Problems in Engineering, vol. 2011, Article ID 678575, 25 pages, doi:10.1155/2011/67857, July 2011.
H. W. Mosteller, “Closed-form solutions for a class of linear time-varying systems,” IEEE Trans. on Automatic Control, vol. 15, no. 3, pp. 389–390, January 1970.
B. Arabzadeh, M. Razzaghi, and Y. Ordokhani, “Numerical solution of linear time varying differential equations using the hybrid of block-pulse and rationalized Haar functions,” Journal of Vibration and Control, vol. 12, no. 10, pp. 1081–1092, October 2006.
A. V. Kamyad and M. Mazandarani, “A new approach for solving of linear time varying control systems,” Advanced Studies in Contemporary Mathematics, vol. 21, no. 3, pp. 321–328, July 2011.
S. Sedaghat and Y. Ordokhani, “Stability and numerical solution of time variant linear systems with delay in both the state and control,” Iranian Journal of Mathematical Sciences and Informatics, vol. 7, no. 1, pp. 43–57, 2012.
J. K. Aggarwal and E. F. Infante, “Some remarks on the stability of time-varying systems,” IEEE Trans. on Automatic Control, vol. 13, no. 6, pp. 722–723, December 1968. [click]
L. Markus and H. Yamabe, “Global stability criteria for differential systems,” Osaka Mathematical Journal, vol. 12, no. 2, pp. 305–317, 1960.
C. A. Desoer, “Slowly varying systems x = A(t)x,” IEEE Trans. on Automatic Control, vol. 14, no. 6, pp. 780–781, December 1969. [click]
J. J. DaCunha, “Stability for time varying linear dynamic systems on time scales,” Journal of Computational and Applied Mathematics, vol. 176, no. 2, pp. 381–410, April 2005. [click]
A. Ilchmann, D. H. Owens, and D. Pratzel-Wolters, “Sufficient conditions for stability of linear time-varying systems,” Systems & Control Letters, vol. 9, no. 2, pp. 157–163, August 1987. [click]
J. Sun, Q.-G. Wang, and Q.-C. Zhong, “A less conservative stability test for second-order linear time-varying vector differential equations,” International Journal of Control, vol. 80, no. 4, pp. 523–526, April 2007. [click]
P. Mullhaupt, D. Buccieri, and D. Bonvin, “A numerical sufficiency test for the asymptotic stability of linear timevarying systems,” Automatica, vol. 43, no. 4, pp. 631–638, April 2007. [click]
S.-L. Tung, Y-T Juang, W.-Y. Wu, and W.-Y. Shieh, “An improved stability test and stabilisation of linear timevarying systems governed by second-order vector differential equations,” International Journal of Systems Science, vol. 42, no. 12, pp. 1975–1980, December 2011.
Y. Yao, K. Liu, D. Sun, V. Balakrishnan, and J. Guo, “An integral function approach to the exponential stability of linear time-varying systems,” International Journal of Control, Automation, and Systems, vol. 10, no. 6, pp. 1096–1101, December 2012. [click]
O. M. Kwon, M. J. Park, J. H. Park, and S. M. Lee, “Enhancement on stability criteria for linear systems with interval time-varying delays,” International Journal of Control, Automation, and Systems, vol. 14, no. 1, pp. 12–20, February 2016. [click]
P.-L. Liu, “New results on delay-range-dependent stability analysis for interval time-varying delay systems with non-linear perturbations,” ISA Transactions, vol. 57, pp. 93–100, July 2015. [click]
H. Chen and P. Hu, “New result on exponential stability for singular systems with two interval time-varying delays,” IET Control Theory and Applications, vol. 7, no. 15, pp. 1941–1949, October 2013. [click]
B. Zhou, “On asymptotic stability of linear time-varying systems,” Automatica, vol. 68, pp. 266–276, June 2016. [click]
G. Chen and Y. Yang, “New stability conditions for a class of linear time-varying systems,” Automatica, vol. 71, pp. 342–347, September 2016. [click]
S. S. Alaviani, “A necessary and sufficient condition for delay-independent stability of linear time-varying neutral delay systems,” Journal of the Franklin Institute, vol. 351, no. 5, pp. 2574–2581, May 2014. [click]
M.-Y. Wu, “A new concept of eigenvalues and eigenvectors and its applications,” IEEE Trans. on Automatic Control, vol. 25, no. 4, pp. 824–826, August 1980. [click]
P. M. Derusso, R. J. Roy, and C. M. Close, State Variables for Engineers, Wiley, New York, 1965.
M.-Y. Wu, “On stability of linear time-varying systems,” International Journal of System Science, vol. 15, no. 2, pp. 137–150, February 1984.
G. Garcia, P. L. D. Peres, and S. Tarbouriech, “Assessing asymptotically stability of linear continuous time-varying systems by computing the envelope of all trajectories,” IEEE Trans. on Automatic Control, vol. 55, no. 4, pp. 998–1003, April 2010. [click]
Author information
Authors and Affiliations
Corresponding author
Additional information
Recommended by Associate Editor Jun Yoneyama under the direction of Editor Duk-Sun Shim. The author would like to thank the Editor and anonymous reviewers for their valuable comments that certainly improved the quality of this paper.
Jing-Min Wang received the M.S. degree in Electrical Engineering from National Taiwan University, Taiwan, R.O.C., in 1981. He is currently an Assistant Professor in the Department of Electrical Engineering, St. John’s University, Taiwan. His research interests include control theory and applications, linear time-varying systems, home automation, optimization, and condition-based maintenance (CBM).
Rights and permissions
About this article
Cite this article
Wan, JM. Explicit solution and stability of linear time-varying differential state space systems. Int. J. Control Autom. Syst. 15, 1553–1560 (2017). https://doi.org/10.1007/s12555-015-0404-5
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12555-015-0404-5