- ▪P.P. Khargonekar, E.D. Sontag, "On the relation between stable matrix fraction factorizations and regulable realizations of linear systems over rings", IEEE Trans. Automat. Control, vol. 27, no. 3, pp. 627–638, 1982. pdf
Abstract
Various types of transfer matrix factorizations are of interest when designing regulators for generalized types of linear systems (delay differential. 2-D, and families of systems). This paper studies the existence of stable and of stable proper factorizations, in the context of the thery of systems over rings. Factorability is related to stabilizability and detectability properties of realizations of the transfer matrix. The original formulas for coprime factorizations (which are valid, in particular, over the field of reals) were given in this paper.
- ▪E.D. Sontag, "Small-input controllability", In Proc.\ IEEE Conf.\ Dec.\ and Control, Orlando, Dec.\ 1982, 1982.
- ▪E.D. Sontag, "Abstract regulation of nonlinear systems: stabilization", In Feedback control of linear and nonlinear systems (Bielefeld/Rome, 1981), pp. 227–243, 1982.
- ▪E.D. Sontag, "Remarks on piecewise-linear algebra", Pacific J. Math., vol. 98, no. 1, pp. 183–201, 1982. pdf
Abstract
Algebraic study of functions defined by piecewise linear (generally discontinuous) equations. File obtained by scanning a reprint.
- ▪E.D. Sontag, "Abstract regulation of nonlinear systems: Stabilization, Part II", In Proc.Princeton Conf.on Information Sciences and Systems, Princeton, March 1982, pp. 431-435, 1982.
- ▪E.D. Sontag, "A characterization of asymptotic controllability", In Dynamical Systems II, pp. 645–648, 1982. pdf
Abstract
This paper was a conference version of the SIAM paper that introduced the idea of control-Lyapunov functions for arbitrary nonlinear systems. (The journal paper was submitted in 1981 but only published in 1983.)
- ▪E.D. Sontag, H.J. Sussmann, "Accessibility under sampling", In Proc.\ IEEE Conf.\ Dec.\ and Control, Orlando, Dec.\ 1982, 1982. pdf
Abstract
This note addresses the following problem: Find conditions under which a continuous-time (nonlinear) system gives rise, under constant rate sampling, to a discrete-time system which satisfies the accessibility property.
- ▪E.D. Sontag, "Linear systems over commutative rings: a (partial) updated survey", In 8th IFAC Triennial World Congress, Vol. 1 Kyoto, 1981, pp. 325–330, 1982. pdf