Stability and Performance Analysis on Self-dual Cones
Emil Vladu
TL;DR
This work extends stability and performance analysis to cone-preserving, possibly nonsymmetric systems on self-dual cones, moving beyond classical positive-system results. It develops a cone-preserving Sylvester criterion and a set of equivalent conditions for $H_ty$ performance in monotone systems, showing that the norm bound can be certified via a stabilizing cone-preserving Riccati solution and interior conic inequalities, with the maximal gain attained at zero frequency. Key contributions include a necessary-and-sufficient condition $\\mu(A) + \\mu(D) < 0$ for cone-preserving Sylvester solvability, and a suite of equivalent tests for the bounded real lemma in the cone setting, plus illustrative examples such as a closed-loop $H_ty$ controller and a positive Sylvester solution in the nonnegative orthant. The results broaden the toolkit for controller synthesis and stability verification in large-scale, cone-preserving systems, enabling performance guarantees beyond the traditional symmetric-cone framework.
Abstract
In this paper, we consider nonsymmetric solutions to certain Lyapunov and Riccati equations and inequalities with coefficient matrices corresponding to cone-preserving dynamical systems. Most results presented here appear to be novel even in the special case of positive systems. First, we provide a simple eigenvalue criterion for a Sylvester equation to admit a cone-preserving solution. For a single system preserving a self-dual cone, this reduces to stability. Further, we provide a set of conditions equivalent to testing a given H-infinity norm bound, as in the bounded real lemma. These feature the stability of a coefficient matrix similar to the Hamiltonian, a solution to two conic inequalities, and a stabilizing cone-preserving solution to a nonsymmetric Riccati equation. Finally, we show that the H-infinity norm is attained at zero frequency.
