Stabilization of a Wave-Heat Cascade System
Hugo Lhachemi, Christophe Prieur, Emmanuel Trélat
TL;DR
This work tackles the problem of stabilizing a one-dimensional wave–heat cascade with internal coupling, using an explicit output-feedback law based on a finite number of modal components. By exploiting a Riesz-spectral structure, the authors perform spectral reduction to isolate unstable parabolic modes and design a finite-dimensional observer plus state-feedback that achieves exponential decay in both the energy space and a stronger parabolic norm, with a prescribed rate. The stabilization remains valid under explicit controllability and observability conditions and extends to pointwise measurements, aided by a Lyapunov functional built on Riesz bases. The results offer a principled, implementable approach to boundary control of coupled hyperbolic–parabolic PDEs, with demonstrated numerical support and clear directions for broader applicability.
Abstract
We consider the output-feedback stabilization of a one-dimensional cascade coupling a reaction-diffusion equation and a wave equation through an internal term, with Neumann boundary control acting at the wave endpoint. Two measurements are available: the wave velocity at the controlled boundary and a temperature-type observation of the reaction-diffusion component, either distributed or pointwise. Under explicit, necessary and sufficient conditions on the coupling and observation profiles, we show that the generator of the open-loop system is a Riesz-spectral operator. Exploiting this structure, we design a finite-dimensional dynamic output-feedback law, based on a finite number of parabolic modes, which achieves arbitrary exponential decay in both the natural energy space and a stronger parabolic norm. The construction relies on a spectral reduction and a Lyapunov argument in Riesz bases. We also extend the design to pointwise temperature or heat-flux measurements.
