Null controllability of damped nonlinear wave equation
Yan Cui, Peng Lu, Yi Zhou
TL;DR
The paper advances internal null controllability for damped nonlinear wave equations across semilinear,quasi-linear, and fully nonlinear regimes under geometric control assumptions. It combines Galerkin approximations, fixed-point arguments, and iterative contraction schemes with robust observability inequalities to construct controls, often in a constructive, numerically amenable manner. Key contributions include precise regularity requirements, explicit constants and conditions on the nonlinearities, and a time-differentiation strategy for fully nonlinear cases. Collectively, the results extend null controllability to broader nonlinear settings with internal control, under GCC-type conditions, and provide a path toward practical computation of controls.
Abstract
In this paper, we investigate the null controllability of nonlinear wave systems. Initially, we employ a combination of the Galerkin method and a fixed point theorem to establish the null controllability for semi-linear wave equations with nonlinear functions that are dependent on velocities, under the geometric control condition. Subsequently, utilizing a novel iterative method, we demonstrate the null controllability for a class of quasi-linear wave systems in a constructive manner. Lastly, we present a control result for a class of fully nonlinear wave systems, serving as an application.
