Control of transport PDE/nonlinear ODE cascades with state-dependent propagation speed

In this paper, we deal with the control of a transport PDE/nonlinear ODE cascade system in which the transport coefficient depends on the ODE state. We develop a PDE-based predictor-feedback boundary control law, which compensates the transport dynamics of the actuator and guarantees global asymptotic stability of the closed-loop system. The stability proof is based on an infinite-dimensional backstepping transformation that is introduced, with the aid of which, a Lyapunov functional is constructed. The relation of the PDE-ODE cascade to an ODE system with a state-dependent input delay, which is defined implicitly via an integral of the ODE state, is also highlighted and the corresponding equivalent predictor-feedback design is presented. The practical relevance of our control framework is illustrated in an example that is concerned with the control of a metal rolling process.