Anti-windup for marginally stable plants and its application to open water channel control systems

Actuator saturation can have a significant impact on control system performance. In particular, when actuators saturate because of large initial condition mismatch at startup, or because of large disturbances, the controller can suffer from so-called integrator windup. This paper describes the application of recent anti-windup and bumpless transfer (AWBT) compensation techniques to the problem of open water channel control. This is nontrivial in light of the (marginally) unstable nature of uncontrolled open water channels, which for the purposes of controller design, can modelled as a concatenation of integrators, linked by saturation-prone gates used to regulate the flow of water. AWBT compensator design is considered within the context of both continuous- and discrete-time controllers and models. All simulation studies are carried out using an experimentally validated, high-fidelity model of the Haughton Main Channel in Queensland, Australia. The AWBT compensation schemes considered achieve excellent performance.