Robust MPC for a Flotation Column Process with time-varying Input Delay through Lyapunov-Krasovskii and Modulating Functionals

This paper introduces an adaptive mechanism, based on the modulating function method and Lyapunov-Krasovskii functional analysis, for the online estimation of time-varying delays in processes with complex multivariable dynamics within a min-max robust model predictive controller (RMPC) framework. Monte Carlo simulations were conducted to test the performance of a nominal RMPC under different time delay uncertainties, along with the RMPC with the proposed modulating function-based adaptive mechanism, showing that the latter is capable of reducing the uncertainty polytope of the controller, demonstrating less control action conservatism and a more robust transient response.