Model reference control of nonlinear time-delayed 1-st order plants

This paper deals with a new approach to the design of a two-degree-of-freedom controller for a first-order nonlinear plant with time-delays. There exist several traditional methods that can solve this problem (gain scheduling, exact linearization, generalized transfer functions for nonlinear systems, etc.). The advantage of the solution proposed in this paper consists in a simple and modular controller design that can be used for a broad class of nonlinear systems. In order to be able to comprise all required steps into a single conference paper, the overall design and the resulting performance of the proposed model reference control of nonlinear time-delayed systems will be documented by an example of a one-tank liquid level control in a real hydraulic plant. Starting from a basic P controller, its structure is gradually extended by a model reference control and finally by a nonlinear disturbance observer taking into account both the filtration of noisy signals and the time-delays always present in control circuits.