Conditioned switching between two-degree-of-freedom controllers for plants with changing dynamics

This paper presents a self-conditioned implementation of any two-degree-of-freedom (TDOF) controller which allows a conditioned transfer when switching between a controller acting in closed-loop and another controller in a bank of idle controllers waiting to take over the control loop. Here, the notion of conditioned transfer is used to mean that after switching, good tracking performance is ensured albeit a jump at plant input may occur. This notion of conditioned transfer is different from the notion of bumpless transfer which refers to the requirement that no bump occurs at the plant input when switching between different controllers. A main feature of our study is that the switching among controllers is driven by the changing dynamics of the plant and moreover the technique is model-free. This is in contrast with most works reported in the literature on bumpless switching, where switching occurs between controllers driving a plant with fixed dynamics.