ABSTRACT
Control of multiple-input-multiple-output (MIMO) systems with model uncertainty is still one of the most difŽcult problems the control engineer has to face in real-world applications. (Now it is considered Y(s) = P(s) U(s), where P is an n × n transfer matrix, P ∈P, and P is the set of possible plants due to uncertainty [see Figure 5.1].) Two of the main characteristics that deŽne a MIMO system are the input and output directionality (different possible vectors to actuate U and different possible vectors to measure Y) and the coupling among control loops (each input ui can affect some outputs yi, and each output can be affected by one or several inputs). This problem, which is known as interaction or coupling, makes the control system design less intuitive since any change in one loop interferes with the rest of the plant loops.
