  This paper addresses the design of robust dynamic output feedback control for
highly uncertain systems in which the unknown disturbance might be excited by
the derivative of the control input. This context appears in many industrial
problems such as the speed control of the hydraulic turbines and the frequency
stabilization in micro grids to cite but few examples. A key feature that has
to be carefully addressed in this context is that too agressive feedback might
lead to the loss of controllability and/or a significant drop in the
closed-loop performance. The paper formulates the problem, underlines its
relevance and gives a rigorous solution in which a dynamic output feedback is
given together with a realistic set of sufficient conditions on the
controller's parameters that enable to assess the behavior of the closed-loop
under different circumstances. A numerical example is given to illustrate the
relevance of the proposed successful design characterization.
