ABSTRACT
This chapter addresses the control of differential algebraic equation (DAE) systems in the presence of time-varying disturbance inputs. It is well-known that for nonlinear ordinary differential equation systems, the presence of disturbance inputs, especially time-varying ones, may lead to significant performance deterioration if they are not accounted for in the controller design. This fact motivated research on eliminating the effect of unmeasured disturbances on the controlled outputs through static state feedback, or if disturbance measurements are available, through static feedforward/state feedback and dynamic feedforward/static state feedback controllers. For a nonlinear high-index DAE system, the presence of time-varying disturbance inputs may have fundamental consequences on the system characteristics and the controller design. More specifically, similar to the case with the manipulated inputs, the disturbance inputs may also appear explicitly in the underlying algebraic constraints. Finally, the synthesis of feedforward/feedback controllers for these classes of regular/nonregular DAE systems are addressed on the basis of the derived state-space realizations.
