Time-Domain Control Design: A Nonsmooth Approach

We present a method to efficiently compute locally optimal feedback controllers for synthesis problems formulated in the time domain. We minimize a time-domain performance objective subject to state or input time-domain constraints. The possibility to include state or input constraints in the design is very appealing from a practical point of view, in particular for plants subject to operational limits as input saturations. Our method is based on a nonsmooth minimization technique, which can handle time-domain constraints as hard constraints. For model-based designs, a stability constraint can also be handled as a hard constraint. The validity and efficiency of the approach are demonstrated through a variety of numerical tests with comparisons with a state-of-the-art technique in constrained optimization.