H and H2 controller design for linear systems is a difficult, nonconvex, nonsmooth optimization problem when the order of the controller is fixed to be less than that of the open-loop plant, a typical requirement in e.g. embedded aerospace control systems. In addition, it is often desired to compute a single controller which stabilizes multiple plants simultaneously.

HIFOO is aimed at solving fixed-order stabilization and performance optimization problems. It depends on a hybrid algorithm for nonsmooth, nonconvex optimization based on quasi-Newton updating and gradient sampling. In particular, HIFOO address the following problems:

HIFOO also handles mixed problems, for example, optimizing the H performance of some plants subject to constraints on H2 performance of other plants.

If you publish work that uses HIFOO, please refer to the following two papers:

and inform us about it by sending us email.

HIFOO is based upon work supported by the National Science Foundation (NSF) under grants DMS-0714321, DMS-1016325 and DMS-1317205. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of NSF.