Input selection and localized disturbance rejection

The control structure selected has a strong effect on the performance of a closed loop system with respect to its disturbance rejection capability. A special capability-localizable disturbance rejection is studied in this work. It is shown that this capability can be related to a particular set of manipulated variables. A new measure, the input disturbance alignment (IDA) is proposed to identify these inputs. Some important features of the new indicator and its relationship with other well-known controllability measures are presented. The case studies included show that the IDA can be used for efficient selection of manipulated variables from a large number of candidate inputs. These then form the best control structure for localized disturbance rejection. (C) 1998 Elsevier Science Ltd. All rights reserved.