Output Feedback Controller Design

Abstract

For DPS, as for most other types of systems, the measured output does not include all the states. There are basically two ways of approaching controller synthesis using the output. One relies primarily on the input/output description of the system; the other on the state-space description. If the input/output approach is taken, care needs to be taken to ensure that internal stability is maintained. Equivalence between internal and external stability if the sub-systems are stabilizable and detectable justifies the use of controller design based on system input/output behaviour. On the other hand, in the state-space approach, the fact that the overall design goal often relates to the input/output behaviour needs to be considered. Several common approaches to input/output controller design are described in the context of DPS. State-space based output controller design is also covered. In this approach, an estimator is combined with state feedback to construct an output feedback controller. The issue of approximation and computation in controller synthesis from earlier chapters is continued in the input/output context.