Improvement of system performance by the use of time-delay elements

The paper explores the possibility of performance improvement by the use of added delay elements. The counterintuitive phenomenon of `improvement by mismatch¿¿ has been noted by several authors in the context of predictor control. This phenomenon is illustrated using a second-order example, and, in the light of this, it is demonstrated how it also may be improved by the use of delay elements. A third-order example of delay-free system improvement is described. A technique for producing good first-order estimates of design parameters is presented