ON THE DETERMINATION OF TIME-DOMAIN SIGNAL LEVELS AT THE SPECIFICATION STAGE IN QUANTITATIVE FEEDBACK THEORY CONTROLLER SYNTHESIS

This paper shows how recent developments in obtaining guaranteed time- domain bounds for a given set of structured and/or unstructured freque ncy-domain bounds can be incorporated into the standard quantitative f eedback theory (QFT) control system design methodology. Since QFT guar antees frequency-domain specifications, one can now determine signal l evels as a function of time for signals both entering and leaving the plant before the design process begins. The result is that the system frequency-domain specifications can be tuned such that the plant input -output signals remain within specified amplitude limits, rate limits or time-dependent transient bounds. Although single-input single-outpu t (SISO) systems are treated here, the same results can be used in mul tiple-input multiple-output or multiple-loop QFT feedback problems, bo th of which make use of SISO equivalents as described by Horowitz in 1 992.