CHARACTERISTIC FREQUENCY-GAIN DESIGN STUDY OF AN AUTOMATIC FLIGHT CONTROL-SYSTEM

Recent work on the application of complex variable theory to the analysis of linear multivariable systems has led to a design approach that integrates the multivariable frequency-response and root-locus techniques. A brief discussion of a two-stage design method that derives from this approach is first undertaken and its application to an automatic flight control system is then considered. The design starts with the introduction of an inner-loop compensator for which root-locus techniques are employed for the adjustment of closed-loop characteristic frequencies. This is followed by an outer-loop gain injector design where frequency-response techniques are employed for the adjustment of open-loop characteristic gains. The overall scheme results in a controlled system whose response is fast, non-oscillatory, accurate in the steady state and largely non-overshooting and non-interactive