ABSTRACT
Eachmethodhasitsownuniquefeatures.Forthefrequencydomainapproach, plentyofanalyticalresultsandtoolsareavailable.Ontheotherhand,themodern controltheoryiseasytoimplementwiththehelpoftheabundantcomputational softwareavailable.Moderncontroltechniquesimposeanotherimportantissueon estimationofalldegreesoffreedomwithalimitednumberofsensors.Thenumber ofsensorsandactuatorsareusuallylessthanthedegreesoffreedomoftruncated (approximate)systems.Estimatingalltheflexiblemodesiscriticaltodesigningan activecontrollawinthetimedomain.
