Flight test identification of SH-2G dynamics in support of digital flight control system development

As part of a contract to upgrade the SH-2G Super Seasprite for the Royal Australian Navy, a new digital flight control system is being developed by Kaman Aerospace. In support of this development a comprehensive closed loop model of the aircraft was developed as an adjunct to flight testing of the new equipment. This paper covers the identification of the open loop aircraft plant model using CIFER (Comprehensive Identification from Frequency Responses). Identification was performed at three airspeeds (hover, 60 knots, and 100 knots) with a common model structure, permitting the derivatives to be interpolated, at any speed, by a closed loop simulation, which is being developed in MATLAB/Simulink and will be optimized with CONDUIT (Control Designer's Unified Interface). Allusion to this Simulink model is made throughout the discussion where appropriate.