C3I Systems/subsystems

A modern military fighter, such as an F-16, carries a multitude of different external store configurations through its design envelope. For certain configuration, flutter or limit cycle oscillations (LCO) restrict the maximum airspeed or the weapon release. As new weapons are introduced into the aircraft's inventory, radical changes may occur in the aircraft structural dynamics to thepoint of potentially encountering flutter. This potential requires an exhaustive certification process to define the flutter/LCO airspeed limit for each new store configuration. The payoffs associated with the removal of flutter speed restrictions include: increased survivability during war-time operations, increased flexibility in store selection, potential cost savings associated with reduced analyses and testing, and inherent reduction in risk associated with flight flutter test. The overall objective of Phase I is to design and test an on-line identification technique for adaptive structural mode suppression for F-16 aircraft. Specific tasks are: i)Acquisition of data and models for F-16 aircraft under different store configurations. (ii)On-line identification of structural modes using Stochastic Realization algorithm; (iii)Evaluation of sensor data and computational requirements for on-line identification of structural modes. Phase II will consist of hardware/software implementation and real-time testing of the robust control concepts bia nonlinear simulations incorporating both rigid body and flexible modes. Phase III will involve flight testing and commercialization. Lockheed Fort Worth Company will provide data and evaluation support during Phases I and II and commercialize the results dkuring Phase III.