Accession Number : ADA609770


Title :   Flight Dynamics Simulation Modeling and Control of a Large Flexible Tiltrotor Aircraft


Descriptive Note : Doctoral thesis


Corporate Author : SAN JOSE STATE UNIV RESEARCH FOUNDATION CA


Personal Author(s) : Juhasz, Ondrej


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a609770.pdf


Report Date : Sep 2014


Pagination or Media Count : 393


Abstract : A high order rotorcraft mathematical model is developed and validated against the XV-15 and a Large Civil Tiltrotor (LCTR) concept. Separate modeling of each rotorcraft component in a multi-body like formulation allows for structural flexibility to be included, which is important when modeling large aircraft where structural modes affect the flight dynamics frequency ranges of interest. Details of the formulation of the mathematical model are given, including derivations of structural, aerodynamic, and inertial loads. Flexibility effects are evaluated by looking at the nature of the couplings between rigid-body modes and wing structural modes and vice versa. A proportional-integral feedback on the structural acceleration is used to improve damping and reduce the overall excitation of a structural mode. A model following control architecture is then implemented on full order flexible LCTR models. The impact of structural feedback investigated. A rigid aircraft model has optimistic performance characteristics, and a control system designed for a rigid aircraft could potentially destabilize a flexible one. The various control systems are flown in a fixed-base simulator. Pilot inputs and aircraft performance are recorded and analyzed.


Descriptors :   *TILT ROTOR AIRCRAFT , AERODYNAMIC CHARACTERISTICS , MATHEMATICAL MODELS , SIMULATION , THESES


Subject Categories : Aerodynamics
      V/STOL


Distribution Statement : APPROVED FOR PUBLIC RELEASE