Integrated flight control design and handling qualities analysis for a tilt rotor aircraft
T Yomchinda, J Horn, N Cameron - AIAA Atmospheric Flight Mechanics …, 2009 - arc.aiaa.org
T Yomchinda, J Horn, N Cameron
AIAA Atmospheric Flight Mechanics Conference, 2009•arc.aiaa.orgILT rotor aircraft present a challenge for flight control designers and handling qualities
engineers. Achieving consistent handling qualities throughout the operational flight
envelope is difficult since the flight dynamics of the aircraft change significantly at various
flight conditions and configurations (eg helicopter mode, conversion mode, and airplane
mode). The requirement to meet both helicopter and fixed-wing flying qualities specifications
over an expanded envelope results in substantial cost and time. In 2008, the University of …
engineers. Achieving consistent handling qualities throughout the operational flight
envelope is difficult since the flight dynamics of the aircraft change significantly at various
flight conditions and configurations (eg helicopter mode, conversion mode, and airplane
mode). The requirement to meet both helicopter and fixed-wing flying qualities specifications
over an expanded envelope results in substantial cost and time. In 2008, the University of …
ILT rotor aircraft present a challenge for flight control designers and handling qualities engineers. Achieving consistent handling qualities throughout the operational flight envelope is difficult since the flight dynamics of the aircraft change significantly at various flight conditions and configurations (eg helicopter mode, conversion mode, and airplane mode). The requirement to meet both helicopter and fixed-wing flying qualities specifications over an expanded envelope results in substantial cost and time. In 2008, the University of Liverpool conducted a workshop/competition on tilt rotor handling qualities, in association with AHS/RAeS Rotorcraft Handling Qualities Conference, to provide experience and education in the integrated flight control design and handling qualities analysis for tilt rotor aircraft. Teams were provided specifications and linear models of an XV-151 tilt rotor simulation model2 and were given the objective of designing a flight control system to deliver Level 1 handling qualities across the envelope for a predefined Search and Rescue (SAR) mission. The requirements to be assessed in the mission were specified. Handling qualities (HQ) of the models in hover and low speed was assigned to be evaluated based on a subset of hover and low speed specifications from the US Army handling qualities specification document, ADS-33E-PRF3. For the models of XV-15 in conversion configuration, HQ was evaluated based on an assigned subset of forward flight specifications in ADS-33E-PRF. HQ of the XV-15 airplane mode models was evaluated using an assigned subset of specifications for aircraft class II category A in MIL-F-8785C4. At the end of the competition, teams’ flight controllers were sent for flight test evaluation. The mission-task-elements (MTEs) evaluations were performed by test pilots using the HELIFLIGHT simulation facility at University of Liverpool, where the pilots provided Cooper-Harper handling qualities rating5 to evaluate the perceived workload and performance. A model following/inversion control is emphasized by its concept for achieving consistent response attributes. 6-10 Ideal response models or command filters are designed to meet the specified response characteristics. Feedback compensation can be tuned to meet disturbance rejection and cross-coupling requirements. The inversion model can be scheduled to account for changing of aircraft dynamics, and thus the other components of the controller can be fixed or tailored to change response types for different operating points. The present work demonstrates a method of flight control design and handling qualities analysis for the XV-15 tilt rotor aircraft simulation model. A flight control system is developed using a model following/inversion design scheme. Its effectiveness of the controller to achieve assessed requirements is investigated.
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