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Piloted Evaluation of Modernized Limited Authority Control Laws in the NASA-Ames Vertical Motion Simulator (VMS)The UH-60 BLACK HAWK was designed in the 1970s, when the US Army primarily operated during the day in good visual conditions. Subsequently, the introduction of night-vision goggles increased the BLACK HAWK'S mission effectiveness, but the accident rate also increased. The increased accident rate is strongly tied to increased pilot workload as a result of a degradation in visual cues. Over twenty years of research in helicopter flight control and handling qualities has shown that these degraded handling qualities can be recovered by modifying the response type of the helicopter in low speed flight. Sikorsky Aircraft Corporation initiated a project under the National Rotorcraft Technology Center (NRTC) to develop modern flight control laws while utilizing the existing partial authority Stability Augmentation System (SAS) of the BLACK HAWK. This effort resulted in a set of Modernized Control Laws (MCLAWS) that incorporate rate command and attitude command response types. Sikorsky and the US Army Aeroflightdynamics Directorate (AFDD) conducted a piloted simulation on the NASA-Ames Vertical h4otion Simulator, to assess potential handling qualities and to reduce the risk of subsequent implementation and flight test of these modern control laws on AFDD's EH-60L helicopter. The simulation showed that Attitude Command Attitude Hold control laws in pitch and roll improve handling qualities in the low speed flight regime. These improvements are consistent across a range of mission task elements and for both good and degraded visual environments. The MCLAWS perform better than the baseline UH-60A control laws in the presence of wind and turbulence. Finally, while the improved handling qualities in the pitch and roll axis allow the pilot to pay more attention to the vertical axis and hence altitude performance also improves, it is clear from pilot comments and altitude excursions that the addition of an Altitude Hold function would further reduce workload and improve overall handling qualities of the aircraft.
Document ID
20030069038
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Sahasrabudhe, Vineet (Sikorsky Aircraft Stratford, CT, United States)
Melkers, Edgar (Sikorsky Aircraft Stratford, CT, United States)
Faynberg, Alexander (Sikorsky Aircraft Stratford, CT, United States)
Blanken, Chris L. (Army Aviation and Missile Command Moffett Field, CA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2003
Subject Category
Aircraft Stability And Control
Meeting Information
Meeting: American Helicopter Society Annual Forum
Location: Phoenix, AZ
Country: United States
Start Date: May 6, 2003
End Date: May 8, 2003
Sponsors: American Helicopter Society, Inc.
Funding Number(s)
CONTRACT_GRANT: NCC2-9019
Distribution Limits
Public
Copyright
Public Use Permitted.

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