Effects of Time-Varying Rotorcraft Dynamics on Pilot Control

Abstract

Advanced control concepts for rotorcraft are under development to improve fuel efficiency and reduce noise. Many of these concepts involve changes in the configuration of the rotorcraft that may induce additional dynamic modes, or that may result in existing dynamic modes exhibiting undesirable characteristics in the region of piloted control. NASA’s Aeronautics Research Mission Directorate has funded programs to investigate the effects of added dynamics on rotorcraft control. A piloted simulation on the NASA Ames Vertical Motion Simulator has been performed to establish detection thresholds for added dynamics. Analysis of the results, and identification of limits on acceptable added dynamics, has not been completed. This paper discusses the initial results from that simulation, including example applications of wavelet scalograms. I. Introduction odern rotorcraft technologies are currently being developed to minimize noise and maximize performance for operations in urban environments. A prime goal of NASA’s Aeronautics Research Mission Directorate (ARMD) is determination of the effects of these technologies (e.g., on-blade control, in-blade control, variable rotor speed) on pilot control. Changes to rotor speed and performance will result in changes in the dynamics of the vehicles; methodologies are needed that predict the level at which pilots detect the added dynamics, and that determine the effects of the added and varying dynamics on pilot performance. In 2007, NASA issued a Research Announcement (NRA) to investigate the effects of added dynamics on pilot control. A team consisting of Hoh Aeronautics, Inc. (HAI) and Systems Technology, Inc. (STI), with NASA Ames Research Center as a collaborating partner, was awarded a two-year contract to investigate this topic. A three-week piloted simulation was conducted on the NASA Ames Vertical Motion Simulator (VMS) in February 2009. While final analysis of the results has not been completed, this paper summarizes the simulation and initial outcomes of the research. Final recommendations will be issued in a formal technical report, and will be summarized in a future technical paper.