Analyzing manipulator characteristics in the closed-loop pilot/vehicle system

The response characteristics of modern, highly augmented aircraft have reached the point where the vehicle and control system dynamics have begun to interact adversely with the actuation dynamics of the human pilot, i.e., the characteristics of the pilot´s neuromuscular system and of the manipulator and feel system by which the pilot´s will is imparted to the aircraft. To address this problem, a simple pilot-vehicle model that can be used to interpret pertinent flight test and simulation results and to serve as a tractable tool for assessing proposed changes in manipulator/feel system characteristics is developed. The model captures the qualitative changes in measured pilot-vehicle transfer functions which accompany changes in manipulator restraints and manipulator/feel system output. It was used to investigate the roll ratchet phenomenon and implicated the combined effects of vehicle dynamics, force output feel systems, and motion cues. These effects were seen to lead to decreased phase lags and increased magnitude peaking of a closed-loop mode arising from the neuromuscular system