Accession Number:

ADA399872

Title:

Suppression of Pilot-Induced Oscillation (PIO)

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT

Personal Author(s):

Report Date:

2002-03-01

Pagination or Media Count:

203.0

Abstract:

Closed loop instability caused by excess phase lag induced by actuator rate limiting has been suspected in many pilot-induced oscillations PIOs and oscillatory departures from controlled flight. As part of the joint AFITTPS program, a longitudinal pilot command notch filter activated by a real-time oscillation verifier ROVER algorithm was developed to eliminate the PIO source for any developing, severe PIO. Closed loop computer simulations were conducted to prepare for the flight test. The HAVE ROVER flight test project was flown using the NF-16D Variable Stability In-flight Simulator Test Aircraft VISTA. A programmable heads-up display HUD was used to generate a tracking task simulating Category A fighter maneuvers. 6 of the 12 evaluation sorties were flown against an airborne target aircraft. Flight test results showed the stick filter was pivotal in preventing aircraft oscillatory departures and suppressing PIOs. With the original threshold settings, the ROVER algorithm correctly characterized pilot observations of the aircraft motion 72 of the time. Further analysis indicated that a high false detection rate was responsible for this relatively low correct detection rate. These results suggested that the threshold values used by ROVER to detect PIO were set too low. By varying the threshold values as part of a parametric study, a maximum overall correct detection rate of 82 was attained.

Subject Categories:

  • Flight Control and Instrumentation
  • Computer Programming and Software
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE