A Comparison of Nonlinear Algorithms to Prevent Pilot-Induced Oscillations Caused by Actuator Rate Limiting
A Comparison of Nonlinear Algorithms to Prevent Pilot-Induced Oscillations Caused by Actuator Rate Limiting

Author: James G. Hanley

Publisher:

Published: 2003-03

Total Pages: 107

ISBN-13: 9781423504085

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The objective of this study was to compare the ability of the Feedback-with-Bypass (FWB) and the Derivative-Switching (DS) flight control system filters to prevent PIO during actuator rate limiting, and the filters' effects on aircraft handling qualities. This comparison was conducted in three steps: computer simulation, ground simulation in the Large Amplitude Multimode Aerospace Research Simulator (LAMARS), and flight tests conducted in the Variable Stability In-flight Simulator Test Aircraft (VISTA). During computer simulation, the FWB filter better reduced the phase lag and prevented sustained or divergent oscillations during the closed-loop analysis. During both ground simulation and flight tests, the FWB filter was more effective at preventing divergent PIO and improving handling qualities. Overall the FWB filter performed better during all tests.

A Comparison of Nonlinear Algorithms in the Prevention of Pilot-Induced Oscillations Caused by Actuator Rate Limiting (Project HAVE PREVENT).
A Comparison of Nonlinear Algorithms in the Prevention of Pilot-Induced Oscillations Caused by Actuator Rate Limiting (Project HAVE PREVENT).

Author:

Publisher:

Published: 2002

Total Pages: 0

ISBN-13:

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This report presents the results of Project HAVE PREVENT, a comparison of nonlinear algorithms in the prevention of pilot-induced oscillations (PlO) caused by actuator rate limiting. The overall test objective was to compare the ability of two flight control system filters in the prevention of PlO during actuator rate limiting. The Air Force Institute of Technology, Engineering Department (AFIT/ENY) requested this testing. The USAF Test Pilot School (TPS), Class O2A, conducted 13 flight tests totaling 21.0 hours at Edwards AFB, California, from 16 to 23 October 2002.

A Nonlinear Pre-Filter to Prevent Departure And/or Pilot-Induced Oscillations (PIO) Due to Actuator Rate Limiting
A Nonlinear Pre-Filter to Prevent Departure And/or Pilot-Induced Oscillations (PIO) Due to Actuator Rate Limiting

Author: Michael Chapa

Publisher:

Published: 1999-03-01

Total Pages: 155

ISBN-13: 9781423546306

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Closed loop instability caused by excess phase lag induced by actuator rate limiting has been suspected in many aircraft departures from controlled flight and pilot-induced oscillations (PIO). As part of the joint Air Force Institute of Technology Test Pilot School (AFITITPS) program, a nonlinear rate limiter pre-filter (RLPF) was developed to minimize the phase lag induced by rate limiting. RLFF performance was evaluated inside the feedback path, but primary emphasis was on the pilot command path. Closed loop computer and motion- based flight simulation were conducted to prepare for the flight test. The HAVE FILTER flight test project was flown using the NF-16D Variable Stability in- flight Simulator Test Aircraft (VISTA) aircraft and evaluated using a software rate limit (SWRL) with and without an RLPF on the pilot command path. A programmable heads-up-display (HUD) was used to generate a fighter tracking task. Flight test results showed the SWRL was useful in preventing departure and/or PIO. However, with low SWRL settings (

Results of Attempts to Prevent Departure And/or Pilot-Induced Oscillations (PIO) Due to Actuator Rate Limiting in Highly-Augmented Fighter Flight Control Systems (HAVE FILTER).
Results of Attempts to Prevent Departure And/or Pilot-Induced Oscillations (PIO) Due to Actuator Rate Limiting in Highly-Augmented Fighter Flight Control Systems (HAVE FILTER).

Author: Michael Chapa

Publisher:

Published: 1999

Total Pages: 76

ISBN-13:

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The objective of this effort was to evaluate the effects of software rate limiting the pilot command with and without a software pre-filter on a highly-augmented fighter aircraft flight control system. The software rate limiter and software pre-filter were designed to provide protection from departure and/or pilot-induced oscillation (PIO). In statically unstable aircraft stabilized with feedback, elevator/stabilator actuator rate limiting may lead to PIOs and/or departure during aggressive maneuvers. This project examined the use of a software rate limiter (SWRL) on the pilot command and compared the results with those for the unprotected airframe. Additionally, a nonlinear rate limiter pre-filter (RLPF) was used in conjunction with the SWRL. Previous attempts to suppress PIO and/or departure tendencies using similar technologies have encountered difficulty with noise-in-the-loop and out-of-trim bias development during filter operation. This project attempted to improve previous designs using a different algorithm for the RLPF. The SWRL was found to help prevent PIO and/or departure. The RLPF plus SWRL was generally found to be more helpful than the SWRL alone at preventing PIO and/or departure. However, handling qualities deficiencies arose when using low SWRL settings and worsened with low SWRL settings used in conjunction with the RLPF.

Control, Mechatronics and Automation Technology
Control, Mechatronics and Automation Technology

Author: Dawei Zheng

Publisher: CRC Press

Published: 2015-12-30

Total Pages: 526

ISBN-13: 1315752158

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This proceedings volume contains selected papers presented at the 2014 International Conference on Control, Mechatronics and Automation Technology (ICCMAT 2014), held July 24-25, 2014 in Beijing, China. The objective of ICCMAT 2014 is to provide a platform for researchers, engineers, academicians as well as industrial professionals from all over th

Aviation Safety and Pilot Control
Aviation Safety and Pilot Control

Author: National Research Council

Publisher: National Academies Press

Published: 1997-03-28

Total Pages: 221

ISBN-13: 0309056888

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Adverse aircraft-pilot coupling (APC) events include a broad set of undesirable and sometimes hazardous phenomena that originate in anomalous interactions between pilots and aircraft. As civil and military aircraft technologies advance, interactions between pilots and aircraft are becoming more complex. Recent accidents and other incidents have been attributed to adverse APC in military aircraft. In addition, APC has been implicated in some civilian incidents. This book evaluates the current state of knowledge about adverse APC and processes that may be used to eliminate it from military and commercial aircraft. It was written for technical, government, and administrative decisionmakers and their technical and administrative support staffs; key technical managers in the aircraft manufacturing and operational industries; stability and control engineers; aircraft flight control system designers; research specialists in flight control, flying qualities, human factors; and technically knowledgeable lay readers.