Robust Adaptive Algorithms for Reconfigurable Flight Control Systems
Robust Adaptive Algorithms for Reconfigurable Flight Control Systems

Author:

Publisher:

Published: 1998

Total Pages: 0

ISBN-13:

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The objective of the project was to develop adaptive algorithms for application to reconfigurable flight control. An emphasis of the research was on robustness issues related to unmodelled dynamics and actuator saturation. Areas of investigation included: (1) the development of real time parameter identification algorithms for situations where the information content of the data varies significantly over time; (2) the incorporation of integral compensation in adaptive control algorithms with bias cancellation capabilities; and (3) the design of command limiting methods for the alleviation of problems associated with actuator saturation. The results showed that relatively simple multivariable adaptive control algorithms could be designed that were effective in providing flight control reconfiguration over a wide range of flight conditions. A detailed fighter aircraft model was used to evaluate the performance of the reconfigurable control laws in simulations.

New Adaptive Methods for Reconfigurable Flight Control Systems. Appendix I (of 2).
New Adaptive Methods for Reconfigurable Flight Control Systems. Appendix I (of 2).

Author:

Publisher:

Published: 1995

Total Pages: 116

ISBN-13:

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The report discusses methods for the design of reconfigurable flight control systems. Model reference adaptive control algorithms were developed which allow for the rapid identification of aircraft parameters after failures or damages and for automatic control redesign. These algorithms are simple enough that they can be implemented in real-time with existing computers. Simulation results were obtained using a detailed nonlinear model of a fighter aircraft. The results demonstrate the ability of the adaptive algorithms to automatically readjust trim values after failures, to restore tracking of the pilot commands despite the loss of actuator effectiveness, and to coordinate the use of the remaining surfaces in order to maintain the decoupling between- the rotational axes. The report also discusses analytical results that were obtained during the course of the research regarding the stability and convergence properties of multivariable adaptive control algorithms, the use of averaging methods for the analysis of transient response and robustness, and the estimation of uncertainty in dynamic models. A modified recursive least-squares algorithm with forgetting factor is also described which gives fast adaptation under normal conditions while keeping the sensitivity to noise limited when signal to noise ratios are poor.

Adaptive and Reconfigurable Flight Control
Adaptive and Reconfigurable Flight Control

Author: Huang Yih-Shiun

Publisher:

Published: 2001-03-01

Total Pages: 168

ISBN-13: 9781423530602

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An indirect adaptive and reconfigurable flight control system is developed. The three-module controller consists of: (1) a system identification module, (2) a parameter estimate smoother, and (3) a proportional and integral compensator for tracking control. Specifically: (1) The identification of a linear discrete-time control system's open-loop gain is addressed. The classical Kalman filter theory for linear control systems is extended and the control system's state and loop gain are jointly estimated on-line. Explicit formulae for the loop gain's estimate and estimation error covariance are derived. The estimate is unbiased and the predicted covariance is reliable. (2) An adaptive smoother is developed to reduce the fluctuations automatically in the gain estimate, and bursting, caused by instances of poor excitation. (3) Special attention is given to the design of a proportional and integral tracking controller. The outputs of the system identification and gain smoother modules are used to adjust the tracking controller's gain continuously in order to compensate for a possible reduction in the loop gain due to control surface area loss, thus achieving the benefits of adaptive and reconfigurable control. The performance of the adaptive and reconfigurable controller in the face of a simulated control surface failure is examined in carefully designed experiments. The adaptive controller developed in this dissertation and illustrated in a flight control Context is applicable to a wide range of control problems.

Adaptive Compensation of Nonlinear Actuators for Flight Control Applications
Adaptive Compensation of Nonlinear Actuators for Flight Control Applications

Author: Dipankar Deb

Publisher: Springer Nature

Published: 2021-07-22

Total Pages: 129

ISBN-13: 9811641617

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This book provides a basic understanding of adaptive control and its applications in Flight control. It discusses the designing of an adaptive feedback control system and analyzes this for flight control of linear and nonlinear aircraft models using synthetic jet actuators. It also discusses control methodologies and the application of control techniques which will help practicing flight control and active flow control researchers. It also covers modelling and control designs which will also benefit researchers from the background of fluid mechanics and health management of actuation systems. The unique feature of this book is characterization of synthetic jet actuator nonlinearities over a wide range of angles of attack, an adaptive compensation scheme for such nonlinearities, and a systematic framework for feedback control of aircraft dynamics with synthetic jet actuators.

Dynamic Inversion-based Adaptive/reconfigurable Control of the X-33 on Ascent
Dynamic Inversion-based Adaptive/reconfigurable Control of the X-33 on Ascent

Author: David B. Doman

Publisher:

Published: 2002

Total Pages: 14

ISBN-13:

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A quaternion-based attitude control system is developed for the X-33 in the ascent flight phase. A nonlinear control law commands body-axis rotation rates that align the angular velocity vector with an Euler axis defining the axis of rotation that will rotate the body-axis system into a desired-axis system. The magnitudes of the commanded body rates are determined by the magnitude of the rotation error. The commanded body rates form the input to a dynamic inversion-based adaptive/reconfigurable control law. The indirect adaptive control portion of the control law uses online system identification to estimate the current control effectiveness matrix to update a control allocation module. The control allocation nominally operates in a minimum deflection mode; however, if a fault is detected, it can operate in a null-space injection mode that excites and decorrelates the effectors without degrading the vehicle response to enable online system identification. The overall 5 stem is designed to provide fault and damage tolerance for the X-33 on ascent.

Advances in Gain-Scheduling and Fault Tolerant Control Techniques
Advances in Gain-Scheduling and Fault Tolerant Control Techniques

Author: Damiano Rotondo

Publisher: Springer

Published: 2017-10-14

Total Pages: 269

ISBN-13: 3319629026

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This thesis reports on novel methods for gain-scheduling and fault tolerant control (FTC). It begins by analyzing the connection between the linear parameter varying (LPV) and Takagi-Sugeno (TS) paradigms. This is then followed by a detailed description of the design of robust and shifting state-feedback controllers for these systems. Furthermore, it presents two approaches to fault-tolerant control: the first is based on a robust polytopic controller design, while the second involves a reconfiguration of the reference model and the addition of virtual actuators into the loop. Inaddition the thesis offers a thorough review of the state-of-the art in gain scheduling and fault-tolerant control, with a special emphasis on LPV and TS systems.