Relevant Papers and Abstracts

G.Tao, S.Chen, S.M.Joshi
An adaptive control scheme for systems with unknown actuator failures
Source: Jan/Science Direct (Download)
Journal: Automatica Month: 11 Year: 2002 Volume: 38 Pages: 1027-1034
Abstract:
A state feedback output tracking adaptive control scheme is developed for plants with actuator failures characterized by the failure pattern that some inputs are stuck at some unknown xedvalues at unknown time instants.New controller parametrization andadaptive law are developed under some relaxed system conditions.All closed-loop signals are bounded and the plant output tracks a given reference output asymptotically,despite the uncertainties in actuator failures and plant parameters. Simulation results verify the desired adaptive control system performance in the presence of actuator failures.

S.Wan, G.Campa, M.Napolitano, M.L.Fravolini
Sensor Validation Schemes for a Flight Control System with Dual Physical Redundancy
Source: Web
Journal: American Control Conference Month: 9 Year: 2002
Abstract:
Modren high performance aircraft feature flight control systems with triple physical redundancy in the sensory capabilities to achieve fault-tolerant capabilities. For specific aircraft where weight optimization is of great concern (such as high altitude research aircraft and/or unmanned aircraft), a promising alternative is to use dual physical redundancy with an additional level of redundancy of analytical nature. It is expected that this alternative enables to achieve a comparative level of fault tolerant capabilities as those provided by a triple physical redundancy. In this study, a sensor validation scheme for a flight control system with dual physical redundancy is proposed, with the focus on exploiting analytical redundancy in case of sensor failures. The proposed scheme, based on a set of neural on-line approximators, has shown to provide desirable Sensor Failure Detections, Identification and Accommodation (SFDIA) capabilities following sensor failures. The designed approximators are based on Radial Basis Function Neural Networks which feature stable online learning capabilities. Embedded filters are also introduced in the approximator structure as an effective way of increasing the sensitivity to sensor failure while attenuating sensitivity to noise/disturbance. The schemees have been simulated on a 6 DOF non-linear model of the De Havilland DHC-2 "Beaver" aircraft.

G.Campa, M.Napolitano, B.Seanor, M.L.Fravolini, Y.Song
Application of an Improved LWR Method to Real-Time Aircraft Parameter Identification Problems
Source: Author's page
Journal: American Control Conference Month: 9 Year: 2002
Abstract:
In this paper a recently introduced time domain-based parameter identification (PID) method is considered for the estimation of the aerodynamic coefficients of a specific aircraft. The basic method is the Local Weighted Regression (LWR) technique and it is improved through the addition of a data Retention-and-Deletion (RD) strategy. The resulting PID algorithm was tested using NASA F/A-18 HARV flight data for evaluating its capabilities for in-line real time pID purposes. The results were then compared with theoretical estimates from wind tunnel analysis and with the PID results from the Maximum Likelihood method, a well known PID method for off-line applications.

A.Saberi, J.Han, A.A.Stoorvogel
Constrained stabilization problems for linear plants
Source: Science Direct (Download)
Publisher: Pergamon Journal: Automatica Month: 4 Year: 2002 Volume: 38 Pages: 639-654
Abstract:
Linear systems with magnitude and rate constraints on both the state and control variables are considered. For such systems, semi-global and global constrained stabilization problems are formulated when state feedback controllers are used. Necessary and sufficient conditions for the solvability of the formulated problems are developed. Moreover, design methodologies for such constrained stabilization problems are presented. An important aspect of our development here is a taxonomy of constraints to show clearly for what type of constraints what can or cannot be achieved.

G.Campa, M.L.Fravolini, M.Napolitano
A Library of Adaptive Neural Networks for Control Purposes
Source: Author's website
Journal: 2002 CCA-CACSD Conference Month: 1 Year: 2002
Abstract:

G.Campa, M.L.Fravolini, M.Napolitano, B.Seanor
Neural Networks-Based Sensor Validation for the Flight COntrol System of a B777 Research Model
Source: Authors webpage
Journal: American Control Conference Year: 2002
Abstract:
This paper shows the results of the analysis of a scheme for Sensor Failure, Detection, Identification and Accommodation (SFDIA) using experimental flight data of a research aircraft model. Conventional approaches to the problem are based on observers and Kalman Filters while more recent methods are based on neural approximators. The work described in this paper is based on the use of neural networks (NNs) as on-line learning non-linear approximators. The performances of two different neural architectures were compared. The first architecture is based on a Multi-Layer Perceptron (MLP) NN trained with the Extended Back Propagation algorithm (EBPA). The second architecture is based on a Radial Basis Function (RBF) NN trained with the Extended-MRAN (EMRAN) algorithms. The EMRAN algorithm is a training algorithm recently developed for RBF networks which has shown remarkable learning capabilities at a fraction of the memory requirements and computational effort typically associated with RBF NNs. The experimental data for this study are acquired from the flight-testing of a 1/24th semi-scale B777 research model designed, built, and flown at West Virginia University (WVU).

M.G.Perhinschi, M.Lando, L.Massotti, G.Campa, M.Napolitano, M.L.Fravolini
Real-Time Parameter Estimation Issues for the NASA IFCS F-15 Fault Tolerant Systems
Source: Authors webpage
Journal: American Control Conference Year: 2002
Abstract:
This paper focuses on specific issues relative to real-time on-line estimation of aircraft aerodynamic parameters at nominal and post-actuator failure flight conditions. A specific parameter identification (PID) method, based on Fourier Transform, has been applied to an approximated mathematical model of the NASA IFCS F-15 aircraft. In this effort different options relative to the application of this PID method are evaluated and compared. Particularly the direct evaluation of stability and control derivatives versus the estimation of the coefficients of the state space system matrices evaluation has been considered. Furthemore the options of considering individual control surfaces (left and right) vs. total surfaces as inputs to the PID process has been debated. Finally, since the PID method relies on the use of derivative terms the option of using time domain derivatives versus frequency domain derivatives has also been assessed. The results are presented in terms of the accuracy and reliability of the estimates of selected stability and control derivatives.

R.M. Murray, J.Hauser, A.Jadbabaie, M.B. Milam, N. Petit, W.B Dunbar, R. Franz
Online Control Customization via Optimization-Based Control
Source: Jan
Publisher: IEEE Year: 2002 Chapter: 6
Abstract:
In this chapter, we present a framework for online control customization that makes use of finite-horizon, optimal control combined with real-time trajectory generation and optimization. The results are based on a novel formulation of receding-horizon optimal control that replaces the traditional terminal constraints with a control Lyapunov function -based terminal cost. This formulation leads to reduced computational requirements and sallows proof of stability under a variety of realistic assumptions on computation. By combining these theoretical advances with advances in computational power for real-time, embedded systems, we demonstrate the efficacy of online control customization via optimization-based control. The results are demonstrated using a nonlinear, flight control experiment at Caltech.

W.Siwakosit, R.A.Hess
Multi-Input/Multi-Output Reconfigurable Flight Control Design
Source: AIAA
Publisher: AIAA Journal: Journal of Guidance, Control and Dynamics Month: 12 Year: 2001 Volume: 24 Number: 6
Abstract:
A multi-input/multi-output recon” gurable ‘ ight control systemdesign utilizing a robust controller and an adap-tive ” lter is presented. The robust control design consists of a reduced-order, linear dynamic inversion controller with an outer-loop compensation matrix derived from quantitatitve feedback theory (QFT). A principle feature of the scheme is placement of the adaptive ” lter in series with the QFT compensator, thus exploiting the inher-ent robustness of the nominal ‘ ight control system in the presence of plant uncertainties. An example of the scheme is presented in a pilot-in-the-loop computer simulation using a simpli” ed model of the lateral – directional dynamics of the NASA F-18 high-angle-of-attack research vehicle that included nonlinear antiwindup logic and actuator limitations. Prediction of handling qualities and pilot-induced oscillation tendencies in the presence of these nonlinearities is included in the example.

M.G.Perhinschi, G.Campa, M.Napolitano, M.Lando, L.Massotti, M.L.Fravolini
Modeling and Simulation of Failures for Primary Control Surfaces
Source:
Journal: 2002 AIAA Modeling and Simulation Conference Month: 12 Year: 2001
Abstract:

S.Kanev, M.Verhaegen, G.Nijsse
A Method for the Design of Fault-Tolerant SYstems in Case of Sensor and Actuator Faults
Source: Author's website
Journal: University of Twente Month: 11 Year: 2001
Abstract:

A.S.Lewis
Robust Output Feedback Using Sliding Mode Control
Source: AIAA
Publisher: AIAA Journal: Journal of Guidance, Control and Dynamics Month: 10 Year: 2001 Volume: 24 Number: 5
Abstract:

P.A.Gili, M.Battipede
Adaptive Neurocontroller for a Nonlinear Combat Aircraft Model
Source: AIAA
Publisher: AIAA Journal: Journal of Guidance, Control and Dynamics Month: 10 Year: 2001 Volume: 24 Number: 5
Abstract:

J.S.Brinker, K.Wise
Flight Testing of Reconfigurable Control Law on the X-36 Tailless Aircraft
Source: CiteSeer?
Publisher: American Institute of Aeronautics and Astronautics, Inc. Journal: Journal of Guidance, Control and Dynamics Month: 9 Year: 2001 Volume: 24 Number: 5
Abstract:
Piloted simulation and flight-test results from the evaluation of a reconfigurable flight control law for the X-36 tailless fighter aircraft are presented. The reconfigurable control law, which is based on dyanmic inversion in an explicit model following framework, employs an online neural network to adaptively regulate the error in the plant inversion, which may be due to modeling unvertainties, failures, or damage. Simulated actuator failures, which caused effectors to be locked at prescribed positions, were injected to evaluate the stability and handling qualities of the reconfiguable control law under fialures. The control law was not given any knowledge of the actuator failure, and fault detection logic was not employed. Piloted simulation testing was used to compare the reconfigurable control law to the X-36 dynamic inversion control laws under simulated actuator fialures. The creconfigurable control law showed improved handling qualities and departure resistance relative to the baseline X-36 control laws.

C.N.Jones
Consistency-Based Diagnosis for Hybrid Dynamic Systems
Source: Me (Download)
Month: 8 Year: 2001
Abstract:
Rapid detection and isolation of faults in modern systems improves safety, performance and reduces operational costs drastically. To date, expert-systems have been the method of choice, but the field of model-based diagnosis (MBD) has emerged which offers many benefits. A model of the correct structure and behavior of the device allows the diagnostic program to detect unexpected failures, or faults which have never before been seen. The heart of model-based diagnosis is the model, which has traditionally taken the form of a qualitative logic program. These languages are not familiar to most developers who are used to quantitative dynamic, or hybrid dynamic models. This thesis presents a novel method of consistency-based diagnosis (one form of MBD), which allows the use of any model type for which an appropriate calculation engine can be written. This new technique computes the same result as any other method built upon consistency-based diagnosis given perfect knowledge, but degrades gracefully in the presence of uncertainty, which can be caused by noise or modelling errors. As a proof of concept, a quantitative hybrid dynamic model was created for the fluid power circuit of a single-degree of freedom hydraulic test bench and a calculation engine based upon hcc (hybrid concurrent constraint programming) was developed. The model and engine were used to diagnose various failures on the physical test bench with approximately 85\% accuracy. The ability to use any model type, and specifically, quantitative hybrid dynamic models, represents an important contribution to the field of model-base diagnosis.

M.L.Steinberg
Comparison of Intelligent, Adaptive, and Nonlinear Flight Control Laws
Source: AIAA
Publisher: AIAA Journal: Journal of Guidance, Control and Dynamics Month: 8 Year: 2001 Volume: 24 Number: 4
Abstract:

M.Idan, M.Johnson, A.J.Calise
A Hierarchical Approach to Adaptive Control for Improved Flight Saftey
Source: CiteSeer (Download)
Journal: AIAA Journal on Guidance, Control and Dynamics Month: 7 Year: 2001
Abstract:
Following failures of primary aerodynamic actuators, safe flight can be maintained by introducing alternative actuation systems, such as secondary aerodynamic suraces and propulsion, for critical stability and control augmentation tasks. This paper presents an intelligent hierarchical flight control system architecture that is designed using nonlinear adaptive synthesis techniques and on-line learning neural networks to enhance flight safety. Pseudo-control hedging is used for proper adaptation in the presence of actuator saturation, rate limits and failure. The hierarchical structure incorporates non-active secondary actuation channels that are engaged after a failure of primary control surface is encountered. The methodology requires only the knowledge that a failure in a specific actuator has occurred, while the failure type and size need not to be known: the neural network element of the secondary channel will adapt to the fialed actuator effect. The secondary channels are designed to account for the typically lower authority and degraded performance that can be expected with secondary actuation systems. Theproposed hierarchical flight control architecture is attractive in particular as a retrofit to existing certified flight control system for enhanced flight safety. The proposed flight control architecture is evaluated in a non-linear flight simulation environment, demonstrating its retrofit features.

I.A.Shkolnikov, Y.Shtessel
Aircraft Nonminimum Phase Control in Dynamic Sliding Manifolds
Source: AIAA
Publisher: AIAA Journal: Journal of Guidance, Control and Dynamics Month: 6 Year: 2001 Volume: 24 Number: 3
Abstract:

J.D. Boskovic, R.K. Mehra
A Robust Adaptive Reconfigurable Flight Control Scheme for Accommodation of Control Effector Failures
Source:
Journal: Proceedings of the American Control Conference Month: 6 Year: 2001
Abstract:

J.D. Boskovic, S.M.Li, R.K. Mehra
Robust Supervisory Fault-Tolerant Flight Control System
Source:
Journal: Proceedings of the American Control Conference Month: 6 Year: 2001
Abstract:

L.Wills, S.Kannan, S.Sander, M.Guler, B.Heck, J.V.R.Prasad, D.Schrage, G.Vachtsevanos
An Open Platform for Reconfigurable Control
Source: Jan
Publisher: IEEE Journal: IEEE Control systems Magazine Month: 6 Year: 2001
Abstract:
None

W.Reinelt
Control of Multivariable Systems with Hard Constraints
Source: Author's website (Download)
Journal: ECC 2001 Month: 5 Year: 2001
Abstract:
A general framework for the design of multivariable control systems subject to hard constraints on each control channel is developed. The design procedure is an extension of the well-known H-inf Loop Shaping Design Procedure and is based on the calculation of the maximum possible control amplitutde for a certain class of reference signals. Special attention is given to the adaption of the design weights in order to meet the prescribed bounds on the control signal. A multivariable simulation example, the control of the vertical dynamnics of an aircraft illustrates the suggested procedure.

W.Reinelt
Design of optimal control systems with bounded control signals
Source: Author's website (Download)
Journal: ECC 2001 Month: 5 Year: 2001
Abstract:
The design of optimal controllers for systems subject to hard bounds on the control signal is considered. Optimality refers to the fact that we achieve the smallest possible worst case error (i.e. difference between reference signal and plant output) during runtime. The external reference signal is bounded in amplitude and rate, which encounters for many practical situations. Moreover, a conservative design is avoided by these assumptions. The resulting constrained and infinite dimensional optimization problem is re-casted to an unconstrained and finite dimensional one by applying the notion of Pareto-optimal solutions and Ritz approximation. Moreover, the presented framework allows to asses feasibility of the constraint control problem, and to display the tradeoff between the two objectives. A simulation example illustrates the developed theory.

W.Reinelt, M.Canale
Robust control of SISO systems subject to hard input constraints
Source: (Download)
Journal: ECC 2001 Month: 5 Year: 2001
Abstract:
The design of robust controllers that guarantee prescribed hard bounds on the control signal when facing model uncertainty is considered. Our approach to avoid a conservative design is to describe the external signals quite accuratly by means of "admissible sets", hard bounded in amplitude and rate. The core problem to solve is the calculation of the maximum output amplitude of a set of systems. This problem will be solved for a certain parameterisation of the set in a computationally attrtactive way. Controller design can then be formulated by employing a double Youla parameterisation of uncertain plant and stabilising controllers. We demonstrate, how the employed model uncertainty can be identified by means of standard identification techniques. Moreover, we present a combination with an MPC scheme, that allows us to obtain faster time responses and invites the possibility to encounter for time domain and fequency domain performance specifications.

J.J.Burken, P.Lu, Z.Wu, C.Bahm
Two Reconfigurable Flight-Control Design Methods: Robust Servomechanism and Control Allocation
Source: Web? (Download)
Publisher: AIAA Journal: Journal of Guidance, Control and Dynamics Month: 5 Year: 2001 Volume: 24 Number: 3
Abstract:
Two methods are discussed for design of reconfigurable flight-control systems when one or more control surfaces are jammed. The first is a robust servomechanism control approach, which is a generalization of the classical proportional-plus-integral control to multi-input/multi-output systems. The second proposed method is a control-allocation approach based on a quadratic programming formulation. The formulation is formally analyzed, and a globally convergent fixed-point iteration algorithm is used to make onboard implementation of this method feasible. The two methods are applied to reconfigurable entry flight control design for the X-33 vehicle. Nonlinear six-degree-of-freedom simulation demonstrate simultaneous tracking of angle-of-attack and roll-angle commands during control surface failures. The control-allocation method appears to offer more uniform and good performance at the expense of modestly higher computation requirements.

Y.Song, G.Campa, M.Napolitano, B.Seanor, M.G.Perhinschi
Comparison of On-Line Parameter Estimation Techniques Within a Fault Tolerant Flight Control System
Source: Author's page
Journal: AIAA Journal on Guidance, Control and Dynamics Month: 5 Year: 2001
Abstract:
This paper describes the results of a study where two on-line parameter identification (PID) methods are compared for application within a fault tolerant flight control system. One of the PID techniques is time-domain based while the second is featured in the frequency fomain. The time domain method was directly suitable for the on-line estimates of the dimensionless aircraft stability derivatives. The frequency domain method was modified from its original formulation to provide direct estimates of the stability derivatives. This effort was conducted within the research activities of the NASA IFCS F-15 program. The comparison is performed through dynamic simulations with a specific procedure to model the aircraft aerodynamics following the occurrence of a battle damage/failure on a primary control surface. The two PID methods show similar performance in terms of accuracy of the estimates, convergence time, and robustness to noise. However, the frequency domain-based method outperforms the time domain-based method in terms of computational requirements for on-line real time applications. The study has also emphasized the advantages of using ``ad-hoc'' short pre-programmed maneuvers to provide enough excitation following the occurrence of the actuator failure to allow the parameter estimation process.

A.J.Calise, N.Hovakimyan, M.Idan
Adaptive Output Feedback Control of Nonlinear Systems using Neural Networks
Source: Authors webpage
Publisher: Elsevier Preprint Month: 3 Year: 2001
Abstract:

Y.Huang
Adaptive and Reconfigurable Flight Control
Source: Website (Download)
Month: 3 Year: 2001
Abstract:

J.D. Boskovic, S.M.Li, R.K. Mehra
Robust Adaptive Variable Structure Control of Spacecraft Under Control Input Saturation
Source: CiteSeer?
Publisher: American Institute of Aeronautics and Astronautics, Inc. Journal: Journal of Guidance, Control and Dynamics Month: 1 Year: 2001 Volume: 24 Number: 1
Abstract:
In this paper we propose two globally stable control algorithms for robust stabilization of spacecraft in the presence of control input saturation, parametric uncertainty and external disturbances. The control algorithms are based on variable structure control design and have the following properties: 1) fast and accurate response in the presense of bounded external distrubances and parametric uncertainty; 2) explicit accounting for control input saturation; 3) computational simplicity and straightforward tuning. We include a detailed stability analysis for the resulting closed-loop system. The stability proof is based on a Lyapunov-like analysis and the properties of the quaternion representation of spacecraft dynamics. It is also shown that an adaptive version of the proposed controller results in substantially simpler stability analysis and improved overall response. We also include numerical simulations to illustrate the spacecraft performance obtained using the proposed controllers.

I.E. Kose, F.Jabbari
Control of Systems with Actuator Amplitude and Rate Constraints
Source: IEEE
Publisher: IEEE Journal: ACC Year: 2001
Abstract:
This paper studies the problem of controller synthesis for systems subject to amplitude and rate saturation constraints in the actuators. It is assumed that dynamic models of order at least 1 are known for the actuators. The controllers designed are dynamic LTI controllers that use only the output of the plant, and not neciessarily the states of the actuator. The solvability conditions for the problem are expressed as finite-dimensional linear matrix inequalities. In addition to stabilization, disturbance attenuation in terms of the usual Hinf-norm is also considered. An application to an F/A-18 aircraft model demonstrates the methods developed.

M.L.Fravolini, G.Campa, M.Napolitano, Y.Song
Minimal Resource Allocating Networks for Aircraft SFDIA
Source: Author's website
Year: 2001
Abstract:

G.Campa, M.L.Fravolini, B.Seanor, M.Napolitano, D.D.Gobbo, S.Gururajan
On-line Learning Neural Networks for Sensor Validation for the Flight Control System of a B777 Research Scale Model
Source: Author's website
Journal: International Journal of Robust and Nonlinear Control Year: 2001
Abstract:

E.N.Johnson, A.J.Calise
Neural Network Adaptive Control of Systems with Input Saturation
Source: CiteSeer (Download)
Year: 2001
Abstract:
In the application of adaptive flight control, significant issues arise due to limiations on the plant inputs, such as actuator displacement limits. The concept of utilizing a modified reference model to prevent an adaptation law from "seeing" this system-input characteristic is described. The method allows correct adaptation while the plant input is saturated. To apply the method, estimates of actuator positions must be found. However, the adaptation law can correct for errors in these estimates. A theorem of boundedness for all system signals is included for a single hidden layer nerual network adaptive law. The domain of attraction is also discussed.

M.C.Cotting, J.J.Burken
Reconfigurable Control Design for the Full X-33 Flight Envelope
Source: NASA
Journal: AIAA Year: 2001
Abstract:
A reconfigurable control law for the full X-33 flight envelope has been designed to accommodate a failed control surface and redistribute the control effort among the remaining working surfaces to retain satisfactory stability and performance. An offline nonlinear constrained optimization approach has been used for the X-33 reconfigurable control design method. Using a nonlinear, six-degree-of-freedom simulation, three example failures are evaluated: ascent with a left body flap jammed at maximum deflection; entry with a right inboard elevon jammed at maximum deflection; and landing with a left rudder jammed at maximum delfection. Failure detection and identification are accomplished in the actuator controller. Failure response comparisons between the nominal control mixer and the reconfigurable control suyssystem (mixer) show the benefits of reconfiguration. Single aerosurface jamming failures are considered. The cases evaluated are representative of the study conducted to prove the adequate and safe performance of the reconfigurable control mixer throughout the full flight envelope. The X-33 flight control system incorporates reconfigurable flight control in the existing baseline system.

Y.Diao, K.M.Passino
Intelligent Fault Tolerant Control Using Adaptive Schemes and Multiple Models
Source: IEEE
Publisher: IEEE Journal: 2001 American Control Conference Year: 2001
Abstract:

D.D.Gobbo, A.Mili
Re-engineering Fault Tolerance Requirements: A Case Study in Specifying Fault Tolerant Flight Control Systems
Source: IEEE
Publisher: IEEE Year: 2001
Abstract:

G.Campa, M.Napolitano, M.L.Fravolini
Extended Minimal Resourece Allocating Neural Networks for Aircraft SFDIA
Source: Author's page
Year: 2001
Abstract:
This paper presents an Adaptive Nerual Network (ANN) based tool for the modeling, simulation and analysis of aircraft Sensor Fialure, Detection, Identification and Accommodation (SFDIA) problem. The tool is based on a SFDIA scheme in which learning NNs are used as on-line non-linear approximators of the analytically redundant portion of the system dynamics. This can provide validation capability to measurement devices, allowing sensors failures to be detected, identified and accommodated. In the context of online learning the issues of critical importance are learning speed, number of parameters to be updated, and stability of the learning algorithm. To address these problems, a library comprising different online learning Adaptive Neural Network is presented, and an Extended Minimal Resource Allocating Network (EMRAN) featuring a fully tuned Radial Basis Functions (RBF) is eventually selected between all the candidate architectures. The study has been performed on a detailed nonlinear 6DOF aircraft model of an aircraft.

J.B.Davidson, F.J.Lallman, W.T.Bundick
Real-Time Adaptive Control Allocation applied to a High Performance Aircraft
Source: NASA (Download)
Journal: 5th SIAM Conference on Control & Its Applications Year: 2001
Abstract:
This paper presents the development and application of one approach to the control of aircraft with large numbers of control effectors. This approach, referred to as real-time adaptive control allocation, combines a nonlinear method for control allocation with actuator failure detection and isolation. The control allocator maps moment (or angular acceleration) commands into physical control effector commands as functions of individual control effectiveness and availability. The actuator failure detection and isolation algorithm is a model-based approach that uses models of the actuators to predict actuator behavior and an adaptive decision threshold to achieve acceptable false alarm/missed detection rates. This integrated approach provides control reconfiguration when an aircraft is subjected to actuator failure, thereby improving maneuverability and survivability of the degraded air craft. This method is demonstrated on a next generation military aircraft (Lockheed-Martin Innovative Control Effector) simulation that has been modified to include a novel nonlinear fluid flow control control effector based on passive porosity. Desktop and real-time piloted simulation results demonstrate the performance of this integrated adaptive control allocation approach.

A.Saberi, J.Han, A.A.Stoorvogel
Constrained Stabilization Problems for Linear Plants
Source: Author's webpage
Year: 2001
Abstract:
Linear systems with magnitude and rate constraints on both the state and control variables are considered. For such systems, semi-global and global constrained stabilization problesm are formulated when state as well as measurement feedback controllers are used. Necessary and sufficient conditions for the solvability of all the formulated problems are developed. Moreover, design methodologies for such constrained stabilization problems are developed.

B.Seanor, Y.Song, M.Napolitano, G.Campa
Comparison of On-line and Off-line Parameter Estimation Techniques using the NASA F/A-18 HARV Flight Data
Source: Authors webpage
Publisher: AIAA Journal: AIAA Year: 2001
Abstract:
In recent years several Parameter Identification (PID) techniques have been proposed for on-line real-time applications. Historically aircraft parameter estimation has been performed off-line using recorded flight data from specifically designed maneuvers. Flight data from the NASA F/A-18 High Alpha Research Vehicle (HARV) aircraft is used for this study and is compared with baseline wind tunnel estimates. This paper shows a comparison of the results of a recently developed frequency-based PID technique with the results from the traditional Maximum Likelihood method. The comparison is performed for both longitudinal and lateral-directional dynamics for maneuvers at an angle of attack of $\alpha=20\degrees$ and $\alpha=30\degrees$. Results of the two estimation processes are compared with available wind tunnel estimates.

M.Idan, M.Johnson, A.J.Calise, J.Kaneshige
Intelligent Aerodynamic/Propulsion Flight Control for Flight Safety: A Nonlinear Adaptive Approach
Source: SiteCeer
Year: 2001
Abstract:
This paper presents an intelligent fault tolerant flight control system that blends aerodynamic and propulsion actuation for safe flight operation in the presence of actuator failures. Fault tolerance is obtained by a nonlinear adaptive control strategy based on on-line learning neural networks and actuator reallocation scheme. The adaptive control block incorporates a recently developed technique for adaptation in the presence of actuator saturation, rate limits and failure. The proposed integrated aerodynamic/propulsion flight control system is evaluated in a nonlinear flight simulation environment.

Z.Yang
A Hybrid System Approach Towards Redundant Fault-Tolerant Control Systems
Source: IEEE
Publisher: IEEE Journal: Proceedings of the 39th IEEE Conference on Decision and Control Month: 12 Year: 2000
Abstract:

W.Reinelt
Maximum Output Amplitude of Linear Systems for certain Input Constraints
Source: Author's website (Download)
Journal: 39th IEEE CDC Month: 12 Year: 2000
Abstract:
We determine the maximum output amplitude of a system, when the input is bounded by certain constraints. In particular, amplitutde and rate of change (i.e. the first derivative) have to be bounded. We show properties of the worst case input and present an algorithm that allows construction of this input and calculates the maximum amplitude of the output. The solution of this problem is a necessary and important step within a couple of recently developed controller-design procedures, dealing with plants with hard-bounded inputs. Nevertheless, it is interesting as a ssytem theoretic task itself and terefore stated seperatly.

S.Kanev, M.Verhaegen
Controller Reconfiguration for Non-Linear Systems
Source: Author's website
Journal: University of Twente Month: 10 Year: 2000
Abstract:

CAA
Aviation Saftey Review 1990-1999
Source: CAA Website (Download)
Publisher: Westward documedia Limited, 37 Windsor Street, Cheltenham, England Month: 10 Year: 2000
Abstract:

J.D. Boskovic, S.M.Li, R.K. Mehra
Reconfigurable Flight Control Design Using Multiple Switching Controllers and On-line Estimation of Damage-Related Parameters
Source: IEEE
Publisher: IEEE Journal: Proceedings of the 2000 IEEE International Conference on Control Applications Month: 9 Year: 2000
Abstract:

A.J.Calise, S.Lee, M.Sharma
Development of a Reconfigurable Flight Control Law for the X-36 Tailless Fighter Aircraft
Source: web (?)
Publisher: AIAA Journal: AIAA Guidance, Navigation, and Control Conference Month: 8 Year: 2000
Abstract:
This paper describes a neural network based direct adaptive control approach to the problem of reconfigurable flight control. The control law was first tested using a model of a taillesss fighter aircraft configured with multiple and redundant control actuation devices, and subsequently tested both in piloted simulation and in flight test on the X-36 aircraft. The model aircraft was used for design and to illustrate the level to which handling qualities can be maintained in the presence of failures in the actuation channels. Of significance here is the speed with which recovery and maintenance of handling qualities can take place. The main advantage lies in eliminating the need for parameter identification during the recovery phase, and limiting the potential need for parameter identification in the problem of control reallocation following a failure. A second by-product of this work is that the need for an accurate aerodynamic data base for the purpose of flight control design can be significantly reduced. Moreover, the need for extensive off-line analysis, in-flight tuning and validation of gain schedules, and contingency coding necessary to handle a la rge set of possible failure modes is substantially reduced. Thus the overall approach may also be viewed as a direct path to substantially reducin gthe cost associated with the devlopment of new aircraft.

Y.Zhang, J.Jiang
Integrated Design of Reconfigurable Fault-Tolerant Control Systems
Source:
Publisher: AIAA Journal: Journal of Gauidance Month: 7 Year: 2000 Volume: 24 Number: 1 Pages: 133-136
Abstract:
None

R.J.Patton
Soft Computing Approaches to Fault Diagnosis for Dynamic Systems: A Survey
Source: Author's website (Download)
Journal: 4th IFAC Symposium on Fault Detection Supervision and Safety for Technical Processes Month: 6 Year: 2000 Volume: 1 Pages: 298-311
Abstract:

A.I.Belkharraz, K.Sobel
Fault Tolerant Flight Control for a Class of Control Surface Failures
Source: IEEE
Publisher: IEEE Journal: Proceedings of the American Control Conference Month: 6 Year: 2000
Abstract:

J.D. Boskovic, S.M.Li, R.K. Mehra
A Decentralized Fault-Tolerant Scheme for Flight Control Applications
Source: AACC
Journal: Proceedings of the American Control Conference Month: 6 Year: 2000
Abstract:

E.C.Kerrigan, A.Bemporad, D.Mignone, M.Morari, J.M.Maciejowski
Multi-objective Prioritisation and Reconfiguration for the Control of Constrained Hybrid Systems
Source: Mihai's website (Download)
Publisher: AACC? Journal: Proceedings of the American Control Conference Month: 6 Year: 2000
Abstract:
In many application, the control objectives and constraints can be assigned a hierarchy of levels of priority. Often a disturbance or a fault occurs, resulting in some constraints or objectives being violated. Inadequate handling of this situation might result in component or even system-wide failures. This paper presents several methods for handling a large class of multi-objective formulations and prioritisations for model predivtive control of hybrid systems, using the new mixed logiv dynamical (MLD) framework. A new method, which does not require logic variables for prioritising soft constraints, is also presented.

Z.Yang
Synthesis of Robust Restructurable/Reconfigurable Control by Model-Matching Strategy
Source:
Year: 2000
Abstract:

J.M.Maciejowski
Fault Tolerant Aspects of MPC
Source: Mihai's website (Download)
Publisher: The Institution of Electrical Engineers Journal: IEE Year: 2000
Abstract:
None

L.P.Bolduc
Redundancy Management System for the X-33 Vehicle and Mission Computer
Source: IEEE
Publisher: IEEE Year: 2000
Abstract:

Z.Yang, M.Blanke
The Robust Control Mixer Module Method for Control Reconfiguration
Source:
Year: 2000
Abstract:

J.D. Boskovic, S.M.Li, R.K. Mehra
Study of an Adaptive Reconfigurable Control Scheme for Tailless Advanced Fighter Aircraft (TAFA) in the Presence of Wing Damage
Source: IEEE
Publisher: IEEE Year: 2000
Abstract:

A.J.Calise, H.Lee, N.Kim
High Bandwidth Adaptive Flight Control
Source: Author's website
Publisher: AIAA Journal: AIAA Year: 2000
Abstract:

L.Wills, S.Kannan, B.Heck, G.Vachtsevanos, C.Restrepo, S.Sander, D.Schrage, J.V.R.Prasad
An Open Software Infrastructure for Reconfigurable Control Systems
Source: Web?
Year: 2000
Abstract:
Recent advances in software technology have the potential to revolutionize control system design. This paper descirbes a new software infrastructure for complex control systems, which exploits new and emerging software technologies. It presents an open control platform (OCP) for complex systems, including those that must be reconfigured or customized in real-time for extreme-performance applications. An application of the OCP to the control system design of an autonomous aerial vehicle is described.

Y.Zhang, J.Jiang
An Interacting Multiple-Model Based Fault Detection, Diagnosis and Fault-Tolerant Control Approach
Source: CDC CD
Journal: Proceedings of the 38th Conference on Decision & Control Month: 12 Year: 1999
Abstract:

K.Wise, J.S.Brinker, A.J.Calise, D.F.Enns, M.R.Elgersma, P.Voulgaris
Direct Adaptive Reconfigurable Flight Control for a Tailless Advanced Fighter Aircraft
Source: Jan
Publisher: John Wiley & Sons, Ltd Journal: International Journal of Robust and Nonlinear Control Month: 12 Year: 1999 Volume: 9 Number: 14 Pages: 999-1012
Abstract:
This paper presents a direct adaptive reconfigurable flight control approach and demonstrates its effectiveness via an application to an advanced tailles fighter aircraft. The reconfigurable control law is based on a dynamic inversion controller in an explicit model following architecture. An on-line neural network is used to adaptively regulate the error between the desired response model and the actual vehicle response. An on-line control allocation scheme generates individual control effector commands to yield the moments commanded by the controller, while prioritizing critical axes and optimizing performance objectives such as maneuver load alleviation. An on-line system identification module generates estimates of the vehicle's stability and control derivatives for use in control allocation and command limiting. The reconfigurable control laws are demonstrated by comparing their performance to a dynamic inversion control law when unknown failure/damage are induced.

F.Blanchini
The gain scheduling and the robust state feedback stabilization problems
Source: Author's website
Month: 11 Year: 1999
Abstract:

J.J.Burken, P.Lu, Z.Wu
Reconfigurable Flight Control Designs with Application to the X-33 Vehicle
Source: NASA
Publisher: NASA Month: 8 Year: 1999
Abstract:

S.F.Wu, M.J.Grimble, W.Wei
QFT Based Robust/Fault Tolerant Flight Control Design For a Remote Pilotless Vehicle
Source: IEEE
Publisher: IEEE Journal: Proceedings of the 1999 IEEE International Conference on Control Applications Month: 8 Year: 1999
Abstract:

W.Reinelt
H-inf Loop Shaping for Systems with Hard Bounds
Source: Author's website (Download)
Journal: Int Symposium on Quantitative Feedback Theory and Robust Frequency Domain Methods Month: 8 Year: 1999
Abstract:
We study multivariable control systems with hard bounded control signals. The reference signals are hard-bounded in their amplitude and speed, which appears in many applications. This description leads therefore to a non-conservative controller design. The design procedure itself is based on H-inf Loop Shaping; the problem of systematic adaption on the weights when receiving a too large control signal after a loop shaping step is discussed. Finally, deisgn examples are given.

Y.Zhenyu, S.Huazhang, C.Zongji
The Frequency-Domain Heterogeneous Control Mixer Module for Control Reconfiguration
Source: IEEE
Publisher: IEEE Journal: Proceedings of the 1999 IEEE International Conference on Control Applications Month: 8 Year: 1999
Abstract:

S.E.Lyshevski, K.R.Dunipace, R.D.Colgren
Identification and Reconfigurable Control of Multivariable Aircraft
Source:
Publisher: AACC Journal: Proceedings of the American Control Conference Month: 6 Year: 1999
Abstract:

J.D. Boskovic, R.K. Mehra
Stable Multiple Model Adaptive Flight Control for Accommodation of a Large Class of Control Effector Failures
Source: Jan
Journal: Proceedings of the American Control Conference Month: 6 Year: 1999
Abstract:
In this paper we propose a new parameterization for the modeling of control effector failures in flight control applications. The failures include float, lock-in-place, hard-over, and loss of effectiveness. It is shown that the resulting representation leads naturally to a multiple model formulation of the corresponding control problem that can be solved using a multiple model adaptive reconfigurable control approach. We derive stable multiple model adaptive reconfigurable control algorithms for the most complex case when one of the effectors undergoes float, lock-in-place or hard-over failure, while all others lose effectiveness. The stability of the overall reconfigurable control system is demonstrated using the Lyapunov method and the separation between identification and control arising in the context of indirect adaptive control. The approach is illustrated through numerical simulation of the F-18 aircraft carrier landing maneuver.

L.Yan, N.Sundararajan, P.Saratchandran
Fault Tolerant Flight Controller Using Minimal Resource Allocating Neural Networks (MRAN)
Source: IEEE
Journal: Proceedings of the American Control Conference Month: 6 Year: 1999
Abstract:

M.Napolitano, G.Molinaro, M.Innocenti, B.Seanor, D.Martinelli
A Complete Hardware Package for a Fault Tolerant Flight Control System Using On-Line Learning Neural Networks
Source:
Publisher: AACC Journal: Proceedings of the American Control Conference Month: 6 Year: 1999
Abstract:

E.A.Jonckheere, G.R.Yu
Propulsion Control of Crippled Aircraft by Hinf Model Matching
Source: IEEE
Publisher: IEEE Journal: IEEE Transactions on Control Systems Technology Month: 3 Year: 1999 Volume: 7 Number: 2
Abstract:

K.S.Wallace
Application of Reconfigurable Avionics for the Bantam Launch Vehicle
Source: IEEE
Publisher: IEEE Year: 1999
Abstract:

I.K.Konstantopoulos, P.J.Antsaklis
An Optimization Approach to Control Reconfiguration
Source:
Publisher: Kluwer Academic Publishers Journal: Dynamics and Control Year: 1999
Abstract:

M.L.Steinberg, A.B.Page
Nonlinear Adaptive Flight Control with Genetic Algorithm Design Optimization
Source: Jan
Publisher: John Wiley & Sons, Ltd. Journal: International Journal of Robust and Nonlinear Control Year: 1999 Volume: 9 Pages: 1097-1115
Abstract:
This paper examines the use of a nonlinear adaptive control law for multi-axis control of a high-performance aircraft with stabilator, aileron and rudder failures. The control law is based on a backstepping design approach with fixed parameter optim ization done using a stochastic genetic algorithm. The control law is demonstrated on a six-degree-of-freedom simulation with nonlinear aerodynamic and engine models, actuator models with saturation, and turbulence. There are substantial difference between the control law design and simulation models, which are used to demonstrate some robustness aspects of this control law. To deal with actuator saturation, the Lyapunov function is modified so that hte growth of integrated error and the rate of change of parameter growth are both reduced when the surface commands are growing at a rate that will likely saturate the actuators.

C.Cox, S.Stepniewski, C.Jorgensen, R.Saeks, C.Lewis
On the Design of a Neural Network Autolander
Source: Jan
Publisher: John Wiley & Sons, Ltd. Journal: International Journal of Robust and Nonlinear Control Year: 1999 Volume: 9 Pages: 1071-1096
Abstract:
A research program directed at the development of an autolander for NASA's X-33 prototype reusable launch vehicle is described. The autolander is based on a new linear quadratic adaptive critic algorithm. It is implemented by an array of Functional Link neural networks and is trained by a modified Levenberg-Marquardt method. A full stability theory is developed for the new adaptive critic algorithm. Simulation results are presented for the linear-quadratic case.

P.S.Maybeck
Multiple Model Adaptive Algorithms for Detecting and Compensating Sensor and Actuator/Surface Failures in Aircraft Flight Control Systems
Source: Jan
Publisher: John Wiley & Sons, Ltd. Journal: International Journal of Robust and Nonlinear Control Year: 1999 Volume: 9 Pages: 1051-1070
Abstract:
Multiple model adaptive estimation (MMAE) methods have been incorporated into the design of a flight control system for the variable in-flight stability test aircraft (VISTA) F-16, providing it with the capability to detect and compensate for sensor and control surface/actuator failures. The algorithm consists of a 'front end' estimator for the control system, composed of a bank of parallel Kalman filter, each matched to a specific hypothesis about the failure status of the system (fully functional or a failure in any one sensor or surface/actuator), and a means of blending the filter outputs through a probability-weighted average. For multiple failures, a hierarchical structure is used to keep the number of online filters to a minimum. To compensate for failed control surfaces or actuators, a 'back end' algorithm redistributes control commands (that would normally be sent to surfaces detected as having failed) to the non-failed surefaces, accomplishing the same control action on the aircraft. Failures are demonstrated detectable in less than one second, even at low dynamic pressure (20 000 ft and 0.4 Mach), with an aircraft output nearly identical to that anticipated from a fully functional aircraft in the same environment.

R.L.Eberhardt, D.G.Ward
Indirect Adaptive Flight Control System Interactions
Source: Jan
Journal: International Journal of Robust and Nonlinear Control Year: 1999 Number: 9 Pages: 1013-1031
Abstract:
An indirect adaptive control system approach is presented and demonstrated via the nonlinear six degree of freedom simulation of a tailless fighter aircraft. A summary of the tailless aircraft configuration is given. The modular control system architecture is described and interactions between the modules are identified and illustrated using nonlinear simulation results. Mitigation approaches for addressing the adverse interactions are presented and illustrated using nonlinear simulation results. Simulation results that demonstrate the reconfiguration capability are also given.

Y.Shtessel, J.Buffington
Multiple Time Scale Flight Control Using Re-configurable Sliding Modes
Source: Jan
Publisher: AIAA Journal: AIAA Journal on Guidance, Control and Dynamics Year: 1999 Volume: 22 Number: 6 Pages: 873-883
Abstract:
A dual time scale aircraft flight control problem is addressed via continuous sliding mode control. Sliding surface boundary layer reconfiguration is used to account for actuator dynamics, deflection limits and rate limits. A re-configurable sliding mode flight controller is designed that achieves robust, high accuracy tracking of outer loop command angles before and after damage to an aircraft. Angular rate commands are robustly tracked in an inner loop. The re-configurable flight control strategy is based on a continuous sliding mode controller with direct boundary layer adaptation for re-configuration. On-line explicit system or damage identification is not required. The re-configurable sliding mode flight control technique is applied to a nonlinear flight dynamics model of an F-16 aircraft. Computer simulations demonstrate stability and high accuracy tracking performance without violation of actuator limits.

X.Xu, P.J.Antsaklis
Stabilization of second-order LTI switched systems
Source:
Year: 1999
Abstract:

S.Kanev, M.Verhaegen
A Bank of Reconfigurable LQG Controllers for Linear Systems Subjected to Failures
Source: CiteSeer (Download)
Year: 1999
Abstract:
In this paper an approach for controller reconfiguration is presented. The starting point in the analysis is a sufficiently accurate continuous linear time-invariant (LTI) model of the nominal system. Based on a bank of reconfigurable LQG controllers, each designed for a particular combination of total faults, the reconfiguration consists in two operation modes. In the first mode a switching is invoked towards one of the pre-designed LQG controllers on the basis of the information about only the combination of total faults that is in effect. In the second mode, which is activated in cases of partial and component faults, a dynamic correction procedure is initaited which tries to reconfigure the currently active controller in such a way, that the failed closed-loop system remains stable and its performance is as close as possible to the performance of the closed-loop system with only total faults present in the system. In cases of partial faults the second mode is prectically an extension of the modified pseudo-inverse method. In cases of component faults the second mode is based on an LMI optimization problem. The approach is illustrated using a model of a real-life space robot manipulator, in which total, partial and component faults are simulated.

J.Buffington, P.Chandler, M.Pachter
On-Line System Identification for Aircraft with Distributed Control Effectors
< b>Source: Jan
Journal: International Journal of Robust and Nonlinear Control Year: 1999
Abstract:
An algorithm is presented for the identification of aircraft stability derivatives and distributed control dervatives, in real time. Feeback control correlates the effectors' displacement with the aerodynamic angles, while the most commonly used control allocation algorithms correlate the effectors. The result is that valid derivative estimation is not possible. This paper addresses the effector identification problem by including decorrelation excitation in to the control allocation cost function while still satisfying the desired control moment, and therefore does not introduce any residual perturbations into the motion variables. A two-step identification algorithm is used where the stability derivative and a generalized control derivative are identified in the first step. Results are shown for a stability axis roll maneuver with the stabbility and control derivatives being identified for five differential lateral directional effecotrs. Published in 1999 by John Wiley & Sons, Ltd. This article is a US Government work and is in the public domain in the United States.

E.A.Jonckheere, P.Lohsoonthorn, S.K.Bohacek
From Sioux City to the X-33
Source: Jan
Publisher: Elsevier Science Ltd Journal: Annual Review in Control 23 Year: 1999 Pages: 91-108
Abstract:

D.Henrion, S.Tarbouriech, V.Kucera
Control of linear systems subject to input constraints: a polynomial approach. Part I - SISO plants
Source:
Year: 1999
Abstract:

J.D. Boskovic, R.K. Mehra
A Multiple Model-based Reconfigurable Flight Control System Design
Source: Jan
Publisher: IEEE Journal: Proceedings on the 37th IEEE Conference on Decision & Control Month: 12 Year: 1998
Abstract:
In this paper we considered a problem of designing a reconfigurable control strategy that achieves acceptable flight performance in the presence of wing battle damage for a Tailless Advanced Fighter Aircraft (TAFA). This is a complex practical prolem since wing damage results in abrupt variation in the aircraft dynamics. Hence fast and accurate control reconfiguration is vital for assuring aircraft survivability. Our suggested reconfigurable controller is based on the recently developed concept of multiple models, switching, and tuning. The overall control system consists of multiple parallel identification models, describing different percentages of wing damage, and corresponding controllers. Based on a suitably chosen switching mechanism, the system quickly finds the model that is closest to the current damage mode, and switches to the corresponding controller achieving excellent overall performance. In addition, the boundedness of the signals in the system is guaranteed if the switching interval is chosen to be sufficiently small. It was shown that the key element is the design of sufficiently robust individual controllers for each of the damage conditions. This has been accomplished using a combination of inverse dynamics and output error feedback control laws. The properties of the overall system are illustrated through simulations using linearized TAFA models provided by Boeing. Simulation results have demonstrated the potential of the multiple model-based approach to solve complex practiacal reconfigurable control design problems.

M.Gopinathan, J.D. Boskovic, R.K. Mehra, C.Rago
A Multiple Model Predictive Scheme for Fault-Tolerant Flight Control Design
Source: CDC CD
Publisher: IEEE Journal: Proceedings of the 37th IEEE Conference on Decision & Control Month: 12 Year: 1998
Abstract:

C.Rago, R.Prasanth, R.K. Mehra, R.Fortenbaugh
Failure Detection and Identification and Fault Tolerant Control using the IMM-KF with application to the Eagle-Eye UAV
Source: Jan
Publisher: IEEE Journal: Proceedings on the 37th IEEE Conference on Decision & Control Month: 12 Year: 1998
Abstract:
In this paper we describe a novel approach to Sensor/Actuator Failure Detection and Identification (FDI) and Fault Tolerant Control based on the Interacting Multiple Model (IMM) Kalman Filter approach. Failures are mapped into different (and unique) statespace model representations. The IMM algorithm computes (on-line) the posterior probability of each failure model, that can be interpreted as a failure indicator. The fault tolerant control approach presented in the paper is based on a multiple model control law, where an optimal controller is designed for each actuator failure model, and the control action is a combination of the individual outputs of each controller weighted by the posterior probability associated with that model. The new FDI-FTC approach was tested on a linear simulation of Bell Helicopter's Eagle-Eye Unmanned Air Vehicle (UAV). All single sensor and actuator failures were detected and properly identified, as well as some simultaneous failures. The controller performance was virtually unaffected by sensor failures, and performed well in teh presence of actuator failures, stabilizing the aircraft and performing the desired maneuver in all cases.

M.Huzmezan, J.M.Maciejowski
Reconfigurable Flight Control of a High Incidence Research Model Using Predictive Control
Source: Mihai's Website (Download)
Publisher: Conference Publication Journal: UKACC International Confrence on CONTROL Month: 9 Year: 1998 Number: 455
Abstract:
This paper describes a scheme for fault-tolerant control of an aircraft with a high angle of incidence. The scheme is an example of a generic scheme proposed in (Maciejowski, 1997), adapted to the particular needs of this application. It combines the use of a high-fidelity model of the aircraft with model predictive control, and assumes the availability of information about the fault which has occurred from and FDI system. This paper examines the performance of the proposed fault-tolerant scheme in the presence of severe failures of control surfaces and of the aircraft structure. It contains details of a modelling methodology which enables updating of the model with failure information, and of a methodology for on-line re-linearisation. The modelling methodology follows that introduced in (Huzmezan and Maciejowski, 1998).

M.Huzmezan, J.M.Maciejowski
Reconfiguration and Scheduling in Flight Using Quasi-LPV High-Fidelity Models and MBPC Control
Source:
Journal: Proceedings of the American Control Conference Month: 6 Year: 1998
Abstract:

M.Huzmezan
Theory and Aerospace Applications of Constrained Model Based Predictive Control
Source: Mihai
Month: 3 Year: 1998
Abstract:

D.M. Littleboy
A Review of Fault Detection, Isolation and Reconfiguration Methods for Air Vehicles
Source: Jan
Month: 3 Year: 1998
Abstract:
Without duplicated hardware or a fault detection and control reconfiguration scheme, future inherently unstable air vehicles will have a low chance of surviving following a fault. Future air vehicles may have redundant controls in order to satisfy other performance requirements, and thus lend themselves to fault detection, isolation and reconfiguration (FDIR. This report review the methods currently available for the FDIR of air vehicles in the areas of non-linear estimation, fault detection and isolation, and reconfigurable control. Each review gives a vrief outline of past and current methods and describes in detail which techniques are to be used for future investigations. The combination of these techniques into a single FDIR method that uses neural networks for non-linear state estimation to enable the fault detection, and control allocation for the reconfiguration of the control laws is also described.

F.Blanchini, S.Miani, W.Ukovich
Control of production-distribution systems with unknown inputs and system failures
Source: Author's website
Publisher: IEEE Journal: IEEE Transactions on Automatic Control Month: 2 Year: 1998
Abstract:

J.M.Maciejowski
The Implicit Daisy-Chaining Property of Constrained Predictive Control
Source: Jan
Journal: Applied Math and Computer Science Year: 1998 Volume: 8 Number: 4 Pages: 695-711
Abstract:

M.Ryu, S.Hong
Toward Automatic Synthesis of Schedulable Real-Time Controllers
Source: CiteSeer (Download)
Year: 1998
Abstract:
This paper presents an automatic approach to synthesizing schedulable timing constraints for real-time control systems. Given the performance specifications and schedulability constraints of a real-time control system, the approach derives task-level timing constraints which can guarantee these requirements. The control performance is specified in terms of control output responses such as steady syste error, maximum overshoot, settling time, and rise time, and the task-level timing constraints include task periods and deadlines. The approach consists of two components with a clean interface. The first component translates the pserformance specifications into a set of system-level timing constraints such as loop processing periods and input-to-output latency, via control theoretic modeling and optimization. The second then derives task-level timing constraints from the intermediate system-level timing constraints optimizing the system schedulability using period calibration method. Our approach contributes to both the control and real-time areas: (1) it allows control engineers to take into consideration the effect of task scheduling at the early stage of system design; and (2) it makes it possible to streamline the design of real-time control system, since timing constraints are derived in an automatic manner.

Y.Diao, K.M.Passino
Fault Tolerant Stable Adaptive Fuzzy/Neural Control for a Turbine Engine
Source: (Download)
Journal: IEEE Transactions on Control Systems Technology Year: 1998
Abstract:
Stimulated by the growing demand for improving the reliability and performance of systems, fault tolerant control has been receiving significant attention since its goal is to detect the occurrence of faults and achieve satisfactory system performance in the presence of faults. To develop an intelligent fault tolerant control system, we begin by constructing a design model of the system using a hierarchical learning structure in the form of Takagi-Sugeno fuzzy systems. Afterwards, the fault tolerant control scheme is designed based on stable adaptive fuzzy/neural control, where its on-line learning capabilities are used to capture the unknown dynamics caused by faults. Finally, the effectiveness of the proposed methods has been studied by extensive analysis of system zero dynamics and asymptotic tracking abilities for both indirect and idirect adaptive control cases, and by ``component level model'' simulation of the General Electric XTE46 turbine engine.

A.J.Calise, S.Lee, M.Sharma
Direct Adaptive Reconfigurable Control of a Tailless Fighter Aircraft
Source: Group website (Download)
Publisher: AIAA Year: 1998
Abstract:
This paper describes a neural network based direct adaptive control approach to the problem of reconfigurable flight control. A Tailless fighter aircraft configuration with multiple and redundant control actuation devices is used to illustrate the level to which handling quelities can be maintained in the presence of large scale failures in the actuation channels. Of signicnace here is the speed with which recovery and maintenance of handling qualities can take place. The main advantage lies in eliminating the need for parameter identification during the recovery phase, and limiting the potential need for parameter identification to teh problem of control allocation following the failure. A second by-product of this work is that the need for an accurate aerodynamic database for purposes of flight control design can be significantly reduced. Moreover, the need for extensive off-line analysis, in-flight tuning and validation of gain schedules, and contingency coding necessary to handle a large set of possible failure modes is substantially reduced. Thus the overall approach may also be viewed as a direct path to substantially reducing the cost associated with the development of new aircraft.

J.J.Burken, F.W.Burcham
Flight-Test Results of Propulsion-Only Emergency Control System on MD-11 Airplane
Source: Library
Publisher: AIAA Journal: Journal of Guidance, Control and Dynamics Month: 10 Year: 1997 Volume: 20 Number: 5
Abstract:

F.W.Burcham, J.J.Burken, T.A.Maine, C.G.Fullerton
Development and Flight Test of an Emergency Flight Control System Using Only Engine Thrust on an MD-11 Transport Airplane
Source:
Publisher: NASA Month: 10 Year: 1997
Abstract:

M.Huzmezan
Reconfigurable Flight Control Methods and Related Issues - A Survey
Source: Mihai
Month: 9 Year: 1997
Abstract:

R.J.Patton
Fault-Tolerant Control Systems: The 1997 Situation
Source: Author's website (Download)
Journal: IFAC Symposium on Fault Detection Supervision and Safety for Technical Processes Month: 8 Year: 1997 Volume: 3 Pages: 1033-1054
Abstract:

M.Bodson, J.E.Groszkiewicz
Multivariable Adaptive Algorithms for Reconfigurable Flight Control
Source: IEEE
Publisher: IEEE Journal: Transactions on Control Systems Technology Month: 3 Year: 1997 Volume: 5 Number: 2 Pages: 217-229
Abstract:

K.S.Narendra, J.Balakrishnan
Adaptive Control Using Multiple Models
Source: Library
Journal: IEEE Transactions on Automatic Control Month: 2 Year: 1997 Volume: 42 Number: 2
Abstract:
Intelligent control may be viewed as the ability of a controller to operate in multiple environments by recognizing which environment is currently in existence and servicing it appropriatly. An important prerequisit for an intelligent controller is the ability to adapt rapidly to any unknown but constant operating environment. This paper presents a general methodology for such adaptive control using multiple models, switching, and tuning. The approach was first introduced in [1]and [2] for improving the transient response of adaptive in a stable fashion. This paper proposes different switching and tuning schemes for adaptive ocntrol which combine fixed and adaptive models in novel ways. The principal mathematical results are the proofs of stability when these differnt schemes are used in the context of model reference control of an unknown linear time-invariant system. A variety of simulation results are presented to demonstrate the efficiency of the proposed methods.

L.Giarre, M.Milanese, M.Taragna
\Hinf Identification and Model Quality Evaluation
Source: Eng Library
Journal: IEEE Transactions on Automatic Control Month: 2 Year: 1997 Volume: 42 Number: 2
Abstract:
Set membership \Hinf identification is investigated using time-domain data and mixed parametric and nonparametric models as well as supposing power bounded measurement errors. The problem of optimally estimating the unknown parameters and evaluating the minimal worst case identification error, called radius of information, is solbed. For classes of models affine in the parameters, the radius of information is obtained as function of the \Hinf norm of the unmodeled dynamics. A method is given for estimating this norm from the available data and some general a priori information on the unmodeled dynamics, thus allowing the actual evaluation of the radius of information. The radius represents a measure of the "predictive ability" of the considered class of models, and it is then used for comparing the quality of different classes of models and for the order selection of their parametric part. The effectiveness of the proposed procedure is tested on some numerical examples and compared with standard statistical criteria for model order selection.

F.Blanchini
Set invariance in control - a survey
Source: Author's website
Year: 1997
Abstract:
The properties of positively invariant sets are involved in many different problems in control theory, such as constrained control, robustness analysis, synthesis and optimization. In this paper we provide an overview of the literature concerning positively invariant sets and their application to the analysis and synthesis of control systems.

B.Dutertre, V.Stavridou
Avionics Systems Requirements: A Comparison of RSML and SCR
Source: CiteSeer (Download)
Year: 1997
Abstract:
This paper discusse and compares RSML and SCR, two approaches for the rigorous specification of control systems requirements. We give examples of RSML and SCR specifications for parts of a generica store management system. We discuss the merits and limitations of the two methods and examine how safety verification can be supported in both cases.

F.W.Burcham, J.J.Burken, T.A.Maine, J.Bull
Emergency Flight Control Using Only Engine Thrust and Lateral Center-of-Gravity Offset: A First Look
Source:
Publisher: NASA Journal: NASA Technical Memorandum Year: 1997
Abstract:

G.Schram, B.Verschoor, J.M.Sousa, H.B.Verbruggen
Flight Control Reconfiguration Using Multiple Fuzzy Controllers
Source: IEEE
Publisher: IEEE Year: 1997
Abstract:

N.E.Wu, T.Chen
Reliability Prediction for Self-Repairing Flight Control Systems
Source: IEEE
Publisher: IEEE Journal: Proceedings of the 35th Conference on Decision and Control Month: 12 Year: 1996
Abstract:

J.B.Davidson, D.Andrisani
Lateral-Directional Eigenvector Flying Qualities Guidelines for High Performance Aircraft
Source:
Publisher: NASA Month: 12 Year: 1996
Abstract:

W.C.Durham, K.A.Bordignon
Multiple Control Effector Rate Limiting
Source: Jan
Publisher: AIAA Journal: Journal of Guidance, Control and Dynamics Month: 2 Year: 1996 Volume: 19 Number: 1
Abstract: