VSTOL aircraft flight control system design using H/sub infinity / controllers and a switching strategy

Hyde, Richard; Glover, K.

doi:10.1109/cdc.1990.203330

Cited by 15 publications

(5 citation statements)

References 13 publications

(6 reference statements)

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“…Then, &-stability and the asymptotic stability of system (12) are the result, arguing as in Theorem 3.1.…”

Section: P ( V ) ( a ( V ) + M ( X T ) + L ( V ) ) + ( A ( V ) + M mentioning

confidence: 89%

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Robustness and stability of LPV plants through frozen systems analysis

Fromion

Monaco

Normand‐Cyrot

1996

Int. J. Robust Nonlinear Control

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“…Then, &-stability and the asymptotic stability of system (12) are the result, arguing as in Theorem 3.1.…”

Section: P ( V ) ( a ( V ) + M ( X T ) + L ( V ) ) + ( A ( V ) + M mentioning

confidence: 89%

“…Corollary 3.2 ensures continuity around any input in L, which is relevant in tracking problems. of system (12); see also Reference 7, for an overview of various methods and their links (particularly p-analysis and Q stability).…”

Section: Remarksmentioning

confidence: 99%

Robustness and stability of LPV plants through frozen systems analysis

Fromion

Monaco

Normand‐Cyrot

1996

Int. J. Robust Nonlinear Control

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“…Experience has shown this to be well suited to GVAM designs, in that the weights are straightforward to select and the designs exhibit good robust performance -ie, a controller designed for a particular airspeed works well over a large range of speeds either side of the design point. Details of the linear designs used here can be found in Hyde and Glover (1990). This loop-shaping procedure has been compared with other H-infinity design approaches with application to the GVAM in Williams and Hyde (1990).…”

Section: Introductionmentioning

confidence: 98%

“…A discussion of the limitations and stability properties of this scheme can be found inHyde and Glover (1990).Controllers from the loop-shaping procedure are implemented as shown inFig 2where W is the precompensator chosen by the designer and Kx is from the optimisation procedure. The motive for this particular structure is to avoid directly exciting the dynamics of Km with the references.…”

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confidence: 99%

A comparison of different scheduling techniques for H-infinity controllers

Hyde

Glover

1991

Transactions of the Institute of Measurement and Control

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Several approaches to designing schedule H-infinity control systems are compared. These include a controller switching approach and also parameter scheduling of an observer representation of the controller. They are illustrated by application to a Generic VSTOL Aircraft Model (GVAM) supplied by The Royal Aerospace Establishment (RAE) at Bedford. The switched design has been tested on the simulator at RAE Bedford. The linear H-infinity designs make use of a loop-shaping followed by robust stabilisation to additive perturbations of a normalised coprime factorisation of the shaped plant. The different scheduling approaches are compared with respect to achieved robust stability levels, performance and complexity of implementation.

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“…Conceptually, gain scheduling is simple and has been proven successful; however, it does not guarantee stability and fulfillment of desired handling qualities after failure. Therefore, several approaches have been investigated in the attempt to enhance tracking quality including adaptive control, such as neural network adaptive controllers [20], nonlinear control such as feedback linearization [21], optimal control [22], and robust control [23]. [24] The robustness of different adaptive control laws was investigated, and the results showed that the baseline dynamic inversion controller was reasonably robust.…”

Section: Chapter 2 Literature Reviewmentioning

confidence: 99%

Parameter Estimation Analysis for Hybrid Adaptive Fault Tolerant Control

Eshak¹

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Research efforts have increased in recent years toward the development of intelligent fault tolerant control laws, which are capable of helping the pilot to safely maintain aircraft control at post failure conditions. Researchers at West Virginia University (WVU) have been actively involved in the development of fault tolerant adaptive control laws in all three major categories: direct, indirect, and hybrid. The first implemented design to provide adaptation was a direct adaptive controller, which used artificial neural networks to generate augmentation commands in order to reduce the modeling error. Indirect adaptive laws were implemented in another controller, which utilized online PID to estimate and update the controller parameter. Finally, a new controller design was introduced, which integrated both direct and indirect control laws. This controller is known as hybrid adaptive controller. This last control design outperformed the two earlier designs in terms of less NNs effort and better tracking quality. The performance of online PID has an important role in the quality of the hybrid controller; therefore, the quality of the estimation will be of a great importance. Unfortunately, PID is not perfect and the online estimation process has some inherited issues; the online PID estimates are primarily affected by delays and biases. In order to ensure updating reliable estimates to the controller, the estimator consumes some time to converge. Moreover, the estimator will often converge to a biased value. This thesis conducts a sensitivity analysis for the estimation issues, delay and bias, and their effect on the tracking quality. In addition, the performance of the hybrid controller as compared to direct adaptive controller is explored. In order to serve this purpose, a simulation environment in MATLAB/SIMULINK has been created. The simulation environment is customized to provide the user with the flexibility to add different combinations of biases and delays to the explored derivatives. Biases were considered in the range-500% to 500% and delays in the range 0.5 to 40 seconds. The stability and control derivatives considered in this research effort are a combination of decoupled derivatives in the three channels, longitudinal, lateral, and directional. Numerous simulation scenarios and flight conditions are considered to provide more credibility to the obtained results. In addition, a statistical analysis has been conducted to assess the results. The performance of the control laws has been evaluated in terms of the integral of the error in tracking the three desired angular rates, pitch, roll, and yaw. In addition, the effort of the neural networks exerted to compensate for tracking errors is considered in the analysis as well. The results show that in order to obtain reliable estimates for the investigated derivatives, the estimator needs to generate values with less than five seconds delay. In addition, derivatives estimates are within 50% or-15% off the exact values. Moreover, the importance of updating de...

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VSTOL aircraft flight control system design using H/sub infinity / controllers and a switching strategy

Cited by 15 publications

References 13 publications

Robustness and stability of LPV plants through frozen systems analysis

Robustness and stability of LPV plants through frozen systems analysis

A comparison of different scheduling techniques for H-infinity controllers

Parameter Estimation Analysis for Hybrid Adaptive Fault Tolerant Control

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