This paper presents a comparative study of three Linear Para meter Varying (LPV) model- ing approaches and their application to the longitudinal motion of a Boeing 747 series 100/200. The three approaches used to obtain the quasi-LPV models are Jacobian linearisation, state transformation, and function substitution. Development of linear parameter varying models are a key step in applying LPV control synthesis. The models are obtained for the Up-and- Away flight envelope of the Boeing 747-100/200. Comparisons of the three models in terms of their advantages, drawbacks and modeling difficulty are pre sented. Open-loop time responses show the three quasi-LPV models matching the behavior of the nonlinear model when in the trim region. Differences between the models are more apparent as the response of the aircraft deviates from the nominal trim conditions.

Journal ArticleCopyright © 2012 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Journal of The Franklin Institute. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of The Franklin Institute (2012), DOI: 10.1016/j.jfranklin.2011.06.026This paper proposes a new sliding mode observer for fault reconstruction, applicable for a class of linear parameter varying (LPV) systems. Observer schemes for actuator and sensor fault reconstruction are presented. For the actuator fault reconstruction scheme, a virtual system comprising the system matrix and a fixed input distribution matrix is used for the design of the observer. The fixed input distribution matrix is instrumental in simplifying the synthesis procedure to create the observer gains to ensure a stable closed-loop reduced order sliding motion. The 'output error injection signals' from the observer are used as the basis for reconstructing the fault signals. For the sensor fault observer design, augmenting the LPV system with a filtered version of the faulty measurements allows the sensor fault reconstruction problem to be posed as an actuator fault reconstruction scenario. Simulation tests based on a high-fidelity nonlinear model of a transport aircraft have been used to demonstrate the proposed actuator and sensor FDI schemes. The simulation results show their efficacy. © 2011 The Franklin Institute. Published by Elsevier Ltd. All rights reserved

Presents the design of a reconfigurable linear parameter varying (LPV) controller for the Boeing 747-100/200 longitudinal axis in the up-and-away flight regime. The control objectives are to obtain decoupled flight-path angle and velocity command tracking and achieve good disturbance rejection characteristics during normal operation and in the presence of an elevator fault. The LPV controller is synthesized using a quasi-LPV model of the aircraft longitudinal axis based on the Jacobian linearization approach. The controller schedules on three parameters: flight altitude and velocity and a fault identification signal. During normal flight operations, the LPV controller uses the elevators and thrust for flight maneuvers. The stabilizer is used to trim the aircraft. Two elevator fault scenarios are contemplated-lock and float. The proposed control strategy is to use the stabilizer as the alternative longitudinal control surface. Simulation results with elevator faults present show that the reconfigured controller stabilizes the faulted system at the expense of a factor of a designed one-third reduction in the tracking responsiveness of the longitudinal axis and has good disturbance rejection properties.