Composite nonlinear H∞ based output feedback controller for an un-crewed helicopter in its hover flight
Aircraft Engineering and Aerospace Technology
ISSN: 0002-2667
Article publication date: 7 January 2021
Issue publication date: 16 February 2021
Abstract
Purpose
This paper aims to propose output feedback-based control algorithms for the flight control system of a scaled, un-crewed helicopter in its hover flight mode.
Design/methodology/approach
The proposed control schemes are based on H∞ control and composite nonlinear control. The gains of the output feedback controllers are obtained as the solution of a set of linear matrix inequalities (LMIs).
Findings
In the proposed schemes, the finite-time convergence of system states to trim condition is achieved with minimum deviation from the steady-state. As the proposed composite nonlinear output feedback design improves the transient response, it is well suited for a scaled helicopter flight. The use of measured output vector instead of the state vector or its estimate for feedback provides a simple control structure and eliminates the need for an observer in real-time application. The proposed control strategies are relevant to situations in which a simple controller is essential due to economic factors, reliability and hardware implementation constraints.
Practical implications
The proposed control strategies are relevant to situations in which a simple controller is essential due to economic factors, reliability and hardware implementation constraints. They also have significance in applications where the number of measurement quantities needs to be minimized such as in a fully functional rotor-craft unmanned aerial vehicle.
Social implications
The developed output feedback control algorithms can be used in small-scale helicopters for numerous civilian and military applications.
Originality/value
This work addresses the LMI-based formulation and solution of an output feedback controller for a hovering un-crewed helicopter. The stability and robustness of the closed-loop system are proved mathematically and the performance of the proposed schemes is compared with an existing strategy via simulation studies.
Keywords
Citation
Thomas, F. and Johnson, M.S. (2021), "Composite nonlinear
Publisher
:Emerald Publishing Limited
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