Static Bifurcation in Mechanical Control Systems

Kwatny, Harry G.; Chang, B.C.; Wang, Shiu-Ping

doi:10.1007/978-3-540-44925-6_4

Cited by 7 publications

(3 citation statements)

References 17 publications

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“…Bifurcation analysis is used to study aircraft control properties and how they change with the ight condition and parameters of the aircraft. The paper extends results previously introduced in [4,5]. There it was shown that the ability to regulate a system is lost at points associated with bifurcation of the trim equations; ordinarily indicating stall in an aircraft.…”

Section: Nomenclaturesupporting

confidence: 78%

Nonlinear Analysis of Aircraft Loss of Control

Kwatny¹,

Dongmo²,

Chang³

et al. 2013

Journal of Guidance, Control, and Dynamics

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Loss-of-Control (LOC) is a major factor in fatal aircraft accidents. Although denitions of LOC remain vague in analytical terms, it is generally associated with ight outside of the normal ight envelope, with nonlinear inuences, and with a signicantly diminished capability of the pilot to control the aircraft. Primary sources of nonlinearity are the intrinsic nonlinear dynamics of the aircraft and the state and control constraints within which the aircraft must operate. This paper examines how these nonlinearities aect the ability to control the aircraft and how they may contribute to loss-of-control. Specically, the ability to regulate an aircraft around stall points is considered, as is the question of how damage to control eectors impacts the capability to remain within an acceptable envelope and to maneuver within it. It is shown that even when a sucient set of steady motions exist, the ability to regulate around them or transition between them can be dicult and nonintuitive, particularly for impaired aircraft. Examples are provided using NASA's Generic Transport Model.

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Section: Nomenclaturesupporting

confidence: 78%

Nonlinear Analysis of Aircraft Loss of Control

Kwatny¹,

Dongmo²,

Chang³

et al. 2013

Journal of Guidance, Control, and Dynamics

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“…From this observation, necessary conditions for a static bifurcation point can be obtained as follows (Kwatny et al, 2003):…”

Section: Bifurcation Analysis Of Control Systemsmentioning

confidence: 99%

Bifurcation Analysis of Flight Control Systems

Thomas

Kwatny

Chang

2005

IFAC Proceedings Volumes

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“…From the above theorem the necessary conditions for a static bifurcation point can be summarized as follows [10]. Proposition 2.3: The equilibrium point (x , u , µ ) is a static bifurcation point of (1) only if one of the following conditions is true for its linearization:…”

Section: A Static Bifurcation Pointsmentioning

confidence: 99%

Bifurcation-induced limits of a controller-reconfigured F-16 subject to actuator failures

Thomas¹,

Kwatny²,

Chang³

Proceedings of 2005 IEEE Conference on Control Applications, 2005. CCA 2005.

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Complex systems like the F-16 when subject to actuator failures operate in nonlinear regimes and probably in the vicinity of bifurcation points. Therefore in designing reconfigured controllers a designer must be aware of all bifurcation points, and their characteristics, within the impaired flight envelope. This work is the first step in that direction. The other limitations that were identified are the stability limits and the control saturation points. We considered both the nominal system, and the reconfigured system with the left elevator stuck. The nominal controller is designed according to the guidelines in the literature. The reconfigured controller is designed as a regulator with disturbance rejection capabilities. The bifurcations are associated with attempting to regulate the velocity and orientation of the aircraft. The main issues at the bifurcation points, in both the nominal and reconfigured system, are that the aircraft becomes uncontrollable and the control inputs become dependent.

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Static Bifurcation in Mechanical Control Systems

Cited by 7 publications

References 17 publications

Nonlinear Analysis of Aircraft Loss of Control

Nonlinear Analysis of Aircraft Loss of Control

Bifurcation Analysis of Flight Control Systems

Bifurcation-induced limits of a controller-reconfigured F-16 subject to actuator failures

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