Investigating Impaired Aircraft's Flight Envelope Variation Predictability Using Least-Squares Regression Analysis

Norouzi, Ramin; Kosari, Amirreza; Sabour, Mohammad Hossein

doi:10.2514/1.i010760

Cited by 7 publications

(3 citation statements)

References 60 publications

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“…In a similar sense, Norouzi et al built linear and also nonlinear least squares estimation models to predict aircraft flight envelope parameters in case of a failure. Finally, they chose the best polynomial fit for the prementioned case (Norouzi et al , 2020).…”

Section: Introductionmentioning

confidence: 99%

Thrust modelling of a target drone engine with nonlinear least – squares estimation based on series expansions

Kaba

Metin²,

Turan³

2022

AEAT

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Purpose The purpose of this study is to build a high accuracy thrust model under various small turbojet engine shaft speeds by using robust, ordinary, linear and nonlinear least squares estimation methods for target drone applications. Design/methodology/approach The dynamic shaft speeds from the test experiment of a target drone engine is conducted. Then, thrust values are calculated. Based on these, the engine thrust is modeled by robust linear and nonlinear equations. The models are benefited from quadratic, power and various series expansion functions with several coefficients to optimize the model parameters. Findings The error terms and accuracy of the model are given using sum of squared errors, root mean square error (RMSE) and R-squared (R2) error definitions. Based on the multiple analyses, it is seen that the RMSE values are no more than 17.7539 and the best obtained result for robust least squares estimation is 15.0086 for linear at all cases. Furthermore, the R2 value is found to be 0.9996 as the highest with the nonlinear Fourier series expansion model. Originality/value The motivation behind this paper is to propose robust nonlinear thrust models based on power, Fourier and various series expansion functions for dynamic shaft speeds from the test experiments.

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Section: Introductionmentioning

confidence: 99%

Thrust modelling of a target drone engine with nonlinear least – squares estimation based on series expansions

Kaba

Metin²,

Turan³

2022

AEAT

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“…While methods have been proposed to compute reachable sets under system impairment, due to their computational complexity, these have either used reduced order models, or have been limited to offline applications [20]. Given a sufficiently tight bound on the trajectory deviation growth dynamics, our approach can be applied online to higher dimensional systems with no additional computational cost for the growth in system dimension.…”

Section: Introductionmentioning

confidence: 99%

Online Inner Approximation of Reachable Sets of Nonlinear Systems with Diminished Control Authority

El-Kebir¹,

Ornik²

2021

2021 Proceedings of the Conference on Control and Its Applications

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This work presents a method of efficiently computing inner approximations of forward reachable sets for nonlinear control systems with diminished control authority, given an a priori computed reachable set for the nominal system. The method functions by shrinking a precomputed convex reachable set based on a priori knowledge of the system's trajectory deviation growth dynamics. The trajectory deviation growth dynamics determine an upper bound on the minimal deviation between two trajectories emanating from the same point that are generated by control inputs from the nominal and diminished set of control inputs, respectively. These growth dynamics are a function of a given Hausdorff distance bound between the nominal convex space of admissible controls and the possibly unknown impaired space of admissible controls. Because of its relative computational efficiency compared to direct computation of the off-nominal reachable set, this procedure can be applied to onboard fault-tolerant path planning and failure recovery. We consider the implementation of the approximation procedure by way of numerical integration and a root finding scheme, and we present two illustrative examples, namely an application to a control system with quadratic nonlinearities and aircraft wing rock dynamics.

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“…While other methods have been proposed to compute reachable sets under system impairment, due to their computational complexity, these have either used reduced order models, or have been limited to offline applications [17]. In more extreme cases of system impairments, such as those were very little is known about the system's present capabilities, more conservative methods for computing reachable sets exist [18].…”

mentioning

confidence: 99%

Online Guaranteed Reachable Set Approximation for Systems with Changed Dynamics and Control Authority

El-Kebir¹,

Pirosmanishvili²,

Ornik³

2022

Preprint

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This work presents a method of efficiently computing inner and outer approximations of forward reachable sets for nonlinear control systems with changed dynamics and diminished control authority, given an a priori computed reachable set for the nominal system. The method functions by shrinking or inflating a precomputed reachable set based on prior knowledge of the system's trajectory deviation growth dynamics, depending on whether an inner approximation or outer approximation is desired. These dynamics determine an upper bound on the minimal deviation between two trajectories emanating from the same point that are generated on the nominal system using nominal control inputs, and by the impaired system based on the diminished set of control inputs, respectively. The dynamics depend on the given Hausdorff distance bound between the nominal set of admissible controls and the possibly unknown impaired space of admissible controls, as well as a bound on the rate change between the nominal and off-nominal dynamics. Because of its computational efficiency compared to direct computation of the off-nominal reachable set, this procedure can be applied to on-board fault-tolerant path planning and failure recovery. In addition, the proposed algorithm does not require convexity of the reachable sets unlike our previous work, thereby making it suitable for general use. We raise a number of implementational considerations for our algorithm, and we present three illustrative examples, namely an application to the heading dynamics of a ship, a lower triangular dynamical system, and a system of coupled linear subsystems.

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Investigating Impaired Aircraft's Flight Envelope Variation Predictability Using Least-Squares Regression Analysis

Cited by 7 publications

References 60 publications

Thrust modelling of a target drone engine with nonlinear least – squares estimation based on series expansions

Thrust modelling of a target drone engine with nonlinear least – squares estimation based on series expansions

Online Inner Approximation of Reachable Sets of Nonlinear Systems with Diminished Control Authority

Online Guaranteed Reachable Set Approximation for Systems with Changed Dynamics and Control Authority

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