A Modification to Adaptive Control with Time-varying Learning Rate for Improved Transient Performance

2022-01-01
© 2022, American Institute of Aeronautics and Astronautics Inc. All rights reserved.In this study, we propose a new adaptive weight update law using frequency-limited estimation of the matched uncertainty. Many adaptive parameter adjustment laws try to suppress the effects of uncertainties using forcing terms consisting of tracking error only. However, it has been widely studied that including the uncertainty estimation error in the adaptation law enhances the transient performance significantly. In our proposed solution, low-frequency estimation of the uncertainty is included in the adaptation in a time-varying learning rate structure. Also, with the proposed architecture, an explicit bound on the convergence rate of frequency-limited uncertainty estimation error is presented. Unlike the other filter-based methods, the proposed modification term compensates the information lost when the signal is filtered to suppress the high-frequency content. Furthermore, the proposed solution introduces a regulation term to the standard adaptive weight update law which behaves like a stability augmentation in the adaptive system. The closed-loop stability of the proposed solution is illustrated through Lyapunov’s stability theorem. Morevover, efficacy of the proposed solution is revealed by the numerical simulations.
AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022

Suggestions

A modeling and simulation tool for safe store separation envelope generation using monte carlo simulations
Unal, Kenan; Baran, Özgür Uğraş (2018-01-01)
© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.When an air released store is developed or undergoes substantial updates, integration to aircraft is realized through a certification process. One of the most important steps of the certification process is to determine safe separation envelope. For this process there are several approaches: full scale flight tests, computational fluid dynamics (CFD) simulation techniques and wind tunnel captive trajectory tests. Separ...
Investigation of a Solution Approach to Quadratic Eigenvalue Problem for Thermoacoustic Instabilities
Öztürkmen, Musa Onur; Özyörük, Yusuf (2022-01-01)
© 2022, American Institute of Aeronautics and Astronautics Inc.. All rights reserved.The interactions between the unsteady heat release and pressure fluctuations in a combustion chamber may lead to thermoacoustic instabilities. Linear stability characteristics of the chamber may be determined by solving the nonhomogeneous wave equation in frequency domain that takes these interactions into account. The discretization of the wave equation with frequency-dependent source terms due to heat release and impedanc...
An adaptive flight controller design for a tilt-prop fixed wing uav for all flight modes
Yayla, Metehan; Kutay, Ali Türker (2020-01-01)
© 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.In this study, we propose an autonomous flight control strategy (which is valid for all flight modes including vertical flight, hover, and level flight) for a vertical takeoff and landing capable, tilt-prop, fixed wing, tricopter unmanned aerial vehicle. In the inner loop of proposed hierarchical architecture, desired control forces and moments are generated using adaptive control theory, and these forces and moments a...
A multi-point optimization for transonic airfoil design
Hager, J.O.; Eyi, Sinan; Lee, K.D. (1992-01-01)
© 1992 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.A two-point, aerodynamic design method is presented which improves the aerodynamic performance of transonic airfoils over a range of the flight envelope. It couples an Euler flow solver and a numerical optimization tool. The major limitation of single-point design is the poor off-design performance. Two-point design is used to extend the optimized performance range over more of the desired flight envelope. The method ...
An analysis of stochastic disturbances on nonlinear missile-target engagements based on the adjoint method
Sezer, Emrah; Nalcı, Mehmet Ozan; Kutay, Ali Türker (2016-01-01)
© 2016, American Institute of Aeronautics and Astronautics Inc. All rights reserved.A stochastic adjoint analysis tool that can capture the dominant nonlinearities of a typical missile-target engagement scenario, in addition to the dominant dynamics and stochastic error sources of a missile is developed. The two dimensional, nonlinear missile target terminal engagement problem is modeled in state dependent coefficient form, to generate a set of truth data. Dominant missile dynamics regarding the miss distan...
Citation Formats
M. Yayla and A. T. Kutay, “A Modification to Adaptive Control with Time-varying Learning Rate for Improved Transient Performance,” presented at the AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022, California, Amerika Birleşik Devletleri, 2022, Accessed: 00, 2022. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85123896856&origin=inward.