Neural Network Based Adaptive Control for Nonlinear Dynamic Regimes

Uncertainties;Nonlinear dynamic regimes;Fighter aircraft;High angle of attack;Composite adaptive control;Supermaneuverability;Adaptive control;Neural networks;Nonlinear dynamic inversion

Shin, Yoonghyun ; Mechanical Engineering

University:Georgia Institute of Technology

Department:Mechanical Engineering

关键词: Uncertainties;    Nonlinear dynamic regimes;    Fighter aircraft;    High angle of attack;    Composite adaptive control;    Supermaneuverability;    Adaptive control;    Neural networks;    Nonlinear dynamic inversion;   

Others  :  https://smartech.gatech.edu/bitstream/1853/7577/1/shin_yoonghyun_200512_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

Adaptive control designs using neural networks (NNs) based on dynamic inversion areinvestigated for aerospace vehicles which are operated at highly nonlinear dynamic regimes. NNs play a key role as the principal element of adaptation to approximately cancel the effect of inversion error, which subsequently improves robustness to parametric uncertainty and unmodeled dynamics in nonlinear regimes. An adaptive control scheme previously named composite model reference adaptive control is further developed so that it can be applied to multi-input multi-output output feedback dynamic inversion. It can have adaptive elements in both the dynamic compensator (linear controller) part and/or in the conventional adaptive controller part, also utilizing state estimation information for NN adaptation. This methodology has more flexibility and thus hopefully greater potential than conventional adaptive designs for adaptive flight control in highly nonlinear flight regimes. The stability of the control system is proved through Lyapunov theorems, and validated with simulations.The control designs in this thesis also include the use of pseudo-control hedging techniques which are introduced to prevent the NNs from attempting to adapt to various actuation nonlinearities such as actuator position and rate saturations. Control allocation is introduced for the case of redundant control effectors including thrust vectoring nozzles. A thorough comparison study of conventional and NN-based adaptive designs for a system under a limit cycle, wing-rock, is included in this research, and the NN-based adaptive control designs demonstrate their performances for two highly maneuverable aerial vehicles, NASA F-15 ACTIVE and FQM-117B unmanned aerial vehicle (UAV), operated under various nonlinearities and uncertainties.