Robust Tracking Control of Aerial Robots Via a Simple Learning Strategy-Based Feedback Linearization

• Published in: IEEE access Vol. 8; pp. 1653 - 1669
• Main Authors: Mehndiratta, Mohit, Kayacan, Erkan, Reyhanoglu, Mahmut, Kayacan, Erdal
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptation; Computational modeling; Control systems; Control theory; Cost function; Disturbances; Feedback control; Feedback linearization; Feedback linearization control; Learning; learning control; Mathematical model; Modelling; Nonlinear dynamical systems; nonlinear system; Nonlinear systems; Real time; Robot control; Robust control; Strategy; Tracking control; Tracking problem; uncertain systems; Uncertainty; unmanned aerial vehicle; Unmanned aerial vehicles; Wind effects
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2019.2962512

To facilitate accurate tracking in unknown/uncertain environments, this paper proposes a simple learning (SL) strategy for feedback linearization control (FLC) of aerial robots subject to uncertainties. The SL strategy minimizes a cost function defined based on the closed-loop error dynamics of the nominal system via the gradient descent technique to find the adaptation rules for feedback controller gains and disturbance estimate in the feedback control law. In addition to the derivation of the SL adaptation rules, the closed-loop stability for a second-order uncertain nonlinear system is proven in this paper. Moreover, it is shown that the SL strategy can find the global optimum point, while the controller gains and disturbance estimate converge to a finite value which implies a bounded control action in the steady-state. Furthermore, utilizing a simulation study, it is shown that the simple learning-based FLC (SL-FLC) framework can ensure desired closed-loop error dynamics in the presence of disturbances and modeling uncertainties. Finally, to validate the SL-FLC framework in real-time, the trajectory tracking problem of a tilt-rotor tricopter unmanned aerial vehicle under uncertain conditions is studied via three case scenarios, wherein the disturbances in the form of mass variation, ground effect, and wind gust, are induced. The real-time results illustrate that the SL-FLC framework facilitates a better tracking performance than that of the traditional FLC method while maintaining the nominal control performance in the absence of modeling uncertainties and external disturbances, and exhibiting robust control performance in the presence of modeling uncertainties and external disturbances.