This article presents an optimal tracking controller retrofitted with a nonlinear adaptive integral compensator, specifically designed to ensure robust and accurate positioning of Vertical Take-Off and Landing (VTOL) Unmanned Aerial Vehicles (UAVs) that utilize contra-rotating motorized propellers for differential thrust generation. The baseline position controller is synthesized by employing a fixed-gain Linear Quadratic Integral (LQI) tracking controller that stabilizes position by tracking both state variations and pitch-axis tracking error integral, which adjusts the voltage to control each coaxial propeller’s speed accurately. Additionally, the baseline tracking control law is supplemented with a rate-varying integral compensator. It operates as a nonlinear scaling function of the tracking-error velocity and the braking acceleration to enhance the accuracy of reference tracking without sacrificing its robustness against exogenous disruptions. The controller’s performance is analyzed by performing experiments on a tailored hardware-in-the-loop aero-pendulum testbed, which is representative of VTOL UAV dynamics. Experimental results demonstrate significant improvements over the nominal LQI tracking controller, achieving 17.9%, 61.6%, 83.4%, 43.7%, 35.8%, and 6.8% enhancement in root mean squared error, settling time, overshoot during start-up, overshoot under impulsive disturbance, disturbance recovery time, and control energy expenditure, respectively, underscoring the controller’s effectiveness for potential UAV and drone applications under exogenous disturbances.


    Access

    Download


    Export, share and cite



    Title :

    Robust Position Control of VTOL UAVs Using a Linear Quadratic Rate-Varying Integral Tracker: Design and Validation


    Contributors:


    Publication date :

    2025




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    Unknown




    Position Tracking for VTOL UAVs

    Abdessameud, Abdelkader / Tayebi, Abdelhamid | Springer Verlag | 2013


    Adaptive Position Tracking of VTOL UAVs

    Roberts, A. / Tayebi, A. | Tema Archive | 2011


    A linear quadratic tracker for VTOL-UAV trajectory control with multivariable constraints

    Giroux, Richard / Gourdeau, Richard / Pelletier, Michel et al. | AIAA | 2000


    Formation Control of VTOL UAVs

    Abdessameud, Abdelkader / Tayebi, Abdelhamid | Springer Verlag | 2013


    Linear Quadratic Tracker with Integrator using Integral Reinforcement Learning

    Park, On / Shin, Hyosang / Tsourdos, Antonios | IEEE | 2019