|Nonlinear Cascade Control for a New Coaxial Tilt-rotor UAV
Shengming Li, Zongyang Lv, Lin Feng, Yuhu Wu, and Yingshun Li*
International Journal of Control, Automation, and Systems, vol. 20, no. 9, pp.2948-2958, 2022
Abstract : This paper proposes a nonlinear control strategy for a newly-designed coaxial tilt-rotor (CTR) unmanned aerial vehicle (UAV), which is a special class of tilt-rotor (TR) UAVs with two pairs of coaxial rotors, two servos, and a rear rotor. The CTRUAV is an underactuated system, and the controller is designed in cascade form. The proposed controller includes two sub-controllers: an inner-loop attitude controller and an outer-loop velocity controller. Each sub-controller is proposed by using a backstepping-like feedback linearization method to control and stabilize the CTRUAV. The developed control strategy can realize the motion control for the CTRUAV. The asymptotic stability of the resulting closed-loop system is analyzed by the Lyapunov method. Finally, simulations and real flight tests are performed to validate the effectiveness of the proposed control system.
Cascade control, coaxial rotors, tilt rotor, unmanned aerial vehicle (UAV).
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