An enhanced coupling nonlinear control for quadrotor with suspended double‐pendulum payload

Abstract

AbstractIn the field of logistics transportation, unmanned aerial vehicles are commonly utilized for cargo transport in a suspended manner, and the suspended payloads will exhibit the double‐pendulum dynamic characteristics (dPDC). However, due to the underactuation and load‐swing problems caused by the dPDC, it is challenging to design controllers for a quadrotor with a suspended double‐pendulum type payload. Existing related studies simplify the dPDC to a single‐pendulum dynamic characteristic, which results in degraded transient performance. To overcome the issue, this article presents a novel controller approach that considers the real dynamic characteristics, that is, dPDC. The proposed approach tackles the quadrotor position control and anti‐swing problem in two steps. First, a composite signal incorporating both the quadrotor position and the payload swing angles is introduced to restrain the payload swing. Second, a nonlinear controller based on the energy analysis method is proposed to overcome the coupling between rotation and translation, which addresses the underactuation problem. Theoretical analysis confirms the asymptotic stability of the system under this control strategy. Numerical and experimental results are provided to demonstrate the effectiveness of the proposed controller.