Payload trajectory tracking control for aerial transportation systems with cable length online optimization

TL;DR

This paper presents a backstepping control method for cable-suspended aerial systems with variable-length cables, enabling precise payload trajectory tracking and online cable length optimization amidst complex nonlinear dynamics.

Contribution

It introduces a novel control strategy and an online cable length generator that adaptively optimize cable length during payload transportation, enhancing system flexibility and performance.

Findings

Effective payload trajectory tracking demonstrated in simulations.

Successful online cable length optimization balancing system constraints.

Guaranteed asymptotic stability of the control system.

Abstract

Cable-suspended aerial transportation systems are employed extensively across various industries. The capability to flexibly adjust the relative position between the multirotor and the payload has spurred growing interest in the system equipped with variable-length cable, promising broader application potential. Compared to systems with fixed-length cables, introducing the variable-length cable adds a new degree of freedom. However, it also results in increased nonlinearity and more complex dynamic coupling among the multirotor, the cable and the payload, posing significant challenges in control design. This paper introduces a backstepping control strategy tailored for aerial transportation systems with variable-length cable, designed to precisely track the payload trajectory while dynamically adjusting cable length. Then, a cable length generator has been developed that achieves online optimization of the cable length while satisfying state constraints, thus balancing the multirotor's motion and cable length changes without the need for manual trajectory planning. The asymptotic stability of the closed-loop system is guaranteed through Lyapunov techniques and the growth restriction condition. Finally, simulation results confirm the efficacy of the proposed method in managing trajectory tracking and cable length adjustments effectively.