Disturbance Observer-Based Distributed Formation-Tracking Control for Multi-Cluster Quadrotor Cooperative Suspended Payload Systems

Abstract

Multi-Cluster Quadrotor Cooperative Suspended Payload Systems (MQCSPS) offer enhanced payload capacity and transportation flexibility, making them promising for autonomous aerial transportation in complex and uncertain environments. However, unknown external disturbances and the coupled dynamics among multiple quadrotors and the payload pose significant challenges to accurate formation tracking and stable cooperative transportation. To address the distributed formation-tracking control problem of an MQCSPS subject to unknown disturbances, a disturbance-observer-based distributed formation-tracking control method is proposed. Specifically, distributed sliding-mode formation controllers and sliding-mode tracking controllers are designed for the payload and quadrotors, respectively, enabling accurate trajectory tracking of the quadrotors while maintaining the desired distributed formation of the payload. A disturbance observer is incorporated to estimate and compensate for the effects of unknown disturbances, thereby improving the disturbance-rejection capability of the closed-loop system. Through Lyapunov-based stability analysis, the uniform ultimate boundedness of the closed-loop tracking errors is established. Simulation results demonstrate that the proposed method achieves accurate payload formation tracking and stable quadrotor motion in the presence of disturbances, validating its effectiveness for cooperative aerial transportation in complex environments.

Received: 30 July 2026 | Revised: 8 September 2026 | Accepted: 14 September 2026

Conflicts of Interest

The authors declare that they have no conflicts of interest to this work.

Data Availability Statement

Data sharing is not applicable to this article as no new data were created or analyzed in this study.

Author Contribution Statement

Wei Liu: Conceptualization, Methodology, Formal analysis, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization. Xuejun Liu: Software, Supervision, Funding acquisition. Bo Liu: Validation, Investigation, Project administration.