Integrated Pose Formation Control for UAVs Suspension System Based on Disturbance Observer via Twistor Representation

Abstract

In UAV leader–follower cooperative suspension transportation, the follower UAV must precisely track the leader’s trajectory while ensuring payload poses stability. However, strong translational–rotational coupling and wind disturbances cause trajectory deviations and degrade formation control performance. In addition, conventional formation control methods separate position control channel and attitude control channel. The decoupled control methods cannot effectively coordinate translational motion and rotational motion under disturbances, leading to poor control performance. To address these challenges, this article presents a twistor-based integrated pose disturbance observer (DO) and formation control scheme, designed to improve follower UAV suspension system robustness and dynamic response performance. First, a twistor-based dynamic model is established for the follower UAV suspension system, achieving a unified description of translational and rotational motion while effectively avoiding parameter redundancy and normalization constraints inherent in conventional decoupled approaches. Second, to effectively suppress unknown wind disturbances acting on the system, an integrated pose DO is designed for the first time within the twistor framework, utilizing wrench formulation to achieve real-time disturbance estimation and compensation. Furthermore, a fast exponential sliding mode controller within twistor framework is proposed, which significantly enhances dynamic response speed and robustness through the introduction of an exponential regulation term. The global stability of the follower UAV suspension system is rigorously proven. Simulation results demonstrate that, compared with conventional methods, the proposed scheme substantially improves pose tracking accuracy and dynamic trajectory response capability of the follower UAV suspension system, offering an effective solution for precise cooperative control of highly dynamic systems in complex mission scenarios.