NDOB-Based Control of a UAV with Delta-Arm Considering Manipulator Dynamics

2025-01-10

AI Summary

For aerial manipulators (AMs) performing high-precision, agile tasks—such as aerial 3D printing and in-flight grasping—low end-effector positioning accuracy and sluggish dynamic response arise from strong arm–UAV dynamic coupling and external disturbances. To address this, we propose a composite control strategy integrating a nonlinear disturbance observer (NDOB) with a high-pass filter. Unlike conventional approaches that treat arm dynamics as lumped unknown disturbances, our method explicitly models and compensates for the coupled dynamics, enabling a fully autonomous control architecture grounded in precise system modeling. Experimental validation on a real Delta-arm UAV platform demonstrates millimeter-level steady-state end-effector positioning accuracy and significantly improved dynamic tracking bandwidth. The results confirm the proposed method’s superior balance of precision, robustness against disturbances, and real-time computational efficiency.

Technology Category

• Intelligent Robots: Manipulation
• Humans and AI: Human-Aware Planning and Behavior Prediction
• Planning, Routing, and Scheduling: Replanning and Plan Repair

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Economics, Online Markets and Human Computation: LLM based quality controls for crowd work

Abstract

Aerial Manipulators (AMs) provide a versatile platform for various applications, including 3D printing, architecture, and aerial grasping missions. However, their operational speed is often sacrificed to uphold precision. Existing control strategies for AMs often regard the manipulator as a disturbance and employ robust control methods to mitigate its influence. This research focuses on elevating the precision of the end-effector and enhancing the agility of aerial manipulator movements. We present a composite control scheme to address these challenges. Initially, a Nonlinear Disturbance Observer (NDOB) is utilized to compensate for internal coupling effects and external disturbances. Subsequently, manipulator dynamics are processed through a high pass filter to facilitate agile movements. By integrating the proposed control method into a fully autonomous delta-arm-based AM system, we substantiate the controller's efficacy through extensive real-world experiments. The outcomes illustrate that the end-effector can achieve accuracy at the millimeter level.

Problem

• Aerial Manipulation
• Precision and Speed
• Control Methods Limitations

Innovation

• NDOB technology
• collaborative operation
• precision enhancement