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

TL;DR

This paper introduces a novel control scheme for UAVs with delta arms that uses a nonlinear disturbance observer and high pass filtering to improve precision and agility, validated through real-world experiments.

Contribution

It presents a composite control method combining NDOB and manipulator dynamics processing, enhancing UAV end-effector accuracy and agility over existing approaches.

Findings

Achieves millimeter-level end-effector accuracy.

Enhances UAV agility and precision.

Validated through extensive real-world experiments.

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.