Control Barrier Function-Based Quadratic Programming for SafeOperation of Tethered UAVs

TL;DR

This paper introduces a Control Barrier Function Quadratic Programming framework that ensures tethered UAVs operate safely within tether length limits while maintaining accurate trajectory tracking, validated through simulations with disturbances.

Contribution

The paper develops a novel CBF-QP control method that directly incorporates tether constraints into UAV trajectory tracking, ensuring safety and precision simultaneously.

Findings

TUAVs respect tether length constraints in simulations

Tracking errors converge to zero under the proposed control

Control inputs remain bounded despite disturbances

Abstract

Consider an unmanned aerial vehicle (UAV) physically connected to the ground station with a tether operating in a space, tasked with performing precise maneuvers while constrained by the physical limitation of its tether, which prevents it from flying beyond a maximum allowable length. Violating this tether constraint could lead to system failure or operational hazards, making it essential to enforce safety constraints dynamically while ensuring the drone can track desired trajectories accurately. This paper presents a Control Barrier Function Quadratic Programming Framework (CBF-QP) for ensuring the safe and efficient operation of tethered unmanned aerial vehicles (TUAVs). The framework leverages nominal backstepping control to achieve trajectory tracking, augmented with control barrier functions to ensure compliance with the tether constraint. In this proposed method, the tether constraint is directly embedded in the control design and therefore guarantees the TUAV remains within a predefined operational region defined by the maximum tether length while achieving precise trajectory tracking. The effectiveness of the proposed framework is validated through simulations involving set-point tracking, dynamic trajectory following, and disturbances such as incorrect user inputs. The results demonstrate that the TUAV respects the tether constraint ||x(t)||</= Lmax, with tracking errors converging to zero and the control input remaining bounded.