Safe Quadrotor Navigation using Composite Control Barrier Functions

TL;DR

This paper presents a scalable safety filter for quadrotor navigation that guarantees collision avoidance using composite control barrier functions, validated through experiments in complex indoor and outdoor environments.

Contribution

It introduces a novel composite control barrier function approach that ensures safety for multirotor robots with high computational efficiency in complex scenes.

Findings

Guarantees collision avoidance in cluttered environments

Scales efficiently with thousands of constraints

Successfully tested on quadrotors with onboard LiDAR

Abstract

This paper introduces a safety filter to ensure collision avoidance for multirotor aerial robots. The proposed formalism leverages a single Composite Control Barrier Function from all position constraints acting on a third-order nonlinear representation of the robot's dynamics. We analyze the recursive feasibility of the safety filter under the composite constraint and demonstrate that the infeasible set is negligible. The proposed method allows computational scalability against thousands of constraints and, thus, complex scenes with numerous obstacles. We experimentally demonstrate its ability to guarantee the safety of a quadrotor with an onboard LiDAR, operating in both indoor and outdoor cluttered environments against both naive and adversarial nominal policies.