Non-cascaded Control Barrier Functions for the Safe Control of Quadrotors

TL;DR

This paper introduces a non-cascaded Control Barrier Function (CBF) integrated with Quadratic Programming to enhance quadrotor safety during normal and abnormal states, applicable to various control schemes and tested in simulations.

Contribution

It proposes a novel non-cascaded CBF that ensures safety for quadrotors under different control architectures, including cascaded and non-cascaded controllers.

Findings

Successfully maintains safety during trajectory tracking.

Ensures safety during aggressive maneuvers.

Establishes a non-conservative safe region.

Abstract

Researchers have developed various cascaded controllers and non-cascaded controllers for the navigation and control of quadrotors in recent years. It is vital to ensure the safety of a quadrotor both in normal state and in abnormal state if a controller tends to make the quadrotor unsafe. To this end, this paper proposes a non-cascaded Control Barrier Function (CBF) for a quadrotor controlled by either cascaded controllers or a non-cascaded controller. Incorporated with a Quadratic Programming (QP), the non-cascaded CBF can simultaneously regulate the magnitude of the total thrust and the torque of the quadrotor determined a controller, so as to ensure the safety of the quadrotor both in normal state and in abnormal state. The non-cascaded CBF establishes a non-conservative forward invariant safe region, in which the controller of a quadrotor is fully or partially effective in the navigation or the pose control of the quadrotor. The non-cascaded CBF is applied to a quadrotor performing trajectory tracking and a quadrotor performing aggressive roll maneuvers in simulations to evaluate the effectiveness of the non-cascaded CBF.