Three-dimensional Nonlinear Path-following Guidance with Bounded Input Constraints

TL;DR

This paper introduces a nonlinear guidance law for UAVs that enables accurate three-dimensional path-following under input constraints, with proven convergence and demonstrated effectiveness through simulations.

Contribution

It presents a novel, general nonlinear guidance strategy that handles arbitrary smooth paths without relying on path geometry, suitable for bounded control inputs.

Findings

UAVs can follow complex 3D paths accurately with the proposed guidance law.

The guidance law guarantees convergence within a fixed time regardless of initial conditions.

Simulations validate the effectiveness of the approach across various scenarios.

Abstract

In this paper, we consider the tracking of arbitrary curvilinear geometric paths in three-dimensional output spaces of unmanned aerial vehicles (UAVs) without pre-specified timing requirements, commonly referred to as path-following problems, subjected to bounded inputs. Specifically, we propose a novel nonlinear path-following guidance law for a UAV that enables it to follow any smooth curvilinear path in three dimensions while accounting for the bounded control authority in the design. The proposed solution offers a general treatment of the path-following problem by removing the dependency on the path's geometry, which makes it applicable to paths with varying levels of complexity and smooth curvatures. Additionally, the proposed strategy draws inspiration from the pursuit guidance approach, which is known for its simplicity and ease of implementation. Theoretical analysis guarantees that the UAV converges to its desired path within a fixed time and remains on it irrespective of its initial configuration with respect to the path. Finally, the simulations demonstrate the merits and effectiveness of the proposed guidance strategy through a wide range of engagement scenarios, showcasing the UAV's ability to follow diverse curvilinear paths accurately.