Design of a Smooth Landing Trajectory Tracking System for a Fixed-wing Aircraft

TL;DR

This paper develops a finite-time linear quadratic tracking controller for fixed-wing aircraft landing, ensuring smooth touchdown by optimizing trajectory tracking within flight constraints.

Contribution

It introduces a novel finite-time LQT approach for aircraft landing control using a linearized model and solves the Riccati equation with Dormand Prince algorithm.

Findings

Satisfactory tracking performance demonstrated in simulations

Finite-time convergence of tracking errors achieved

Controller effectively handles different initial conditions

Abstract

This paper presents a landing controller for a fixed-wing aircraft during the landing phase, ensuring the aircraft reaches the touchdown point smoothly. The landing problem is converted to a finite-time linear quadratic tracking (LQT) problem in which an aircraft needs to track the desired landing path in the longitudinal-vertical plane while satisfying performance requirements and flight constraints. First, we design a smooth trajectory that meets flight performance requirements and constraints. Then, an optimal controller is designed to minimize the tracking error, while landing the aircraft within the desired time frame. For this purpose, a linearized model of an aircraft developed under the assumption of a small flight path angle and a constant approach speed is used. The resulting Differential Riccati equation is solved backward in time using the Dormand Prince algorithm. Simulation results show a satisfactory tracking performance and the finite-time convergence of tracking errors for different initial conditions of the flare-out phase of landing.