Tracking of Ground Mobile Targets by Quadrotor Unmanned Aerial Vehicles

Abstract

This paper focuses on the development of control and guidance laws for quadrotor Unmanned Aerial Vehicles (UAVs) to track maneuvering ground targets. Proportional Derivative (PD) control law is a popular choice to be used as a tracking controller for quadrotors, but it is often inefficient due to practical acceleration constraints and a number of parameters that need to be tuned. The paper proposes a Proportional Navigation (PN)-based switching strategy to address the problem of mobile target tracking. The experiments and numerical simulations performed using nonmaneuvering and maneuvering targets show that the proposed PN-based switching strategy not only carries out effective tracking but also results into smaller oscillations and errors when compared to the widely used PD tracking method. The proposed PN-based switching strategy presents an important question with regard to when the switching should happen that would minimize the positional error between the UAV and the target. An optimal switching strategy, which is based on the analytical solutions of the PN and PD methods, is proposed. The numerical simulations not only validate the theoretical results with regard to the optimality of the proposed method for both nonmaneuvering and maneuvering targets but also demonstrate that the proposed method is robust to measurement noise.