Advanced UAV Aerodynamics, Flight Stability and Control

7Dynamics Modelling and System Identification of Small Unmanned Helicopters

Cunjia Liu and Wen‐Hua Chen

Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough, UK

7.1 Introduction

Small unmanned helicopters are versatile and are promising platforms for tasks such as surveillance and reconnaissance in confined and dynamic surroundings, due to their abilities in hovering and low‐altitude cruising, and their manoeuvrability.

To this end, the flight dynamics of helicopters need to be understood so that their operational capabilities can be fully exploited. However, in order to apply modern control strategies and to design aircraft that work in a broad range of flight conditions, a precise mathematical model is a necessary. The model should not only have an accurate reflection of the main dynamic characteristics of the helicopter, but should also involve some simplification, to allow control design and real‐time prediction. Due to the complexity of the dynamics of helicopters, developing such a model is a challenge.

In the control community, there are two well‐established approaches for modelling system behaviour:

• first‐principles modelling, where models describing dynamics are built from scratch based on underlying physical laws
• system identification, where algorithms are used to find the relationship between the inputs and outputs of a given system using data collected from experiments.

A typical first‐principles mathematical model for a general ...