UWE Bristol Engineering showcase 2015

Elisha Nyakabau
Beng Aerospace Systems Engineering
Project Supervisor
Nigel Gunton
An Investigation into Auto-Stabilisation of a Helicopter
This project looks at the creation of an automatic stabilisation system for a helicopter, a single rotor helicopter to be specific. The
behaviour of helicopters is complex and understanding the mechanisms at work requires numerical modelling and simulation, only
through this can the flying qualities and stability be identified. Once identified can an augmentation system be designed to stabilise
the aircraft and improve the handling qualities.
Project summary
Creation of a mathematical model for simulation
Analysis of dynamic stability at different flight
conditions
Design and testing of a linearized feedback
controller
Assessment of helicopter stabilisation methods
An understanding of control theory is required to be able to create an
automatic flight controller that is capable of trimming the aircraft in a wide
range of flight modes such as hover where a helicopter is most unstable. The
project covers some of the basic control theory required before undertaking
the design of such a controller.
2 Column Grid
Type Spec: Calibri 24pt,
Align Left,
(Bold for headings medium for paragraphs of text). Space for your research,
theory, experiments, analysis, simulations, pictures, tables, diagrams,
flowcharts, text
Project Objectives
To first gain an understanding of helicopter flight
dynamics and simulation modelling
Creation of a validated dynamic model of a
helicopter using Simulink
Trim and Linearization of the model
Asses the dynamics of the helicopter
Use classic feedback control techniques to develop a
linear controller
The Modelling
The software used for modelling is
Simulink and Matlab. The model
used is based on Nasa single rotor
helicopter model.
The Helicopter
The simulation model is configured
to the Bell AH-1G Huey Cobra.
The Huey Cobra is a 2 bladed
military helicopter and has been in
service since 1971.
Project Conclusion
Modelled and Simulated a Bell AH-1 Helicopter.
Designed and simulated a working Stability
Augumentation System (SAS) with ATT (Attitude
Retention System)
SAS
The Stability Augmentation System is modelled
using full state feedback (pole placement). Linear
Quadratic Regulation (LQR) used to gain the
optimal gain matrix K which is used to close the
loop
ATT
Attitude Retention System, forms the outer loop of
the linearized controller and provides flight modes
for the pilot such as Attitude hold and Altitude
hold.
Displacement
Lateral displacement due to random velocity disturbances at 104 kts with SAS
0.08
Lateral Displacement (ft)
0.06
0.04
0.02
0
-0.02
-0.04
-0.06
-0.08
-0.1
-0.12
0 20 40 60 80 100 120 140 160 180 200
Time (t)