readme.txt

library of aircraft models to be used with Simulink

Airlib is a library of aircraft models to be
used with Simulink 3.1 (Matlab 5.3) or later.

The library consists simply in two nonlinear 
general aircraft models, one in continuous-time, 
the other in discrete-time. Both blocks are largely
based on blocks from the FDC toolbox, written by 
Marc Rauw and available at the matlabcentral website.

The type of aircraft is entirely specified by the
inertial and aerodynamic parameters typed on the mask.
The mask has a very detaliled help that illustrates the 
meaning of inputs, states, outputs and mask parameters.

The library comes with an example, the simulink file
airlibex.mdl, that shows 13 different aircraft models 
including among others, a Boeing 747, an F4 Phantom,
an F104 Starfighter, an X15, an IAI Pioneer (unmanned),
a Convair 880 and four different Cessna models.
Each model is a link to one of the two library blocks,
but of course with different parameters on the mask.

All of those models were taken from this website:
http://www.aae.uiuc.edu/m-selig/apasim/Aircraft-uiuc.html
mantained by Michael S. Selig, Rob Deters, and Glen Dimock 
(thanks for the models) at the university of Urbana-Champaign. 

An example showing a Boeing 747 in a (closed loop) 
straight and level flight is also given. Finally,
the file airtrim.mdl could be easily invoked to 
find a trim point for a given aircraft. 

Altough the trim points were computed using the entire
trimmod utility, in May 2003 a very effective matlab 
function (air3m.m) was added to allow the user to easily 
trim any given aircraft for any combination of desired 
speed, altitude, and flight path angle. Moreover, when 
those desired conditions are supplied as matrices, then 
the input and state vectors for the resulting trim points 
are given as 5D matrices that are ready to be used with 
the block "interpolate matrix" from the Aerospace Blockset.
Modifying the function to give as output also the 5D matrices
A,B,C,D to be used with the "3D controller" block, (also 
from the Aerospace Blockset) should be immediate.

In February 2004, the function ab2dv.m and the model 
fdcwind.mdl were added. The first is a function that
recovers the aerodynamic derivatives of an aircraft
given its inertial data, some trim point values,
and the longitudinal and lateral A and B matrices.
The second is a file that compares two different but 
equivalent ways to handle the wind in the equations.
This also proves that the way in which FDC handles 
the wind is fully correct provided that the right 
initial conditions are chosen for V,alpha,beta 
whenever the initial value of the wind is nonzero.

In July 2006 a full guidance and control system 
based on the feedback linearization of the aircraft
kinematic and dynamics was added. The scheme includes
a waypoint generation system, and can be easily adapted
to any aicraft with known aerodynamics coefficients.

This library should be an useful complement
to the Aerospace Blockset, from The Mathworks, 
(http://www.mathworks.com/products/aeroblks/).
Even for those who use the Aerosim Blockset:
(http://www.u-dynamics.com/aerosim/default.htm)
the library could serve as an useful collection of 
drag-and-drop ready-to-use nonlinear aircraft models.

This is an OPEN project, so feel free to contribute 
in any way, in particular, if you have inertial and 
aerodynamic data of an aircraft that is not in the 
library, you can send it to me and i will be pleased 
to put it in the library along with your name.

You can redistribute it and/or modify this software
under the terms of the GNU GPL License as published
by the Free Software Foundation (see the file GPL.txt).

Giampiero Campa, Feb 2004