inputs.hlp

MATLAB在飞行动力学和控制中应用的工具

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Inputs to the system BEAVER.
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The system BEAVER contains the nonlinear dynamic model of the
DHC-2 'Beaver' aircraft, which consists of twelve state equations,
forces and moment equations, airdata equations, and many addi-
tional output equations. BEAVER is a graphical Simulink block-
diagram.

The first level of BEAVER contains a number of input and output
ports, which are needed to connect other subsystems (e.g. command
generators, autopilots, sensor models, etc.) to the aircraft mo-
del. For simulation purposes, aircraft linearization and the de-
termination of steady-state trimmed flight conditions, the system
BEAVER can be treated as a BLACK-BOX model, which can be accessed
through this input and output ports only.

S-function inputs of the system BEAVER:
=======================================
There are twelve (scalar) Inport blocks, which means that the
system must be accessed with an input vector of length twelve.
This input vector (THE inputvector to the system BEAVER) has been
defined as:

  u     = [uaero'  uprop'  uwind']'

  uaero = [deltae deltaa deltar deltaf]'
  uprop = [n pz]'
  uwind = [uw vw ww uwdot vwdot wwdot]'

where:

  deltae: elevator deflection [rad]
  deltaa: ailerons deflection [rad]
  deltar: rudder deflection [rad]
  delfaf: flap deflection [rad]

  n     : engine speed [RPM]
  pz    : manifold pressure ["Hg]

  uw    : wind & turbulence velocity along XB-axis [m/s]
  vw    : wind & turbulence velocity along YB-axis [m/s]
  ww    : wind & turbulence velocity along ZB-axis [m/s]
  uwdot : d(uw)/dt [m/s^2]
  vwdot : d(vw)/dt [m/s^2]
  wwdot : d(ww)/dt [m/s^2]

Inputvariables which are send to the Matlab workspace:
======================================================
During simulations, the time-trajectories of these inputvariables
are recorded in the matrix 'In' in the Matlab workspace. The matrix
'In' contains twelve columns and N rows, where N is the number of
time-steps taken during the simulation. The twelve columns cor-
respond with the twelve elements of the inputvector u, so:

  In == [  u'(t0)  ;  u'(t1)  ;  u'(t2)  ;  ...  ;  u'(tN)  ]

The twelve columns of 'In' therefore correspond with the variables
deltae, deltaa, deltar, deltaf, n, pz, uw, vw, ww, uwdot, vwdot,
and wwdot (in this particular order), respectively. The outputs
from the system BEAVER are send to the matrix 'Out', and a time-
axis is send to the vector time. See OUTPUTS.HLP for more info.

Using the Matlab-macro RESULTS.M
================================
Although the time-trajectories of the input variables are thus
send to the matrix 'In' in the Matlab workspace, analyzing these
results still may be difficult, because it is not easy to memo-
rize the exact definition of this matrix. For this reason, the
Matlab program RESULTS.M has been created. The file RESULTS.M
can be found in the subdirectory TOOLS.
     If you run RESULTS.M after a simulation, the time-trajec-
tories of deltae, deltaa, deltar, deltaf, n, pz, uw, vw, ww,
uwdot, vwdot, and wwdot will be extracted from the matrix 'In' as
separate VECTORS. These vectors can be plotted against the vector
time, which was created together with the matrices 'In' and 'Out'.
The resulting plot commands look like:

        plot(time,uwdot)
        plot(time,deltae)

        etc.

The helpfiles AEROMOD.HLP, ENGMOD.HLP, FWIND.HLP, explain where
the inputvariables from the inputvector u are used in the system
BEAVER. See OUTPUTS.HLP for an exact definition of the outputvec-
tor from the system BEAVER. See also LEVEL1.HLP to find out how
the definition of the inputvector u is related to the graphical
block-diagram structure of the first level of the system BEAVER.
Type HELP RESULTS at the Matlab command line for more info about
the program RESULTS.M.

Note: if you want to adapt the system BEAVER for implementing a
dynamic model of another aircraft, it may well be possible that
you need other inputvariables than the twelve listed above. In
that case, the first level of BEAVER needs to be changed accor-
ding to your own wishes, see LEVEL1.HLP. Also, RESULTS.M needs to
be edited.

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The FDC toolbox, Copyright Marc Rauw 1994-1998.