level1.hlp

MATLAB在飞行动力学和控制中应用的工具

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Level 1 of the system BEAVER
============================
The first level of the system BEAVER contains the Inports and
Outports to and from the nonlinear aircraft model, To Workspace
blocks to store the input and outputvectors along with a time-
vector in the Matlab workspace, Mux blocks to combine the scalar
signals from the different Inport blocks into vector signals, and
Demux blocks to extract scalar output signals from the different
output vectors. The actual model of the 'Beaver' dynamics is con-
tained in the subsystem 'Beaver dynamics and output equations',
i.e., level 1 is needed only to manage the input/output signals
to and from the system BEAVER.

S-function inputs & outputs vs. inputs & outputs which are send
to the Matlab workspace.
===============================================================
It is important to notice that the number of outputs which are
send to the Matlab workspace by means of To Workspace blocks is
considerably larger than the number of Outport blocks, represen-
ting 'S-function outputs' of the system BEAVER. The Outport
blocks are needed for connecting other systems to the output-side
of the system BEAVER, e.g., systems with models of sensor dyna-
mics, controllers, etc. Unfortunately, Simulink does not accept
vector outputs to be connected to Outport blocks within the first
level of a graphical system; therefore, only a small subset of
the output variables from BEAVER have actually been connected to
the Outport blocks.

By default, the sixteen outputs which were needed to simulate
the 'Beaver' autopilot are connected to Outports. If other out-
put signals are needed by systems which ought to be connected
to BEAVER, it is necessary to add more Outport blocks to this
list of 'S-function outputs'. For instance: if you want to exa-
mine control laws which use accelerations as reference signals,
these signals must be connected to new Outport blocks in the
first level of BEAVER. Currently, the accelerations are send to
the Matlab workspace only, but they cannot yet be used as inputs
to other Simulink systems, connected to the output side of the
system BEAVER.

Currently, it is not possible to send complete vectors through
individual Inport and Outport blocks in the first level of a
graphical system (where they serve to connect the graphical sys-
tem to other Simulink systems, or to provide access to the system
for analytical tools such as trim and linearization routines).
Inports and Outports in the first level of graphical Simulink
systems only accept SCALAR signals, which is really a serious
limitation of Simulink! Hopefully, this problem will be solved
in future versions of Simulink!

S-function inputs
=================
   deltae, deltaa, deltar, deltaf, n, pz, uw, vw, ww, uwdot,
   vwdot, and wwdot

   When connecting other systems to a block 'S-function' which
   calls the system BEAVER, or when you want to access the sys-
   tem BEAVER directly from the Matlab command-line, a vector of
   length twelve must always be used as inputvector:

   u = [deltae, deltaa, deltar, deltaf, n, pz, uw, vw, ww, uwdot,
        vwdot, wwdot]'

   The time-trajectories of these twelve 'S-function inputs' are
   collected in the matrix In in the Matlab workspace.

S-function outputs
==================
   V, alpha, beta, p, q, r, psi, theta, phi, xe, ye, H, Hdot,
   pb/2V, qc/V, rb/2V

   The first thirteen outputs (states + climb velocity Hdot) are
   needed by the control laws of the 'Beaver' autopilot; the last
   three outputs (dimensionless rotational velocities) are needed
   by the linear state-space model of the dynamics of the steering
   column/steering wheel, cables, control surfaces, and hydraulic
   actuators, used in the 'Beaver' autopilot. These sixteen 'S-
   function outputs' form a subset of the 89 outputs which are
   send to the matrix Out in the Matlab workspace.

See INPUTS.HLP and OUTPUTS.HLP for the exact definitions of these
input and output signals, respectively.

Inputs & outputs which are sent to the Matlab workspace
=======================================================
There are three 'To Workspace' blocks. The first one is used to
send the inputs to the system BEAVER to the matrix In in the Mat-
lab workspace, including the wind and turbulence velocity compo-
nents and their time-derivatives. The second To Workspace block
sends ALL outputs to the matrix Out in the Matlab workspace.
In order to be able to plot the results against time, a third
To Workspace block is connected to a Clock block, which yields
a time-axis in the vector time. Therefore, results can be plot-
ted by typing:

    plot(time,Out(:,1))
    plot(time,In(:,6))

and so on. The exact definitions of the matrices In and Out can
be found by double-clicking the corresponding Mux blocks in the
first level of BEAVER, or by viewing the help texts INPUTS.HLP
and OUTPUTS.HLP.

The Matlab macro RESULTS.M
==========================
In stead of directly using the matrices In and Out for plotting
and analyzing results, it is also possible to first run the Mat-
lab program RESULTS.M, which has been included in the directory
TOOLS. This program will extract the trajectories of individual
inputs from the vector In and the trajectories of individual out-
puts from the vector Out. The plotting commands, given above
may then be replaced by:

    plot(time,V)
    plot(time,pz)

Note: RESULTS.M can be used only for the default definitions of
the matrices In and Out, as listed in INPUTS.HLP and OUTPUTS.HLP!
Type HELP RESULTS for more info.

More info
=========
See also LEVEL2.HLP, INPUTS.HLP, and OUTPUTS.HLP. See COLORS.HLP
for an overview of the color conventions, used in the block-dia-
grams from FDC 1.2.

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The FDC toolbox, Copyright Marc Rauw 1994-1998.