aeromod.hlp

MATLAB在飞行动力学和控制中应用的工具

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AEROMOD (Beaver) is a masked Simulink subsystem, used to compute
aerodynamic force and moment coefficients for the DHC-2 'Beaver'.
The aerodynamic model is aircraft-dependent, hence, this block
must be replaced if models of other aircraft are to be implemen-
ted in the simulation structure of FDC. Instant replacement of
the block AEROMOD (Beaver) is possible only if the same inputs
and outputs to and from this block remain the same. However, the
internal structure of a new block AEROMOD may look completely
different. For instance, the aerodynamic model of the DHC-2 'Bea-
ver', contained in AEROMOD (Beaver) determines the force and mo-
ment coefficients by means of evaluation of six polynomial equa-
tions, whereas in other cases, it is more customary to compute
aerodynamic forces and moments by means of interpolation in large
multi-dimensional tables. The block AEROMOD is contained in the
subsystem 'Aerodynamics Group (Beaver)' of the system BEAVER.

The force coefficient with respect to beta-dot has not been in-
cluded in the block AEROMOD (Beaver), because it would have yiel-
ded an algebraic loop. Therefore, the beta-dot equation has been
written out as an explicit equation, which has been included in
the block XDOTCORR, in the subsystem 'Aircraft Equations of
Motion'. See XDOTCORR.HLP for more details.


Inputvectors: x, uaero, ydl (the inputvariables which are not
used by AEROMOD are displayed between accolades).
==============================================================
  x    = [V alpha beta p q r psi theta phi xe ye H]'     (states)
  uaero= [deltae deltaa deltar deltaf]'      (aerodynamic inputs)
  ydl  = [pb/2V qc/V rb/2V]'           (dimensionless velocities,
                                   computed in the block DIMLESS)

where:

 {V    : airspeed [m/s]                                         }
  alpha: angle of attack [rad]
  beta : sideslip angle [rad]
 {p    : roll rate [rad/s]                                      }
 {q    : pitch rate [rad/s]                                     }
 {r    : yaw rate [rad/s]                                       }
 {psi  : yaw angle [rad]                                        }
 {theta: pitch angle [rad]                                      }
 {phi  : roll angle [rad]                                       }
 {xe   : x-coordinate in Earth-fixed reference frame [m]        }
 {ye   : y-coordinate ''     ''          ''      ''  [m]        }
 {H    : altitude above sea-level [m]                           }

  deltae: elevator deflection [rad]
  deltaa: deflection of the ailerons [rad]
  deltar: rudder deflection [rad]
  deltaf: flap setting [rad]

  pb/2V: dimensionless roll rate [-]
  qc/V : dimensionless pitch rate [-]
  rb/2V: dimensionless yaw rate [-]

Outputvector: Caero.
====================
  Caero = [CXa CYz CZa Cla Cma Cna]'

where:

  CXa, CYa, CZa: dimensionless aerodynamic force coefficients
  Cla, Cma, Cna: dimensionless aerodynamic moment coefficients.

Parameters, which must be set in the Matlab Workspace.
======================================================
  AM = matrix with stability and control derivatives of the
       'Beaver' (valid only for the nonlinear aerodynamic model
       of the DHC-2 'Beaver', see ref.[1]). The matrix AM can
       be loaded into the Matlab workspace from file by calling
       LOADER.M. Run MODBUILD.M first if this datafile does not
       yet exist. Type HELP LOADER or HELP MODBUILD for more info.

References.
===========
[1]  R.T.H. Tjee and J.A. Mulder. Stability and Control Deriva-
     tives of the De Havilland DHC-2 "Beaver" aircraft. Report
     LR-556, Delft University of Technology, 1988.

More info.
==========
See also FMDIMS.HLP, DIMLESS.HLP, and AEROGRP.HLP. See the help
file XDOTCORR.HLP for more info about the correction to beta-dot
which in the case of the 'Beaver' aircraft is needed to compen-
sate for the neglection of the beta-dot influence upon the aero-
dynamic sideforce Ya (CYa).

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The FDC toolbox, Copyright Marc Rauw 1994-1998.