fmdims.hlp

MATLAB在飞行动力学和控制中应用的工具

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FMDIMS is a masked  Simulink subsystem, used to compute forces
(in [N]) and moments (in [Nm]) from dimensionless force and mo-
ment coefficients, using the dynamic pressure and some geometric
properties of the aircraft. In the 'Beaver' model, FMDIMS is used
in the subsystem blocks 'Aerodynamics Group' and 'Engine Group',
in order to be applied to aerodynamic forces and moments, and
forces and moments due to operation of the engine, respectively.

Inputvectors: yad1 and Caero or Cprop (the inputvariables which
are not actually used by FMDIMS are displayed between brackets).
=================================================================
  yad1 = [a M qdyn]'                (airdata variables which are
                                  computed in the block AIRDATA1)

  Caero= [CXa CYa CZa Clt Cma Cna]'   (dimensionless aerodynamic
                                   force and moment coefficients,
                                             computed in AEROMOD)

  Cprop= [CXp CYp CZp Clp Cmp Cnp]'    (dimensionless propulsive
                                        force and moment coeffi-
                                      cients, computed in ENGMOD)
where:

 {a    : speed of sound [m/s]                                   }
 {M    : Mach number [-]                                        }
  qdyn : dynamic pressure [N/m^2]

  CXa, CYa, CZa: aerodynamic force coefficients along the air-
                 craft's body-axes
  Cla, Cma, Cna: aerodynamic moment coefficients along the air-
                 craft's body-axes
  CXp, CYp, CZp: engine force coefficients along the aircraft's
                 body-axes
  Clp, Cmp, Cnp: engine moment coefficients along the aircraft's
                 body-axes

Outputvector: FMaero or FMprop.
===============================
  FMaero= [Xa Ya Za La Ma Na]'   (vector with aerodynamic forces
                                                     and moments)
  FMprop= [Xp Yp Zp Lp Mp Np]'   (vector with engine forces and
                                                         moments)
where:

  Xa, Ya, Za: aerodynamic forces along aircraft's body-axes [N]
  La, Ma, Na: aerodynamic moments along aircraft's body-axes [Nm]

  Xp, Yp, Zp: propulsive forces along aircraft's body-axes [N]
  Lp, Mp, Np: propulsive moments along aircraft's body-axes [Nm]

Equations.
==========
The following expressions are used:

  X = CX*qdyn*S,   Y = CY*qdyn*S,   Z = CZ*qdyn*S
  L = Cl*qdyn*S*b, M = Cm*qdyn*S*c, N = Cn*qdyn*S*b

where:

  S       : wing area [m^2]
  c = cbar: mean aerodynamic chord [m]
  b       : wing span [m]

  CX, CY, ... , Cn may equal CXa, ... Cna, CXp, ... Cnp, or any
  other sequence of force and moment coefficients which have been
  made dimensionless in the same way.

Parameters which must be loaded in the Matlab Workspace.
========================================================
  GM1 = vector with some important geometrical properties of the
        'Beaver' aircraft, and the mass of the aircraft (which is
        assumed to be constant during the motions of interest).
        Here, the wing span b, mean aerodynamic chord cbar, and
        wing area S are extracted from GM1. GM1 can be loaded in-
        to the workspace from file by applying LOADER.M. Run
        MODBUILD.M first if the datafile does not exist. Type
        HELP LOADER or HELP MODBUILD for more details.

More info:
==========
See the helpfiles AEROMOD.HLP and/or ENGMOD.HLP, which refer to
the blocks in which the dimensionless force and moment coeffi-
cients are calculated. See AIRDATA1.HLP for more details about
the meaning of the vector yad1 (from which qdyn is extracted).

See AEROGRP.HLP and ENGGRP.HLP for more details about the subsys-
tems 'Aerodynamics Group' and 'Engine Group', respectively.

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The FDC toolbox, Copyright Marc Rauw 1994-1998.