uvw.hlp

MATLAB在飞行动力学和控制中应用的工具

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UVW is a masked Simulink subsystem, which is used to compute the
body-axes velocities u, v, and w. Since the aircraft model uses
the true airspeed V, angle of attack alpha, and sideslip angle
beta as state variables, the equations for u, v, and w are simple
output equations. The body-axes velocity components are needed
to solve the equations for the coordinates xe, ye, and the alti-
tude H, so the block UVW cannot be deleted from the system! UVW
is included in the subsystem 'Aircraft Equations of Motion' of
the S-function BEAVER.

Since u, v, and w are no state variables, the time-derivatives of
u, v, and w don't have to be computed to solve the equations of
motion. However, for some purposes, knowledge of these time-deri-
vatives still may be useful; therefore, a block UVWDOT has been
included in the subsystem 'Additional Outputs' within the S-func-
tion BEAVER. See UVWDOT.HLP for more details.

Inputvectors: x and yhlp (the inputvariables which are not used
in the block UVW are displayed between accolades).
===============================================================
  x    = [V alpha beta p q r psi theta phi xe ye H]'     (states)

  yhlp = [cos(alpha) sin(alpha) cos(beta) sin(beta) ...
          ... tan(beta) sin(psi) cos(psi) sin(theta) ...
          ... cos(theta) sin(phi) cos(phi)]'
          (frequently used sines and cosines, coming from HLPFCN)

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]                           }

 of yhlp are used: cos(alpha), cos(beta), sin(alpha) and sin(beta)

Outputvector: ybvel (bvel = 'body-axes velocities').
====================================================
  ybvel = [u v w]',

where:

  u     : component of the true airspeed V along XB-axis [m/s]
  v     : component of the true airspeed V along YB-axis [m/s]
  w     : component of the true airspeed V along ZB-axis [m/s]

More info.
==========
See EQMOTION.HLP for more info about the subsystem 'Aircraft
Equations of Motion', in which UVW is contained. See HLPFCN.HLP
for more details about the inputvector yhlp to the block UVW.
The outputs from UVW are used by the block XYHDOT in the sub-sub-
system '12 ODEs'; see 12ODES.HLP and XYHDOT.HLP for more info.

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The FDC toolbox, Copyright Marc Rauw 1994-1998.