moreouts.hlp

MATLAB在飞行动力学和控制中应用的工具

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System BEAVER - subsystem 'Additional Outputs'
==============================================
The 3rd-level subsystem 'Additional Outputs' of the system BEAVER
contains a number of masked subsystem blocks which generate out-
put signals that were not needed for solving the equations of
motion, and which could not logically be placed in one of the
other subsystems (i.e., 'Airdata Group', 'Aerodynamics Group',
'Engine Group', or 'Aircraft Equations of Motion'). The subsystem
'Additional Outputs' can be deleted from the system BEAVER, with-
out affecting the solution of the equations of motion, and it is
easy to add more output equations to the list that is currently
contained in this subsystem.

Since the outputs from this subsystem are in no way involved in
the actual solution of the state equations, the outputs may de-
pend not only upon the state-vector x and the inputvectors uaero,
uprop, and uwind, but also upon the time-derivative of the state
vector, xdot. If the outputs from the subsystem 'Additional Out-
puts' were needed for solving the state equations, this would
not be possible, because it would yield an algebraic loop.

By default, the subsystem 'Additional Outputs' contains masked
subsystem blocks ACCEL, FLPATH, and UVWDOT, which determine
accelerations and specific forces, flightpath variables, and
time-derivatives of the velocity components u, v, and w (which
are NOT state variables!), respectively. More output equations
may be included in this subsystem!

Inputs to the subsystem 'Additional Outputs':
=============================================
  x    = [V alpha beta p q r psi theta phi xe ye H]'     (states)

  xdot = dx/dt = [Vdot alphadot betadot pdot qdot rdot ...
                  ... psidot thetadot phidot xedot yedot Hdot]'
                                (time-derivative of state-vector)

  yhlp = [cos(alpha) sin(alpha) cos(beta) sin(beta) tan(beta) ...
          ... sin(psi) cos(psi) sin(theta) cos(theta) ...
          ... sin(phi) cos(phi) ]'
                  (sines & cosines, computed in the block HLPFCN)

  Ftot = [Fx Fy Fz]'              (total forces along body-axes,
                                    computed in the block FMSORT)

  Fgrav= [Xgr Ygr Zgr]'         (gravity forces along body-axes,
                                   computed in the block GRAVITY)

where:

  V        : airspeed [m/s]
 {alpha    : angle of attack [rad] or [deg]                      }
  beta     : sideslip angle [rad] or [deg]
 {p        : roll-rate [rad/s] or [deg/s]                        }
 {q        : pitch-rate [rad/s] or [deg/s]                       }
 {r        : yaw-rate [rad/s] or [deg/s]                         }
  psi      : yaw-angle [rad] or [deg]
  theta    : pitch-angle [rad] or [deg]
  phi      : roll-angle [rad] or [deg]
 {xe       : X-coordinate in Earth-axes [m]                      }
 {ye       : Y-coordinate in Earth-axes [m]                      }
 {H        : altitude [m]                                        }

  Vdot     : time-derivative of airspeed [m/s^2]
  alphadot : time-derivative of alpha [rad/s] or [deg/s]
  betadot  : time-derivative of beta [rad/s] or [deg/s]
 {pdot     : time-derivative of p [rad/s^2] or [deg/s^2]         }
 {qdot     : time-derivative of q [rad/s^2] or [deg/s^2]         }
 {rdot     : time-derivative of r [rad/s^2] or [deg/s^2]         }
 {psidot   : time-derivative of psi [rad/s] or [deg/s]           }
 {thetadot : time-derivative of theta [rad/s] or [deg/s]         }
 {phidot   : time-derivative of phi [rad/s] or [deg/s]           }
 {xedot    : time-derivative of xe [m/s]                         }
 {yedot    : time-derivative of ye [m/s]                         }
  Hdot     : time-derivative of H [m/s]

  Fx       : total external force along XB-axis [N]
  Fy       : total external force along YB-axis [N]
  Fz       : total external force along ZB-axis [N]

  Xgr      : gravity force along XB-axis [N]
  Ygr      : gravity force along YB-axis [N]
  Zgr      : gravity force along ZB-axis [N]

The variables which are not used by any of the masked subsystems
within the subsystem 'Additional Outputs' have been bracketed be-
tween accolades. Of the vector yhlp, only sin(alpha), cos(alpha),
sin(beta), and cos(beta) are used within the subsystem 'Additional
Outputs'.

Outputs from the subsystem 'Additional Outputs':
================================================
  yfp  = [gamma fpa chi Phi]'             (flightpath parameters)

  yuvw = [udot vdot wdot]'  (time-derivatives (!) of u, v, and w)

  yacc = [Ax Ay Az axk ayk azk]'    (specific forces and accele-
                                                         rations)

where:

  gamma    : flightpath angle [rad] or [deg]
  fpa      : flightpath acceleration [m/s^2]
  chi      : azimuth angle [rad] or [deg]
  Phi      : bank angle [rad] or [deg]

  udot     : time-derivative of u [m/s^2]
  vdot     : time-derivative of v [m/s^2]
  wdot     : time-derivative of w [m/s^2]

  Ax       : specific force along XB-axis [g]
  Ay       : specific force along YB-axis [g]
  Az       : specific force along ZB-axis [g]
  axk      : kinematic acceleration along XB-axis [g]
  ayk      : kinematic acceleration along YB-axis [g]
  azk      : kinematic acceleration along ZB-axis [g]

Note: the time-derivatives of the body-axes velocity components,
udot, vdot, and wdot, are not needed for solving the equations of
motion, because the true airspeed V, angle of attack alpha, and
sideslip angle beta have been used as state variables in stead of
u, v, and w.

Variables which must be set in Matlab workspace:
================================================
  GM1      : Vector which contains some basic geometrical pro-
             perties of the aircraft, as well as its mass (which
             is considered to be constant during the motions of
             interest). Here, the value of the mass is needed
             by the masked subsystem block ACCEL. GM1 can be loa-
             ded to workspace from file by the routine LOADER.M.
             Use MODBUILD.M first if the datafile does not yet
             exist. Type HELP LOADER or HELP MODBUILD for more
             info.

  xinco    : Initial value of state vector. The block FLPATH ex-
             tracts the initial value of the angle of attack from
             xinco, in order to compute the bank angle. Type HELP
             ACTRIM at the Matlab command line for more info
             about the determination of steady-state trimmed
             flight conditions. If datafiles with initial condi-
             tions exist, uses INCOLOAD.M to retrieve them. Type
             HELP INCOLOAD for more info.

More info:
==========
See FLPATH.HLP, ACCEL.HLP, and UVWDOT.HLP for more info about the
masked subsystem blocks, contained in 'Additional Outputs'. See
HLPFCN.HLP, FMSORT.HLP, and GRAVITY.HLP for more info about the
inputvectors to this subsystem.

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The FDC toolbox, Copyright Marc Rauw 1994-1998.