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Build up a 3D spacecraft model. You can enter vertices and faces
directly or geometric primitives:
'antenna'
'box'
'cylinder'
'ellipsoid'
'rwa'
'surface of revolution'
'triangle'
'truss'
When entering mass properties the various vectors for each component
are defined as follows
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--- rA --- b --- rB ---
|
rB is the position of the component origin wrt the point of rotation
b is the rotation matrix
rA is the position of the rotation point wrt the origin of the body
rOffset is a vector used to temporarily move the component (after all
of the above) to the right position in the picture
bOffset is a transformation matrix to temporarily rotate the component
The last two are not used outside of Build3DSC.
When you create a body, bHinge is the rotation structure at the hinge
It may be of the form
bHinge.b (3,3) Transformation matrix
.q (4,1) Quaternion
.a (3,1) Unit Vector
.angle (1,1) Angle about the unit vector
You must include the last two to use a rotation angle.
Build3DSC will compute the total body mass properties and attach the
data structure .mass which is
mass.mass (1,1) mass
mass.cM (3,1) center-of-mass
mass.inertia (3,3) inertia matrix
If you do not wish to use the computed body mass properties, you can manually
alter the output structure.
The commands you use from the script are:
'init' The first command
'add' Once for each component
'add body' After all components are entered
'add units' Any time but always prior to 'compute paths'
'add name' Any time
'add qecitobody' Any time
'add reci' Any time
'add veci' Any time
'add omega' Any time
'add qlvlh' Any time
'compute paths' Always last. You need to 'add units' prior to using this
'component list' Any time
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Form:
g = Build3DSC( mode, gNew, gX )
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Inputs
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mode (1,:) See above
gNew If 'add' Spacecraft image data structure
.name
.rOffset (3,1) Offset from reference
.bOffset (3,1) Rotation wrt reference axes
.faceColor (1,3) Color of faces. available colors are:
'solar cell', 'mirror', 'gold foil', 'aluminum', 'steel',
'aluminum truss', 'radiator', 'white', 'black', 'magenta'
more colors can be added in the SetColor subfunction
.specularExponent (1,1) SpecularExponent
.specularColorReflectance (1,3) specularColorReflectance,...
.rB (3,1) Location of reference pt wrt rotation point
.rA (3,1) Location wrt origin after rotation
.b (3,3) Transformation matrix
and
.v (:,3) Vertex list
.f (:,:) Face list
or
.type (1,:) 'antenna', 'box', 'cylinder', 'ellipsoid',
'rwa', 'surface of revolution', 'truss'
.info (:) Parameters defining the geometric solid
.optical .sigmaT (1,1) Transmission coefficient
.sigmaA (1,1) Absorption coefficient
.sigmaD (1,1) Diffuse reflection coefficient
.sigmaS (1,1) Specular reflection coefficient
.thermal .alpha (1,1) Absorptivity
.epsilon (1,1) Emissivity
.cP (1,1) Specific heat
.temperature (1,1) Temperature (deg-K)
.magnetic .dipole (3,1) Dipole
.aero
.cD (1,1) Drag coefficient
.sigmaN (1,1) Normal surface accommodation coefficient
.sigmaT (1,1) Tangential surface accommodation coefficient
.mass .mass (1,1) Mass
.inertia (3,3) Inertia matrix
.cM (3,1) Center of mass wrt origin
.rF .flux (1,1) flux
.u (3,1) Unit vector
.r (3,1) Vector from reference to rF centroid
.inside If included the component is considered
to be inside the spacecraft and will
not be used in aero or optical disturbance
calculations.
'add units' (1,:) ''m' 'in' 'ft'
'add name' (1,:) any name
'add qecitobody' (4,1) Quaternion from ECI to Body
'add reci' (3,1) Vector origin to spacecraft in ECI coordinates
'add veci' (3,1) Velocity in the ECI frame
'add omega' (3,1) Angular velocity in the body frame
'add qlvlh' (4,1) Quaternion from ECI to LVLH (local vertical local horizontal coordinates)
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Outputs
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g Output
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