Path: CubeSat/Simulation
% Right-hand-side for a CubeSat orbit and attitude dynamical model.
Includes drag and optical surface disturbances, magnetic dipole,
gravity gradient, rigid body dynamics and power. Uses the J70
atmosphere model and applies a point-mass gravity model. Computes sun
location with SunV1 and accounts for eclipses from the Earth. The
surface parameters in surfData are passed to both the optical and
aerodynamic disturbance model functions.
The states are [position;velocity;quaternion;angular velocity; battery charge].
The battery charge must always be the last state. Its units are J. If there
are wheel states they must be between the spacecraft angular velocity and the
battery charge, and the indices be logged in kWheels.
Can output the disturbance forces and torques for post-processing.
There is also a call to retrieve the default data structure.
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Form:
[xDot,dist,power] = RHSCubeSat( x, t, d )
d = RHSCubeSat
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Inputs
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x (14,1) [r;v;q;w;wRWA;b]
t (1,1) Time, sec
d (.) Data structure
.jD0 (1,1) Julian date of epoch
.mass (1,1) Spacecraft mass (kg)
.inertia (3,3) Inertia matrix (kg-m2)
.dipole (3,1) Residual dipole (ATM^2)
.power (.) Power data, see SolarCellPower
.aeroModel * Handle, see CubeSatAero
.opticalModel * Handle, see CubeSatRadiationPressure
.surfData (.) optional; empty to skip drag/optical calcs
.cD (3,1) Drag coefficient
.cM (3,1) Center of mass (m)
.area (1,n) Area (m2)
.nFace (3,n) Face normals
.rFace (3,n) Face locations (m)
.att (.) Attitude model
.sigma (3,n) Optical coefficients
.planet (1) Planet effects flag
.atm (.) optional; empty to skip J70 and use AtmDens2
.kWheels (n), empty if no wheels, indices of wRWA
.inertiaRWA (1,1), optional, polar inertia (kg-m2)
.tRWA (3,1), optional, wheel torque (Nm)
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Outputs
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x (14,1) d[r;v;q;w;b]/dt
dist (.) Disturbances data
.fTotal (3,1) Total force, ECI frame (N)
.tTotal (3,1) Total torque, body frame (Nm)
.fAerodyn (3,1) Aerodynamic force
.tAerodyn (3,1) Aerodynamic torque
.fOptical (3,1) Optical force
.tOptical (3,1) Optical torque
.tMag (3,1) Magnetic torque
.tGG (3,1) Gravity gradient torque
power (1,1) Power from solar cells (W)
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See also SolarCellPower, CubeSatAero, CubeSatRadiationPressure,
SolarFluxPrediction, CubeSatEnvironment, CubeSatSimulation,
CubeSatRWASimulation
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AeroUtils: Coord/QIToBDot Common: Quaternion/QForm Common: Time/Date2JD CubeSat: Power/SolarCellPower CubeSat: Simulation/CubeSatAero CubeSat: Simulation/CubeSatEnvironment CubeSat: Simulation/CubeSatRadiationPressure Math: Linear/Cross Math: Linear/Mag SC: Disturbances/GravityGradientFromR SC: Environs/SolarFluxPrediction
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