Path: Interplanetary/Optimization
% Compute optimal planar trajectory, direct method, with fmincon.
Fixed-time transfer between two circular, heliocentric orbits with electric
propulsion. The cost function is the total mass of the vehicle. Requires
the Optimization Toolbox from Mathworks. A plot display shows the
progress of the optimization.
Specific combinations of parameters may not provide a solution. fmincon will
fail to converge in that case. The power is calculated from the thrust,
exhaust velocity, and thrust efficiency. The engine mass is calculated from
the specific power.
P = 0.5 T*uE/eta
mE = P/sigma
The total mass is
m0 = mP + (1 + f)*mF + mE
where mP is the mass of the payload, f is the fuel structural fraction, and mE
is the mass of the engine.
Type PlanarHelioOptimal for a demo to Mars. Display mode can be 'off',
'iter', 'iter-detailed', 'notify', or 'final'. 'off' or 'final' will also
turn off the plot display.
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Form:
d0 = PlanarHelioOptimal
[phi, thrust, t, data] = PlanarHelioOptimal( d, maxIter, iterDisp )
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Inputs
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d (.) Data structure
.uE Exhaust velocity
.r0 Initial radius
.rF Final radius
.mu Gravitational parameter of the sun
.f Fuel structural fraction
.tF Final time (s)
.eta Thrust efficiency
.sigma Specific power (W/kg)
.scale [distance; v radial; v tangential]
.dVF Additional velocity to allow at final
maxIter (1) Maximum number of iterations (default 8000)
iterDisp ('') Display mode, default 'iter-detailed'
thrust0 (1) Initial thrust, optional
phi0 (:) Initial angles, optional
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Outputs
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phi (1,n) Thrust angle (rad)
t (1,n) Times (s)
thrust (1,1) Thrust (N)
data (.) Results data structure
.p (1,1) Power (W)
.mD (1,1) Dry mass (kg)
.mF (1,1) Fuel mass (kg)
.dV (1,1) Delta-V (km/s)
.dF (1,1) Final distance achieved (km)
.vF (1,1) Final velocity achieved (km/s)
.xEnd (5,1) Final state [u,v,r,mF,theta]
.cEq (3,1) Equality constraints
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See also SimulatePlanarHelioTrajectory, PlanarHelioOptimalSlidingTime,
ThrustElectric
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Interplanetary: Optimization/RHS2DCylindricalOrbit Interplanetary: Optimization/SimulatePlanarHelioTrajectory StraightLine: ConstantAccel/ThrustElectric StraightLine: ConstantThrust/DVConstantThrust Common: Database/Constant Math: Linear/Mag
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