def __init__(self, mass=1000, Tmax=0.1, Isp=2500, Vinf=3.0, nseg=20):
# First we call the constructor for the base PyGMO problem
# (dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_earth_mars_sundmann,
self).__init__(7 + nseg * 3, 0, 1, 9 + nseg, nseg + 1, 1e-4)
# We then define some data members (we use the double underscore to
# indicate they are private)
from PyKEP import MU_SUN, AU
from PyKEP.planets import jpl_lp
from PyKEP.sims_flanagan import spacecraft, leg_s
self.__earth = jpl_lp('earth')
self.__mars = jpl_lp('jupiter')
self.__sc = spacecraft(mass, Tmax, Isp)
self.__Vinf = Vinf * 1000
# here we construct the trajectory leg in Sundman's variable t =
# (r/10AU)^1.5 s
self.__leg = leg_s(nseg, 1.0 / (100 * AU)**1.0, 1.0)
self.__leg.set_mu(MU_SUN)
self.__leg.set_spacecraft(self.__sc)
# This is needed to use the plotting function plot_sf_leg
self.__leg.high_fidelity = False
self.__nseg = nseg
# The bounds on Sundman's variable can be evaluated considering
# circular orbits at r=1AU and r=0.7AU (for example)
self.set_bounds([
5000, 2400, 10000, self.__sc.mass / 10, -self.__Vinf,
-self.__Vinf, -self.__Vinf
] + [-1] * 3 * nseg, [
8000, 2500, 150000, self.__sc.mass, self.__Vinf, self.__Vinf,
self.__Vinf
] + [1] * 3 * nseg)
def __init__(self, mass=1000, Tmax=0.1, Isp=2500, Vinf=3.0, nseg=20):
# First we call the constructor for the base PyGMO problem
# (dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_earth_mars_sundmann, self).__init__(7 + nseg * 3, 0, 1, 9 + nseg, nseg + 1, 1e-4)
# We then define some data members (we use the double underscore to
# indicate they are private)
from PyKEP import MU_SUN, AU
from PyKEP.planets import jpl_lp
from PyKEP.sims_flanagan import spacecraft, leg_s
self.__earth = jpl_lp('earth')
self.__mars = jpl_lp('jupiter')
self.__sc = spacecraft(mass, Tmax, Isp)
self.__Vinf = Vinf * 1000
# here we construct the trajectory leg in Sundman's variable t =
# (r/10AU)^1.5 s
self.__leg = leg_s(nseg, 1.0 / (100 * AU) ** 1.0, 1.0)
self.__leg.set_mu(MU_SUN)
self.__leg.set_spacecraft(self.__sc)
# This is needed to use the plotting function plot_sf_leg
self.__leg.high_fidelity = False
self.__nseg = nseg
# The bounds on Sundman's variable can be evaluated considering
# circular orbits at r=1AU and r=0.7AU (for example)
self.set_bounds([5000, 2400, 10000, self.__sc.mass / 10, -self.__Vinf, -self.__Vinf, -self.__Vinf] + [-1]
* 3 * nseg, [8000, 2500, 150000, self.__sc.mass, self.__Vinf, self.__Vinf, self.__Vinf] + [1] * 3 * nseg)
def __init__(self, mass=2000, Tmax=0.5, Isp=3500, Vinf_dep=3, Vinf_arr=2, nseg1=5, nseg2=20):
#First we call the constructor for the base PyGMO problem
#(dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_EVMe,self).__init__(17 + 3 * (nseg1+nseg2), 0, 1, 14 + 1 + nseg1+nseg2 + 3, nseg1+nseg2 + 3, 1e-4)
#We then define some data members (we use the double underscore to indicate they are private)
from PyKEP import planet_ss, MU_SUN
from PyKEP.sims_flanagan import spacecraft, leg
self.__earth = planet_ss('earth')
self.__venus = planet_ss('venus')
self.__mercury = planet_ss('mercury')
self.__sc = spacecraft(mass,Tmax,Isp)
self.__Vinf_dep = Vinf_dep*1000
self.__Vinf_arr = Vinf_arr*1000
self.__leg1 = leg()
self.__leg2 = leg()
self.__leg1.set_mu(MU_SUN)
self.__leg1.set_spacecraft(self.__sc)
self.__leg2.set_mu(MU_SUN)
self.__leg2.set_spacecraft(self.__sc)
self.__nseg1 = nseg1
self.__nseg2 = nseg2
#And the box-bouds (launch windows, allowed velocities etc.)
lb = [3000,100,mass/2] + [-self.__Vinf_dep]*3 + [-6000]*3 + [200,mass/9] + [-6000]*3 + [-self.__Vinf_arr]*3 + [-1,-1,-1] * (nseg1+nseg2)
ub = [4000,1000,mass] + [self.__Vinf_dep]*3 + [6000]*3 + [2000,mass] + [6000]*3 + [ self.__Vinf_arr]*3 + [1,1,1] * (nseg1+nseg2)
self.set_bounds(lb,ub)
def __init__(self, mass=1000, Tmax=0.05, Isp=2500, Vinf=3.0, nseg=20):
# First we call the constructor for the base PyGMO problem
# (dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_earth_mars, self).__init__(6 + nseg * 3, 0, 1,
8 + nseg, nseg + 1, 1e-4)
# We then define some data members (we use the double underscore to
# indicate they are private)
from PyKEP import MU_SUN
from PyKEP.planet import jpl_lp
from PyKEP.sims_flanagan import spacecraft, leg
self.__earth = jpl_lp('earth')
self.__mars = jpl_lp('mars')
self.__sc = spacecraft(mass, Tmax, Isp)
self.__Vinf = Vinf * 1000
self.__leg = leg()
self.__leg.set_mu(MU_SUN)
self.__leg.set_spacecraft(self.__sc)
self.__nseg = nseg
self.set_bounds([
2480, 2400, self.__sc.mass / 10, -self.__Vinf, -self.__Vinf,
-self.__Vinf
] + [-1] * 3 * nseg, [
2490, 2500, self.__sc.mass, self.__Vinf, self.__Vinf,
self.__Vinf
] + [1] * 3 * nseg)
def __init__(self, mass=2000, Tmax=0.5, Isp=3500, Vinf_dep=3, Vinf_arr=2, nseg1=5, nseg2=20):
# First we call the constructor for the base PyGMO problem
# (dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_EVMe, self).__init__(17 + 3 * (nseg1 + nseg2),
0, 1, 14 + 1 + nseg1 + nseg2 + 3, nseg1 + nseg2 + 3, 1e-4)
# We then define some data members (we use the double underscore to
# indicate they are private)
from PyKEP import MU_SUN
from PyKEP.planets import jpl_lp
from PyKEP.sims_flanagan import spacecraft, leg
self.__earth = jpl_lp('earth')
self.__venus = jpl_lp('venus')
self.__mercury = jpl_lp('mercury')
self.__sc = spacecraft(mass, Tmax, Isp)
self.__Vinf_dep = Vinf_dep * 1000
self.__Vinf_arr = Vinf_arr * 1000
self.__leg1 = leg()
self.__leg2 = leg()
self.__leg1.set_mu(MU_SUN)
self.__leg1.set_spacecraft(self.__sc)
self.__leg2.set_mu(MU_SUN)
self.__leg2.set_spacecraft(self.__sc)
self.__nseg1 = nseg1
self.__nseg2 = nseg2
# And the box-bounds (launch windows, allowed velocities, etc.)
lb = [3000, 100, mass / 2] + [-self.__Vinf_dep] * 3 + [-6000] * 3 + [200, mass / 9] + [-6000] * 3 + [-self.__Vinf_arr] * 3 + [-1, -1, -1] * (nseg1 + nseg2)
ub = [4000, 1000, mass] + [self.__Vinf_dep] * 3 + [6000] * 3 + [2000, mass] + [6000] * 3 + [self.__Vinf_arr] * 3 + [1, 1, 1] * (nseg1 + nseg2)
self.set_bounds(lb, ub)
def __init__(
self,
t=[epoch(8.233141758995751e+003),
epoch(8.289990617468195e+003)],
r=[[-660821073.83843112, -85286653.193055451, -3513417.5052384529],
[-660832082.91625774, -85197143.615338504,
-3513971.6825616611]],
v=[[7873.9701471924709, -16990.277371090539, -58.967610944493998],
[7869.0526122101373, -16988.601525093596, -58.937906751346844]],
m0=2000,
Tmax=0.1,
Isp=2000,
mu=MU_JUPITER,
n_seg=10,
high_fidelity=False,
optimize_mass=False):
"""
USAGE: one_lt_leg(t = [epoch(8.233141758995751e+003), epoch(8.289990617468195e+003)],
r = [[-660821073.83843112, -85286653.193055451, -3513417.5052384529], [-660832082.91625774, -85197143.615338504, -3513971.6825616611]],
v = [[7873.9701471924709, -16990.277371090539, -58.967610944493998], [7869.0526122101373, -16988.601525093596, -58.937906751346844]],
m0 = 2000,
Tmax = 0.1,
Isp = 2000,
mu = MU_JUPITER,
n_seg = 10,
high_fidelity = False)
* t: starting and final epochs
* r: starting and final position (m)
* v: starting and final velocity (m/s)
* m0: starting mass (k)
* Tmax: maximum allowed thrust (N)
* Isp: specific impulse (s)
* mu = central body gravity parameter (m^3/s^2)
* n_seg = number of segments,
* high_fidelity = compute the trajectory in high fidelity mode
* optimize_mass = when False the problem is built as a constraint satisfaction problem. When True mass gets optimized
"""
self.__t = t
self.__r = r
self.__v = v
self.__opt_mass = optimize_mass
self.__sc = spacecraft(m0, Tmax, Isp)
self.__leg = leg()
self.__leg.set_mu(mu)
self.__leg.set_spacecraft(self.__sc)
self.__leg.high_fidelity = high_fidelity
dim = 1 + n_seg * 3
c_dim = n_seg + 7
#First we call the constructor for the base PyGMO problem
#As our problem is n dimensional, box-bounded (may be multi-objective), we write
#(dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(one_lt_leg, self).__init__(dim, 0, 1, c_dim, n_seg, 1e-4)
#And we compute the bounds
lb = [m0 / 2] + [-1.0] * n_seg * 3
ub = [m0] + [1.0] * n_seg * 3
self.set_bounds(lb, ub)
def __init__(self, t = [epoch(8.233141758995751e+003), epoch(8.289990617468195e+003)], r = [[-660821073.83843112, -85286653.193055451, -3513417.5052384529], [-660832082.91625774, -85197143.615338504, -3513971.6825616611]], v = [[7873.9701471924709, -16990.277371090539, -58.967610944493998], [7869.0526122101373, -16988.601525093596, -58.937906751346844]], m0 = 2000, Tmax = 0.1, Isp = 2000, mu = MU_JUPITER, n_seg = 10, high_fidelity = False, optimize_mass = False ): """ USAGE: one_lt_leg(t = [epoch(8.233141758995751e+003), epoch(8.289990617468195e+003)], r = [[-660821073.83843112, -85286653.193055451, -3513417.5052384529], [-660832082.91625774, -85197143.615338504, -3513971.6825616611]], v = [[7873.9701471924709, -16990.277371090539, -58.967610944493998], [7869.0526122101373, -16988.601525093596, -58.937906751346844]], m0 = 2000, Tmax = 0.1, Isp = 2000, mu = MU_JUPITER, n_seg = 10, high_fidelity = False) * t: starting and final epochs * r: starting and final position (m) * v: starting and final velocity (m/s) * m0: starting mass (k) * Tmax: maximum allowed thrust (N) * Isp: specific impulse (s) * mu = central body gravity parameter (m^3/s^2) * n_seg = number of segments, * high_fidelity = compute the trajectory in high fidelity mode * optimize_mass = when False the problem is built as a constraint satisfaction problem. When True mass gets optimized """ self.__t = t self.__r = r self.__v = v self.__opt_mass = optimize_mass self.__sc = spacecraft(m0,Tmax,Isp) self.__leg = leg() self.__leg.set_mu(mu) self.__leg.set_spacecraft(self.__sc) self.__leg.high_fidelity = high_fidelity dim = 1 + n_seg * 3 c_dim = n_seg + 7 #First we call the constructor for the base PyGMO problem #As our problem is n dimensional, box-bounded (may be multi-objective), we write #(dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation) super(one_lt_leg,self).__init__(dim,0,1,c_dim,n_seg,1e-4) #And we compute the bounds lb = [m0/2] + [-1.0] * n_seg * 3 ub = [m0] + [1.0] * n_seg * 3 self.set_bounds(lb,ub)
def __init__(self,mass=1000,Tmax=0.05,Isp=2500,Vinf=3.0,nseg=20):
#First we call the constructor for the base PyGMO problem
#(dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_earth_mars,self).__init__(6 + nseg*3,0,1,8 + nseg,nseg+1,1e-4)
#We then define some data members (we use the double underscore to indicate they are private)
from PyKEP import planet_ss, MU_SUN
from PyKEP.sims_flanagan import spacecraft, leg
self.__earth = planet_ss('earth')
self.__mars = planet_ss('mars')
self.__sc = spacecraft(mass,Tmax,Isp)
self.__Vinf = Vinf*1000
self.__leg = leg()
self.__leg.set_mu(MU_SUN)
self.__leg.set_spacecraft(self.__sc)
self.__nseg = nseg
self.set_bounds([2480,2400,self.__sc.mass/10,-self.__Vinf,-self.__Vinf,-self.__Vinf] + [-1] * 3 *nseg,[2490,2500,self.__sc.mass,self.__Vinf,self.__Vinf,self.__Vinf] + [1] * 3 * nseg)
def __init__(self, mass=1000, Tmax=0.05, Isp=2500, Vinf=3.0, nseg=20):
# First we call the constructor for the base PyGMO problem
# (dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_earth_mars, self).__init__(
6 + nseg * 3, 0, 1, 8 + nseg, nseg + 1, 1e-4
)
self.earth = jpl_lp('earth')
self.mars = jpl_lp('mars')
self.sc = spacecraft(mass, Tmax, Isp)
self.Vinf = Vinf * 1000
self.leg = leg()
self.leg.set_mu(MU_SUN)
self.leg.set_spacecraft(self.sc)
self.nseg = nseg
self.set_bounds(
[2480, 2400, self.sc.mass / 10, -self.Vinf, -self.Vinf, -self.Vinf] + [-1]* 3 * nseg,
[2490, 2500, self.sc.mass, self.Vinf, self.Vinf, self.Vinf] + [1] * 3 * nseg
)
def _pl2pl_fixed_time_ctor(self, ast0=gtoc7(7422), ast1=gtoc7(14254), t0=epoch(9818),
t1=epoch(10118), sc=spacecraft(2000, 0.3, 3000), n_seg=5, obj="fin_m"):
"""
Constructs a Planet 2 Planet problem with fixed time.
Chromosome is defined as:
x = [m_f, Th_0_x, Th_0_y, Th_0_z, .., Th_n_x, Th_n_y, Th_n_z]
, where 'm_f' is the final mass, while 'Th_i_j' is the throttle component in direction 'j' (x,y,z) for the 'i'-th segment.
USAGE: problem.pl2pl_fixed_time(ast0=gtoc7(7422), ast1=gtoc7(14254), t0=epoch(9818),
t1=epoch(10118), sc=spacecraft(2000, 0.3, 3000), n_seg = 5)
* ast0: first planet
* ast0: second planet
* t0: departure epoch (from planet ast0)
* t1: arrival epoch (to planet ast1)
* sc: spacecraft object
* n_seg: number of segments
"""
# We construct the arg list for the original constructor exposed by
# boost_python
from PyGMO.problem._problem import _pl2pl2_fixed_time_objective
def objective(x):
return {
"fin_m": _pl2pl2_fixed_time_objective.FIN_M,
"crit_m": _pl2pl2_fixed_time_objective.FIN_INI_M
}[x]
arg_list = []
arg_list.append(ast0)
arg_list.append(ast1)
arg_list.append(t0)
arg_list.append(t1)
arg_list.append(sc)
arg_list.append(n_seg)
arg_list.append(objective(obj))
self._orig_init(*arg_list)
def __init__(self,
seq = [planet_ss('earth'),planet_ss('venus'),planet_ss('earth')],
n_seg = [10]*2,
t0 = [epoch(0),epoch(1000)],
tof = [[200,500],[200,500]],
vinf_dep=2.5,
vinf_arr=2.0,
mass=4000.0,
Tmax=1.0,
Isp=2000.0,
fb_rel_vel = 6,
multi_objective = False,
high_fidelity=False):
"""
prob = mga_lt_nep(seq = [planet_ss('earth'),planet_ss('venus'),planet_ss('earth')], n_seg = [10]*2,
t0 = [epoch(0),epoch(1000)], T = [[200,500],[200,500]], Vinf_dep=2.5, Vinf_arr=2.0, mass=4000.0, Tmax=1.0, Isp=2000.0,
multi_objective = False, fb_rel_vel = 6, high_fidelity=False)
* seq: list of PyKEP.planet defining the encounter sequence for the trajectoty (including the initial planet)
* n_seg: list of integers containing the number of segments to be used for each leg (len(n_seg) = len(seq)-1)
* t0: list of PyKEP epochs defining the launch window
* tof: minimum and maximum time of each leg (days)
* vinf_dep: maximum launch hyperbolic velocity allowed (in km/sec)
* vinf_arr: maximum arrival hyperbolic velocity allowed (in km/sec)
* mass: spacecraft starting mass
* Tmax: maximum thrust
* Isp: engine specific impulse
* fb_rel_vel = determines the bounds on the maximum allowed relative velocity at all fly-bys (in km/sec)
* multi-objective: when True defines the problem as a multi-objective problem, returning total DV and time of flight
* high_fidelity = makes the trajectory computations slower, but actually dynamically feasible.
"""
#1) We compute the problem dimensions .... and call the base problem constructor
self.__n_legs = len(seq) - 1
n_fb = self.__n_legs - 1
# 1a) The decision vector length
dim = 1 + self.__n_legs * 8 + sum(n_seg) * 3
# 1b) The total number of constraints (mismatch + fly-by + boundary + throttles
c_dim = self.__n_legs * 7 + n_fb * 2 + 2 + sum(n_seg)
# 1c) The number of inequality constraints (boundary + fly-by angle + throttles)
c_ineq_dim = 2 + n_fb + sum(n_seg)
# 1d) the number of objectives
f_dim = multi_objective + 1
#First we call the constructor for the base PyGMO problem
#As our problem is n dimensional, box-bounded (may be multi-objective), we write
#(dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_nep,self).__init__(dim,0,f_dim,c_dim,c_ineq_dim,1e-4)
#2) We then define some class data members
#public:
self.seq = seq
#private:
self.__n_seg = n_seg
self.__vinf_dep = vinf_dep*1000
self.__vinf_arr = vinf_arr*1000
self.__sc = spacecraft(mass,Tmax,Isp)
self.__leg = leg()
self.__leg.set_mu(MU_SUN)
self.__leg.set_spacecraft(self.__sc)
self.__leg.high_fidelity = high_fidelity
fb_rel_vel*=1000
#3) We compute the bounds
lb = [t0[0].mjd2000] + [0, mass / 2, -fb_rel_vel, -fb_rel_vel, -fb_rel_vel, -fb_rel_vel, -fb_rel_vel, -fb_rel_vel] * self.__n_legs + [-1,-1,-1] * sum(self.__n_seg)
ub = [t0[1].mjd2000] + [1, mass, fb_rel_vel, fb_rel_vel, fb_rel_vel, fb_rel_vel, fb_rel_vel, fb_rel_vel] * self.__n_legs + [1,1,1] * sum(self.__n_seg)
#3a ... and account for the bounds on the vinfs......
lb[3:6] = [-self.__vinf_dep]*3
ub[3:6] = [self.__vinf_dep]*3
lb[-sum(self.__n_seg)*3-3:-sum(self.__n_seg)*3] = [-self.__vinf_arr]*3
ub[-sum(self.__n_seg)*3-3:-sum(self.__n_seg)*3] = [self.__vinf_arr]*3
# 3b... and for the time of flight
lb[1:1+8*self.__n_legs:8] = [el[0] for el in tof]
ub[1:1+8*self.__n_legs:8] = [el[1] for el in tof]
#4) And we set the bounds
self.set_bounds(lb,ub)
def __init__(self, seq = [ganymede,europa], tf = epoch(8.174621347386377e+03), vf = [-1610.7520437617632, 5106.5676929998444, 122.39394967587651], n_seg = [10]*2, m0 = 2000, Tmax = 0.1, Isp = 2000, mu = MU_JUPITER, high_fidelity = False, obj = 'none' ): """ USAGE: mga_incipit_lt(seq = [io,io], t0 = [epoch(7305.0),epoch(11323.0)], tof = [[100,200],[3,200]]) * seq: list of jupiter moons defining the trajectory incipit * t0: list of two epochs defining the launch window * tof: list of n lists containing the lower and upper bounds for the legs flight times (days) * n_seg: list containing the number of segments for each leg * m0: starting mass (k) * Tmax: maximum allowed thrust (N) * Isp: specific impulse (s) * high_fidelity = compute the trajectory in high fidelity mode """ #1) We compute the problem dimensions .... and call the base problem constructor self.__n_legs = len(seq) n_fb = self.__n_legs - 1 # 1a) The decision vector length dim = self.__n_legs * 8 + sum(n_seg) * 3 - 1 # 1b) The total number of constraints (mismatch + fly-by + boundary + throttles c_dim = self.__n_legs * 7 + n_fb * 2 + 1 + sum(n_seg) # 1c) The number of inequality constraints (fly-by angle + throttles) c_ineq_dim = n_fb + sum(n_seg) # 1d) the number of objectives f_dim = 1 #First we call the constructor for the base PyGMO problem #As our problem is n dimensional, box-bounded (may be multi-objective), we write #(dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation) super(mga_incipit_lt,self).__init__(dim,0,f_dim,c_dim,c_ineq_dim,1e-4) #2) We then define some class data members #public: self.seq = seq self.obj = obj self.vf = vf self.tf = tf.mjd2000 #private: self.__n_seg = n_seg self.__sc = spacecraft(m0,Tmax,Isp) self.__leg = leg() self.__leg.set_mu(mu) self.__leg.set_spacecraft(self.__sc) self.__leg.high_fidelity = high_fidelity #3) We compute the bounds lb = ( [-4*pi, -pi] + [0, m0 / 1.5, -10000, -10000, -10000, -10000, -10000, -10000] * (self.__n_legs - 1) + [0, m0 / 1.5, -10000, -10000, -10000] + [-1,-1,-1] * sum(self.__n_seg) ) ub = ( [4*pi,pi] + [1, m0, 10000, 10000, 10000, 10000, 10000, 10000] * (self.__n_legs - 1) + [1, m0, 10000, 10000, 10000] + [1,1,1] * sum(self.__n_seg) ) #3a ... and account for the bounds on the starting velocity lb[4:7] = [-3400.0]*3 ub[4:7] = [3400.0]*3 # 3b... and for the time of flight lb[2:2+8*self.__n_legs:8] = [1]*len(seq) ub[2:2+8*self.__n_legs:8] = [700]*len(seq) #4) And we set the bounds self.set_bounds(lb,ub)
def __init__(
self,
seq=[planet_ss('earth'),
planet_ss('venus'),
planet_ss('earth')],
n_seg=[10] * 2,
t0=[epoch(0), epoch(1000)],
tof=[[200, 500], [200, 500]],
vinf_dep=2.5,
vinf_arr=2.0,
mass=4000.0,
Tmax=1.0,
Isp=2000.0,
fb_rel_vel=6,
multi_objective=False,
high_fidelity=False):
"""
prob = mga_lt_nep(seq = [planet_ss('earth'),planet_ss('venus'),planet_ss('earth')], n_seg = [10]*2,
t0 = [epoch(0),epoch(1000)], T = [[200,500],[200,500]], Vinf_dep=2.5, Vinf_arr=2.0, mass=4000.0, Tmax=1.0, Isp=2000.0,
multi_objective = False, fb_rel_vel = 6, high_fidelity=False)
* seq: list of PyKEP.planet defining the encounter sequence for the trajectoty (including the initial planet)
* n_seg: list of integers containing the number of segments to be used for each leg (len(n_seg) = len(seq)-1)
* t0: list of PyKEP epochs defining the launch window
* tof: minimum and maximum time of each leg (days)
* vinf_dep: maximum launch hyperbolic velocity allowed (in km/sec)
* vinf_arr: maximum arrival hyperbolic velocity allowed (in km/sec)
* mass: spacecraft starting mass
* Tmax: maximum thrust
* Isp: engine specific impulse
* fb_rel_vel = determines the bounds on the maximum allowed relative velocity at all fly-bys (in km/sec)
* multi-objective: when True defines the problem as a multi-objective problem, returning total DV and time of flight
* high_fidelity = makes the trajectory computations slower, but actually dynamically feasible.
"""
#1) We compute the problem dimensions .... and call the base problem constructor
self.__n_legs = len(seq) - 1
n_fb = self.__n_legs - 1
# 1a) The decision vector length
dim = 1 + self.__n_legs * 8 + sum(n_seg) * 3
# 1b) The total number of constraints (mismatch + fly-by + boundary + throttles
c_dim = self.__n_legs * 7 + n_fb * 2 + 2 + sum(n_seg)
# 1c) The number of inequality constraints (boundary + fly-by angle + throttles)
c_ineq_dim = 2 + n_fb + sum(n_seg)
# 1d) the number of objectives
f_dim = multi_objective + 1
#First we call the constructor for the base PyGMO problem
#As our problem is n dimensional, box-bounded (may be multi-objective), we write
#(dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_lt_nep, self).__init__(dim, 0, f_dim, c_dim, c_ineq_dim,
1e-4)
#2) We then define some class data members
#public:
self.seq = seq
#private:
self.__n_seg = n_seg
self.__vinf_dep = vinf_dep * 1000
self.__vinf_arr = vinf_arr * 1000
self.__sc = spacecraft(mass, Tmax, Isp)
self.__leg = leg()
self.__leg.set_mu(MU_SUN)
self.__leg.set_spacecraft(self.__sc)
self.__leg.high_fidelity = high_fidelity
fb_rel_vel *= 1000
#3) We compute the bounds
lb = [t0[0].mjd2000] + [
0, mass / 2, -fb_rel_vel, -fb_rel_vel, -fb_rel_vel, -fb_rel_vel,
-fb_rel_vel, -fb_rel_vel
] * self.__n_legs + [-1, -1, -1] * sum(self.__n_seg)
ub = [t0[1].mjd2000] + [
1, mass, fb_rel_vel, fb_rel_vel, fb_rel_vel, fb_rel_vel,
fb_rel_vel, fb_rel_vel
] * self.__n_legs + [1, 1, 1] * sum(self.__n_seg)
#3a ... and account for the bounds on the vinfs......
lb[3:6] = [-self.__vinf_dep] * 3
ub[3:6] = [self.__vinf_dep] * 3
lb[-sum(self.__n_seg) * 3 - 3:-sum(self.__n_seg) *
3] = [-self.__vinf_arr] * 3
ub[-sum(self.__n_seg) * 3 - 3:-sum(self.__n_seg) *
3] = [self.__vinf_arr] * 3
# 3b... and for the time of flight
lb[1:1 + 8 * self.__n_legs:8] = [el[0] for el in tof]
ub[1:1 + 8 * self.__n_legs:8] = [el[1] for el in tof]
#4) And we set the bounds
self.set_bounds(lb, ub)
def __init__(
self,
seq=[ganymede, europa],
tf=epoch(8.174621347386377e+03),
vf=[-1610.7520437617632, 5106.5676929998444, 122.39394967587651],
n_seg=[10] * 2,
m0=2000,
Tmax=0.1,
Isp=2000,
mu=MU_JUPITER,
high_fidelity=False,
obj='none'):
"""
USAGE: mga_incipit_lt(seq = [io,io], t0 = [epoch(7305.0),epoch(11323.0)], tof = [[100,200],[3,200]])
* seq: list of jupiter moons defining the trajectory incipit
* t0: list of two epochs defining the launch window
* tof: list of n lists containing the lower and upper bounds for the legs flight times (days)
* n_seg: list containing the number of segments for each leg
* m0: starting mass (k)
* Tmax: maximum allowed thrust (N)
* Isp: specific impulse (s)
* high_fidelity = compute the trajectory in high fidelity mode
"""
#1) We compute the problem dimensions .... and call the base problem constructor
self.__n_legs = len(seq)
n_fb = self.__n_legs - 1
# 1a) The decision vector length
dim = self.__n_legs * 8 + sum(n_seg) * 3 - 1
# 1b) The total number of constraints (mismatch + fly-by + boundary + throttles
c_dim = self.__n_legs * 7 + n_fb * 2 + 1 + sum(n_seg)
# 1c) The number of inequality constraints (fly-by angle + throttles)
c_ineq_dim = n_fb + sum(n_seg)
# 1d) the number of objectives
f_dim = 1
#First we call the constructor for the base PyGMO problem
#As our problem is n dimensional, box-bounded (may be multi-objective), we write
#(dim, integer dim, number of obj, number of con, number of inequality con, tolerance on con violation)
super(mga_incipit_lt, self).__init__(dim, 0, f_dim, c_dim, c_ineq_dim,
1e-4)
#2) We then define some class data members
#public:
self.seq = seq
self.obj = obj
self.vf = vf
self.tf = tf.mjd2000
#private:
self.__n_seg = n_seg
self.__sc = spacecraft(m0, Tmax, Isp)
self.__leg = leg()
self.__leg.set_mu(mu)
self.__leg.set_spacecraft(self.__sc)
self.__leg.high_fidelity = high_fidelity
#3) We compute the bounds
lb = ([-4 * pi, -pi] +
[0, m0 / 1.5, -10000, -10000, -10000, -10000, -10000, -10000] *
(self.__n_legs - 1) + [0, m0 / 1.5, -10000, -10000, -10000] +
[-1, -1, -1] * sum(self.__n_seg))
ub = ([4 * pi, pi] +
[1, m0, 10000, 10000, 10000, 10000, 10000, 10000] *
(self.__n_legs - 1) + [1, m0, 10000, 10000, 10000] +
[1, 1, 1] * sum(self.__n_seg))
#3a ... and account for the bounds on the starting velocity
lb[4:7] = [-3400.0] * 3
ub[4:7] = [3400.0] * 3
# 3b... and for the time of flight
lb[2:2 + 8 * self.__n_legs:8] = [1] * len(seq)
ub[2:2 + 8 * self.__n_legs:8] = [700] * len(seq)
#4) And we set the bounds
self.set_bounds(lb, ub)
