# RCAIDE/Library/Missions/Segments/Climb/Constant_Throttle_Constant_Speed.py
#
#
# Created: Jul 2023, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# Package imports
import numpy as np
# ----------------------------------------------------------------------------------------------------------------------
# Initialize Conditions
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def unpack_body_angle(segment):
"""
Unpacks and sets the proper value for body angle
Parameters
----------
segment : Segment
The mission segment being analyzed
Notes
-----
This function handles the initialization of the body angle for a climb segment
with constant throttle and constant speed.
**Required Segment Components**
segment:
state:
unknowns:
body_angle : array
Aircraft body angle [rad]
conditions:
frames:
body:
transform_to_inertial : array
Rotation matrix from body to inertial frame
Returns
-------
None
Updates segment conditions directly:
- conditions.frames.body.transform_to_inertial
"""
ctrls = segment.assigned_control_variables
# Body Angle Control
if ctrls.body_angle.active:
segment.state.conditions.frames.body.inertial_rotations[:,1] = segment.state.unknowns.body_angle[:,0]
else:
segment.state.conditions.frames.body.inertial_rotations[:,1] = segment.angle_of_attack
if ctrls.bank_angle.active:
segment.state.conditions.frames.body.inertial_rotations[:,0] = segment.state.unknowns.bank_angle[:,0]
else:
segment.state.conditions.frames.body.inertial_rotations[:,0] = segment.bank_angle
segment.state.conditions.frames.body.inertial_rotations[:,2] = segment.state.conditions.frames.planet.true_heading[:,0]
# ----------------------------------------------------------------------
# Initialize Conditions
# ----------------------------------------------------------------------
[docs]
def initialize_conditions(segment):
"""Sets the specified conditions which are given for the segment type.
Assumptions:
Constant throttle estting, with a constant true airspeed
Source:
N/A
Inputs:
segment.air_speed [meters/second]
segment.altitude_start [meters]
segment.altitude_end [meters]
segment.state.numerics.dimensionless.control_points [Unitless]
conditions.freestream.density [kilograms/meter^3]
Outputs:
conditions.frames.inertial.velocity_vector [meters/second]
Properties Used:
N/A
"""
# unpack
alt0 = segment.altitude_start
v_mag = segment.air_speed
beta = segment.sideslip_angle
alpha = segment.state.unknowns.wind_angle[:,0][:,None]
theta = segment.state.unknowns.body_angle[:,0][:,None]
conditions = segment.state.conditions
# check for initial altitude
if alt0 is None:
if not segment.state.initials: raise AttributeError('initial altitude not set')
alt0 = -1.0 *segment.state.initials.conditions.frames.inertial.position_vector[-1,2]
# Flight path angle
gamma = theta-alpha
# process
v_x = np.cos(beta) *v_mag * np.cos(gamma)
v_y = np.sin(beta) *v_mag * np.cos(gamma)
v_z = -v_mag * np.sin(gamma) # z points down
# pack
conditions.frames.inertial.velocity_vector[:,0] = v_x[:,0]
conditions.frames.inertial.velocity_vector[:,1] = v_y[:,0]
conditions.frames.inertial.velocity_vector[:,2] = v_z[:,0]
[docs]
def update_differentials_altitude(segment):
"""On each iteration creates the differentials and integration funcitons from knowns about the problem. Sets the time at each point. Must return in dimensional time, with t[0] = 0
Assumptions:
Constant throttle setting, with a constant true airspeed.
Source:
N/A
Inputs:
segment.climb_angle [radians]
state.conditions.frames.inertial.velocity_vector [meter/second]
segment.altitude_start [meters]
segment.altitude_end [meters]
Outputs:
state.conditions.frames.inertial.time [seconds]
conditions.frames.inertial.position_vector [meters]
conditions.freestream.altitude [meters]
Properties Used:
N/A
"""
# unpack
t = segment.state.numerics.dimensionless.control_points
I = segment.state.numerics.dimensionless.integrate
# Unpack segment initials
alt0 = segment.altitude_start
altf = segment.altitude_end
conditions = segment.state.conditions
v = segment.state.conditions.frames.inertial.velocity_vector
# check for initial altitude
if alt0 is None:
if not segment.state.initials: raise AttributeError('initial altitude not set')
alt0 = -1.0 *segment.state.initials.conditions.frames.inertial.position_vector[-1,2]
# get overall time step
vz = -v[:,2,None] # Inertial velocity is z down
dz = altf- alt0
dt = dz / np.dot(I[-1,:],vz)[-1] # maintain column array
# Integrate vz to get altitudes
alt = alt0 + np.dot(I*dt,vz)
# rescale operators
t = t * dt
# pack
t_initial = segment.state.conditions.frames.inertial.time[0,0]
segment.state.conditions.frames.inertial.time[:,0] = t_initial + t[:,0]
conditions.frames.inertial.position_vector[:,2] = -alt[:,0] # z points down
conditions.freestream.altitude[:,0] = alt[:,0] # positive altitude in this context
return
# ----------------------------------------------------------------------
# Update Velocity Vector from Wind Angle
# ----------------------------------------------------------------------
[docs]
def update_velocity_vector_from_wind_angle(segment):
# unpack
conditions = segment.state.conditions
v_mag = segment.air_speed
beta = segment.sideslip_angle
alpha = segment.state.unknowns.wind_angle[:,0][:,None]
theta = segment.state.unknowns.body_angle[:,0][:,None]
# Flight path angle
gamma = theta-alpha
# process
v_x = np.cos(beta) *v_mag * np.cos(gamma)
v_y = np.sin(beta) *v_mag * np.cos(gamma)
v_z = -v_mag * np.sin(gamma) # z points down
# pack
conditions.frames.inertial.velocity_vector[:,0] = v_x[:,0]
conditions.frames.inertial.velocity_vector[:,1] = v_y[:,0]
conditions.frames.inertial.velocity_vector[:,2] = v_z[:,0]
return conditions
