# RCAIDE/Library/Missions/Common/Update/orientations.py
#
#
# Created: Jul 2023, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# RCAIDE imports
from RCAIDE.Framework.Core import angles_to_dcms, orientation_product, orientation_transpose
# package imports
import numpy as np
# ----------------------------------------------------------------------------------------------------------------------
# Update Orientations
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def orientations(segment):
""" Updates the orientation of the vehicle throughout the mission for each relevant axis
Assumptions:
This assumes the vehicle has 3 frames: inertial, body, and wind
Inputs:
segment.state.conditions:
frames.inertial.velocity_vector [meters/second]
frames.body.inertial_rotations [Radians]
segment.analyses.planet.mean_radius [meters]
state.numerics.time.integrate [float]
Outputs:
segment.state.conditions:
aerodynamics.angles.alpha [Radians]
aerodynamics.angles.beta [Radians]
aerodynamics.angles.roll [Radians]
frames.body.transform_to_inertial [Radians]
frames.wind.body_rotations [Radians]
frames.wind.transform_to_inertial [Radians]
Properties Used:
N/A
"""
# unpack
conditions = segment.state.conditions
V_inertial = conditions.frames.inertial.velocity_vector
body_inertial_rotations = conditions.frames.body.inertial_rotations
roll_rate = segment.state.conditions.static_stability.roll_rate
pitch_rate = segment.state.conditions.static_stability.pitch_rate
yaw_rate = segment.state.conditions.static_stability.yaw_rate
# ------------------------------------------------------------------
# Body Frame
# ------------------------------------------------------------------
# body frame rotations
phi = body_inertial_rotations[:,0,None]
# body frame tranformation matrices
T_inertial2body = angles_to_dcms(body_inertial_rotations,(2,1,0))
T_body2inertial = orientation_transpose(T_inertial2body)
# transform inertial velocity to body frame
V_body = orientation_product(T_inertial2body,V_inertial)
# project inertial velocity into body x-z plane
V_stability = V_body * 1.
# calculate angle of attack
alpha = np.arctan2(V_stability[:,2],V_stability[:,0])[:,None]
# calculate side slip
beta = np.arctan2(V_stability[:,1],V_stability[:,0])[:,None]
# pack aerodynamics angles
conditions.aerodynamics.angles.alpha[:,0] = alpha[:,0]
conditions.aerodynamics.angles.beta[:,0] = beta[:,0]
conditions.aerodynamics.angles.phi[:,0] = phi[:,0]
# pack transformation tensor
conditions.frames.body.transform_to_inertial = T_body2inertial
# ------------------------------------------------------------------
# Wind Frame
# ------------------------------------------------------------------
# back calculate wind frame rotations
wind_body_rotations = body_inertial_rotations * 0.
wind_body_rotations[:,0] = 0 # no roll in wind frame
wind_body_rotations[:,1] = alpha[:,0] # theta is angle of attack
wind_body_rotations[:,2] = beta[:,0] # beta is side slip angle
# wind frame tranformation matricies
T_wind2body = angles_to_dcms(wind_body_rotations,(2,1,0))
T_wind2inertial = orientation_product(T_wind2body,T_body2inertial)
# pack wind rotations
conditions.frames.wind.body_rotations = wind_body_rotations
# pack transformation tensor
conditions.frames.wind.transform_to_inertial = T_wind2inertial
# ------------------------------------------------------------------
# Rotation rates
# ------------------------------------------------------------------
stability_frame_rotations = np.concatenate((np.concatenate((roll_rate, pitch_rate), axis=1), yaw_rate), axis=1)
phi = body_inertial_rotations[:, 0]
theta = body_inertial_rotations[:, 1]
reverse_transformation = np.zeros_like(T_body2inertial)
reverse_transformation[:, 0, 0] = 1
reverse_transformation[:, 0, 1] = np.sin(phi)*np.tan(theta)
reverse_transformation[:, 0, 2] = np.cos(phi)*np.tan(theta)
reverse_transformation[:, 1, 1] = np.cos(phi)
reverse_transformation[:, 1, 2] = -np.sin(phi)
reverse_transformation[:, 2, 1] = np.sin(phi) /np.cos(theta)
reverse_transformation[:, 2, 2] = np.cos(phi) /np.cos(theta)
inertial_rotations = orientation_product(reverse_transformation,stability_frame_rotations)
segment.state.conditions.frames.inertial.angular_velocity_vector = inertial_rotations
return
