Source code for RCAIDE.Library.Mission.Common.Residuals.flight_dynamics
# RCAIDE/Library/Missions/Common/Residuals/flight_dynamics.py
#
#
# Created: Jul 2023, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
import RCAIDE
import numpy as np
# ----------------------------------------------------------------------------------------------------------------------
# Residual Total Forces
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def flight_dynamics(segment):
"""
Evaluates flight dynamics residuals for mission segment analysis
Parameters
----------
segment : Segment
The mission segment being analyzed
Returns
-------
None
Updates segment residuals directly
Notes
-----
This function calculates the residuals for force and moment equations
in all three axes. It handles special cases for transition and ground
segments, including acceleration calculations and final velocity constraints.
The function processes:
1. Force equation residuals (F = ma)
2. Moment equation residuals (M = Iα)
3. Special handling for:
- Transition segments
- Ground operations (takeoff, landing)
**Required Segment State Variables**
state.conditions.frames.inertial:
- velocity_vector : array
Vehicle velocity [m/s]
- acceleration_vector : array
Vehicle acceleration [m/s²]
- total_force_vector : array
Net forces [N]
- total_moment_vector : array
Net moments [N⋅m]
- angular_velocity_vector : array
Angular rates [rad/s]
- angular_acceleration_vector : array
Angular accelerations [rad/s²]
state.conditions.weights:
- total_mass : array
Vehicle mass [kg]
analyses.aerodynamics.vehicle.mass_properties:
- moments_of_inertia.tensor : array
Inertia tensor [kg⋅m²]
**Segment Types**
Special handling for:
- Transition segments
* Constant acceleration
* Constant angle
* Linear climb
- Ground segments
* Takeoff
* Landing
* Ground operations
**Major Assumptions**
* Rigid body dynamics
* Principal axes aligned with body axes
* Constant inertia properties
* Valid mass properties
* Non-zero final velocity for ground segments
See Also
--------
RCAIDE.Framework.Mission.Segments
RCAIDE.Framework.Mission.Segments.Transition
RCAIDE.Framework.Mission.Segments.Ground
"""
transition_seg_flag = type(segment) == RCAIDE.Framework.Mission.Segments.Transition.Constant_Acceleration_Constant_Angle_Linear_Climb
ground_seg_flag = (type(segment) == RCAIDE.Framework.Mission.Segments.Ground.Landing) or\
(type(segment) == RCAIDE.Framework.Mission.Segments.Ground.Takeoff) or \
(type(segment) == RCAIDE.Framework.Mission.Segments.Ground.Ground)
if transition_seg_flag or ground_seg_flag:
v = segment.state.conditions.frames.inertial.velocity_vector
D = segment.state.numerics.time.differentiate
segment.state.conditions.frames.inertial.acceleration_vector = np.dot(D,v)
FT = segment.state.conditions.frames.inertial.total_force_vector
a = segment.state.conditions.frames.inertial.acceleration_vector
if transition_seg_flag:
omega = segment.state.conditions.frames.inertial.angular_velocity_vector
D = segment.state.numerics.time.differentiate
segment.state.conditions.frames.inertial.angular_acceleration_vector = np.dot(D,omega)
MT = segment.state.conditions.frames.inertial.total_moment_vector
ang_acc = segment.state.conditions.frames.inertial.angular_acceleration_vector
m = segment.state.conditions.weights.total_mass
I = segment.analyses.aerodynamics.vehicle.mass_properties.moments_of_inertia.tensor
if ground_seg_flag:
vf = segment.velocity_end
if vf == 0.0: vf = 0.01
segment.state.residuals.force_x[:,0] = FT[1:,0]/m[1:,0] - a[1:,0]
segment.state.residuals.final_velocity_error = (v[-1,0] - vf)
else:
if segment.flight_dynamics.force_x:
segment.state.residuals.force_x[:,0] = FT[:,0]/m[:,0] - a[:,0]
if segment.flight_dynamics.force_y:
segment.state.residuals.force_y[:,0] = FT[:,1]/m[:,0] - a[:,1]
if segment.flight_dynamics.force_z:
segment.state.residuals.force_z[:,0] = FT[:,2]/m[:,0] - a[:,2]
if segment.flight_dynamics.moment_x:
segment.state.residuals.moment_x[:,0] = MT[:,0]/I[0,0] - ang_acc[:,0]
if segment.flight_dynamics.moment_y:
segment.state.residuals.moment_y[:,0] = MT[:,1]/I[1,1] - ang_acc[:,1]
if segment.flight_dynamics.moment_z:
segment.state.residuals.moment_z[:,0] = MT[:,2]/I[2,2] - ang_acc[:,2]
return
