# ISC License
#
# Copyright (c) 2024, Autonomous Vehicle Systems Lab, University of Colorado at Boulder
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
# Unit Test Script
# Module Name: linearTranslationNDOF
# Author: Peter Johnson
# Creation Date: March 7, 2024
#
import inspect
import os
import numpy as np
import pytest
import numpy
import matplotlib.pyplot as plt
# plt.rcParams['text.usetex'] = True
filename = inspect.getframeinfo(inspect.currentframe()).filename
path = os.path.dirname(os.path.abspath(filename))
splitPath = path.split('simulation')
from Basilisk.utilities import SimulationBaseClass, unitTestSupport, macros
from Basilisk.simulation import spacecraft, linearTranslationNDOFStateEffector, gravityEffector
from Basilisk.architecture import messaging
# uncomment this line is this test is to be skipped in the global unit test run, adjust message as needed
# @pytest.mark.skipif(conditionstring)
# uncomment this line if this test has an expected failure, adjust message as needed
# @pytest.mark.xfail() # need to update how the RW states are defined
# provide a unique test method name, starting with test_
[docs]
@pytest.mark.parametrize("function", ["translatingBodyNoInput"
, "translatingBodyLockAxis"
, "translatingBodyCommandedForce"])
def test_translatingBody(show_plots, function):
r"""
**Validation Test Description**
This unit test sets up a spacecraft with four single-axis translating rigid bodies attached to a rigid hub. Each
translating body's center of mass is off-center from the translating axis and the position of the axis is arbitrary.
The scenario includes gravity acting on both the spacecraft and the effector.
**Description of Variables Being Tested**
In this file we are checking the principles of conservation of energy and angular momentum. Both the orbital and
rotational energy and angular momentum must be maintained when conservative forces like gravity are present.
Therefore, the values of the variables
- ``finalOrbAngMom``
- ``finalOrbEnergy``
- ``finalRotAngMom``
- ``finalRotEnergy``
against their initial values.
"""
eval(function + '(show_plots)')
[docs]
def translatingBodyNoInput(show_plots):
r"""
This test does not use any input messages or lock flags, so the links are free to move.
"""
scObject = spacecraft.Spacecraft()
scObject.ModelTag = "spacecraftBody"
unitTaskName = "unitTask" # arbitrary name (don't change)
unitProcessName = "TestProcess" # arbitrary name (don't change)
# Create a sim module as an empty container
unitTestSim = SimulationBaseClass.SimBaseClass()
# Create test thread
testProcessRate = macros.sec2nano(0.001) # update process rate update time
testProc = unitTestSim.CreateNewProcess(unitProcessName)
testProc.addTask(unitTestSim.CreateNewTask(unitTaskName, testProcessRate))
# Create four translating rigid bodies
translatingBodyEffector = linearTranslationNDOFStateEffector.linearTranslationNDOFStateEffector()
translatingBodyEffector.ModelTag = "translatingBodyEffector"
# define properties
translatingBody1 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody1.setMass(np.random.uniform(5.0, 50.0))
translatingBody1.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody1.setDCM_FP([[0.0, -1.0, 0.0], [0.0, 0.0, -1.0], [1.0, 0.0, 0.0]])
translatingBody1.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody1.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody1.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody1.setRhoInit(np.random.uniform(-5.0, 10.0))
translatingBody1.setRhoDotInit(0.05)
translatingBody1.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody1)
translatingBody2 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody2.setMass(np.random.uniform(5.0, 50.0))
translatingBody2.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody2.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody2.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody2.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody2.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody2.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody2.setRhoDotInit(0.05)
translatingBody2.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody2)
translatingBody3 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody3.setMass(np.random.uniform(5.0, 50.0))
translatingBody3.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody3.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody3.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody3.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody3.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody3.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody3.setRhoDotInit(0.05)
translatingBody3.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody3)
translatingBody4 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody4.setMass(np.random.uniform(5.0, 50.0))
translatingBody4.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody4.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody4.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody4.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody4.setFHat_P([[0.0], [0.0], [1.0]])
translatingBody4.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody4.setRhoDotInit(0.05)
translatingBody4.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody4)
# Add body to spacecraft
scObject.addStateEffector(translatingBodyEffector)
# Define mass properties of the rigid hub of the spacecraft
scObject.hub.mHub = 750.0
scObject.hub.r_BcB_B = [[0.0], [0.0], [1.0]]
scObject.hub.IHubPntBc_B = [[900.0, 0.0, 0.0], [0.0, 800.0, 0.0], [0.0, 0.0, 600.0]]
# Set the initial values for the states
scObject.hub.r_CN_NInit = [[-4020338.690396649], [7490566.741852513], [5248299.211589362]]
scObject.hub.v_CN_NInit = [[-5199.77710904224], [-3436.681645356935], [1041.576797498721]]
scObject.hub.sigma_BNInit = [[0.0], [0.0], [0.0]]
scObject.hub.omega_BN_BInit = [[0.1], [-0.1], [0.1]]
# Add test module to runtime call list
unitTestSim.AddModelToTask(unitTaskName, translatingBodyEffector)
unitTestSim.AddModelToTask(unitTaskName, scObject)
# Add Earth gravity to the simulation
earthGravBody = gravityEffector.GravBodyData()
earthGravBody.planetName = "earth_planet_data"
earthGravBody.mu = 0.3986004415E+15 # meters!
earthGravBody.isCentralBody = True
scObject.gravField.gravBodies = spacecraft.GravBodyVector([earthGravBody])
# Log the spacecraft state message
datLog = scObject.scStateOutMsg.recorder()
unitTestSim.AddModelToTask(unitTaskName, datLog)
# Initialize the simulation
unitTestSim.InitializeSimulation()
# Add energy and momentum variables to log
scObjectLog = scObject.logger(["totOrbAngMomPntN_N", "totRotAngMomPntC_N", "totOrbEnergy", "totRotEnergy"])
unitTestSim.AddModelToTask(unitTaskName, scObjectLog)
# Add states to log
rho1Data = translatingBodyEffector.translatingBodyOutMsgs[0].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho1Data)
rho2Data = translatingBodyEffector.translatingBodyOutMsgs[1].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho2Data)
rho3Data = translatingBodyEffector.translatingBodyOutMsgs[2].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho3Data)
rho4Data = translatingBodyEffector.translatingBodyOutMsgs[3].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho4Data)
# Setup and run the simulation
stopTime = 5000 * testProcessRate
unitTestSim.ConfigureStopTime(stopTime)
unitTestSim.ExecuteSimulation()
# Extract the logged variables
orbAngMom_N = scObjectLog.totOrbAngMomPntN_N
rotAngMom_N = scObjectLog.totRotAngMomPntC_N
rotEnergy = scObjectLog.totRotEnergy
orbEnergy = scObjectLog.totOrbEnergy
rho1 = rho1Data.rho
rho1Dot = rho1Data.rhoDot
rho2 = rho2Data.rho
rho2Dot = rho2Data.rhoDot
rho3 = rho3Data.rho
rho3Dot = rho3Data.rhoDot
rho4 = rho4Data.rho
rho4Dot = rho4Data.rhoDot
# Set up the conservation quantities
timeSec = scObjectLog.times() * 1e-9
initialOrbAngMom_N = [orbAngMom_N[0, 0], orbAngMom_N[0, 1], orbAngMom_N[0, 2]]
finalOrbAngMom = orbAngMom_N[-1]
initialRotAngMom_N = [rotAngMom_N[0, 0], rotAngMom_N[0, 1], rotAngMom_N[0, 2]]
finalRotAngMom = rotAngMom_N[-1]
initialOrbEnergy = orbEnergy[0]
finalOrbEnergy = orbEnergy[-1]
initialRotEnergy = rotEnergy[0]
finalRotEnergy = rotEnergy[-1]
# Plotting
plt.close("all")
plt.figure()
plt.clf()
plt.plot(timeSec, (orbAngMom_N[:, 0] - initialOrbAngMom_N[0]) / initialOrbAngMom_N[0],
timeSec, (orbAngMom_N[:, 1] - initialOrbAngMom_N[1]) / initialOrbAngMom_N[1],
timeSec, (orbAngMom_N[:, 2] - initialOrbAngMom_N[2]) / initialOrbAngMom_N[2])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Orbital Angular Momentum')
plt.figure()
plt.clf()
plt.plot(timeSec, (orbEnergy - initialOrbEnergy) / initialOrbEnergy)
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Orbital Energy')
plt.figure()
plt.clf()
plt.plot(timeSec, (rotAngMom_N[:, 0] - initialRotAngMom_N[0]) / initialRotAngMom_N[0],
timeSec, (rotAngMom_N[:, 1] - initialRotAngMom_N[1]) / initialRotAngMom_N[1],
timeSec, (rotAngMom_N[:, 2] - initialRotAngMom_N[2]) / initialRotAngMom_N[2])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Rotational Angular Momentum')
plt.figure()
plt.clf()
plt.plot(timeSec, (rotEnergy - initialRotEnergy) / initialRotEnergy)
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Rotational Energy')
plt.figure()
plt.clf()
plt.plot(rho1Data.times() * 1e-9, rho1, label=r'$\rho_1$')
plt.plot(rho2Data.times() * 1e-9, rho2, label=r'$\rho_2$')
plt.plot(rho3Data.times() * 1e-9, rho3, label=r'$\rho_3$')
plt.plot(rho4Data.times() * 1e-9, rho4, label=r'$\rho_4$')
plt.legend(loc='best')
plt.xlabel('time (s)')
plt.ylabel('Displacement')
plt.figure()
plt.clf()
plt.plot(rho1Data.times() * 1e-9, rho1Dot, label=r'$\dot{\rho}_1$')
plt.plot(rho2Data.times() * 1e-9, rho2Dot, label=r'$\dot{\rho}_2$')
plt.plot(rho3Data.times() * 1e-9, rho3Dot, label=r'$\dot{\rho}_3$')
plt.plot(rho4Data.times() * 1e-9, rho4Dot, label=r'$\dot{\rho}_4$')
plt.legend(loc='best')
plt.xlabel('time (s)')
plt.ylabel('Displacement Rate')
if show_plots:
plt.show()
plt.close("all")
# Testing setup
accuracy = 1e-12
np.testing.assert_allclose(finalOrbEnergy, initialOrbEnergy, rtol=accuracy, err_msg="Orbital energy is not constant.")
np.testing.assert_allclose(finalRotEnergy, initialRotEnergy, rtol=accuracy,
err_msg="Rotational energy is not constant.")
for i in range(3):
np.testing.assert_allclose(finalOrbAngMom, initialOrbAngMom_N, rtol=accuracy,
err_msg="Orbital angular momentum is not constant.")
np.testing.assert_allclose(finalRotAngMom, initialRotAngMom_N, rtol=accuracy,
err_msg="Rotational angular momentum is not constant.")
[docs]
def translatingBodyLockAxis(show_plots):
r"""
This test locks the axis, so the displacement is kept constant throughout the simulation.
"""
scObject = spacecraft.Spacecraft()
scObject.ModelTag = "spacecraftBody"
unitTaskName = "unitTask" # arbitrary name (don't change)
unitProcessName = "TestProcess" # arbitrary name (don't change)
# Create a sim module as an empty container
unitTestSim = SimulationBaseClass.SimBaseClass()
# Create test thread
testProcessRate = macros.sec2nano(0.001) # update process rate update time
testProc = unitTestSim.CreateNewProcess(unitProcessName)
testProc.addTask(unitTestSim.CreateNewTask(unitTaskName, testProcessRate))
# Create four translating rigid bodies
translatingBodyEffector = linearTranslationNDOFStateEffector.linearTranslationNDOFStateEffector()
translatingBodyEffector.ModelTag = "translatingBodyEffector"
# define properties
translatingBody1 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody1.setMass(np.random.uniform(5.0, 50.0))
translatingBody1.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody1.setDCM_FP([[0.0, -1.0, 0.0], [0.0, 0.0, -1.0], [1.0, 0.0, 0.0]])
translatingBody1.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody1.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody1.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody1.setRhoInit(np.random.uniform(-5.0, 10.0))
translatingBody1.setRhoDotInit(0.05)
translatingBody1.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody1)
translatingBody2 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody2.setMass(np.random.uniform(5.0, 50.0))
translatingBody2.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody2.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody2.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody2.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody2.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody2.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody2.setRhoDotInit(0.05)
translatingBody2.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody2)
translatingBody3 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody3.setMass(np.random.uniform(5.0, 50.0))
translatingBody3.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody3.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody3.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody3.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody3.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody3.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody3.setRhoDotInit(0.05)
translatingBody3.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody3)
translatingBody4 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody4.setMass(np.random.uniform(5.0, 50.0))
translatingBody4.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody4.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody4.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody4.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody4.setFHat_P([[0.0], [0.0], [1.0]])
translatingBody4.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody4.setRhoDotInit(0.05)
translatingBody4.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody4)
# Add body to spacecraft
scObject.addStateEffector(translatingBodyEffector)
# Define mass properties of the rigid hub of the spacecraft
scObject.hub.mHub = 750.0
scObject.hub.r_BcB_B = [[0.0], [0.0], [1.0]]
scObject.hub.IHubPntBc_B = [[900.0, 0.0, 0.0], [0.0, 800.0, 0.0], [0.0, 0.0, 600.0]]
# Set the initial values for the states
scObject.hub.r_CN_NInit = [[-4020338.690396649], [7490566.741852513], [5248299.211589362]]
scObject.hub.v_CN_NInit = [[-5199.77710904224], [-3436.681645356935], [1041.576797498721]]
scObject.hub.sigma_BNInit = [[0.0], [0.0], [0.0]]
scObject.hub.omega_BN_BInit = [[0.1], [-0.1], [0.1]]
# Add test module to runtime call list
unitTestSim.AddModelToTask(unitTaskName, translatingBodyEffector)
unitTestSim.AddModelToTask(unitTaskName, scObject)
# Add Earth gravity to the simulation
earthGravBody = gravityEffector.GravBodyData()
earthGravBody.planetName = "earth_planet_data"
earthGravBody.mu = 0.3986004415E+15 # meters!
earthGravBody.isCentralBody = True
scObject.gravField.gravBodies = spacecraft.GravBodyVector([earthGravBody])
# create lock message
lockArray = messaging.ArrayEffectorLockMsgPayload()
lockArray.effectorLockFlag = [1, 0, 0, 1]
lockMsg = messaging.ArrayEffectorLockMsg().write(lockArray)
translatingBodyEffector.motorLockInMsg.subscribeTo(lockMsg)
# Log the spacecraft state message
datLog = scObject.scStateOutMsg.recorder()
unitTestSim.AddModelToTask(unitTaskName, datLog)
# Initialize the simulation
unitTestSim.InitializeSimulation()
# Add energy and momentum variables to log
scObjectLog = scObject.logger(["totOrbAngMomPntN_N", "totRotAngMomPntC_N", "totOrbEnergy", "totRotEnergy"])
unitTestSim.AddModelToTask(unitTaskName, scObjectLog)
# Add states to log
rho1Data = translatingBodyEffector.translatingBodyOutMsgs[0].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho1Data)
rho2Data = translatingBodyEffector.translatingBodyOutMsgs[1].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho2Data)
rho3Data = translatingBodyEffector.translatingBodyOutMsgs[2].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho3Data)
rho4Data = translatingBodyEffector.translatingBodyOutMsgs[3].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho4Data)
# Setup and run the simulation
stopTime = 5000 * testProcessRate
unitTestSim.ConfigureStopTime(stopTime)
unitTestSim.ExecuteSimulation()
# Extract the logged variables
orbAngMom_N = scObjectLog.totOrbAngMomPntN_N
rotAngMom_N = scObjectLog.totRotAngMomPntC_N
rotEnergy = scObjectLog.totRotEnergy
orbEnergy = scObjectLog.totOrbEnergy
rho1 = rho1Data.rho
rho1Dot = rho1Data.rhoDot
rho2 = rho2Data.rho
rho2Dot = rho2Data.rhoDot
rho3 = rho3Data.rho
rho3Dot = rho3Data.rhoDot
rho4 = rho4Data.rho
rho4Dot = rho4Data.rhoDot
# Set up the conservation quantities
timeSec = scObjectLog.times() * 1e-9
initialOrbAngMom_N = [orbAngMom_N[0, 0], orbAngMom_N[0, 1], orbAngMom_N[0, 2]]
finalOrbAngMom = orbAngMom_N[-1]
initialRotAngMom_N = [rotAngMom_N[0, 0], rotAngMom_N[0, 1], rotAngMom_N[0, 2]]
finalRotAngMom = rotAngMom_N[-1]
initialOrbEnergy = orbEnergy[0]
finalOrbEnergy = orbEnergy[-1]
initialRotEnergy = rotEnergy[0]
finalRotEnergy = rotEnergy[-1]
# Plotting
plt.close("all")
plt.figure()
plt.clf()
plt.plot(timeSec, (orbAngMom_N[:, 0] - initialOrbAngMom_N[0]) / initialOrbAngMom_N[0],
timeSec, (orbAngMom_N[:, 1] - initialOrbAngMom_N[1]) / initialOrbAngMom_N[1],
timeSec, (orbAngMom_N[:, 2] - initialOrbAngMom_N[2]) / initialOrbAngMom_N[2])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Orbital Angular Momentum')
plt.figure()
plt.clf()
plt.plot(timeSec, (orbEnergy - initialOrbEnergy) / initialOrbEnergy)
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Orbital Energy')
plt.figure()
plt.clf()
plt.plot(timeSec, (rotAngMom_N[:, 0] - initialRotAngMom_N[0]) / initialRotAngMom_N[0],
timeSec, (rotAngMom_N[:, 1] - initialRotAngMom_N[1]) / initialRotAngMom_N[1],
timeSec, (rotAngMom_N[:, 2] - initialRotAngMom_N[2]) / initialRotAngMom_N[2])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Rotational Angular Momentum')
plt.figure()
plt.clf()
plt.plot(timeSec, (rotEnergy - initialRotEnergy) / initialRotEnergy)
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Rotational Energy')
plt.figure()
plt.clf()
plt.plot(rho1Data.times() * 1e-9, rho1, label=r'$\rho_1$')
plt.plot(rho2Data.times() * 1e-9, rho2, label=r'$\rho_2$')
plt.plot(rho3Data.times() * 1e-9, rho3, label=r'$\rho_3$')
plt.plot(rho4Data.times() * 1e-9, rho4, label=r'$\rho_4$')
plt.legend(loc='best')
plt.xlabel('time (s)')
plt.ylabel('Displacement')
plt.figure()
plt.clf()
plt.plot(rho1Data.times() * 1e-9, rho1Dot, label=r'$\dot{\rho}_1$')
plt.plot(rho2Data.times() * 1e-9, rho2Dot, label=r'$\dot{\rho}_2$')
plt.plot(rho3Data.times() * 1e-9, rho3Dot, label=r'$\dot{\rho}_3$')
plt.plot(rho4Data.times() * 1e-9, rho4Dot, label=r'$\dot{\rho}_4$')
plt.legend(loc='best')
plt.xlabel('time (s)')
plt.ylabel('Displacement Rate')
if show_plots:
plt.show()
plt.close("all")
# Testing setup
accuracy = 1e-12
np.testing.assert_allclose(finalOrbEnergy, initialOrbEnergy, rtol=accuracy,
err_msg="Orbital energy is not constant.")
np.testing.assert_allclose(finalRotEnergy, initialRotEnergy, rtol=accuracy,
err_msg="Rotational energy is not constant.")
for i in range(3):
np.testing.assert_allclose(finalOrbAngMom, initialOrbAngMom_N, rtol=accuracy,
err_msg="Orbital angular momentum is not constant.")
np.testing.assert_allclose(finalRotAngMom, initialRotAngMom_N, rtol=accuracy,
err_msg="Rotational angular momentum is not constant.")
[docs]
def translatingBodyCommandedForce(show_plots):
r"""
This test includes a commanded force to the link, so energy is not conserved.
"""
scObject = spacecraft.Spacecraft()
scObject.ModelTag = "spacecraftBody"
unitTaskName = "unitTask" # arbitrary name (don't change)
unitProcessName = "TestProcess" # arbitrary name (don't change)
# Create a sim module as an empty container
unitTestSim = SimulationBaseClass.SimBaseClass()
# Create test thread
testProcessRate = macros.sec2nano(0.001) # update process rate update time
testProc = unitTestSim.CreateNewProcess(unitProcessName)
testProc.addTask(unitTestSim.CreateNewTask(unitTaskName, testProcessRate))
# Create four translating rigid bodies
translatingBodyEffector = linearTranslationNDOFStateEffector.linearTranslationNDOFStateEffector()
translatingBodyEffector.ModelTag = "translatingBodyEffector"
# define properties
translatingBody1 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody1.setMass(np.random.uniform(5.0, 50.0))
translatingBody1.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody1.setDCM_FP([[0.0, -1.0, 0.0], [0.0, 0.0, -1.0], [1.0, 0.0, 0.0]])
translatingBody1.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody1.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody1.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody1.setRhoInit(np.random.uniform(-5.0, 10.0))
translatingBody1.setRhoDotInit(0.05)
translatingBody1.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody1)
translatingBody2 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody2.setMass(np.random.uniform(5.0, 50.0))
translatingBody2.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody2.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody2.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody2.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody2.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody2.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody2.setRhoDotInit(0.05)
translatingBody2.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody2)
translatingBody3 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody3.setMass(np.random.uniform(5.0, 50.0))
translatingBody3.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody3.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody3.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody3.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody3.setFHat_P([[3.0 / 5.0], [4.0 / 5.0], [0.0]])
translatingBody3.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody3.setRhoDotInit(0.05)
translatingBody3.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody3)
translatingBody4 = linearTranslationNDOFStateEffector.translatingBody()
translatingBody4.setMass(np.random.uniform(5.0, 50.0))
translatingBody4.setIPntFc_F([[np.random.uniform(5.0, 100.0), 0.0, 0.0],
[0.0, np.random.uniform(5.0, 100.0), 0.0],
[0.0, 0.0, np.random.uniform(5.0, 100.0)]])
translatingBody4.setDCM_FP([[1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0]])
translatingBody4.setR_FcF_F([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody4.setR_F0P_P([[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)],
[np.random.uniform(-1.0, 1.0)]])
translatingBody4.setFHat_P([[0.0], [0.0], [1.0]])
translatingBody4.setRhoInit(np.random.uniform(-5.0, 5.0))
translatingBody4.setRhoDotInit(0.05)
translatingBody4.setK(np.random.random())
translatingBodyEffector.addTranslatingBody(translatingBody4)
# Add body to spacecraft
scObject.addStateEffector(translatingBodyEffector)
# Define mass properties of the rigid hub of the spacecraft
scObject.hub.mHub = 750.0
scObject.hub.r_BcB_B = [[0.0], [0.0], [1.0]]
scObject.hub.IHubPntBc_B = [[900.0, 0.0, 0.0], [0.0, 800.0, 0.0], [0.0, 0.0, 600.0]]
# Set the initial values for the states
scObject.hub.r_CN_NInit = [[-4020338.690396649], [7490566.741852513], [5248299.211589362]]
scObject.hub.v_CN_NInit = [[-5199.77710904224], [-3436.681645356935], [1041.576797498721]]
scObject.hub.sigma_BNInit = [[0.0], [0.0], [0.0]]
scObject.hub.omega_BN_BInit = [[0.1], [-0.1], [0.1]]
# Add test module to runtime call list
unitTestSim.AddModelToTask(unitTaskName, translatingBodyEffector)
unitTestSim.AddModelToTask(unitTaskName, scObject)
# Add Earth gravity to the simulation
earthGravBody = gravityEffector.GravBodyData()
earthGravBody.planetName = "earth_planet_data"
earthGravBody.mu = 0.3986004415E+15 # meters!
earthGravBody.isCentralBody = True
scObject.gravField.gravBodies = spacecraft.GravBodyVector([earthGravBody])
# Create the force message
cmdArray = messaging.ArrayMotorForceMsgPayload()
cmdArray.motorForce = [0.1, -0.2, 0.3, -0.15] # [Nm]
cmdMsg = messaging.ArrayMotorForceMsg().write(cmdArray)
translatingBodyEffector.motorForceInMsg.subscribeTo(cmdMsg)
# Log the spacecraft state message
datLog = scObject.scStateOutMsg.recorder()
unitTestSim.AddModelToTask(unitTaskName, datLog)
# Initialize the simulation
unitTestSim.InitializeSimulation()
# Add energy and momentum variables to log
scObjectLog = scObject.logger(["totOrbAngMomPntN_N", "totRotAngMomPntC_N", "totOrbEnergy", "totRotEnergy"])
unitTestSim.AddModelToTask(unitTaskName, scObjectLog)
# Add states to log
rho1Data = translatingBodyEffector.translatingBodyOutMsgs[0].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho1Data)
rho2Data = translatingBodyEffector.translatingBodyOutMsgs[1].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho2Data)
rho3Data = translatingBodyEffector.translatingBodyOutMsgs[2].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho3Data)
rho4Data = translatingBodyEffector.translatingBodyOutMsgs[3].recorder()
unitTestSim.AddModelToTask(unitTaskName, rho4Data)
# Setup and run the simulation
stopTime = 5000 * testProcessRate
unitTestSim.ConfigureStopTime(stopTime)
unitTestSim.ExecuteSimulation()
# Extract the logged variables
orbAngMom_N = scObjectLog.totOrbAngMomPntN_N
rotAngMom_N = scObjectLog.totRotAngMomPntC_N
rotEnergy = scObjectLog.totRotEnergy
orbEnergy = scObjectLog.totOrbEnergy
rho1 = rho1Data.rho
rho1Dot = rho1Data.rhoDot
rho2 = rho2Data.rho
rho2Dot = rho2Data.rhoDot
rho3 = rho3Data.rho
rho3Dot = rho3Data.rhoDot
rho4 = rho4Data.rho
rho4Dot = rho4Data.rhoDot
# Set up the conservation quantities
timeSec = scObjectLog.times() * 1e-9
initialOrbAngMom_N = [orbAngMom_N[0, 0], orbAngMom_N[0, 1], orbAngMom_N[0, 2]]
finalOrbAngMom = orbAngMom_N[-1]
initialRotAngMom_N = [rotAngMom_N[0, 0], rotAngMom_N[0, 1], rotAngMom_N[0, 2]]
finalRotAngMom = rotAngMom_N[-1]
initialOrbEnergy = orbEnergy[0]
finalOrbEnergy = orbEnergy[-1]
initialRotEnergy = rotEnergy[0]
# Plotting
plt.close("all")
plt.figure()
plt.clf()
plt.plot(timeSec, (orbAngMom_N[:, 0] - initialOrbAngMom_N[0]) / initialOrbAngMom_N[0],
timeSec, (orbAngMom_N[:, 1] - initialOrbAngMom_N[1]) / initialOrbAngMom_N[1],
timeSec, (orbAngMom_N[:, 2] - initialOrbAngMom_N[2]) / initialOrbAngMom_N[2])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Orbital Angular Momentum')
plt.figure()
plt.clf()
plt.plot(timeSec, (orbEnergy - initialOrbEnergy) / initialOrbEnergy)
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Orbital Energy')
plt.figure()
plt.clf()
plt.plot(timeSec, (rotAngMom_N[:, 0] - initialRotAngMom_N[0]) / initialRotAngMom_N[0],
timeSec, (rotAngMom_N[:, 1] - initialRotAngMom_N[1]) / initialRotAngMom_N[1],
timeSec, (rotAngMom_N[:, 2] - initialRotAngMom_N[2]) / initialRotAngMom_N[2])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Rotational Angular Momentum')
plt.figure()
plt.clf()
plt.plot(rho1Data.times() * 1e-9, rho1, label=r'$\rho_1$')
plt.plot(rho2Data.times() * 1e-9, rho2, label=r'$\rho_2$')
plt.plot(rho3Data.times() * 1e-9, rho3, label=r'$\rho_3$')
plt.plot(rho4Data.times() * 1e-9, rho4, label=r'$\rho_4$')
plt.legend(loc='best')
plt.xlabel('time (s)')
plt.ylabel('Displacement')
plt.figure()
plt.clf()
plt.plot(rho1Data.times() * 1e-9, rho1Dot, label=r'$\dot{\rho}_1$')
plt.plot(rho2Data.times() * 1e-9, rho2Dot, label=r'$\dot{\rho}_2$')
plt.plot(rho3Data.times() * 1e-9, rho3Dot, label=r'$\dot{\rho}_3$')
plt.plot(rho4Data.times() * 1e-9, rho4Dot, label=r'$\dot{\rho}_4$')
plt.legend(loc='best')
plt.xlabel('time (s)')
plt.ylabel('Displacement Rate')
if show_plots:
plt.show()
plt.close("all")
# Testing setup
accuracy = 1e-12
np.testing.assert_allclose(finalOrbEnergy, initialOrbEnergy, rtol=accuracy,
err_msg="Orbital energy is not constant.")
for i in range(3):
np.testing.assert_allclose(finalOrbAngMom, initialOrbAngMom_N, rtol=accuracy,
err_msg="Orbital angular momentum is not constant.")
np.testing.assert_allclose(finalRotAngMom, initialRotAngMom_N, rtol=accuracy,
err_msg="Rotational angular momentum is not constant.")
if __name__ == "__main__":
translatingBodyNoInput(True)
# translatingBodyLockAxis(True)
# translatingBodyCommandedForce(True)