# ISC License
#
# Copyright (c) 2022, 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
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# 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: spinningBodies
# Author: João Vaz Carneiro
# Creation Date: October 17, 2022
#
import inspect
import os
import pytest
import numpy
import matplotlib.pyplot as plt
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, spinningBodyTwoDOFStateEffector, 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("cmdTorque1, lock1, theta1Ref, cmdTorque2, lock2, theta2Ref", [
(0.0, False, 0.0, 0.0, False, 0.0)
, (0.0, True, 0.0, 0.0, False, 0.0)
, (0.0, False, 0.0, 0.0, True, 0.0)
, (0.0, True, 0.0, 0.0, True, 0.0)
, (1.0, False, 0.0, -2.0, False, 0.0)
, (0.0, False, 10.0 * macros.D2R, 0.0, False, -5.0 * macros.D2R)
, (0.0, False, -5.0 * macros.D2R, 0.0, False, 10.0 * macros.D2R)
])
def test_spinningBody(show_plots, cmdTorque1, lock1, theta1Ref, cmdTorque2, lock2, theta2Ref):
r"""
**Validation Test Description**
This unit test sets up a spacecraft with a single-axis rotating rigid body attached to a rigid hub. The spinning
body's center of mass is off-center from the spinning 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.
"""
[testResults, testMessage] = spinningBody(show_plots, cmdTorque1, lock1, theta1Ref, cmdTorque2, lock2, theta2Ref)
assert testResults < 1, testMessage
def spinningBody(show_plots, cmdTorque1, lock1, theta1Ref, cmdTorque2, lock2, theta2Ref):
__tracebackhide__ = True
testFailCount = 0 # zero unit test result counter
testMessages = [] # create empty list to store test log messages
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(0.0002) # update process rate update time
testProc = unitTestSim.CreateNewProcess(unitProcessName)
testProc.addTask(unitTestSim.CreateNewTask(unitTaskName, testProcessRate))
# Create two hinged rigid bodies
spinningBody = spinningBodyTwoDOFStateEffector.SpinningBodyTwoDOFStateEffector()
# Define properties of spinning body
spinningBody.mass1 = 100.0
spinningBody.mass2 = 50.0
spinningBody.IS1PntSc1_S1 = [[100.0, 0.0, 0.0], [0.0, 50.0, 0.0], [0.0, 0.0, 50.0]]
spinningBody.IS2PntSc2_S2 = [[50.0, 0.0, 0.0], [0.0, 30.0, 0.0], [0.0, 0.0, 40.0]]
spinningBody.dcm_S10B = [[-1.0, 0.0, 0.0], [0.0, -1.0, 0.0], [0.0, 0.0, 1.0]]
spinningBody.dcm_S20S1 = [[0.0, -1.0, 0.0], [0.0, .0, -1.0], [1.0, 0.0, 0.0]]
spinningBody.r_Sc1S1_S1 = [[2.0], [-0.5], [0.0]]
spinningBody.r_Sc2S2_S2 = [[1.0], [0.0], [-1.0]]
spinningBody.r_S1B_B = [[-2.0], [0.5], [-1.0]]
spinningBody.r_S2S1_S1 = [[0.5], [-1.5], [-0.5]]
spinningBody.s1Hat_S1 = [[0], [0], [1]]
spinningBody.s2Hat_S2 = [[0], [-1], [0]]
spinningBody.theta1Init = 0 * macros.D2R
spinningBody.theta2Init = 5 * macros.D2R
spinningBody.k1 = 1000.0
spinningBody.k2 = 500.0
if theta1Ref != 0.0 or theta2Ref != 0.0:
spinningBody.c1 = 500
spinningBody.c2 = 200
if lock1:
spinningBody.theta1DotInit = 0 * macros.D2R
else:
spinningBody.theta1DotInit = 2.0 * macros.D2R
if lock2:
spinningBody.theta2DotInit = 0 * macros.D2R
else:
spinningBody.theta2DotInit = -1.0 * macros.D2R
spinningBody.ModelTag = "SpinningBody"
# Add spinning body to spacecraft
scObject.addStateEffector(spinningBody)
# Create the torque message
cmdArray = messaging.ArrayMotorTorqueMsgPayload()
cmdArray.motorTorque = [cmdTorque1, cmdTorque2] # [Nm]
cmdMsg = messaging.ArrayMotorTorqueMsg().write(cmdArray)
spinningBody.motorTorqueInMsg.subscribeTo(cmdMsg)
# Create the locking message
lockArray = messaging.ArrayEffectorLockMsgPayload()
lockFlag = [0, 0]
if lock1:
lockFlag[0] = 1
if lock2:
lockFlag[1] = 1
lockArray.effectorLockFlag = lockFlag
lockMsg = messaging.ArrayEffectorLockMsg().write(lockArray)
spinningBody.motorLockInMsg.subscribeTo(lockMsg)
# Create the reference messages
angle1Ref = messaging.HingedRigidBodyMsgPayload()
angle1Ref.theta = theta1Ref
angle1Ref.thetaDot = 0.0
angle1RefMsg = messaging.HingedRigidBodyMsg().write(angle1Ref)
spinningBody.spinningBodyRefInMsgs[0].subscribeTo(angle1RefMsg)
angle2Ref = messaging.HingedRigidBodyMsgPayload()
angle2Ref.theta = theta2Ref
angle2Ref.thetaDot = 0.0
angle2RefMsg = messaging.HingedRigidBodyMsg().write(angle2Ref)
spinningBody.spinningBodyRefInMsgs[1].subscribeTo(angle2RefMsg)
# 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 = [[0.01], [-0.01], [0.01]]
# Add test module to runtime call list
unitTestSim.AddModelToTask(unitTaskName, spinningBody)
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)
# Add energy and momentum variables to log
scObjectLog = scObject.logger(["totOrbAngMomPntN_N", "totRotAngMomPntC_N", "totOrbEnergy", "totRotEnergy"])
unitTestSim.AddModelToTask(unitTaskName, scObjectLog)
# Initialize the simulation
unitTestSim.InitializeSimulation()
# Add states to log
theta1Data = spinningBody.spinningBodyOutMsgs[0].recorder()
theta2Data = spinningBody.spinningBodyOutMsgs[1].recorder()
unitTestSim.AddModelToTask(unitTaskName, theta1Data)
unitTestSim.AddModelToTask(unitTaskName, theta2Data)
# Setup and run the simulation
stopTime = 25000*testProcessRate
unitTestSim.ConfigureStopTime(stopTime)
unitTestSim.ExecuteSimulation()
# Extract the logged variables
orbAngMom_N = unitTestSupport.addTimeColumn(scObjectLog.times(), scObjectLog.totOrbAngMomPntN_N)
rotAngMom_N = unitTestSupport.addTimeColumn(scObjectLog.times(), scObjectLog.totRotAngMomPntC_N)
rotEnergy = unitTestSupport.addTimeColumn(scObjectLog.times(), scObjectLog.totRotEnergy)
orbEnergy = unitTestSupport.addTimeColumn(scObjectLog.times(), scObjectLog.totOrbEnergy)
theta1 = theta1Data.theta
theta1Dot = theta1Data.thetaDot
theta2 = theta2Data.theta
theta2Dot = theta2Data.thetaDot
# Setup the conservation quantities
initialOrbAngMom_N = [[orbAngMom_N[0, 1], orbAngMom_N[0, 2], orbAngMom_N[0, 3]]]
finalOrbAngMom = [orbAngMom_N[-1]]
initialRotAngMom_N = [[rotAngMom_N[0, 1], rotAngMom_N[0, 2], rotAngMom_N[0, 3]]]
finalRotAngMom = [rotAngMom_N[-1]]
initialOrbEnergy = [[orbEnergy[0, 1]]]
finalOrbEnergy = [orbEnergy[-1]]
initialRotEnergy = [[rotEnergy[0, 1]]]
finalRotEnergy = [rotEnergy[-1]]
# Plotting
plt.close("all")
plt.figure()
plt.clf()
plt.plot(orbAngMom_N[:, 0] * 1e-9, (orbAngMom_N[:, 1] - orbAngMom_N[0, 1]) / orbAngMom_N[0, 1],
orbAngMom_N[:, 0] * 1e-9, (orbAngMom_N[:, 2] - orbAngMom_N[0, 2]) / orbAngMom_N[0, 2],
orbAngMom_N[:, 0] * 1e-9, (orbAngMom_N[:, 3] - orbAngMom_N[0, 3]) / orbAngMom_N[0, 3])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Orbital Angular Momentum')
plt.figure()
plt.clf()
plt.plot(orbEnergy[:, 0] * 1e-9, (orbEnergy[:, 1] - orbEnergy[0, 1]) / orbEnergy[0, 1])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Orbital Energy')
plt.figure()
plt.clf()
plt.plot(rotAngMom_N[:, 0] * 1e-9, (rotAngMom_N[:, 1] - rotAngMom_N[0, 1]) / rotAngMom_N[0, 1],
rotAngMom_N[:, 0] * 1e-9, (rotAngMom_N[:, 2] - rotAngMom_N[0, 2]) / rotAngMom_N[0, 2],
rotAngMom_N[:, 0] * 1e-9, (rotAngMom_N[:, 3] - rotAngMom_N[0, 3]) / rotAngMom_N[0, 3])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Rotational Angular Momentum')
plt.figure()
plt.clf()
plt.plot(rotEnergy[:, 0] * 1e-9, (rotEnergy[:, 1] - rotEnergy[0, 1]) / rotEnergy[0, 1])
plt.xlabel('time (s)')
plt.ylabel('Relative Difference')
plt.title('Rotational Energy')
plt.figure()
plt.clf()
plt.plot(theta1Data.times() * 1e-9, theta1)
plt.xlabel('time (s)')
plt.ylabel('theta1')
plt.figure()
plt.clf()
plt.plot(theta1Data.times() * 1e-9, theta1Dot)
plt.xlabel('time (s)')
plt.ylabel('theta1Dot')
plt.figure()
plt.clf()
plt.plot(theta2Data.times() * 1e-9, theta2)
plt.xlabel('time (s)')
plt.ylabel('theta2')
plt.figure()
plt.clf()
plt.plot(theta2Data.times() * 1e-9, theta2Dot)
plt.xlabel('time (s)')
plt.ylabel('theta2Dot')
if show_plots:
plt.show()
plt.close("all")
# Testing setup
accuracy = 1e-12
finalOrbAngMom = numpy.delete(finalOrbAngMom, 0, axis=1) # remove time column
finalRotAngMom = numpy.delete(finalRotAngMom, 0, axis=1) # remove time column
finalRotEnergy = numpy.delete(finalRotEnergy, 0, axis=1) # remove time column
finalOrbEnergy = numpy.delete(finalOrbEnergy, 0, axis=1) # remove time column
for i in range(0, len(initialOrbAngMom_N)):
# check a vector values
if not unitTestSupport.isArrayEqualRelative(finalOrbAngMom[i], initialOrbAngMom_N[i], 3, accuracy):
testFailCount += 1
testMessages.append(
"FAILED: Spinning Body integrated test failed orbital angular momentum unit test")
for i in range(0, len(initialRotAngMom_N)):
# check a vector values
if not unitTestSupport.isArrayEqualRelative(finalRotAngMom[i], initialRotAngMom_N[i], 3, accuracy):
testFailCount += 1
testMessages.append(
"FAILED: Spinning Body integrated test failed rotational angular momentum unit test")
if cmdTorque1 == 0 and cmdTorque2 == 0 and theta1Ref == 0.0 and theta2Ref == 0.0:
for i in range(0, len(initialRotEnergy)):
# check a vector values
if not unitTestSupport.isArrayEqualRelative(finalRotEnergy[i], initialRotEnergy[i], 1, accuracy):
testFailCount += 1
testMessages.append("FAILED: Spinning Body integrated test failed rotational energy unit test")
for i in range(0, len(initialOrbEnergy)):
# check a vector values
if not unitTestSupport.isArrayEqualRelative(finalOrbEnergy[i], initialOrbEnergy[i], 1, accuracy):
testFailCount += 1
testMessages.append("FAILED: Spinning Body integrated test failed orbital energy unit test")
if theta1Ref != 0.0 or theta2Ref != 0.0:
if not unitTestSupport.isDoubleEqual(theta1[-1], theta1Ref, 0.01):
testFailCount += 1
testMessages.append("FAILED: Spinning Body integrated test failed angle 1 convergence unit test")
if not unitTestSupport.isDoubleEqual(theta2[-1], theta2Ref, 0.01):
testFailCount += 1
testMessages.append("FAILED: Spinning Body integrated test failed angle 2 convergence unit test")
if testFailCount == 0:
print("PASSED: " + " Spinning Body gravity integrated test")
assert testFailCount < 1, testMessages
# return fail count and join into a single string all messages in the list
# testMessage
return [testFailCount, ''.join(testMessages)]
if __name__ == "__main__":
spinningBody(True, 0.0, False, 0.0 * macros.D2R, 0.0, False, 0.0 * macros.D2R)