#
# ISC License
#
# Copyright (c) 2016, 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: ETcontrol
# Author: Julian Hammerl
# Creation Date: May 20, 2021
#
import numpy as np
import pytest
from Basilisk.architecture import bskLogging
from Basilisk.architecture import messaging # import the message definitions
from Basilisk.fswAlgorithms import etSphericalControl # import the module that is to be tested
# Import all of the modules that we are going to be called in this simulation
from Basilisk.utilities import SimulationBaseClass
from Basilisk.utilities import macros, RigidBodyKinematics, orbitalMotion
from Basilisk.utilities import unitTestSupport # general support file with common unit test functions
# import packages as needed e.g. 'numpy', 'ctypes, 'math' etc.
# 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(conditionstring)
# provide a unique test method name, starting with test_
[docs]@pytest.mark.parametrize("accuracy", [1e-8])
def test_etSphericalControl(show_plots, accuracy): # update "module" in this function name to reflect the module name
r"""
**Validation Test Description**
The behavior of the Electrostatic Tractor Spherical Relative Motion Control is tested. The electrostatic force
between the servicer and the debris is calculated using a single sphere to represent each spacecraft. The simulation
is run for a single update cycle and the resulting forces and torques acting on each body
are compared to hand-computed truth values.
**Test Parameters**
Args:
accuracy (float): relative accuracy value used in the validation tests
**Description of Variables Being Tested**
The module output messages for the inertial control force vector and body control force vector are compared to
the truth values obtained from a Matlab simulation.
"""
# each test method requires a single assert method to be called
# pass on the testPlotFixture so that the main test function may set the DataStore attributes
[testResults, testMessage] = etSphericalControlTestFunction(show_plots, accuracy)
assert testResults < 1, testMessage
[docs]def etSphericalControlTestFunction(show_plots, accuracy):
"""Test method"""
testFailCount = 0 # zero unit test result counter
testMessages = [] # create empty array to store test log messages
unitTaskName = "unitTask" # arbitrary name (don't change)
unitProcessName = "TestProcess" # arbitrary name (don't change)
bskLogging.setDefaultLogLevel(bskLogging.BSK_WARNING)
# Create a sim module as an empty container
unitTestSim = SimulationBaseClass.SimBaseClass()
# Create test thread
testProcessRate = macros.sec2nano(0.5) # update process rate update time
testProc = unitTestSim.CreateNewProcess(unitProcessName)
testProc.addTask(unitTestSim.CreateNewTask(unitTaskName, testProcessRate))
# Construct algorithm and associated C++ container
module = etSphericalControl.etSphericalControl()
module.ModelTag = "ETcontrol" # update python name of test module
# Add test module to runtime call list
unitTestSim.AddModelToTask(unitTaskName, module)
# Initialize the test module configuration data
mu = 3.986004418e14 # [m^3/s^2] Earth's gravitational parameter
L0 = 20.
Ki = 4e-7
Pi = 1.85 * Ki ** 0.5
module.K = [Ki, 0.0, 0.0,
0.0, Ki, 0.0,
0.0, 0.0, Ki]
module.P = [Pi, 0.0, 0.0,
0.0, Pi, 0.0,
0.0, 0.0, Pi]
module.L_r = 30.
module.theta_r = 0.
module.phi_r = 0.
module.mu = mu
# Create input message and size it because the regular creator of that message
# is not part of the test.
oe = orbitalMotion.ClassicElements()
oe.a = 42164. * 1e3 # [m] geostationary orbit
oe.e = 0.
oe.i = 10.*macros.D2R
oe.Omega = 20.*macros.D2R
oe.omega = 30.*macros.D2R
oe.f = 40.*macros.D2R
r_TN_N, v_TN_N = orbitalMotion.elem2rv(mu, oe)
servicerNavTransOutData = messaging.NavTransMsgPayload() # Create a structure for the input message
servicerNavTransOutData.r_BN_N = r_TN_N
servicerNavTransOutData.v_BN_N = v_TN_N
servicerTransMsg = messaging.NavTransMsg().write(servicerNavTransOutData)
r_DT_N = np.array([2., -L0, -3.]) # relative position between debris and servicer
r_DN_N = r_TN_N + r_DT_N
v_DN_N = v_TN_N
debrisNavTransOutData = messaging.NavTransMsgPayload() # Create a structure for the input message
debrisNavTransOutData.r_BN_N = r_DN_N
debrisNavTransOutData.v_BN_N = v_DN_N
debrisTransMsg = messaging.NavTransMsg().write(debrisNavTransOutData)
beta_TH = [0.972960339471760, 0.107600839071972, -0.0289291519077161, 0.202319898714648] # initial EP
sigma_TN = RigidBodyKinematics.EP2MRP(beta_TH) # MRP
servicerNavAttOutData = messaging.NavAttMsgPayload()
servicerNavAttOutData.sigma_BN = sigma_TN
servicerAttMsg = messaging.NavAttMsg().write(servicerNavAttOutData)
servicerConfigOutData = messaging.VehicleConfigMsgPayload()
servicerConfigOutData.massSC = 500.
servicerVehicleConfigMsg = messaging.VehicleConfigMsg().write(servicerConfigOutData)
debrisConfigOutData = messaging.VehicleConfigMsgPayload()
debrisConfigOutData.massSC = 2000.
debrisVehicleConfigMsg = messaging.VehicleConfigMsg().write(debrisConfigOutData)
# compute electrostatic force between servicer and debris using single sphere for both S/C
R_T = 2.
R_D = 3.
V_T = 25000.
V_D = -25000.
kc = 8.9875517923e9
L = np.linalg.norm(r_DT_N)
q_T = (L*(L*R_T*V_T-R_T*R_D*V_D))/(kc*(L**2.-R_T*R_D))
q_D = (L * (L * R_D * V_D - R_T * R_D * V_T)) / (kc * (L ** 2. - R_T * R_D))
Fc = kc*q_T*q_D/L**2.
Fc_N = Fc*(-r_DT_N/np.linalg.norm(r_DT_N)) # electrostatic force acting on servicer
eForceOutData = messaging.CmdForceInertialMsgPayload()
eForceOutData.forceRequestInertial = Fc_N
eForceMsg = messaging.CmdForceInertialMsg().write(eForceOutData)
# Setup logging on the test module output message so that we get all the writes to it
dataLogInertial = module.forceInertialOutMsg.recorder()
unitTestSim.AddModelToTask(unitTaskName, dataLogInertial)
dataLogBody = module.forceBodyOutMsg.recorder()
unitTestSim.AddModelToTask(unitTaskName, dataLogBody)
# connect the message interfaces
module.servicerTransInMsg.subscribeTo(servicerTransMsg)
module.debrisTransInMsg.subscribeTo(debrisTransMsg)
module.servicerAttInMsg.subscribeTo(servicerAttMsg)
module.servicerVehicleConfigInMsg.subscribeTo(servicerVehicleConfigMsg)
module.debrisVehicleConfigInMsg.subscribeTo(debrisVehicleConfigMsg)
module.eForceInMsg.subscribeTo(eForceMsg)
# Need to call the self-init and cross-init methods
unitTestSim.InitializeSimulation()
unitTestSim.TotalSim.SingleStepProcesses()
# This pulls the actual data log from the simulation run.
forceInertialOutput = dataLogInertial.forceRequestInertial
forceBodyOutput = dataLogBody.forceRequestBody
# set the filtered output truth states
trueInertialVector = [[-0.00714223893615245,
0.00267752848271998,
0.000883681113161883]]
trueBodyVector = [[-0.00541988234898216,
0.00542736415350300,
0.000360862543207430]]
# compare the module results to the truth values
for i in range(0, len(trueInertialVector)):
# check vector values
if not unitTestSupport.isArrayEqual(forceInertialOutput[i], trueInertialVector[i], 3, accuracy):
testFailCount += 1
print(forceInertialOutput[i])
testMessages.append("FAILED: " + module.ModelTag + " Module failed "
+ "Inertial Force Output" + " unit test at t="
+ str(forceInertialOutput[i, 0] * macros.NANO2SEC) + "sec\n")
if not unitTestSupport.isArrayEqual(forceBodyOutput[i], trueBodyVector[i], 3, accuracy):
testFailCount += 1
print(forceBodyOutput[i])
testMessages.append("FAILED: " + module.ModelTag + " Module failed "
+ "Body Force Output" + " unit test at t="
+ str(forceBodyOutput[i, 0] * macros.NANO2SEC) + "sec\n")
# print out success message if no error were found
if testFailCount == 0:
print("PASSED: " + module.ModelTag)
print("This test uses an accuracy value of " + str(accuracy))
else:
print("FAILED " + module.ModelTag)
print(testMessages)
# each test method requires a single assert method to be called
# this check below just makes sure no sub-test failures were found
return [testFailCount, ''.join(testMessages)]
#
# This statement below ensures that the unitTestScript can be run as a
# stand-along python script
#
if __name__ == "__main__":
test_etSphericalControl(
False, # show_plots
1e-8 # accuracy
)