Source code for scenarioAttitudeFeedbackNoEarth

#
#  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.
#

r"""
Overview
--------

Demonstrates how to simulate an attitude control scenario without having any gravity
bodies present. In essence, the 3-U cube-sat spacecraft is hovering in deep space.  The goal is to
stabilize the tumble of a spacecraft and point it towards a fixed inertial direction.
This script sets up a 6-DOF spacecraft which is hovering in deep space.  The scenario duplicates
the scenario in :ref:`scenarioAttitudeFeedback` without adding
Earth gravity body to the simulation.

The script is found in the folder ``basilisk/examples`` and executed by using::

      python3 scenarioAttitudeFeedbackNoEarth.py

When the simulation completes 3 plots are shown for the MRP attitude history, the rate
tracking errors, as well as the control torque vector.

The simulation layout is shown in the following illustration.  A single simulation process is created
which contains both the spacecraft simulation modules, as well as the Flight Software (FSW) algorithm
modules.

.. image:: /_images/static/test_scenarioAttitudeFeedbackNoEarth.svg
   :align: center

The spacecraft simulation is identical to :ref:`scenarioAttitudeFeedback`.
The primary difference is that the gravity body is not included.


Illustration of Simulation Results
----------------------------------
The following simulation runs should output identical results to the scenario runs in
:ref:`scenarioAttitudeFeedback` as the attitude pointing goal
is an inertial orientation, and thus independent of the satellite being in Earth orbit or
hovering in deep space.

::

    show_plots = True, useUnmodeledTorque = False, useIntGain = False, useKnownTorque = False

.. image:: /_images/Scenarios/scenarioAttitudeFeedbackNoEarth1000.svg
   :align: center

.. image:: /_images/Scenarios/scenarioAttitudeFeedbackNoEarth2000.svg
   :align: center

::

    show_plots = True, useUnmodeledTorque = True, useIntGain = False, useKnownTorque = False

.. image:: /_images/Scenarios/scenarioAttitudeFeedbackNoEarth1100.svg
   :align: center

.. image:: /_images/Scenarios/scenarioAttitudeFeedbackNoEarth2100.svg
   :align: center

::

    show_plots = True, useUnmodeledTorque = True, useIntGain = True, useKnownTorque = False

.. image:: /_images/Scenarios/scenarioAttitudeFeedbackNoEarth1110.svg
   :align: center

.. image:: /_images/Scenarios/scenarioAttitudeFeedbackNoEarth2110.svg
   :align: center

::

    show_plots = True, useUnmodeledTorque = True, useIntGain = False, useKnownTorque = True

.. image:: /_images/Scenarios/scenarioAttitudeFeedbackNoEarth1101.svg
   :align: center

.. image:: /_images/Scenarios/scenarioAttitudeFeedbackNoEarth2101.svg
   :align: center


"""

#
# Basilisk Scenario Script and Integrated Test
#
# Purpose:  Integrated test of the spacecraft(), extForceTorque, simpleNav() and
#           mrpFeedback() modules.  Illustrates spacecraft attitude control in deep
#           space without a planet or gravity body setup.
# Author:   Hanspeter Schaub
# Creation Date:  Sept. 13, 2018
#
import os

import matplotlib.pyplot as plt
import numpy as np
# The path to the location of Basilisk
# Used to get the location of supporting data.
from Basilisk import __path__
# import message declarations
from Basilisk.architecture import messaging
from Basilisk.fswAlgorithms import attTrackingError
from Basilisk.fswAlgorithms import inertial3D
# import FSW Algorithm related support
from Basilisk.fswAlgorithms import mrpFeedback
from Basilisk.simulation import extForceTorque
from Basilisk.simulation import simpleNav
# import simulation related support
from Basilisk.simulation import spacecraft
# import general simulation support files
from Basilisk.utilities import SimulationBaseClass
from Basilisk.utilities import macros
from Basilisk.utilities import unitTestSupport  # general support file with common unit test functions
# attempt to import vizard
from Basilisk.utilities import vizSupport

bskPath = __path__[0]
fileName = os.path.basename(os.path.splitext(__file__)[0])



[docs] def run(show_plots, useUnmodeledTorque, useIntGain, useKnownTorque): """ The scenarios can be run with the followings setups parameters: Args: show_plots (bool): Determines if the script should display plots useUnmodeledTorque (bool): Specify if an external torque should be included useIntGain (bool): Specify if the feedback control uses an integral feedback term useKnownTorque (bool): Specify if the external torque is feed forward in the contro """ # Create simulation variable names simTaskName = "simTask" simProcessName = "simProcess" # Create a sim module as an empty container scSim = SimulationBaseClass.SimBaseClass() # set the simulation time variable used later on simulationTime = macros.min2nano(10.) # # create the simulation process # dynProcess = scSim.CreateNewProcess(simProcessName) # create the dynamics task and specify the integration update time simulationTimeStep = macros.sec2nano(.1) dynProcess.addTask(scSim.CreateNewTask(simTaskName, simulationTimeStep)) # # setup the simulation tasks/objects # # initialize spacecraft object and set properties scObject = spacecraft.Spacecraft() scObject.ModelTag = "bsk-Sat" # define the simulation inertia I = [900., 0., 0., 0., 800., 0., 0., 0., 600.] scObject.hub.mHub = 750.0 # kg - spacecraft mass scObject.hub.r_BcB_B = [[0.0], [0.0], [0.0]] # m - position vector of body-fixed point B relative to CM scObject.hub.IHubPntBc_B = unitTestSupport.np2EigenMatrix3d(I) # add spacecraft object to the simulation process scSim.AddModelToTask(simTaskName, scObject) # setup extForceTorque module # the control torque is read in through the messaging system extFTObject = extForceTorque.ExtForceTorque() extFTObject.ModelTag = "externalDisturbance" # use the input flag to determine which external torque should be applied # Note that all variables are initialized to zero. Thus, not setting this # vector would leave it's components all zero for the simulation. if useUnmodeledTorque: extFTObject.extTorquePntB_B = [[0.25], [-0.25], [0.1]] scObject.addDynamicEffector(extFTObject) scSim.AddModelToTask(simTaskName, extFTObject) # add the simple Navigation sensor module. This sets the SC attitude, rate, position # velocity navigation message sNavObject = simpleNav.SimpleNav() sNavObject.ModelTag = "SimpleNavigation" scSim.AddModelToTask(simTaskName, sNavObject) # # setup the FSW algorithm tasks # # setup inertial3D guidance module inertial3DObj = inertial3D.inertial3D() inertial3DObj.ModelTag = "inertial3D" scSim.AddModelToTask(simTaskName, inertial3DObj) inertial3DObj.sigma_R0N = [0., 0., 0.] # set the desired inertial orientation # setup the attitude tracking error evaluation module attError = attTrackingError.attTrackingError() attError.ModelTag = "attErrorInertial3D" scSim.AddModelToTask(simTaskName, attError) # setup the MRP Feedback control module mrpControl = mrpFeedback.mrpFeedback() mrpControl.ModelTag = "mrpFeedback" scSim.AddModelToTask(simTaskName, mrpControl) mrpControl.K = 3.5 if useIntGain: mrpControl.Ki = 0.0002 # make value negative to turn off integral feedback else: mrpControl.Ki = -1 # make value negative to turn off integral feedback mrpControl.P = 30.0 mrpControl.integralLimit = 2. / mrpControl.Ki * 0.1 if useKnownTorque: mrpControl.knownTorquePntB_B = [0.25, -0.25, 0.1] # # Setup data logging before the simulation is initialized # numDataPoints = 100 samplingTime = unitTestSupport.samplingTime(simulationTime, simulationTimeStep, numDataPoints) attErrorLog = attError.attGuidOutMsg.recorder(samplingTime) mrpLog = mrpControl.cmdTorqueOutMsg.recorder(samplingTime) scSim.AddModelToTask(simTaskName, attErrorLog) scSim.AddModelToTask(simTaskName, mrpLog) # # create simulation messages # # create the FSW vehicle configuration message vehicleConfigOut = messaging.VehicleConfigMsgPayload() vehicleConfigOut.ISCPntB_B = I # use the same inertia in the FSW algorithm as in the simulation configDataMsg = messaging.VehicleConfigMsg().write(vehicleConfigOut) # The primary difference is that the gravity body is not included. # When initializing the spacecraft states, only the attitude states must be set. The position and velocity # states are initialized automatically to zero. scObject.hub.sigma_BNInit = [[0.1], [0.2], [-0.3]] # sigma_BN_B scObject.hub.omega_BN_BInit = [[0.001], [-0.01], [0.03]] # rad/s - omega_BN_B # if this scenario is to interface with the BSK Viz, uncomment the following lines viz = vizSupport.enableUnityVisualization(scSim, simTaskName, scObject , modelDictionaryKeyList="3USat" # , saveFile=fileName ) # # connect the messages to the modules # sNavObject.scStateInMsg.subscribeTo(scObject.scStateOutMsg) attError.attNavInMsg.subscribeTo(sNavObject.attOutMsg) attError.attRefInMsg.subscribeTo(inertial3DObj.attRefOutMsg) mrpControl.guidInMsg.subscribeTo(attError.attGuidOutMsg) extFTObject.cmdTorqueInMsg.subscribeTo(mrpControl.cmdTorqueOutMsg) mrpControl.vehConfigInMsg.subscribeTo(configDataMsg) # # initialize Simulation # scSim.InitializeSimulation() # # configure a simulation stop time and execute the simulation run # scSim.ConfigureStopTime(simulationTime) scSim.ExecuteSimulation() # # retrieve the logged data # dataLr = mrpLog.torqueRequestBody dataSigmaBR = attErrorLog.sigma_BR dataOmegaBR = attErrorLog.omega_BR_B timeAxis = attErrorLog.times() np.set_printoptions(precision=16) # # plot the results # plt.close("all") # clears out plots from earlier test runs plt.figure(1) for idx in range(3): plt.plot(timeAxis * macros.NANO2MIN, dataSigmaBR[:, idx], color=unitTestSupport.getLineColor(idx, 3), label=r'$\sigma_' + str(idx) + '$') plt.legend(loc='lower right') plt.xlabel('Time [min]') plt.ylabel(r'Attitude Error $\sigma_{B/R}$') figureList = {} pltName = fileName + "1" + str(int(useUnmodeledTorque)) + str(int(useIntGain))+ str(int(useKnownTorque)) figureList[pltName] = plt.figure(1) plt.figure(2) for idx in range(3): plt.plot(timeAxis * macros.NANO2MIN, dataLr[:, idx], color=unitTestSupport.getLineColor(idx, 3), label='$L_{r,' + str(idx) + '}$') plt.legend(loc='lower right') plt.xlabel('Time [min]') plt.ylabel('Control Torque $L_r$ [Nm]') pltName = fileName + "2" + str(int(useUnmodeledTorque)) + str(int(useIntGain)) + str(int(useKnownTorque)) figureList[pltName] = plt.figure(2) plt.figure(3) for idx in range(3): plt.plot(timeAxis * macros.NANO2MIN, dataOmegaBR[:, idx], color=unitTestSupport.getLineColor(idx, 3), label=r'$\omega_{BR,' + str(idx) + '}$') plt.legend(loc='lower right') plt.xlabel('Time [min]') plt.ylabel('Rate Tracking Error [rad/s] ') if show_plots: plt.show() # close the plots being saved off to avoid over-writing old and new figures plt.close("all") return figureList
# # This statement below ensures that the unit test scrip can be run as a # stand-along python script # if __name__ == "__main__": run( True, # show_plots False, # useUnmodeledTorque False, # useIntGain False # useKnownTorque )