ThreeAxisControl:

Path: SCPro/ProControl

% Implements and simulates a spacecraft with reaction wheels and thrusters.
 This script demonstrates:
 
 * 3-axis earth pointing attitude control with reaction wheels and thrusters
 * Disturbance modeling
 * Inertia computations
 * Thruster maneuvers

 The control system is designed for either Earth pointing or inertially fixed
 attitude. It does not allow attitude maneuvers. Thrusters can be used for
 attitude control. Thrusters are pulsewidth modulated and off-pulse for either
 east/west or north/south stationkeeping. The simulation also includes a single
 liquid apogee engine.

 It is assumed that an IMU/Star tracker package is available that outputs a
 valid attitude quaternion in all modes.

 Disturbance modeling is for solar pressure only.

 The simulation propagates the orbit, the attitude and the reaction wheel
 rates. The reaction wheels are assume to take torque commands and produce that
 torque. That is to say they have a current feedback loop that compensates for
 back emf.
   
 The controller is a simple PID controller in all modes. The inertia
 matrix is for the deployed mode.

 The wheels are Honeywell HR0610 wheels with 12 NMs max momentum at
 6000 rpm. Max torque is 0.055 Nm.

 The thrusters are EADS monopropellant thrusters:

   http://www.space-propulsion.com/spacecraft-propulsion/hydrazine-thrusters/1n-thruster.html

   CHT 0.5 0.5 N (north, east west)
   CHT 20 N (base panel)
   
 The apogee engine is a 400 N "S400-12":
   http://www.space-propulsion.com/spacecraft-propulsion/apogee-motors/index.html

   S400-12 420 N 318 sec

 We put all properties into this script to make it self-contained.
 For more elaborate models they would be put in databases, etc.

  ------------------------------------------------------------------------
  See also Inertias, PIDMIMO, QError, QLVLH, U2Q, Constant, Plot2D, 
  TimeGUI, TimeLabl, CosD, RK4, Date2JD, MassProp, El2RV, Period, SunV1, 
  ThrusterCommand, RHSRWA, ThreeAxisControlDisturb
  ------------------------------------------------------------------------
%
  -----------------------------------------------------------------------------
  Copyright (c) 2007 Princeton Satellite Systems, Inc. All rights reserved.
  2017.1 Update function handles
  -----------------------------------------------------------------------------

Children:

AerospaceUtils: Coord/QLVLH
SC: BasicOrbit/El2RV
SC: BasicOrbit/Period
SC: Ephem/SunV1
SCPro: DynamicalModels/RHSRWA
SCPro: DynamicalModels/ThreeAxisControlDisturb
SCPro: ProControl/ThrusterCommand
Common: Control/PIDMIMO
Common: Database/Constant
Common: GUIs/Figui
Common: GUIs/TimeGUI
Common: Graphics/Plot2D
Common: Graphics/TimeLabl
Common: MassProperties/Inertias
Common: MassProperties/MassProp
Common: Quaternion/QError
Common: Quaternion/U2Q
Common: Time/Date2JD
Math: Integration/RK4
Math: Trigonometry/CosD

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