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 -----------------------------------------------------------------------------
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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