New In Version 2015.1

Contents

Major changes in v2015.1

All toolboxes have been updated to handle the new graphics engine in R2014b. Graphics handles are now a unique type of object, and must be preallocated with a special function. In addition, the zbuffer renderer is no longer supported, so all graphics use the OpenGL renderer.

Our new Missions module gives you several different missions from which you can start your own designs! These are:

New Features by Module

New Reaction Wheel RHS

RHSSpacecraftWithRWA.m is a new right-hand-side for spacecraft with reaction wheels. It makes it easier than ever to model reaction wheel controlled spacecraft. It includes Coulomb and viscous friction which can be specified per wheel, a simple gravity model and quaternion kinematics. A new demo, SpacecraftWithRWADemo, shows how to use it with PID3Axis.m. You can test the controller with various wheel parameters, disturbance torques, and initial wheel and body rates. Consider an example with an initial body rate around x, a steady disturbance torque of 1e-4 Nm around y, and a goal of returning to a nominal quaternion. The first set of figures show the controller response with no friction or damping. The body rates return to zero and the wheel torque matches the input disturbance torque.

Body rates, no damping or frictionWheel torques

The next set of figures shows the response with a wheel damping coefficient of 5e-6 Nms, typical for CubeSat wheels. Note that the addition of damping, which is proportional to wheel speed, turns our steady disturbance torque into a ramp. This results in an attitude offset.

Body rates look the same with dampingTotal disturbance is now a ramp due to damping

The final set of figures shows the response with a Coulomb friction torque of 1e-3 Nm. This causes limit cycling in the wheel speed around zero, leading to oscillations in the body rates. The friction torque in this case is larger than the disturbance torque!

Body rates with influence of Coulomb frictionWheel torques

Walker Delta Constellations

A new constellation design function enables you to produce Keplerian elements for any number of satellites in a Walker Delta or Star constellation.

Walker Delta Polar Star

Lunar Mission Demos

The LunarMissionSim demo computes a transfer orbit between LEO and the moon, calculated a delta-V for the lunar orbit injection, and simulates the final orbit to show that the insertion worked as expected. This uses the new maneuver function OrbMnvrInsertion.

Transfer Orbit from LEO Lunar Orbit

LunarMissionDesign plans a complete mission from LEO to lunar landing, calculating all the delta-V magnitudes and simulating a powered landing using BilinearTangent. The script generates plots and a table with the results, copied below.

Descent Simlation
Julian Date 2457522.27 days
Transfer Orbit $\Delta V$ 3.04 km/s
Transfer stage mass 496.22 kg
Insertion Impulse 202139.25 lbf-s
Insertion Engine ATK Star 26B TE-M-442-1
Transfer Orbit $\Delta V$ 3.04 km/s
V$_infty$ 0.78 km/s
Perigee altitude lunar orbit 200.00 km
Circular orbit altitude 200.00 km
Descent orbit altitude 11.50 km
Insertion $\Delta V$ 0.582 km/s
Circularization $\Delta V$ 0.282 km/s
Orbit lowering $\Delta V$ 0.736 km/s
Landing $\Delta V$ 2.46 km/s
Mission total $\Delta V$ 4.06 km/s
Mass dry 30.00 kg
Mass fuel 98.40 kg
I$_sp$ 285.00 sec
Peak thrust 284.20 N
Acceleration ratio 1.36
Landing time 18.55 min

Change List

Directories

A new folder called SCModels has been added to SC/, for stored versions of CAD models, to separate them from other data files.

A Missions/ module was added with folders for AlphaCentauri, AsteroidProspector, Comsat attitude control, FastReorientation, LunarMission, and SunNadir. This replaces the AttitudeControl/ module.

A Constellations folder was added to Orbit for the WalkerConstellation function.

The magnetic control functions were consolidated into a new MagneticControl folder in SC/.

The following sections list those functions which have been added or relocated since Version 2014.1

SCT Pro

AeroUtils/CAD/ExportDXF.m
AeroUtils/CAD/ThrusterCAD.m

CubeSat/Demos/MissionPlanning/RepeatingGroundTrackDemo.m

Link/RF/PowerReceived.m

Orbit/Constellations/WalkerConstellation.m
Orbit/Demos/OrbitManeuver/OptimalFPA.m
Orbit/Demos/OrbitSim/EarthOrbitDragDemo.m
Orbit/OrbitCoord/LocusOfVisibility.m
Orbit/OrbitCoord/RToNu.m
Orbit/OrbitCoord/TrueAnomalySpacing.m
Orbit/OrbitManeuver/OrbMnvrInsertion.m
Orbit/OrbitManeuver/OrbMnvrLowerApogee.m
Orbit/OrbitManeuver/PatchedConicPlanner.m
Orbit/OrbitManeuver/RHSOptimalFPA.m
Orbit/OrbitMechanics/OrbitDrag.m
Orbit/OrbitMechanics/OrbitVel2D.m
Orbit/RHSOrbit/RHSGeoJ2.m
Orbit/Visualization/TrajectoryPlot.m

Propulsion/Chemical/RocketH2O2.m
Propulsion/Rocket/RocketChemical.m

SC/Demos/Attitude/Timeline.m
SC/Demos/CAD/BuildFlatPlates.m
SC/Environs/EarthEnvironment.m
SC/Environs/MagFieldData.m
SC/Environs/PlanetEnvironment.m
SC/Ephem/PlanetRotation.m
SC/SCModels/ContentsLines.m

SCPro/Demos/ProControl/SolarMomentumControl.m
SCPro/Demos/ProControl/SpacecraftWithRWADemo.m
SCPro/Demos/ProMissions/DFDSpaceStation.m
SCPro/DynamicalModels/RHSSpacecraftWithRWA.m
SCPro/ProActuators/ReactionWheelFriction.m

SpacecraftEstimation/DemoFuns/LatLonToNEU.m
SpacecraftEstimation/DemoFuns/RHSEarthOrbitUKF.m
SpacecraftEstimation/DemoFuns/TelescopeUKF.m
SpacecraftEstimation/Demos/UKF/UKFOrbitAnglesDemo.m

The following functions were relocated from the AttitudeControl module.

SC/Demos/MagneticControl/MagControl.m
SC/Demos/MagneticControl/MagSim.m
SCPro/Demos/ProControl/SCPointingDemo.m
SC/MagneticControl/MagControlThreeAxis.m
SC/MagneticControl/MagControlTwoAxis.m
SCPro/Demos/ProControl/MAPControlSim.m
SCPro/ProAttitude/AttitudeTarget.m

Core

Common/Demos/Control/MatchFilterTest.m
Common/General/CPIAdjust.m
Common/Graphics/DisplayLatexTable.m
Common/Graphics/GPoly.m
Common/Graphics/VantagePoint.m
Common/Time/JD2Array.m
Math/BilinearInterpolation.m
Math/FitEllipse.m
Math/Geometry/SegmentIntersection.m