Karla Vega University of California, Berkeley Attitude Determination and Control 6/9/2015

Outline  Requirements  Hardware  Attitude Determination  Dynamics  Attitude Control  Types  Disturbances  Integration and Test  Summary  ACS in CubeSats  CINEMA *Lecture notes from Dr. Glenn Lightsey’s Spacecraft Dynamics and Controls Graduate Course at University of Texas at Austin 6/9/2015TRIO-CINEMA Meeting

Getting Underway 6/9/2015TRIO-CINEMA Meeting

Requirements and Flowdowns 6/9/2015TRIO-CINEMA Meeting

Tree Diagram 6/9/2015TRIO-CINEMA Meeting

Impact of ACS on S/C Configuration 6/9/2015TRIO-CINEMA Meeting

Some Standard Configurations 6/9/2015TRIO-CINEMA Meeting

Hardware 6/9/2015TRIO-CINEMA Meeting

Star Sensors 6/9/2015TRIO-CINEMA Meeting

Earth Sensors 6/9/2015TRIO-CINEMA Meeting

Earth Sensors Cont. 6/9/2015TRIO-CINEMA Meeting

Sun Sensors 6/9/2015TRIO-CINEMA Meeting

Magnetometers 6/9/2015TRIO-CINEMA Meeting

GPS 6/9/2015TRIO-CINEMA Meeting

Typical External Sensor Performance 6/9/2015TRIO-CINEMA Meeting

Gyros 6/9/2015TRIO-CINEMA Meeting

6/9/2015TRIO-CINEMA Meeting

6/9/2015TRIO-CINEMA Meeting

Typical Gyro Performance 6/9/2015TRIO-CINEMA Meeting

Typical Inertial Sensor Performance 6/9/2015TRIO-CINEMA Meeting

Sensor Selection 6/9/2015TRIO-CINEMA Meeting

Sensor Selection Continued 6/9/2015TRIO-CINEMA Meeting

Actuators 6/9/2015TRIO-CINEMA Meeting  Torque Coils  Wheels  Reaction Wheels  Momentum Wheels  Controlled Moment Gyros  Thrusters

Wheels 6/9/2015TRIO-CINEMA Meeting

Wheels Continued 6/9/2015TRIO-CINEMA Meeting

Thrusters 6/9/2015TRIO-CINEMA Meeting

Thrusters Continued 6/9/2015TRIO-CINEMA Meeting

Attitude Determination and Control 6/9/2015TRIO-CINEMA Meeting

Attitude Determination 6/9/2015TRIO-CINEMA Meeting  Frames of Reference  Parameterization  Geometry  Estimation  Statistics  Observability

Attitude Parameterization 6/9/2015TRIO-CINEMA Meeting

Propagating Attitudes 6/9/2015TRIO-CINEMA Meeting

Propagating Euler Angles 6/9/2015TRIO-CINEMA Meeting

Propagating Quaternions 6/9/2015TRIO-CINEMA Meeting

Geometry of Attitude Determination 6/9/2015TRIO-CINEMA Meeting

Implementation 6/9/2015TRIO-CINEMA Meeting

Implementation Continued 6/9/2015TRIO-CINEMA Meeting

Implementation Continued 6/9/2015TRIO-CINEMA Meeting

Estimation Theory: combining several measurement 6/9/2015TRIO-CINEMA Meeting

Dynamics: Euler’s Equations 6/9/2015TRIO-CINEMA Meeting

Integration 6/9/2015TRIO-CINEMA Meeting

Attitude Control 6/9/2015TRIO-CINEMA Meeting

Disturbances 6/9/2015TRIO-CINEMA Meeting

Some Typical Disturbance Torque Magnitudes 6/9/2015TRIO-CINEMA Meeting

Gravity Gradient 6/9/2015TRIO-CINEMA Meeting

Gravity Gradient, circular orbit 6/9/2015TRIO-CINEMA Meeting

Stability Diagram for GG in circular Orbit 6/9/2015TRIO-CINEMA Meeting

Effects of Elliptical Orbits 6/9/2015TRIO-CINEMA Meeting

Design of GG Satellites 6/9/2015TRIO-CINEMA Meeting

Magnetic Attitude Control 6/9/2015TRIO-CINEMA Meeting

Magnetic Controls, Continued 6/9/2015TRIO-CINEMA Meeting

Using Magnets 6/9/2015TRIO-CINEMA Meeting

Comments of Field Models 6/9/2015TRIO-CINEMA Meeting

Momentum Bias 6/9/2015TRIO-CINEMA Meeting

Integration and Test 6/9/2015TRIO-CINEMA Meeting

I&T Continued 6/9/2015TRIO-CINEMA Meeting

Summary 6/9/2015TRIO-CINEMA Meeting

ACS in CubeSats 6/9/2015TRIO-CINEMA Meeting  Passive Control  Magnets aligned with magnetic field  Active Control  Torque Coils  Solar panels as sun sensors  Reaction Wheels ($$)  Digital sun sensors ($$)

ACS: CINEMA (more on Wednesday) 6/9/2015TRIO-CINEMA Meeting  Spin-stabilized satellite Desired Attitude: Ecliptic normal System pointing requirement Science: ±10° Determination: ±1° Control: ±1°  Hardware  V-slit sun sensor  Solar panels (3 current sensors) TBR  Magnetometer  Torque Coil

Some Useful References 6/9/2015TRIO-CINEMA Meeting