ACS
This presentation is the property of its rightful owner.
Sponsored Links
1 / 10

ACS Dave Auslander, Dave Pankow, Sandhu Jaikarn, Yao-Ting Mao, PowerPoint PPT Presentation


  • 90 Views
  • Uploaded on
  • Presentation posted in: General

ACS Dave Auslander, Dave Pankow, Sandhu Jaikarn, Yao-Ting Mao, UC Berkeley Space Sciences Laboratory University of California, Berkeley February 8, 2010. ACS Agenda. AGENDA Hardware Requirements Software Requirements Control Design Model Issues. Requirements. ACS Hardware.

Download Presentation

ACS Dave Auslander, Dave Pankow, Sandhu Jaikarn, Yao-Ting Mao,

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Acs dave auslander dave pankow sandhu jaikarn yao ting mao

  • ACS

  • Dave Auslander,

  • Dave Pankow,

  • Sandhu Jaikarn,

  • Yao-Ting Mao,

  • UC Berkeley Space Sciences Laboratory

  • University of California, Berkeley

  • February 8, 2010


Acs agenda

ACS Agenda

  • AGENDA

    Hardware Requirements

    Software Requirements

    Control Design

    Model Issues


Requirements

Requirements

ACS Hardware

  • Actuators

    • Torque Coils:

      • 1.23 Am2 (62 turns copper wire 26 inch gauge) at 5.2W

      • 10% Duty  5.3 x 10-5 N-m at 650km orbit altitude

      • Orientation perpendicular to spin axis : Pointing

      • Orientation parallel to spin axis: Spin

  • Sensors:

    • Sun Sensor

      • V-Slit sun sensor oriented looking up at the spin plane

      • Contains two collimated photodiode devices with a

      • 5° x 80° FOV

    • Magnetometer

      • 25 nT resolution in engineering mode

      • Cadence: 1 vector/s at 0.1W

      • Note: Torque coils and magnetometer can be active simultaneously.


Requirements1

Requirements

Software Modes

  • Detumble Mode

    • Detumble maneuver using B-Dot control

  • Initialization Mode

    • Acquire attitude using currents in solar panels

    • Spin-up and initialize sun sensors.

  • Spin-Up/Precession Modes

    • Establish desired spin rate of 4 RPM

    • Establish sun normal orientation (Spin axis normal to sun vector)

  • Nominal Mode

    • Idle mode. ACS OFF.


Design

Design

ACS Control Laws

  • Detumble

    • B-Dot controller from magnetometer data to reduce angular velocities from launch vehicle separations .


Design1

Design

ACS Control Laws

  • Spin/Precession Controller

  • Same laws apply in ground based control

    • Spin Controller

    • Precession Controller

E = hf - h (hf is desired final angular momentum)

E = kB - k (kB is desired final orientation)


Issues

Issues

Sun Sensor Model

kss is a constant derived geometrically and through simulations.


Issues1

Issues

Sun Sensor Model

Non-Linear!

Need to investigate sun sensor activation model


Issues2

Issues

Sun Sensor Model

  • Must rely on uplinked data, system clock, and magnetometer data when the sun is outside the range of the sun sensors or the satellite is in shadow.

  • Multiple pulses (glint) and/or lack of pulses from failed sensor may affect satellite behavior. This behavior is difficult to predict and design for


Acs dave auslander dave pankow sandhu jaikarn yao ting mao

End


  • Login