Ballast Algorithm v1 Requirement

Safety requirements

  • Do not ballast under 3000m MSL when over land (for fire safety)
  • When CUTDOWN NOW command is received, wait to ballast until after cutter has cooled to below alcohol ignition point
    • Suspend ballast for 1 minute after cutdown command

Control requirements

Normal Ballast Mode

  • Start with Delay of 1 minute for inertial stabilization of vertical velocity. This also allows time to take the moving average of vertical velocity.
  • Altitude Low setpoint
    • Ballast when below X threshold altitude, threshold set by ground control, default to 8000m or may be adjusted automatically according to conditions
  • Vertical Velocity setpoints
    • -10m/min maximum descent rate target

Static Ballast Release

To compensate for the continual diffusion of helium through the balloon envelope

  • Every hour, release 4 grams ballast

Conditional Ballasting

  • If sunrise is imminent
    • temporarily lower ballasting threshold altitude to 3000m
    • After sunrise has occurred, set back to normal

Sunset Ballasting

DO NOT USE ON SPEEDBALL-1 - unlikely to have any advantage over standard routines

  1. Record maximum helium temperature reached in daytime, convert to K
  2. Uplink predicted epochtime of sunset along predicted path
  3. Uplink forecast evening OAT in K (do this well before sunset)
  4. Resume normal ballasting until sunset
  5. 15 minutes before sunset, arm Ballast Sunset Drop Mode
    1. use ratio of these temperatures to calculate weight required to drop at sunset. See image: (insert here later)
    2. Trigger sunset drop by -31m/min vertical velocity
    3. Tell ballast controller to drop X grams of weight
  6. To exit sunset ballast, and return to normal:
    1. Wait for any positive velocity
software/speedball1/ballastalgorithm.txt · Last modified: 2018/07/29 17:58 (external edit)
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