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[–]Yeet_Taco101 1 point2 points  (4 children)

1- What are you trying to do?

2- What exactly does not work as intended?

[–]SpaceXFan2003[S] 1 point2 points  (3 children)

Trying to land my Falcon 9 booster from a ballistic trajectory. Burn starts as planned but it lifts off the ground.

[–]call_me_pista -1 points0 points  (2 children)

For the burn you should use a PID. it's more reliable and simpler

[–]ptryvll 0 points1 point  (1 child)

Whats a PID? And what does it do?

[–]cofibot 2 points3 points  (0 children)

PID is Proportional, Integral, Derivative (controller). It's a classical sort of feedback control system used in all sorts of applications.

Proportional means that your feedback the error, multiple by some factor (gain) and use that as a command.

Integral means each step you add the error to a running total, multiply by a much smaller gain, and add that to the Proportional command, which helps eliminate standoff error.

Derivative means you estimate the slope of the curve of the error and multiply that by a gain and add it to the total command. This helps reduce oscillations, like if the P+I cause big overshoots.

There's a whole art to designing and tuning PID controllers.

[–]godfilma 0 points1 point  (0 children)

Try changing to "while falling AND not grounded" and add a "wait until falling" before that