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Jun 19, 2009, 12:04 PM
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We Hard Code Takeoffs Becuz


Payload & engine performance is mostly constant. Sensors capable of detecting the first few feet of altitude R heavy, expensive, & unreliable. It takes a lot of fuel & time to hunt for equilibrium thrust. An adaptive takeoff algorithm gets U on North Korean headlines, but all roads lead to hard coding.

Rocket launches R hard coded. Put the SSME at 104% & go. John Carmack was the first to use a carefully tuned PID controller & burn a lot of fuel to take off. For some reason, rocket hobbyists all copied him.

Maybe we've gotten jaded about physics. Went from a totally adaptive vision to over 200 parameters in configuration files. Some of it is configuring your own GPS system.

BIAS BUSTERS

Now for the first time ever, it's a graph of neutral pitch vs. neutral yaw on the same IMU. They're coming out consistent on the same day, but not days apart. Suspect there R mechanical instabilities in the gyros which keep any temperature table from getting the last bit of gyro bias. Since we're using another gyro as the thermometer, it squares the error from mechanical instability.

Yaw bias from pitch bias is busted yet again, but hopefully we still can get yaw bias from position, the most cooly deadly looking a piece of calculation as ever U have laid eyes on.

BUDGET BUSTERS

Sonar is killing the budget. It requires flying low & fast over a sea of electronics & quickly damaging something after only a few minutes every commute. Most propellers have broken on the ground station antenna. Also had a PICOC crash in flight. Not much left after that one. Program termination is a problem for PICOC.

Sonar guided takeoffs work. It jumps into the sonar field out of control, goes crazy with the first error ridden position readings, & finally achieves equilibrium. Stopping the ascent before it lifts above the sonar field is a failure point, however the sonar field extends slightly over 10m high.

Sonar guided landings suck. That is a descent into a sea of electronics, loss of position sensing, hard landing.

Still entering significant oscillations after a certain time on most flights.
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