Unreasonable Rocket Discussion

Given the following snippit of C code we are attempting to add damping or differential correction to the pitch stability. The values gain and DiffPitchRoll are constant doubles used to adjust the various gains. This chunk of code runs 75 times a second and er.Pitch is the IMU raw pitch output. Given we want rate damping what should the sign of the differential correction be ?



/*****************Code Snippit *******************/



static double pitch_prev;
double cur_pitch=PitchConvert(er.Pitch);
double pitch_err=Target_Pitch-cur_pitch;
double pitch_change=(cur_pitch-pitch_prev);



Elevator_Correction_Cmd=(-((pitch_err)*gain))?(pitch_change*(double)DiffPitchRoll);



pitch_prev=cur_pitch;



/*****************End Snippit *******************/








What should the Red ? Be?



If you choose ‘-‘ goto this video: Minus Video
http://uk.youtube.com/watch?v=L-v-F3xnmhU


If you choose ‘+’ goto this video: Plus Video
http://uk.youtube.com/watch?v=ikaxvvFq0Ks


(We have a tethered burn time waiver inplace.)



The vehicle was undamaged in both videos above, We need to work on the altitude control a little bit more and we did eventually tangle the ropes around the the GPS antenna mast 3 flights after the “Plusâ€

Nice :)

HAha! That's awesome! Looks like Armadillo has company! Way to go guys!

congratulations with this flight!! looks darn cool

After the long test in the video we did two more flights.
We wanted to get the "Landing" down.

We did a short flight...

Take off->go to 2M hover for 5 sec descend slowly.
It worked perfectly.

We then did another flight (without refuling) that that was supposed to do exactly the same thing. It oscillated vertically and ended up way high just like the long flight. I terminated the flight and it broke the GPS antenna on the tether ropes.

For the early stability tests we do not have the 25Kg payload on the vehicle as we wanted to reduce the loads on the tether structure. So with no payload and almost no fuel the engine was having a problem throttling down that low stably. We plan to add the 25Kg payload and try again next weekend. The goal is to take off and land with good vertical control suspended under the tether. When we can do that a bunch of times in a row we will keep the tether, but lower it to the ground so it takes off and lands from the pad and the tether is just there as a safety backup to keep it from flying away.

After that we may do some short free untethered flights.
We have a flight waiver in place that allows us to do testing up to and including a 100 second untethered flight.

Paul took off and landed on the ground (with tether) successfully this morning. They still need to do long duration flights, but they get closer by the day.

whoa, wait a min here! that was really awsome who did that? Are you really looking for help with that code Rob? Are you just teasing me ? What kind of engine's there? Was that pulsing exhaust? Awsome!!!!!!!!!!!!! accelerometers and Gyros?
Anyway
Damn go Job!
Way to go!!!!
Monroe

Oops
Damn good Job! not go job:)

Latest post from Paul has been added! and ive posted it here to
http://spacefellowship.com/Forum/viewtopic.php?t=7695

Good to see the Masten guys popping along! bet it was fun.

Rob

Paul seems to be making progress

"Static Test

Our stuff is packed we hope to do a static test of the new solid cataylist on Saturday."

Boing!

Paul seems to be making some great progress along with Armadillo and Masten!

"We did a 106 second stable hover with the blue ball.
We also started working on the PAD forms for the LLC pads.
More info later..."

Also twittering now:
http://twitter.com/unrocket/

Could be a useful link over the next few weeks!

Rob

Another great update!

http://unreasonablerocket.blogspot.com/ ... tatus.html

Unreasonable Rocket tries for Level 1, 2nd Place of NGLLC09

From: xprize | 30 October 2009 |

Unreasonable Rocket made their first flight attempt for Level One, 2nd Place of the 2009 Northrop Grumman Lunar Lander Challenge. Unsuccessful today, they chase glory tomorrow. Discover why they are called Unreasonable Rocket from Paul Breed, Sr. and find out what happened on one of their flight attempts on Oct 30, 2009 from Paul Breed, Jr. For more info: thelaunchpad.xprize.org

http://www.youtube.com/user/xprize#p/a/u/1/_PO5cTb_T5M

31/10/09
Unreasonable Rocket Launch Attempt for NGLLC Level One

http://www.youtube.com/watch?v=JXwsRJzI8vE