AttoPilot Update March '10 - RC Groups
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Apr 05, 2010, 02:23 AM
Registered User
dmgoedde's Avatar

AttoPilot Update March '10

I have been away from this site for a long time now, so maybe a little update is in order. I have not stopped working or gone away. Quite the contrary. Faster progress than ever. It is sort of freaking me out how much is here as I list it out. Mostly IMU autopilot related:

Tri-copter successfully flown with IMU AttoPilot in a stabilized and assisted attitude mode (Co-Pilot type mode). Planning to offer as a commercial product, likely as part of the standard IMU Atto autopilot system.

GPS + IMU INS filter for heading (without magnetometers!) with uncorrected drift of 2.5 degrees per minute under real flight conditions (tested in flying wings), this has been added to overcome the latency of GPS heading. The GPS heading values are de-weighted depending on the average amount of turning (dHead/dt) over the last few seconds. As mentioned above, even if GPS (measurement) input % is dropped to 0%, I find the estimated heading remains accurate to within 5 degrees for up to 2 minutes. With even very minimal GPS measurement input, this method stays well converged AND allows very fast turns (up to 60 degree bank angles!) without heading overshoot. This means your UAV can execute a 90-180 degree snap similar to a pylon racer and continue on the course without over-shooting the path or over-steering. And in case you are wondering, NO: wind does not confuse this filter in any of my testing, and CenTexFlyer can tell you the kind of conditions we were flying the IMU system in last week... worst possible.

Pitch Airspeed / Throttle Altitude method added (old default was pitch for altitude and throttle for airspeed), plus ability to mix it with old method spread proportionally from mix% A to mix% B over altitude error amount C to D. The mixed method is producing truly spectacular results in altitude and airspeed control. Specifically for hing-wing trainer and motor glider afficianados this method allows AttoPilot to work with your preferred airframe. Even for flying wings, the method gives superior control and saves power by not allowing over-speed condition in steep descents like the old method could allow. Developed a new control method that is almost 100% self tuning - this method is the one that controls airspeed via pitch. User only has to supply a single tuning constant.

Enhanced Assisted flight mode with max roll = 60 degrees, pitch = 45. You can really crank the turns and climb out in ARC assisted mode now. AttoPilot has absolutely no problems (IMU convergence) with high attitudes and g-forces for extended durations. Also implemented enhanced rate dampening methods in assisted flight mode that allow use of 60 degree rolls without spinning up the angular momentum of the airframe too much.

Power feed-forward scheduling in turns to better maintain altitude. This automatic correction is applied in autonomous mode to add extra throttle depending on roll angle. This method makes a few basic assumptions but is in fact model-based (as opposed to fudge-factor would be like "hey... maybe add 5% extra power if the roll is > 10 degrees"). It is also easy to turn off if you don't want it, but I find it adds value so I always use it now.

Motor Start via G-force trigger during autonomous launch. Video coming... This optional feature has been hard-set internally to trigger at 3 G's total felt force. Intended for small hand-launchable sUAS like plank wings (I might make a REALLY tiny plank wing and call it a Planck wing - nerd joke I just made up)

Automatically Tuned Navigation (and it is wind independent as well). Finally took my notes from last year on this one and implemented it in the code. Works as I had hoped. I have even had IMU autopilot customers think they tuned their navigation perfectly and they are all proud of themself, while in reality they had no control over the tuning and the autopilot did that for them. But I will let them enjoy their euphoria and not spoil it.

Some other heavy-hitter modelling and features are coming as well.

Saving of SET.txt to Internal non-Volatile memory. Now you no longer need to have a SET.txt on the micro SD card in order to fly. There are neat little methods to extract the internally settings to the SD card in case you want to know what is in the Atto. These types of features will also be supported through the GCS.

V1.9 created (has most code advancements from the IMU put back into a thermopile autopilot)

Corrected the Xbee modem compatibility issue in code for the V1.8 control board (no hardware fix is required). There had been a logic level issue, but I found a robust fix in code.

Enhanced ground setup procedure. Fix of some old bugs that could allow servo over-travel during ground test, AND added an automatic cycling test of the camera trigger during this procedure.

A LOT of media is coming related to these items listed out above.
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Apr 05, 2010, 06:55 AM
Registered Crasher
Bilox's Avatar
Apr 05, 2010, 09:03 AM
Inherent Tinkerer
Sounds great Dean! Thought you might be hiding out in a cave again!

Apr 05, 2010, 10:56 AM
Gary Mortimer's Avatar
Well now he has told us he can get back into that cave and come up with the next great plan!
Apr 05, 2010, 11:53 AM
Registered User
icebear's Avatar
Great to see you back and thanks for the update Dean - great work!

Suprised to see you tested a Tri-copter - I am testing the german Quadro at the moment.

Apr 05, 2010, 12:00 PM
Gary Mortimer's Avatar
There are more blades coming.
Apr 05, 2010, 02:02 PM
Nemo in a blender
Connexxion's Avatar
Great to have you back Dean.

You're the most important ingredient in every Atto related thread.

Apr 05, 2010, 02:17 PM
Gary Mortimer's Avatar
no no no put him back in the box.
Apr 05, 2010, 02:59 PM
Registered User
Dean is not back just filling in info people have been looking for. If Dean was to come back to rcg in the way he previously was no body would ever get any product. We need to respect his time and space to continue getting the great products he develops.

Apr 05, 2010, 03:07 PM
Gary Mortimer's Avatar
Let him out again in a couple of months Chris, but remember it will be brighter and warmer for him. You did chuck a couple of Easter eggs into the pit did'nt you?? It would only have been fair.
Apr 05, 2010, 07:02 PM
Registered User
when can we get the V1.9 update?
Apr 06, 2010, 03:54 AM
Gary Mortimer's Avatar
If you return your unit to Chris I'm sure he will be able to help you out.
Apr 06, 2010, 02:11 PM
Registered User
Originally Posted by Mecha
when can we get the V1.9 update?
Very soon! Dean is testing as we speak.

I will keep everyone posted.

As Gary mentioned. To get a firmware upgrade you will need to send in your control board and have us do it. Due to ITAR/EAR regulations we are required to do all firmware updates in house. We provide this for free when there is an update for AttoPilot products. End user needs to pay shipping both ways.

We have to play by the rules.

Apr 06, 2010, 03:22 PM
Registered User
v22chap's Avatar
Wondering if ??? the Tri-copter unit of IMU AttoPilot might be used on a twin helicopter ... ie. V-22 , chinook , etc. ,or is there something else in your line that might do the job ??
Apr 06, 2010, 04:37 PM
Registered User
Originally Posted by v22chap
Wondering if ??? the Tri-copter unit of IMU AttoPilot might be used on a twin helicopter ... ie. V-22 , chinook , etc. ,or is there something else in your line that might do the job ??

I will talk with Dean about this. Good question and he may have a very good response.