Howto Inflight ACC - Calibration in MultiWii 2.0

Method A: The Failsafe method (if you have an aux vhannel assigned to arm your copter).

Preparation: uncomment #define InflightAccCalibration

Step 1 :- Copter on ground, Motors off:
- Stick Combo: Throttle + low yaw left + pitch foward + roll right
-> Copter Beeps 2 times: Function activated (do it again to deactivate: copter beeps 3 times)

Step 2 : get airborne and level copter either by trimming TX in hover mode or level it in acro mode.

Step 3: When copter is leveled (no drift) switch off engines while airborne: copter beeps.

Step 4: Switch Engines Back on and land: copter beeps long and new Offsets are stored in EEProm

Step 5: Start again and notice the new new calibration (Important: If you trimmed in level mode: take back all trims on your TX or you will propably crash)


Method B: Using the passthrough function

Preparation: uncomment #define InflightAccCalibration, assign passthrough to one of you aux channels.

Step 1: get airborne and level copter either by trimming TX in hover mode or level it in acro mode.

Step 2: activate switch "passthrough"

Step 3: land and deactivate "passthrough": copter beeps long and new Offsets are stored in EEProm

Step 4: Start again and notice the new new calibration (Important: If you trimmed in level mode: take back all trims on your TX or you will propably crash)

ps.> this function overwrites the ACC/Trim multiwii is providing, feel free to optimiye I bz hand with the usual stick combo after auto trim.

New airframe almost done

My new airframe is almost done, I just need to mill the new Landing legs and the new constructed motor mounts and it is ready.

The new cage is nearly indestructable and has a MK mounting ring ontop, so I can mount the GPS and the cam up there.

GPS finally working

Mit the newest DEV of the MultiWii Code comes a working GPS routine, I have now fully working Return to Home and Position Hold.

I did some test flights and I am pretty impressed by it.

Updates and videos coming soon

Spring...finally!

Let's celebrate it with some FPV footage:

aaaand

good to be back...

Some minor updates: Gyro Calibration / new GoPro Case

Due to the rainy and windy weather right now, there is not much time to fly and have fun.
I made some short flights in the past days but nopthing serious.

I had some pretty rough days in december. I was pretty occupied with my Taekwon-Do club and hat not much time for the ncopters.

But I managed to do some software tweaks:

I finished and perfected the acc autocalibration and I finally managed to restart the gyro calibration routine at startup if the copter has been moved durin calibration. Pretty handy...


Second small projekt was the revision of my fpv gear. I was unhappy with the bold camerahousing and decided to spend some money for the original GoPro skeleton case, this case is lighter and has the opprtunity to connect the video out plugs while the camera is in the case. Abolutely worth the money.
This way the camera is protecteds way better than beforce. Only drawback: The camera has to be mounted upside down but the gopro is capable of rotating the image live so I still can do fpv and all recordings are rotated too. *sigh*
Especially the lens is now secure. And besto of all it looks way sleeker now.

GoPro HD in skeleton case mounten on nDROiiD 2

My FPV deck is now complete. You can attach it in 20 secondes and convert an action Quad to a fpv gear in seconds.

Nils

Introducing the Inflight ACC Calibration

Hi,

I programmed a feature that allows to find the perfect hovering zero point for the ACC sensor while inflight.

At the Shreddiquette community I took part in programming the same procedure after an idea of a fellow programmer and I ported the idea to Multiwii.

Why:

• In reality there is no flat surface, so calibrating the ACC on ground will bring you close to a good value but you still have to find the perfect trim by trial and error.
• Every copter is different so a perfectly flat surface does no recognice the inaccuracies in a copter, COG, bent arms, askew pylons etc.

Doing this inflight makes sure you are defining the zero point while in a perfect stable hover

How:

1. Arm the function with a stick combo (see below)
2. take off and find the point of no drift (in acromode or in hovemode with TX-trimming)
3. disarm via Aux1 and Aux2 (Aux disarming is a requirement) while flying, fon't worry there is a failsafe that prevents the engine from turning off while yu still have throttle > minthrottle. The offset is measured.
4. Land and redo the combo to save the measured values. (be sure to undo the TX-trimming you did while flying in hovermode)
5. Take off again and be happy ;-)
6. You can do the combo again if you do not want to start the calibration anytime before taking off and do the measurement, to disarm the measurement. If you do not want to save the meausred value just do not do the combo. The values are lost after you cut power. You can always repeat the processover and over again  if you are unhapy with the result.

Stick Combo to arm/disarm the calibration.

You can find the code here:

http://code.google.com/p/multiwii/source/browse/#svn%2Fbranches%2Fjevermeister%2F1.9patch2%20-%20inflight%20ACC%2C%20global%20buzzer%2C%20failsafe%202


Nils

How to catch a quadrocopter