Dear Friends,
after a lot of work on Electronic and Frame we are happy to present first flight test of VRCopter complete of VR 2 Axis Gimbal .
In this fly we test this Copter configuration :
- VR Copter Frame .
- VR oring anti vibration system.
- VR Copter Landing Gear
- VR Gimbal Frame and Electronic for GoPro Hero 3.
- GoPro 3 Hero Silver
- VR Brain 4.5
- 4 MK3639 motor
- 4 ESC with SimonK Firmware
- 3DR GPS
- 3DR Telemetry KIT
- 4 APC 12 Propeller.
- 10 Amp 3S battery flight time around 20 min without payload until 24 min.
In this test flight I checked the behavior of the drone in different situations both at high altitude I flew about 50 m high and low altitude.
The video that is present in raw format created with the GOPRO 3 silver model you do not notice the presence of high-frequency vibrations, which were removed by introducing a special anti vibrating plate inserted between the frame of the drone and the gimbal . There are only some low-frequency vibrations due to the influence of the wind at high altitude on the mechanics of the gopro gimbal frame we're still working to improve it further.
Overall, we think that this platform can be an interesting alternative to cars like the Phantom of the DJI is that in the previous version thanks to a range of great flight almost 20 minutes.
This drone configuration will be available in DIY KIT before the end of year in the next week will be available more info about it
original blog post : http://www.virtualrobotix.com/profiles/blogs/vr-copterx4-with-vr-2-axis-brushless-gimbal-a-good-entry-level-pl
more info about status of VR Gimbal project : http://www.virtualrobotix.com/group/vr-gimbal-user-group?xg_source=activity
best
Roberto
Comments
Roberto Navoni: I am happy to hear that (I think it was the link from the prev. post)! There are several other codegems in the opensource arena you could hint your devs at. Thinking of the "D" part again it might be reasonable to base that only on Gyrodata (and not on calculated angles) because it's anyway a relative term and it may be a way to reduce further errors resulting from the angle calculation. Perhaps something to try out for your devs. The next thing is the offset calibration. Just adding up some values and calculating the median will work but you get better offsets with that: https://pixhawk.ethz.ch/px4/docs/calibration__routines_8cpp.html . I use that algo for MAG/GYRO/ACC calibration. You also might consider some kind of temperature compensation for gyro AND acc. Google for picopter there you will find EKF and quaternion IMU stuff that could pull your project ahead.
Cheers Rob
So on VR Gimbal i think that we tried at 250 hz , but i'm not remember tomorrow check the code.
Today we apply some patch propose by Crashpilot :) It work fine ... so now we have to solve only a problem again ... if the pitch and roll is ok the gyro info is ok , but if we have some roll % when we move the roll the pan ,too move ... so the option are two :
1) Use second imu put on landing gear, as in original project so we have right info of speed of rotation of pan or
2) Option implement a right and precise roto translation , what's could be better approach ? Some suggestions ?
best
Roberto
Roberto, so you tried the DCM, but find it's slow? What rate were you running it at? I think by default it runs at 50Hz or something?
Hi Joe,
at the moment is not yet available ... will be soon I think before end of this month.
Thanks
Roberto
Hi CrashPilot i see your friend request but your message with your mail disappear .. can you send me your mail again ? So if you want to contact me live me account on skype is : virtualrobotix
Hi Roberto,
I always enjoy your posts. When will you offer the VR CopterX4 with VR Brushless Gimbal for sale on your store website? How much?
Thanks,
Joe
@R_Lefebvre
the code inside the gimbal is yet implemented to use AHRS DCM used in Arducopter , in our test we see that it is too slow in reaction .. so could be that we need to up the gain .. sure ... suggestions about dcm configuration gain is welcome .
Best
Roberto
@Roberto Navoni: Thank you very much for your offer! I could look at your Imu/sensor calibration parts and perhaps do some improvements there but nothing groundbreaking for sure. But it might take a few days. And I will check that once it's in the repo and PM you. I think R_Lefebvre is the right guy for that job to do something more appropriate! A better copter and bl gimbal are on my 2014 agenda, got too much stuff in between right now.... Greets Kraut Rob
Why wouldn't we just go to DCM to start with then? It works perfectly on my helis! Nothing screws it up.
Put the GPS signal into it for acceleration compensation, the whole thing. Roberto already has that running on VR Brain.
Anyway, pretty exciting that, as good as these things operate, there is more performance to be easily gained.
Hi Kraut Rob,
if you are interest to evaluate new code that will be available for VR Gimbal tomorrow i can share it with you before to release to repository. Now we are reworking on some lib for 3 axis stabilization.
If you want join in development you are welcome :)
On VRGimbal there is available a lot of lib from Arducopter development for AHRS computation using dcm , but is not so simple match the requirment of Brushless Gimbal with a standard DCM code because normally in standard gimbal implementation the priority is on gyro and not on accelerometer. We doing some test using dcm instead brugi stabilization code and we see that the correction work very slow , so we prefer mantain brugi implementation with some patch. If you need more info about our development i can ask to Matteo to speak with you about the new code.
Best
Roberto
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