SingleCopter & CoaxCopter Support

Can I use AUX_OUT for servo control in pixhawk? if Yes, what code change is required to do that? Any pointers will be helpful.

Hi guys!
First time posting, iā€™m working and succesfully flown once a coaxcopter, with a smaller motor than the one in the picture.

Now iā€™m having issues with thrust power, and iā€™m pretty sure is because itā€™s not propperly calibrated, because the coaxcopter weights 1kg and the motor thrust is about 1.3kg (motor: https://hobbyking.com/en_us/contra-rotating-bl-system-375w.html) .

iā€™m using an old APM 2.5 with a custom firmware installed version 3.2.1. Already did PID calibration.

I donā€™t quite understand these parameters, i think these are the problem but havenā€™t figured out yet.

THR_ACCEL_D,0
THR_ACCEL_I,1
THR_ACCEL_IMAX,800
THR_ACCEL_P,0.092
THR_ALT_P,1
THR_DZ,100
THR_MAX,80
THR_MID,510
THR_MIN,130
THR_RATE_P,5
TRIM_THROTTLE,985

Any help will be very usefull.

i attach also full param list
full_param_list.param (4.6 KB)

1 Like

Can you be a bit more specific about the ā€œthrust Powerā€ issues you are seeing?
Can you post a log from the craft?

You would be better served by creating a new topic here rather than tacking onto the bottom of an older and quite long topic.

Initially I would say you are short on thrust.
I would generally, for any copter, expect to have 2:1 thrust to weight ratio.
How many amps are your motors drawing compared to their maximum?
What props are you using and have you tried larger props?

Hi there, How ca I download the firmware for coaxcopter, the link does not work anymore.

hi, i tired the singlecopter firmware for v2 pixhawk, but when i tired arming the motor, all the 4 servos started moving crazily without any inputs from the controller.
please advice.

Iā€™ve updated the wiki page for singlecopter and coaxcopter. If some people here could have a look and then tell me of any issues Iā€™ll fix it up (or you can actually probably edit it yourself). Thanks!

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Hi Randy, @rmackay9

The wiki page looks good! Easy to follow and the flap channels are well explained.
Iā€™m about to try setting up singlecopter on the ducted fan drone shown at the top of this thread. Iā€™m going to be using Navio2 on a Raspberry Pi 3, so Iā€™m sure that will have its own special challenges :slight_smile:. Coaxcopter worked pretty well when I tested it last fall so Iā€™m hopeful for single copter.

As you can see in the OP picture, my frame is oriented in an X format, rather than the + configuration on the wiki. There is a choice in Quadcopter setup between X and + orientations. Is there a way I can setup my singlecopter to navigate in the X orientation?

Thanks!

Hello everyone!

Iā€™m sorry if Iā€™m posting kind of an obvious question here, Iā€™m really a newbie in all this. I was wondering where can you set the FRAME_CLASS value to 9 in order to select the coax flight mode (I just got that from the updated wiki mentioned above). Mission Planner doesnā€™t seem to offer a ā€œsingleā€ or ā€œcoaxā€ class under the Frame Type tab, it just shows many diferent configurations of multicopters. (BTW I made sure my Mission Planner version is up to date) Again, sorry if Iā€™m missing something obvious.

Thank you so much!

Hi John,

Have you installed the Copter 3.5 beta release? You need that.

Also, if for some reason MP isnā€™t showing Single or Coax, you can also change any parameter in the Full Parameter list - you might need to go to MP settings and change the layout to Advanced to see this list.

Thanks for your answer,

I was actually running the arducopter V3.2.1. The parameters list options only shows the following on the FRAME parameter:
0:Plus 1:X 2:V 3:H 4:V-Tail 5:A-Tail 10:Y6B (New)
But anyways, iā€™ll better try out the v3.5 before jumping into any wrong conclusion.

Thanks again!

Wow thatā€™s old. Iā€™m not even sure there was Single and Coax support in that version. You will only find the FRAME_CLASS parameter from version 3.5 forward, it didnā€™t exist before (because all vehicles were separate firmwares but are now merged).

Hello Leonard

Thanks to you and all the others who enabled arducopter to control a Coaxial frame. After a couple of years using quadcopters as research platforms Iā€™m now working on an underwater coax frame. This has coaxially mounted props on channels 5 and 6 and gimbal servos on channels 1 and 2.
After a bit of esc tuning we can get some x y z control with a joystick which is great.
But I notice that the gimbal (x y) control is linked to the throttle. So on the bench all looks good. In the water we need high throttle to control the gimble.
Could you or one of the developers point me at the likely parameters or pwm driver code to tune this relationship?

Thanks again for your work. Iā€™ve attached a photo of the prototype and will post a tank test video as soon as possible.

Kind regards

Martin

HIļ¼Œ How to solve this problem?

Hello Leonard,
Iā€™m absolutely new to autopilots and software they run so I hope for some advise. I hope Iā€™m directing my question to the right person.
Iā€™m building a small single copter. Iā€™m about to buy the Pixhawk Mini because the PX4 is quite large for this drone. Would appreciate it if you could confirm for me whether the Mini is fully compatible with the PX4. Will Ardupilot/Arducopter run properly on Pixhawk Mini in the single copter mode?
If not, what hardware-software combination would you recommend?

One more question: if Mini is acceptable - can I mount it vertically instead of horizontally?

Thanks a million!
Andrew

Hi there! IĀ“m a little confused. Copter documentation says I shouldnĀ“t connect Servos to MAIN ports. Nevertheless, the SingleCopter & CoaxCopter information says they should be connected to MAIN 1 to 4ā€¦
Can anyone clarify me this? Thanks!

The output frequency of the ports are defined in blocks of 4. So you should not put ESCā€™s and servos on the same block of 4 outputs.

I think that is the only issueā€¦

Hi Andrew,

It should be fine. And you can rotate it with the AHRS_ORIENTATION parameter.

Just a warning. I have learnt more since I did the output mixer and I suspect we can do a better job than we have currently. I will hopefully get a chance to improve the controller soon for single and coax copters.

Thank you very much Leonard!
Please keep me posted on any improvements you make for a single copter.

Regards,
Andrew

Hi all, Iā€™m building a singlecopter and was able to fly in stabilize mode. However, in Althold mode the barometer seems to be strongly affected by the propā€™s airflow as it is located directly above the prop. Iā€™ve already shielded the baro with dark foam but that doesnā€™t help. Is there any solution other than just re-locating the baro outside the propā€™s airflow (which is not an option for me right now). Do you think if we tune the control gain carefully they will automatically compensate for that effect?

Hi, do you mind sharing your coding? because currently iā€™m designing a singlecopter and hope to get your coding as reference.

Thanks in advance.