Servers by jDrones

SingleCopter & CoaxCopter Support

(MadD MacKx) #61

@Leonardthall @tridge

Thank you very much… i will change those parameters and post the logs and videos tomorrow

(Jacko) #62

Here is the first crude tuning log for the single copter firmware…

Just single degree of freedom in roll. Aircraft suspended on a string attached to the nose and the tail of the aircraft.

I am varying the P term during flight with CH_6 option. It’s quite a wild machine at this point at least until the string is pulled tight but the roll is locked in all the way through. I do have control as you can see!

Yaw is going to be very hard to tune however. I’ll let you know how things progress let me know if anyone can give any useful input from this log.

Thanks for all your contributions.

(Christopher Gehrich) #63

Bump. Are we getting closer to a firmware that we can attempt to fly?

@Jacko1 @maddmackx @Leonardthall @tridge

(Leonard Hall) #64

Hi Fragmaster,

We are just waiting for someone to send us a video!!

Links to the firmware are above and they are also in master.

(MadD MacKx) #65

Sorry everyone…I thought I had some free time. Turns out I was wrong lol. Any which way, I have done a bit of testing with the new firmware and there have been some HUGE improvements.
Servos are “NOT” buzzing any more
Servo throws and general control’s have been greatly improved

My main concern that I have is still with the throttle. I only have control of the throttle like shown in the video on the bottom 1/4 of the actual controls (i would really like to have throttle control through the full range of the stick.

@Leonardthall @Fragmaster

I will try and post a video when i get back into town (zero hi-speed internet at the moment :frowning: )

(Christopher Gehrich) #66

@maddmackx got any video? Great to hear that servos may stop burning. I’ve had to move my pixhawk onto my hex in order rescue my ZMR250 from the top of a 70ft tree, so I can’'t test this week.

I guess I’m the guy who occasionally cracks the whip. LOL

Thanks all, for working on this project. We’ll get something flying soon!

(MadD MacKx) #67

@Fragmaster @Leonardthall @Jacko1 @tridge @rmackay9

Hopefully this video and file help :smile:
Thanks again everyone

And here it is

The .bin file

And the corresponding video for the log

(Christopher Gehrich) #68

Thanks for the video @maddmackx! Great to see that the servos are no longer burning. You are using two servos? What channel numbers are you using for everything and what is the rotation direction and motor number of your top motor?

(MadD MacKx) #69


Hopefully this helps…if you have any other questions feel free to ask :slight_smile:

(CM) #70

Hey guys. I have a very simple SingleCopter that I have been test flying for over a year now. The vehicle has made over 60 test flights using version 3.3. I haven’t been reading the forums and I didn’t realize that there was so little development on the single/coaxcopter frames. I’d like to help in any way I can. I owe this community a lot. ArduPilot has been such an incredibly useful and fun platform to work with. Please let me know if you would like me to test any code, provide any data, or if there’s anything else I can do.

Here’s a few pictures and videos of the vehicle. If you’re wondering about the unusual design, it was designed to help test controls for a tail-sitter style UAV.
Picture on the ground
Picture in the air
Vertical stability testing
Testing the horizontal limits
Screenshot of frame model

*edit to fix the links and remove signature

(Christopher Gehrich) #71

You are using the default ArduCopter 3.3 Singlecopter profile? Did you have to build the binary yourself or is there a binary already that you simply uploaded and adjusted? If I were to try your binary on my heavy 6S ducted fan singlecopter, I think it would instantly flip over unless I can tune the PIDs first.

Looks really nice! Basically a hovering kite.

(Leonard Hall) #72

Hi CM,

Thanks for posting!!!

Can you tell me where the battery is being mounted and a few more details about the airframe. This looks like it would be a great test bed for single copter.

I would really appreciate it if you could test the new code. The mixing on the actuator is based on more aerodynamic models now so you may have less problems with fast flight. The new quaternion controller also handles higher angles too so that will also help for forward flight.

Thanks and chat soon,

(MadD MacKx) #73

LMAO…I guess me and jacko are now chopped liver??? I would still like to contribuite any help if you still want it. :scream:

(Leonard Hall) #74

Not at all Maddmackx :slight_smile:

We have thousands of people flying multicopter but we are a little short on coax and single copters. Every addition to the groupe is a big step forward. Having someone who can compare the performance of the old code vs the new code is very valuable.

Jacko had his first flight today!! Still needs some tuning work but it is looking good!!

(CM) #75

Correct. I had to build the binary, but otherwise it didn’t require any changes (IIRC). Tuning the controller was a real challenge. Many props and a few motors shafts gave their lives so that it could fly.

Thanks. Hovering kite is a good description. My official name for it was the unimaginative ProtoB for prototype B, but the best name I’ve heard was the Flyangle. It’s nothing compared to the beasts you, maddmackx, and Jacko are building though.

Sure. The battery is located in the center, slightly above the flight controller, on the back side. The airframe is made of carbon rod, a few 3D printed joiners, some Depron foam, and a laser cut wood mount for the Pixhawk. Total weight is 565 grams with battery. The telemetry modem is running at 115200 baud. Sadly, it does not have a GPS. It was designed as a crash-resistant test rig for the sole purpose of testing code and tuning PIDs. I’d be happy to talk about the story behind the project, but that is a wall of text I’m not sure belongs here.
Picture of back

That’s why I’m here. Let’s crash this thing so others don’t have to. Should I try the master branch or one of the binaries floating around here?

You guys have been busy. The quaternion controller sounds exciting and complex(just googled and found a paper). There are a lot of projects where that could come in handy. Is there somewhere to go to read more about the aerodynamic model?

Nothing of the sort. This is just a simple proof of concept test rig. It is a far cry from a practical or even useful vehicle. The only benefit is that I can use this to test the basics of vehicle stability with very little cost or risk. It won’t be until the more refined vehicles like yours are flying that testing of various flight modes can commence.

(Leonard Hall) #76

Hi CM,

If you can compile and run Master, that would be the way to go but the last version I point to above is also fine. You are right, 3.4 is going to be a monster release!! Quaternion implementation has been the most difficult thing I have done on the project, easy to get working, very hard to do right!! The only other thing that really came close was the navigation controller.

Yes, I really like your design for two reasons. The first is because as you say it looks very crash resistant and quick and easy to build. The second is that with the correct CG it transitions into a delta wing plane. This is something we are going to be dealing with more and more and I need to look at handling lifting bodies in multirotors.

Could you tell us what cell count and capacity of battery you are using, what kv and prop diameter? I would also be interested in the basic dimensions and the depth of the flaps.


(CM) #77

Sure. I’ll compile and test it asap. I am looking forward to it. Some of the features implemented in ardupilot are just incredible. This project never ceases to amaze.

Thanks. The final design was a more traditional delta wing. Unfortunately, it only made a few flights before the project ended and it was retired. I may try to build another similar design one day though.

The control surfaces are 7.75 inches wide and 1.5 inches in length. Angled cuts are ~30 degrees. I also have another set of surfaces (somewhere) that is 3 inches in length.

Power system

  • 10*4.7 APC SF Prop
  • 11.1V (3-Cell) 1800mah LiPo Battery
  • 30A** Cheetah ESC
  • 1100kv** A2826 Cheetah Motor
  • 3A** Cheetah BEC
    **These should be correct. Many of the parts for this were scrounged from other projects and were not labeled.
    Total flight time is abysmal. It a race between the motor overheating and the battery voltage dropping under heavy load.

(CM) #78

Hi Leonard,

Sorry to say that I am the bearer of bad news. I compiled from master last night and uploaded today. The behavior was bizarre. At first I though maybe I accidentally built a quadcopter firmware, but I was able to confirm “Single” in the message console. I’ve uploaded a video of the behavior. Needless to say, I did not attempt flight.
Video of test


  • Controls moved before arming (This may have been a dev decision)
  • Controls began jittering motion immediately when vehicle was armed
  • Jittering motion of controls ceases while throttle is applied
  • Servo response seems far too aggressive (might be rates or other parameters)

One other odd potential bug. As a test I changed MOT_SV2_REV and saw no effect, even after restarting the pixhawk.

Is it possible that my build was somehow incorrect? The only change I made was to the frame type in APM_config.h.

(Leonard Hall) #79

Hi CM,

Could you send me a log of that video. I thought I fixed the jittering.

The movement of the servo’s when disarmed is there so you can ground check the aircraft and ensure control surfaces are moving correctly.

To reverse the servo you need to enter -1.

You may also have to change the pids now. When at a low throttle you will find the servo’s move more than at full throttle however there should be no change between zero throttle and quarter throttle.


(CM) #80

Sure. I couldn’t identify the log for that video so I did my best to reproduce the same sequence.
Log File

Oops, good call. Servo reversing works fine.

Tuning the pids shouldn’t take too long once it’s airborne again. I tried the INS and ATC filter setting that you suggested to maddmackx but it did not help.

Also, same as maddmackx, my motors and prop were scrounged from a quad copter and get far hotter than they did in that configuration. This has been a problem since the first flights (on the older 3.3 firmware). Because I never did any calculations I always assumed it was just too heavy. Whatever that problem is, I don’t think it has to do with the proportional throttle servo mapping. I could try flying with the throttle passed-through the controller to test if that makes a difference.