6 inches Racing drone using Ardupilot

Hello All,

I am trying to build kind of a medium/long range FPV racing drone but I want to use Ardupilot as flight firmware. My goal is make something that can fly autonomously and also by flown in Acro mode like racing drones using Betaflight.

I am using a 4in1 Tmotor f45 ESC with Tmotor F80 2500 KV and 6 inches blades.

I made the preliminary configuration going to the charts and putting 6 inches in the graphs so I get the correct values to change the parameters.

However I could not make the drone to fly correctly in position hold nor altitude hold modes, and even in stabilized mode if i am not super gentle with the throttle stick the drone may flip and crash.

I am sure I will have to configure more things to make it fly properly.

Any help?

Thank you in advance.


1 Like

First thing anyone is going to ask you is do you have a log and have you read the tuning guide.

Thanks for your fast reply. No I don’t have a log, I should have put an SD card inside the SD card slot. I went thru the guide and did all the PID Controller Initial Setup. That was enough in my bigger builds.

Yes, you should have, What Flight Controller?

Thanks for replying.

The flight controller is a Matek F405 STD

OK. Yea, you will have to get datafladh logs going for sure.

Hello all,

Finally I got some time for this project. It happened again. In the middle of the air, suddenly the drone does a unwanted flip. If the drone is flying high, it may recover, if not, it crashes.

I was taking a look into the logs, and I already saw an error: motor interlock.

I am not very good analyzing flight logs, I hope I could get some help to learn how to do it better. Find attached the files.

I am using 2 GPS and GPS blend, when I see the GPS tab I see only 1 GPS line, I am not sure if both are working fine and what I can see is the line of the GPS blending or if only GPS1 is working.2021-03-12 12-48-34.bin (362.2 KB) 2021-03-12 12-48-34.log (677.1 KB)

You have RC7 set to motor emergency stop and you hit RC7

Yes, but that happened after the crash. Once I crash I try to minimize the damages so I hit emergency stop.

De-sync maybe - one of your outputs goes to max when it happens. Also looks like your drone is overpowered as the motors are constantly hitting their bottom limits

The drone is totally overpowered. It is a racing drone. I am trying to use it with ardupilot because I am really interested in the autonomous side as well.

This is going to be a challenge to tune. There is a lot going in this graph but some observations:
As @andyp1per says you are bouncing off the motor bottom limits with almost no throttle. The Motor outputs drop to almost zero (~1100us) and it Rolls over due to lack of stability. It would be interesting to know what your MOT_THST_HOVER value is but it hasn’t flown enough to capture that. But it will be very low.

At what throttle percentage do your motors start to turn during Motor Test in Mission planner? Take a read thru here is what I’m getting at:

Good morning, I went through this. 3 of the motors have the idle point at 3-4% and the last one at 5%

I think, if Im not wrong, that when the done flips and crashes, it flips towards motor 3 that is the one that has the 5% iddle.

Another thing, I was told to disactivate the ESC brake to use a racing 4 in 1 ESC type with Ardupilot. I disactivated it. Any thoughts?

I use active braking all the time - its fine

Isn’t that ESC BLHeli_32? Why are you not using Dhsot? And yea re-enable braking it’s an advantage. And connect and configure telemetry.

OK I will turn it on and see.

Yes it is. I am using the standard protocol, since it always worked for me in the bigger drones. I will switch to Dshot. There will be much difference??

Maybe not but if the difference in motor output is due to ESC calibration you don’t have to worry about that.

I increased the minimum throttle and replace the props by 5 inches (to underpower the drone a bit) and now it flies OK. However I will need to adjust the PIDS a little bit to make it fly smooth. I will try auto tune mode.