Maiden flight on a 12S X-Class running Orange Cube, APD 120 amp ESC’s with 13" tri-blade props.
Check out the video for the crash.
Upon inspection after the crash, I noticed the machine screws on motor 3 mounting plate (the motor in the 10 o’clock position) was stripped out–the motor and mounting plate was detached from the arm without any signs of damage from impact. I’m thinking it lost support during flight so I looked at the logs, expecting to see motor 3 going to full throttle in order to correct but didn’t see anything that would suggest this.
This is my first time using Ardupilot so I’m very curious to see what ya’ll see here in the logs.
So far, I’m looking at RCOU C9-C12, and DesRoll and Roll for hints. Desired roll and roll show huge deviation, suggesting mechanical failure
You will need to do the initial parameter setup before trying again. The parameters that the quad is on right now are defaults that are for ~10" props on a 4S battery. The mission planner helper will get you some safe values to start. Follow the tuning guide to complete the tune.
The log is largely useless because it appears you’ve done the absolute bare minimum just to get the motors spinning and RC transmitter connected. You’re probably lucky you didn’t hurt yourself or someone else. While I’m not very familiar with Betaflight, it appears that there isn’t much setup required before a first flight, so perhaps that’s been your experience. ArduPilot covers a MUCH wider array of hardware/frame types/sizes, so it isn’t quite as friendly right out of the gate and requires a little care and feeding.
Please follow all of the steps in the documentation regarding “First Time Setup” and “First Flight and Tuning” (including the initial param setup as mentioned by Allister).
I couple of other observations. You have Dshot150 set but are using the Main outputs (I was wrong here). You won’t get Dshot from those, the Aux outputs must be used on a Cube. Also, Dshot600 is generally more reliable. So, reconfigure and assign the Aux outputs or you will have PWM. If you are using Dshot you will want ESC telemetry either thru a serial port or use the BDshot version of fimrware (Beta for Cube plus). Motor RPM is the best driver for the Dynamic Notch Filter which you will be configuring soon after the basics are complete.
It’s critical that you use Mission Planners Motor Test to confirm correct Motor Order and direction. It’s not the same as Betaflight. Perhaps you did this but in case you didn’t it’s the primary reason a craft flips on take-off.
I have replacement parts coming in two days. I will make the adjustments you recommended and record the next takeoff in slow motion.
It’s always hard to tell from merely looking at a video, but all the basic things were ironed out. I’ve crashed enough times to triple check motor rotation, GPS calibration, etc.
It sucks having to crash a drone, but in moments like this, I deepen my understanding of things, and I thank you all for your input.
Based on the video, I think motor orientation was probably correct. The gains are just way off for the size of the copter. You can immediately see wild overshoots in the attitude control before it just can’t cope anymore.
One other thing you will want to change is the compass priority. At present you have it set for the internal compass. Switch this in the compass setup screen. You will want to use Magfit to do a final mag calibration after the craft is basically flying. You can also set this right away:
INS_ACCEL_FILTER,10
And after you have a proper hover throttle value set these as per the tuning Wiki:
PSC_ACCZ_I
PSC_ACCZ_P
With a high thrust/weight craft as this is likely to be these can be important to reduce a output oscillation problem.
@dkemxr, it’s my habit to also enable/tune harmonic notch filtering after establishing a successful hover, prior to any attempt at autotune. You’re a bit more knowledgeable than I when it comes to copter tuning, so I’ll defer to your advice if you disagree.
Magfit is an outstanding tool, as well, but you have no battery monitoring enabled (it should’ve been enabled by default). The initial parameter setup will help with that. You need battery/current monitoring for magfit to be most effective.
I actually do a lot more filter tuning than just that and run multiple iterations of autotune, per Andy’s video series, but we better avoid confusing things more for now!
If anyone has the time to devote, I highly recommend these videos:
Alright, my extra parts are in and we’re looking to hire a tech to help us look over the gains and GPS settings before the next flight. Zoom or Microsoft teams should work…. Details to follow…
I disabled the internal GPS and set the external GPS as primary. I also changed the DShot protocol to 600 and recalibrated the compass 3x.
Existing problems:
We receive a compass glitch during each calibration.
I can’t get mission planner to save the cells of the battery and prop size (keeps reverting to 4S and 9” props).
I should be able to test it again tomorrow and this weekend but given the thrust / weight of the drone, I’d love to have a second pair of eyes go through the parameters before it takes off. It’s just too dangerous and expensive to crash again and again.
So we’re hiring. If anyone wants to assist with this, we have a solid budget set aside for troubleshooting this drone. Either that or we keep ordering new parts until we stop crashing. Haha
Or GPS Glitch?
Wait for a good GPS fix before calibrating the compass but dont be too worried about a GPS glitch if the compass calibration succeeds.
You can always use a flight with lots of Yaw to refine the compass settings with a log file and MagFit.
Do you mean when you go into the Initial Parameters screen in MissionPlanner?
It doesnt read your existing values, it just allows you to put in new variables (prop size and battery cells) to calculate the new values to write to the FC - and it will offer up a window with changes if there’s anything to change. Usually you only ever need to run this once.
Can you post the latest log or param file now?
Just post the .bin file here from the next flight.
Our test flight was delayed today because of weather.
Tomorrow morning we’ll do a hover test.
We just went from the top and reconfigured everything from fresh rather than chasing parameter changes.
The biggest change was adding electromagnetic shielding between the PDB and orange cube. They’re mounted on opposite sides of a carbon fiber plate with EMF cloth sandwiched between. This brought the compass error way down.
I also pushed the ESC’s another inch away from the orange cube.
This configuration also reduced my wiring by quite a bit—shaved off 1/5 pound of 12 wire.
Next side project I’m going so experiment with EMF shielding the PDB via partial enclosure. The housing will need to work in such a way that rain, dust and magnetic interference is mitigates but air is allowed to flow.
