Hello. We are experiencing a problem in which the motors spin normally and on high speed (according to our control) when tested on QGround Control. However, when we try to test flight with the actual controller, two of the motors are very weak compared to the other ones.
Here is a link to a video of our drone motors spinning with propellers on. Last week all four motors were spinning weak, but for some reason this week one of the motors is just not spinning at all. It’s kind of hard to tell, but we’ve pull the motors on full power with the controller, but it’s too weak to lift up in the air in addition to the nonfunctional motor.
We’ve replace both our ESC, FC, and PMW, and even resoldered the ESC for possible shorts. Last year our other drone with similar problem was fixed when we met with a Bell Engineer at the UTA Competition. Can we please have the same thing done to our drone ASAP? For convenience, we can also come to where you guys are. Thank you so much.
I believe it’s the ESC that needs to be flashed with the correct firmware. I’m unsure on the exact steps needed to flash it but you should just be able to look up a video on YouTube on how to flash a ESC using a Arduino if not @droneblocks can probably explain the steps you would need to go through to flash it.
After a fair amount of scouring for a compatible, in-depth guide on this process that @GymLeaderBrock has mentioned, I’ve found a couple walkthroughs that share some parts of the process but are ultimately different.
This guide seems to be a solid walkthrough for flashing your ESC firmware using this software and an Arduino Uno. The “choose board” and “select hex file” steps might look different; I can’t tell if you should base your input on the Arduino board you’re using or the Flight Controller that the ESC is connecting to. Just to be safe, if there’s an option for a Pixhawk 6C on the “choose board” step, I would pick that. In that case, in place of the hex file, I’d use the PX4 firmware provided to us by Bell (download FMU-V6C here).
However, when you get to the “Connecting to the ESC” part of the guide you hit another roadblock in the form of a mentioned ESC signal connection, which I am not familiar with. I would look at this HolyBro documentation and see if you can’t create an amalgamation of these two flashing methods. Keep in mind that the HolyBro docs are about flashing a different firmware version (called AM32, we use something called BLHeli_32), so don’t accidently flash your ESC with the wrong firmware.
When you overcome the ESC signal hurdle, just follow the rest of the first guide. When you get to the section where you can change your ESCs configuration settings, I found this discussion post from a guy who seems like he was experiencing similar issues with PX4, and solved it himself.
Of course, this is all speculation based off of internet articles and pre-covid forum posts. If someone from Bell could shed some light on this process, that would be great.
First, we decided to replace both the ESC and the FC. Though that did not directly fix the problem, we believe it definitely helped, since the FC we initially used was not being responsive.
Since that did not solve the problem, we had to resort to the internet and served through some videos and forums. We checked the directions that the motors were spinning and corrected them. This did not fix the problem. Through QGroundControl we found that the motors were now spinning the correct direction but were wired incorrectly with their connection to the ESC. By checking the correct motor positions on the drone using the function of being able to power up individual motors on QGC, we were able to fix the incorrectly-wired the motors on the drone with the additional help of the ESC motor configuration. This fixed the problem of our motors spinning at different speeds but now some motors were not able to have the correct props attached to them. While using QGC and both the motor configurations we noticed that 2 of the motors had been paired with the wrong ESC cable. This is because even though the motor direction was correct due to all the motors being able to spin CW, CCW, or not at all the motors can only be threaded in a certain direction. We had put a clockwise threaded motor with a ESC cable that should have been counterclockwise and the opposite for the other motor. So we had to switch the motors again and make sure to get the right ⅓ chance for the wiring of the motor direction and the correct threading depending on the ESC motor connection cable.
Hopefully this helped and I hope you guys will solve the issue soon.
