I use an APM 2.5 running arducopter FW 3.1. It has flown for many months very well. After a crash which broke the micro usb port off the circuit board, one of the motors begins to spin only after the other three are at nearly 15%. I can take off, but the one ESC/motor combination does not provide as much thrust as the other three which seem quite balanced. Once I switch to loiter mode, the quad will hold its position. If I return to stabilize, then the weaker motor drops it's thrust lower than the other three.
I've calibrated the ESC/motor sets simultaneously and when initializing thrust, the lazy motor starts up at the same time as the others and increases in the expected way. Once, I arm the quad, the motor goes back to its lazy ways.
I have the same effect if I replace both the motor and ESC for another motor and ESC.
Since I have no usb port, I can no longer download logs and can no longer upgrade or replace the firmware on the APM.
Any ideas?
Replies
sory to interrupt, but i having this problem, but not the usb broken, what can/should i do so that all the motor able to spin all together once the throttle increasing
Andi,
You can calibrate all the ESCs to begin spinning the motors at the same time using the details on the following link: http://copter.ardupilot.com/wiki/esc-calibration/
If you perform the ALL AT ONCE calibration of the ESCs and find that the motors don't begin spinning simultaneously, here are some reasons that come to mind:
Let me know what happens after performing the calibration.
Do you have a telemetry link? Logs can be downloaded via telemetry.
If not you could try to solder on a new USB port depending on how severe the damage was to the board. If you don't have any extra usb ports lying around you could attempt to solder a USB cable directly to the board giving you essentially a new USB port.
Otherwise, your testing has shown that that specific port on the APM is not functioning as intended. With no other way to access the firmware that I know of there isn't much you can do. If it was just a port or a pin broken a custom motor config could probably let you use a different spot but gaining access to the board still remains an issue. Perhaps taking a close up photo from whats left of your board will provide insight for others to provide assistance.
Here is a pic of the usb port (upside down) near the location on the board where it resided prior to the crash :)
That is totally fixable with a bit of patience and pre-soldering of the pads. That being said it would be even easier with a hot air rework station instead of a single point solder iron but both are doable.
I do have a question about the overall problem though. Lets say for argument sake that your ACC went buggy after the crash and now instead of level it now thinks it is leaning to a certain side (bad ESC / motor side). This would explain how different motors / ESC's all have the same problem manifest and why loiter performance is fine.
I'm willing to bet that if acro mode was on it would fly just fine since that doesn't use the onboard ACC. (acro with trainer off). but i'm also willing to bet that you'll need that USB port to test that theory as well.
If you have another flight computer (any kind) try to connect that and see if the problem follows the flight computer. Although i doubt it.
Maury, after seeing a few people solder these small USB ports onto other circuits, namely smartphones, I am ready to attempt soldering the port back onto the board. I'll do that this weekend. Since I am running an older FW on the 2.5, I will be happy when I can reflash the HW with arducopter 3.2.1. It has many improved functions which I enjoy on some APM 2.6 flight controllers I have on other copters.
Thank you.
Glad to see everything is back on track. I will say that it is slightly rare for an impact to mess up an ACC but it can and does happen from time to time. Double check that your physical flight computer has not moved or a component has come loose while you are at it.
Good luck soldering that USB port. I invested in a soldering workstation like this one and have never regretted the purchase. Some of them even contain heated beds to help reflow soldering type of work. Worth looking into if you ever need an upgrade.
Happy flying!!
Maury,
I attempted to solder the USB port onto the board, but don't have the eyes to see those little pads nor the tool for the accuracy required to solder it to the board. So, I'll settle with use of telemetry and the older version of the FW.
Thanks for the link to the hot gun / soldering station. However, as things stand now, the price does not justify the purchase. The drones I build and fly are for my hobby and a father-and-son club. Neither are at the level of requiring this USB port to be soldered back in place. It was my first build and has some historical significance. However, the club has built many other copters with APM 2.6, KK2 and multi-wii flight controllers. The quad with the APM 2.5 has been flying for nearly one year.
This repair experience has shown me that the extra motor and ESC are in great shape and would be useful parts if needed in the future without any additional testing.
Thanks again for your help.
Sorry to hear you couldn't get the USB port fixed. If you ever needed it fixed and are willing to send it off let me know. I'd patch it right up for you myself.
I still have my first quad assembled and on my wall. Nothing but wood and zip ties. Flew like crap in comparison but its a memory thing. Now and days everything is CNC machined, printed, or molded.
I've been looking for a flying club myself. Sadly, there hasn't been one in my area for years. Either way, enjoy the flying and the community.
I'm interested in you patching the USB port. Can we discuss?
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