BLS-04 4in1 ESC，Bluejay v0.21.0
BLS-04 4in1ESC 45-65A.pdf (75.8 KB)
cuav-7-nano.param (17.9 KB)
cubeorange.param (18.3 KB)
With the same ESC, cubeorange can get RPM, but 7-nano can’t get RPM.
When I perform a bench test with my cuav-7-nano and an ESC using Bluejay I do get ESC RPM in the log when running motor test. The only difference between your parameter file and mine is I have SERVO_BLH_AUTO,1
Hello
I have changed the log bitmask to default and had done a test flight. Please see the log file attached.
Log
Regards
Mithun
You are now collecting data properly for that Flight Controller. Your problem now is the rather large Yaw Bias previously mentioned that you should have been addressing. Because it’s likely the reason you have 2 closely coupled modes of vibration clearly seen on the FFT graph in Web Tools:
Here is the Yaw bias that requires fixing:
And here is the FFT graph:
And while the outputs are not showing much oscillation I would set the vertical accleration controller gains based on hover thrust now as they are at default. Also, check the Motor Ranges for the proper MOT_SPIN_MIN setting.
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Hi
Thankyou for the suggestions. I feel like my CCW motors has slightly higher friction compared to CW when rotated freely by hand. It is not difficult to rotate or anything but there is a small difference compared to CW motors.
I am using Tmotor Air Gear 450. So is this friction difference causing these yaw bias. Is there anything I can do to reduce the friction of two CCW motors.
Thanks
Mithun
Are you sure the motors are level? It’s common for this to happen with twisted arms or motor mounts.
Hello
Yes the motors and arms are level , I checked it using a level checker.
Thanks
Mithun
Replace 2 motors then.
Is this yaw bias a big issue. I know its bad but I cant see any improper yawing while flying and its holding position well. No errors or warnings on MP while flying also.
Thanks
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It can be. The CCW motors are already being commanded higher and under higher attitude demand they can max out which will produce thrust loss errors leading to instability.
Configure for BetaflightX FRAME_TYPE and re-order the outputs and directions accordingly. Then those motors you say have more friction will be on the right side of the craft rather the on opposing arms.. This doesn’t fix anything really but it may highlight the problem. But, I would replace the motors if what you say is true.
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Hi
I interchanged the motors and checked and the yaw bias was still present concluding it was some sort of asymmetry. So I bought a digital level checker and there was indeed a twist in one of the motor mount.
Now I believe the yaw bias has reduced significantly. I had also set the vertical acceleration controller gains based on hover thrust and configured MOT_SPIN_MIN settings. I have also used MagFit to calculate compass offsets and updated the parameters.
Attaching the log file of the flight after all these corrections.
LOG
Regards
Mithun
Yes, fixed. Now you can set a proper notch filter. This looks good:
You could do another hover flight to check it or call it good, disable Raw logging and perform an Auto Tune. You only want Raw logging active to collect data for the notch filter.
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Out of curiosity how are you mounting the 7-Nano? No issue with vibes they look good just interested to know.
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I mounted the 7-Nano using double side tape on a custom 3D printed mount which is screwed to the top plate . Attaching the images
OK, thanks. Some have vibe issues with those frames was one reason I was asking. I have one of those Flight Controllers but haven’t used it for anything yet.
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