Unstable Motors output - Cube Orange Hexarotor x

PX4 Autopilot
1

Hi, I’m the beginner in the PX4.
I use QGC Daily Version master:d31b58f3f 2022-04-22 06:01:09 +0000 to flash firmware PX4 Pro Stable v1.12.3 to my Cube Orange.
I use my custom structure frame, 6xTmotor MN601-S KV170 with FOC ESC Alpha 60A HV 12S, Cube Orange with Here3, Skydroid H12 and 2x6S Battery 16000mAh.

I set the position of sensors like this >
EKF2_GPS_POS_Y = -0.205 m (205 mm from CG)
EKF2_GPS_POS_Z = -0.190 m (190 mm from CG)
EKF2_IMU_POS_Z = -0.15 m (150 mm from CG)

sv
sv1108×1478 374 KB

Calibrate all sensors and radio.
SYS_AUTOSTART = 6001 (hexarotor x)
PWM_MAIN_MIN = 1075 us

Motors test and motor ordering is normal.
I confuse the PWM_MAIN_OUT of this airframe default setting because it’s 12345678 but I think it should be 123456.

I armed in stabilized mode without props and tilt drone 60 degree, then some motors stop and some motor resumed spinning after the drone was placed. So I cannot find the solution to deal with it.
(the method that i test from https://docs.px4.io/master/en/config_mc/pid_tuning_guide_multicopter_basic.html#preconditions)

So I decide to test with props on the ground as the videos and log files.

https://review.px4.io/plot_app?log=ad596ed7-e63a-4f54-abce-35b9bbe2e075

https://review.px4.io/plot_app?log=8ac96d50-454a-4791-a5d5-b09917bdae24

I want to ask some question for the confirmation. Is the FOC ESC need to ESC PWM calibration in the QGC? (in the picture)

image
image705×161 11.8 KB

Please help how to fix this problem. Thank you for the attention.

1 Like
2

I had the same problem until I calibrated ESCs, so I think you should try that. Also, you might have to set the minimum PWM value higher.

3

Thank you pacak.

I don’t sure about the calibration ESCs, because the provider said “FOC ESCs no need to calibrate”.
Could you confirm the FOC ESCs need to calibration?
I use T-motor MN601-S 170KV and ALPHA 60A HV 12S built-in the base of motors.

Should to test PWM_MAIN_MIN more than 1075 us, right?
and PWM_MAIN_OUT is 12345678 is correct? it looks weird.

4

Can’t confirm that, I don’t use the same ESCs.
I know I calibrated different ESCs according to manufacturers notes, and then calibrated them again in QGroundControl.

I can’t tell what you should look for multicopter frame, but for VTOL the parameter is VT_IDLE_PWM_MC; so what PWM it should output after arming and while it’s horizontal.

1 Like
5

Can’t fix it. I set PWM_MAIN_MIN to 1100 or calibrated the ESCs(with Power setting in QGC) but the result as the same as some motors stop in the Manual/Stabilize mode.

= Armed → Thrt20-30% → Some motors stop. → something Thrt or Tilt Roll and Pitch → The dead motors spin but another motors stop
(always there’re 2 motors that stop or spin very low RPM at the same time)
https://review.px4.io/plot_app?log=62207efe-4f18-403c-9185-5f2cc8fe4e07

In Altitude or Position mode if I armed and release the throttle to the center the motors don’t start spinning then disarmed by the systems.

= Armed → Thrt50% → All motors do not spin

But if after arming(Altitude or Position Mode) and push up the throttle about 60-70% the motors starting to spin, then I must to lower the throttle to 20-30% to let it stay on the ground. Then some motors stop spinning after 20-30% about 10 seconds but if I quickly to takeoff it after 20-30% the hexarotor can fly normally.

= Armed → Thrt70% → Motors spin from 0 to fast → Thrt20-30% for 10 sec → Some motors stop
= Armed → Thrt70% → Motors spin from 0 to fast → Thrt30% → Thrt up and control it to smooth takeoff → Fly normally.
https://review.px4.io/plot_app?log=27b7fc3f-76dc-4447-b46a-ecd6d0d2b156
https://review.px4.io/plot_app?log=20bdee2d-dd65-4371-98d8-1ae09c5a23cd
https://drive.google.com/file/d/1W4EMAo-VXO-yw9WSy34W75_WIjLlCY9q/view?usp=sharing

I was test with my Quadrotor with not FOC ESCs it fly normally.
Please help.
What’s my mistake of this symptom?

6

In my case can fixed the hexarotor problem by set the PWM_MAIN_MIN = 1180 us (for this motor combo)
I think the FOC ESCs no need to calibrations as the provider said.
log file : https://review.px4.io/plot_app?log=5d63cd99-a1cd-4c36-a937-265a53389c5f

7

hello,Up,which PCU are you choose？

8

Sorry what’s PCU means?