Difficulty to run GEPRC SPEEDX2 1303.5 3800KV/5500KV motors with ESC

[ashwin]

Hello,

We are developing a quadcopter using VOXL ESC Mini 4-in-1 [M0129] with VOXL2 board.
We are using GEPRC SPEEDX2 1303.5 3800KV/5500KV Motor with a 2S battery.

We are facing issues with the motors running with the ESC.
One of the motors is not spinning even after throttling up. The pilot has to manually spin the propellers for it to start spinning. The ESC firmware is set by the VOXL automatically when voxl-configure-sku is run. Using a 4S battery helps, but we are limited to using a 2S battery.

voxl2:/$ voxl-inspect-sku

family code:   MRB-D0014 (starling-2)
compute board: 4 (voxl2)
hw version:    1
cam config:    27
modem config:  18 (Doodle RM-2450, 2.4GHz)
tx config:     6 (tbs_crossfire)
extras config: 8 (Lepton)
SKU:           MRB-D0014-4-V1-C27-T6-M18-X8

I wanted to understand if your team have worked with these motors.
In either case, would you be able to assist with understanding the motor behavior and debugging the same.

Regards,
Ashwin

[Alex Kushleyev]

Hi @ashwin,

Our ESC needs to be tuned for the motor / propeller in order to achieve the best performance. In some cases, without tuning, the performance will be very poor, as there is an expectation of the ESC parameters to match the actual motor + propeller. This is done to ensure consistent and responsive behavior of the ESC.

If you are changing motor / propeller, you should perform the tuning procedure described here : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md . Since you are using a 2S battery, you can start with the Starling ESC params (https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-params/D0014_starling_1504_3000kv_ms_props/D0014_starling_1504_3000kv_ms_props.xml) and update the tuning parameters as instructed.

Since you mentioned the sinusoidal spinup, not working properly, you will need to enter the correct kV value in to the ESC param file and may need to adjust the start-up power or target spin-up rpm.

the voxl-esc tools come installed on voxl2 in /usr/share/modalai/voxl-esc-tools and the following are useful commands:

• make sure to stop voxl-px4 before using voxl-esc tools : systemctl stop voxl-px4
• voxl-esc-scan.py will tell you which ESC firmware you are using - you should upload the latest, which is 39.20.
• voxl-esc-upload-firmware-all.sh script will autodetect the esc and upload the latest firmware to all 4 of the ESC channels
• voxl-esc-verify-params.py can be used to check which esc params are installed
• voxl-esc-upload-params.py can be used to upload new ESC parameters.

Please let me know if you have any other questions.

Alex