@Alex-Kushleyev Appreciate the suggestions and recommendations, especially about the ESC temps. I saw the >60A current draw in the calibration results and informed the team last night so we're going to be cautious on the first flight.
I did use the low KV initial calibration params but I'll likely use the Starling 2 MAX ESC gains as a starting point per your recommendation.
If I have any additional questions or updates, I'll post here.
Thanks again for the help!
@Alex-Kushleyev We were able to change our setup to calibrate with a Linux PC directly connected to the ESC. The calibration results look much better.
Here's the calibration results for ESC 2 with the current output as well:
https://drive.google.com/file/d/1jXxyAO6eBfVzh6qAuWCJVFvE2Dsa1sZX/view?usp=drive_link
For reference, the Linux PC has Python 3.12.3 (it's actually a Windows PC running Ubuntu 24.04 via WSL).
The VOXL2 has Python 3.6.9 on it. Do you think this difference in behavior is because of the Python version or possibly the VOXL CPUs being too bogged down when running the calibration script directly on it or possibly something else.
Appreciate the help on this. I'll follow up if we have issues with flying our drone with the updated calibration.
@Alex-Kushleyev I'll work on trying out the calibration script running from a Linux PC instead of directly in the VOXL this afternoon.
In the meantime, do you have any feedback regarding the starting calibration file? We followed the instructions as close as possible:
- specifically, make sure that num_cycles_per_rev is correct (usually 6 or 7 corresponding to number of pole pairs), otherwise RPM will not be calculated correctly
- set vbat_nomival_mv to nominal battery voltage
- leave other parameters the same, as they may not be known
We set the num_cycles_per_rev based on the 14-poles of our motor and the vbat_nominal_mv for the 6s battery that we're using, but we also set the motor_kv value to match the value of the motors.
Does the motor_kv value make any difference if just using the calibration script?
We've reviewed other forum posts regarding ESC calibration as well as the instructions for the low KV ESC calibration (even though our motors aren't necessarily low KV). Both the posts and the low KV instructions mention setting the kp and ki to 0 and even setting the pwm_vs_rpm_curve_a... values to 0 to disable the RPM control. Does this matter when just doing calibration with the calibration scripts?
Thanks, I'll provide an update once we're able to run the calibration scripts on a Linux machine instead of directly on the VOXL.
@Alex-Kushleyev We're using the calibration example command referenced in the documentation:
./voxl-esc-calibrate.py --id 0 --pwm-min 10 --pwm-max 95
Hi, we're trying to calibrate the ESCs per the calibration instructions, but we're running into some challenges and the calibration results do not look correct (at least when compared against the reference in the calibration documentation).
Here's some info on our setup:
We're using v1.5.2 of the voxl-esc-tools directly running on the VOXL 2 to do the ESC calibration. The ESC's were running v39.00 FW, but when I upgraded to v39.20 FW today, I noticed the same behavior.
For the starting calibration file, we've use both the Starling 2 MAX calibration parameters (see /usr/share/modalai/voxl-esc-params/D0012_Starling_MAX/esc_params_m0129_f2203_5_1500kv_7x3.7x3.xml) and the low KV calibration parameters as starting points (see /usr/share/modalai/voxl-esc-params/low_kv/mn4006_m0134_6_low_kv.xml) as starting points but made sure the following fields were changed to match our motors and battery:
vbat_nominal_mv = 22200num_cycles_per_rev = 7 (the Lumenier is a 14 pole so 7 pole pairs)motor_kv = 1050We calibrate from 10% - 95% per the instructions, but no matter the ESC/motor, the calibration process maxes out at around 60 - 70% power (11k - 13k RPM).
Here's a link to the calibration results on ESC 2 when using the Starling 2 MAX cal params as a starting point (with the mentioned changes to match the motors and battery):
cal results (Starling 2 MAX)
And here's a link to the calibration results on ESC 2 when using the low-KV cal params as a starting point (with the mentioned changes to match the motors and battery):
cal results (low KV)
You'll need to download the HMTL files to view them locally.
As stated earlier, it looks like the power only goes up to 60 - 70%. It also looks like the voltage command inputs are "overlapping" leading to the same resulting RPM output and there's not as many distinct RPM values as seen in the reference in the documentation. We notice this on all 4 ESCs. I shared the calibration results for ESC 2 since it provides the current output as well.
Does anyone know what might be happening here and what needs to be done differently? Let me know if the calibration parameter files we used initially are needed. Thanks!.
I have a question about setting up the extrinsics and the camera coordinate frame. Where exactly is the camera coordinate frame on the camera? The center of the lens, on the bezel, or somewhere else?
For background, we're looking to use a VOXL 2 with the C29 camera configuration like on the Starling 2 Max but with our own custom frame. The locations of the hires, tracking and ToF sensors won't match the Starling 2 Max because it's a different frame. Our ME looked at the Starling 2 Max CAD and the coordinate frame of the tracking camera appeared to be on the bezel.
So we wanted to get clarification on where the coordinate frame are for the cameras.
Thanks!
@Moderator That's exciting, I'll be on the lookout. Thanks!
Hi. I'm wondering if it's possible to use the hires image sensors as the image feed source for off-the-shelf FPV goggles with the VOXL 2 in addition to being a pipe for the VOXL to do some image processing or computer vision.
I saw this page in the documentation of using third party VTX on the VOXL 2, but it seems like the camera connected to the VTX is not directly connected to the VOXL 2 by the MIPI ports so it doesn't seem like the stream can be used by the VOXL 2.
For background, we're looking to develop a drone that has FPV capability with FPV goggles but also an autonomous mode and we're looking to reuse the hires image sensors for both the FPV goggle feed as well as any type of computer vision for autonomous navigation.
From my investigation, it seems like this wouldn't be possible with off-the-shelf components, we'd have to spin our a custom FPV goggle that can receive the hires image sensor feed from the VOXL 2.
Thanks for the help!