@Myles-Levine ,

You should not have any unmasked static objects appear in the camera view because they may have features that will be tracked and will confuse the algorithm because these features will be stationary with respect to the drone even if the drone is moving.

open vins should support masking parts of the camera(s) to ignore any features in this region. I am not sure how to enable the mask, will double check with colleagues (you could also do a search..).

worst care scenario, the part of the image to be ignored should be blacked out before feeding into open vins - that would be the solution if the mask is not supported. Hopefully that is not needed and mask can be used.

Alex

@SKA , I am not sure. please disable all streams except preview and try again. specifically disable:

• small_video
• large_video
• snapshot

Double check to make sure:
en_raw_preview: true
en_preview: true
en_misp : true

It seems you have at least small_video enabled.

What camera resolution are you requesting? (preview_width, preview_height)

Alex

@qubotics-admin The joystick button to use for turtle mode is set via the VOXL_ESC_T_ON parameter.

@cbay voxl-fpv-px4 is based on voxl-px4 but has some custom tuning code / parameters for our fpv drones that isn't in voxl-px4. So, it's kind of a superset. But there isn't anything related to low level i2c drivers so I have no idea how that could be causing this issue.

@ey , please send us a request via http://www.modalai.com/pages/contact-us

Alex

@austin-c , i don't have any concerns for disabling active freewheeling other than the fact that the responsiveness of the ESC will be reduced, as the RPM reduction will be purely due to air drag acting on the propeller (and small friction in the motor).

I can set up the MN4006 motor with a 13 or 15 inch propeller, do a RPM control tune and compare the RPM response results with regen on and off. This is actually pretty quick to do, i will try to do it in the next few days.

Please ping me if you don't hear back by early next week

Alex

@Jetson-Nano , since we currently have no plans to do the MIPI integration of this sensor, you always have the option to use USB connection and voxl-uvc-server to publish images via MPA. You would need to check if the sensor supports the standard UVC interface and try it out...

Alex

Also, you should note - the motor's open loop RPM speed increases at the same power setting -- this is a consequence of not having active freewheeling. This does not mean, though, that if active freewheeling (regen braking) is disabled, that you would get higher max rpm or more efficiency. It just changes the motor pwm % to rpm mapping.

Alex

@austin-c , i just checked and actually we have an option to disable regen braking, it is just not available yet via a param. Here is the test result with same setup (no prop) with regen braking disabled. You can see that the motor takes a long time to coast down, but there is no regen voltage spike or regen current at all. If you application does not require rapid rpm change (high to low), then it will work fine.

We have not tested this in a while, but at some point we did testing for an application with a smart battery which did not like being re-charged with the regen current.

I will see if we can enable this via param or worst case scenario I can share the latest firmware with regen off.

Regarding your other questions:

• i don't think you can put enough capacitance to really absorb all the charge that needs to be stored.. You could do some basic calculations using the current spikes to see how much capacitance you would need, but it think it would be a LOT.
• regarding multiple TVS diodes, yes just connect an array of them in parallel, simply to distribute the energy (heat) across multiple diodes to prevent them from overheating (also can choose larger package, but they all would have to have same specs).

Also, since your motor is low kv, i just want to make sure you saw this document (you probably did, just double checking) : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/doc/low_kv_motor_tuning.md

Actually the app note for low kv tuning was using the Tmotor MN4006 motor with even larger 15 inch propeller (see Tuning Example section). It should work fine with appropriate parameters, we can help tuning if you tell me the exact propeller.

motor MN4006-23 380kV, 18N24P winding configuration
12 pole pairs (24/2)
15-inch propeller MS1503
6S battery voltage

Alex

@greg_s That would explain a lot what's happening.

If you start fresh and connect to the drone with voxl-portal and goto the VIO tab/menu option, you should be able to pick up the drone and perform a bench test.

Considering Figure 8 is not working, you will need to inspect the front and downward camera, tighten/remount any loose parts and possibly check camera focus & calibration.
Worse case if the forward camera is good and not changed from factory, you can edit /etc/modalai/vio_cam.conf on the drone and disabled the faulty camera (disabled the down camera).
You'll have degraded precision (mainly bad vio in fast yaw motions), but should be able to perform a figure 8 and should get you running until you repair that bottom sensor.