# VOXL M500 vision problem!!

Source: https://forum.modalai.com/topic/105/voxl-m500-vision-problem
Category: Flight Core and Legacy VOXL (https://forum.modalai.com/category/9/flight-core-and-legacy-voxl)
Tags: flight-deck
Posted: 2021-01-20 03:53:34 UTC by Vũ Văn Long
Replies: 12 · Views: 2930

## Vũ Văn Long · 2021-01-20 03:53:34 UTC

Hello, me again my voxl m500 frame is driff while fly in position mode ![Screenshot from 2021-01-20 10-42-11.png](https://forum.modalai.com/assets/uploads/files/1611114412799-screenshot-from-2021-01-20-10-42-11.png)  

here is the voxl/vision-px4.conf text. last time after reset the configuration to the factory -> then i also changed the offboard mode to "off" and the m500 can fly in poistion mode but the performance is not good, it's mean sometime the the driff was maintained. i think the problem is not here. (about reset the vision-config to the factory, i just reset and not config anything...
 pls help me!

## Reply by Chad Sweet (ModalAI staff) · 2021-01-20 03:59:13 UTC

Is the tracking camera looking at interesting "features" when it takes off, or is it just white floor? If it can start on a carpet or something, the vision system will have something to track. this will help VIO reduce drift.

## Reply by Vũ Văn Long · 2021-01-20 04:07:42 UTC

it just is a whitle floor like this ![140399418_1382482975425604_1999387540459859908_n.jpg](https://forum.modalai.com/assets/uploads/files/1611115659841-140399418_1382482975425604_1999387540459859908_n.jpg)

## Reply by Chad Sweet (ModalAI staff) · 2021-01-20 04:11:25 UTC

Can you put some pieces of duct tape on the floor or something to make it more interesting to the VIO system? Especially since it looks like that floor might be reflective. Random small pieces of tape, like electrical or duct tape, would likely help.

You can monitor the VIO stability on QGC. Those numbers should stabilize after takeoff, but obviously you want them stable on the ground too.

## Reply by Vũ Văn Long · 2021-01-20 04:15:45 UTC (in reply to Chad Sweet)

hi, here is the video i just captured https://drive.google.com/file/d/1Am63zD09am8nx_BBpAB2JfTYcf_IFMST/view?usp=sharing

## Reply by Vũ Văn Long · 2021-01-20 04:20:49 UTC

the local NED position is look good at the init state as well as when i move the drone into the other location.

## Reply by Chad Sweet (ModalAI staff) · 2021-01-20 04:24:37 UTC

thanks for sending, I will pass along to someone more familiar. Was this all working before? Do you know what has changed?

## Reply by Vũ Văn Long · 2021-01-20 04:30:17 UTC

last week it used to work normally. i did't changed any strange thing, just re-configuration the drone to the factory state. by "voxl-configure-vision-px4 -f" to take again the NED position cuz before that i had config vision lib by "voxl-configure-modalai-vl" and the local poistion is lost.

## Reply by Vũ Văn Long · 2021-01-20 04:43:07 UTC

pls help me soon. we can set up an online support via teamview to make the problem more clearly.

## Reply by James Strawson (ModalAI staff) · 2021-01-22 00:58:37 UTC

Does this behavior only occur in PX4 position mode? Does it fly in PX4 manual mode?

## Reply by Vũ Văn Long · 2021-01-22 02:56:20 UTC (in reply to James Strawson)

@James-Strawson yes,we only test uav in position mode. we didn't use manual for testing.

## Reply by Chad Sweet (ModalAI staff) · 2021-01-22 04:37:38 UTC

Please try manual mode. it seems there might be a PX4 parameter mismatch. It would be good to see if the m500 flies properly without VIO.

@modaltb Do you have a pointer to the Flight Core factory parmeters? 

The VIO indoor EKF parameters are [here](https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/blob/master/helpers/ekf2_indoor_vio.params)

## Reply by modaltb (ModalAI staff) · 2021-01-22 04:48:31 UTC

There's a few files (as we use DRY even on params ;)  The procedure to do this is [here](https://docs.modalai.com/upload-px4-parameters)

When you reload the airframe (via these parameters) you'll end up losing calibration and having to go through the calibration process.  This is documented [here](https://docs.modalai.com/px4-calibrate-sensors/)

You'll end up loading these, in this order:

- configures core airframe for m500 with 4S battery (standard):
https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/raw/master/platforms/v1.10/m500_4s_config.params

- VIO indoor EKF
https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/raw/master/helpers/ekf2_indoor_vio.params

- Serial params (to be safe, these should be set by default)
https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/blob/master/helpers/mavlink_serial_ports.params

- If needed and applicable, radio
https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/blob/master/helpers/gimbal_dx8_config.params