FC v2 Collision prevention issue with voxl 2

Sean Hickey

What TOF sensor are you using for obstacle distance?

Just confirming, you are using the ARK Flow MR facing downwards just for optical flow and position hold, but not for collision prevention?

Jetson Nano

@Sean-Hickey PMD tof that comes with yellow board M0173 - https://docs.modalai.com/M0173/

Yes optical flow is facing down, it is used for position hold and not for collision prevention.

Sean Hickey

@Jetson-Nano

Can you see if you are using the MO169 or the MO178?

Jetson Nano

@Sean-Hickey I am using M0178

Sean Hickey

@Jetson-Nano

I was able to identify the issue.

mpc_pos_mode - acceleration based doesn't call Collision Prevention in any of the newest PX4 builds..

You need to use mpc_pos_mode - Simple Position Control (0) or mpc_pos_mode - smooth position control (3).

I was able to test this on a similar setup, and confirmed that collision prevention only worked with the mpc_pos_mode indicated above, and notably did not with mpc_pos_mode acceleration.

Jetson Nano

@Sean-Hickey that great, just making sure, did you use optical flow with FC?

Also could you let me know which branch you used, or the Px4 built file. i want to test it out in my setup.

Sean Hickey

@Jetson-Nano

I used VIO with FC, but the path from obstacle detection to Collision Prevention is unchanged between the 2 modes.

I used the mainline ModalAI PX4 SDK branch. I can share the built px4 deb build with you if that's helpful, but I would try changing the mpc_pos_mode parameter first on your current build to see if that fixes your issue.

Jetson Nano

@Sean-Hickey
I already checked with changing the MPC_POS_MODE, did not work.

Could you share the file, I would like to test it out.

Sean Hickey

@Jetson-Nano

https://drive.google.com/file/d/1FmaW4kXma6pxjQO86WugNJq9-5zZ75gU/view?usp=sharing

I attached the link above, I am using parameters:

MPC_POS_MODE: Simple position control
CP_DIST 1.5 m
CP_DELAY 0.4 s
CP_GUIDE_ANG : 0 deg
CP_GO_NO_DATA: Enabled

Sean Hickey

@Jetson-Nano

If this doesn't work, on the mavlink console (after testing the collision prevention) call:
listener obstacle_distance_fused 1
listener collision_constraints 1

and let me know the results.

Jetson Nano

@Sean-Hickey
sorry to disturb you again .
I am not able to flash with the deb file, could you please share the .px4 file

Jetson Nano

@Sean-Hickey

I tested with this firmware modalai_fc-v2_1.14.0-2.0.133.px4 from (http://voxl-packages.modalai.com/dists/fc-v2/sdk-1.6/ ) and it worked, but there is no uavcan thats the only problem.

I checked with the parameters you mentioned.

When i reduce the cp_dist it stops working but with 1.5 m it is working.