<![CDATA[Collision prevention]]>Hi, We are trying to test the collision prevention feature on our Voxl flight deck enabled drone. We've set the PX4 parameters as mentioned in the documentation of collision prevention. Its working fine when I set the cp_dist to 1.5 meters as told. It works well and the drone stops.

However, if at all I keep some other value less than 1.5 m, for example, 1 meter or 1.2 meter, or 0.8 meters, it doesn't stop for the obstacle and I just hear "collision warning" from QgroundControl station. So is 1.5 meter a standard value and we can't use any number less than that?

]]>https://forum.modalai.com/topic/223/collision-preventionRSS for NodeSun, 12 Jul 2026 00:41:49 GMTMon, 03 May 2021 18:58:04 GMT60<![CDATA[Reply to Collision prevention on Thu, 13 May 2021 15:46:52 GMT]]>The only lower bound I've seen is 20cm here:
https://gitlab.com/voxl-public/modal-pipe-architecture/voxl-vision-px4/-/blob/master/src/voa_manager.c#L165

So I'm still puzzled.

If you debug stereo, what kind of data are you seeing? https://docs.modalai.com/voxl-vision-px4-collision-prevention/#debug-tools

]]>https://forum.modalai.com/post/1082https://forum.modalai.com/post/1082Thu, 13 May 2021 15:46:52 GMT<![CDATA[Reply to Collision prevention on Thu, 13 May 2021 15:45:03 GMT]]>I don't think we have tried other values. You can see where PX4 computes min_distance here, that might help

]]>https://forum.modalai.com/post/1081https://forum.modalai.com/post/1081Thu, 13 May 2021 15:45:03 GMT<![CDATA[Reply to Collision prevention on Thu, 13 May 2021 14:44:58 GMT]]>@kiprock No. I'm following the modalai collison prevention documentation.

]]>https://forum.modalai.com/post/1079https://forum.modalai.com/post/1079Thu, 13 May 2021 14:44:58 GMT<![CDATA[Reply to Collision prevention on Thu, 13 May 2021 14:44:22 GMT]]>@modaltb any idea on this?

]]>https://forum.modalai.com/post/1078https://forum.modalai.com/post/1078Thu, 13 May 2021 14:44:22 GMT<![CDATA[Reply to Collision prevention on Wed, 05 May 2021 14:41:42 GMT]]>gauravshukla914 Just curious, are you trying https://github.com/PX4/PX4-Avoidance or something else for collision prevention?

]]>https://forum.modalai.com/post/1041https://forum.modalai.com/post/1041Wed, 05 May 2021 14:41:42 GMT<![CDATA[Reply to Collision prevention on Wed, 05 May 2021 02:59:24 GMT]]>Thanks for your reply @modaltb . That'd be great. I'll look forward to your response.

]]>https://forum.modalai.com/post/1039https://forum.modalai.com/post/1039Wed, 05 May 2021 02:59:24 GMT<![CDATA[Reply to Collision prevention on Tue, 04 May 2021 23:47:18 GMT]]>Hi @gauravshukla914 ,

I didn't know of any limitation, our factory test uses 1.5 --> https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/blob/master/helpers/collision_prevention.params#L7

We'll need to check out what is introducing the limit.

]]>https://forum.modalai.com/post/1034https://forum.modalai.com/post/1034Tue, 04 May 2021 23:47:18 GMT