Hi Forums,
I attached a Maxbotix 1240 sonar to my pixhawk and it works good so far. All testings on my desk show correct sonar values. However while flying in alt hold I can use sonar to rise by standing simply underneath it but then it wont descend again as I go away. I attaced a log showing the copter hovering in approx 3 meters of altitude. As i walk underneath the copter it raises... but then keeps the altitude as I leave. It never comes back down again. I also tried to figure out why this happens and as far as I can see the dsalt does not follow sonar alt.. but I am not sure how it is supposed to be. Could probably someone help me out to find a solution ?
PS: If somebody takes a look into the log... I tried follow me today the first time using my Galaxy S5 with tower app.. The copter was twitching every time it received a new waypoint... is there a way to make this less jerky and more smooth ? especially the yaw was not very nice... I would like to see smoother transitions between the waypoints... probably average them ?
Thanks a lot in advance !
Sebastian
Replies
Did you follow this guide:
http://www.maxbotix.com/articles/067.htm
Use the filter in any case, try to change the position and maybe isolate the device from vibrations.
The easiest way is to use no sonar, because the baro measurements are very good.
Did you tune alt hold?
Cheers Gregor
Honestly nobody ideas ? Is there someone who could take a look at the logfile ? This behavior is strange.. I verifiesd it in multiple flights now. The sonar altiitude matches the baro, but sonar desired alt does not change ! What is wrong ?
Hi Gregor,
yes I did... the sonar is mounted on foam, shielded with a can and I also used the capacitors as suggested in the maxbotix article. As you can see in the log, the values seem to be correct. However I wonder why the copter reacts correctly when I walk underneath it and rises but then keeps the altitude as i leave... I´d expect it to desced again.. but it does not. My alt hold params are fine I guess.. you can see it following the desired altitude perfectly. However.. I dot get the point why it does not follow the desired sonar altitude in sonar mode..
Any other ideas someone ?
Best regards
Seb
Added a screenshot... Alt seems to follow Dalt.. but why does dsAlt not change ? I marked with red arrows where I was walking underneath the copter... it climbed but does not come back down... honestly nobody any ideas ?
Graph.JPG
Added bin file
2015-03-25 18-18-47bin.rar