The Hexa flies well with all default setting except rate roll which had to be reduced to 0.110 to stop it oscillating.
When I switch on altitude hold the hexa climbs and keeps climbing.
I have reduced rate roll in 0.01 stages from 0.11 to 0.06 while reducing throttle rate from 0.3 to zero for each stage via ch6 and it still climbs. I daren't go any further as it is getting unstable.
I have loaded the firmware numerous time, performed erase / reset and gone through the setup.
I have calibrated the ESCs to the radio.
I have fitted screened cable and filter to the sonar.
I have adjusted rate roll and throttle rate to the extremes.
I have even tried adjusting Alt Hold P in desperation.
I have read the AC2 Tweaks and Troubleshooting pages on the Wiki.
I have attached a log which may help.
Is there another PID I should be adjusting?
What am I doing wrong or not doing?
Spec.
Frame DIY 60cm Hexa +, APM1/2560, ESCs Plush 18 Amps, Motors Emax BL2215/25 950Kv, Props 10 x 4.5, Sonar XL-EZ0, GPS Mediatek, Battery 4000mah, AUW 1.9Kg, MP 1.2.12, Fw 2.7.3.
The sonar has screened cable and the recommended 10 ohm resistor and 100µF capacitor fitted.
Replies
It looks like your right and it is the sonar. When I was testing the hexa after the build the sonar read 20cm which is expected as it was too close to the table. When I hung the hexa over the edge of the kitchen table the sonar read about 73cm which is about 5cm out but at least it proved that it wasn't seeing the legs. Pointing it at the kitchen wall also proved it worked at greater distances.
After what you said I held the hexa out of an upstairs window and it read 20cm. After more testing it appears that my sonar reads up to about 2 metres and then goes down again to 20cm. I connected it to an xbee and flew it in my back garden. Between about 2 and 10 feet it mostly shows 30cm on the laptop which is ever more confusing.
How accurate are these sonar units meant to be and is there a better way of testing them?
Looks like I will have to order another sonar like you. Thanks for the input.
I have the same problem, and it seems to be a combination of a non functional Sonar and tuning.
If I do Alt Hold above 10m then the hexa holds within a few metres, but down low it will just climb.
With space I let it climb to see how high it would go and at about 10m to 12m it started the decent and I had to grab control at 2m or it would have hit the deck.
In the CLI the Sonar test gave me 23 when it should be 19 (leg height) but when I moved it there was no change.
Shielded cable and noise filter installed.
I HAVE tuned the throttle and Alt PIDs but just can't seem to nail this one.
So now waiting on a couple of new Sonar's.