You guys have been incredibly helpful so far and I greatly appreciate it. After flying about 15 or so light missions and 1 decent crash, I've rebuilt and made some adjustments and have a couple of questions that I just can't seem to find expert answers for. If anyone could help shed some light on them, I would greatly appreciate it. Thanks in advance!
- Flash Log Review - I've had a few instances of my drone running off and folks pointed to vibration as a likely culprit. I installed my APM on the top board of my F450 with a layer of moongel. Since the moongel doesn't have an adhesive per say, I lightly strapped it with a velcro strap just to keep it in position but hopefully not enough to transfer a bunch of vibration. My logs seem to put me right at the acceptable limit. My question is this. On my past 2 flights, I put the drone through its modes starting in stabilize, to alt hold, to loiter, to stabilize, to draft, to sport. Once I test each out, I have setup a throttle cut switch to drop channel 3 PID to 900 and I have a failsafe set for 950 and RTL. The drone climbs and then on either instance, it just found some random direction to go to and then land itself. The second time yesterday was nearly on the top of a house that was about 75 yards from where it took off. I'm curious if someone could review the log and see if they can find anything. I see a couple ERR_BATT codes but I'm not sure if that is a code being generated by a true error or if I'm triggering it by cutting throttle.
- Power Module - I'm using the 3DR module and I have setup it's warning at 10.7v and 0 mah. I'm using a 3S 3000mah battery. Could that be playing to the issue above?
- Tuning - I've not gone through any of the tuning steps to address custom PID. I'm going to go through the wiki, is it the consensus that that the best resource generally speaking?
Thanks again guys! Everyone have a happy holiday and trouble free flights :)
Replies
ref your para # 2
Did you go thru steps of confirming accuracy of your power module via a good multimeter so that your readings are accurate? I am asking because your max voltage reading was only 11.35 and dipped to as low as 9.88 Volts! Did you start with a partially charged battery?
At 113 seconds into the flight as mode changes to RTL your voltage severely drops and current spikes up to 29 Amps, followed by battery fail safe and your throttle fail safe kicked in (FS_THR_Value). I recommend while setting up your throttle fail safe that you apply slight pressure with your finger in the lowest position that your throttle lever can attain (on one of my radio TXs I can get two different readings if I simply lower throttle and then take my finger off the stick vice holding it in place with slight constant aft pressure (throttle OFF position).
For a 3 cell I set my fail safe at 10.5 V and the mah at 20% of whatever my battery specs are ( in your case 600 mah)
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Your GPS accuracy was not the best; HDOP was >2 on avrg sitting at 2.3 and quantity of satellites was only on avg at 8; possibly explaining why you landed in area other than take-off area.
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BTW not that it would help with your above problem but your RTL_LOIT_TIME is set to 3 seconds only, it is recommended that this should be at least 5 seconds or greater, thus giving your multicopter time to settle prior to going into decent landing phase.
Rejean, thanks so much for your reply. I've noticed the huge fluctuations in voltage on Mission Planner. I'm not sure if the sensor is too sensitive or if there is a problem somewhere. I'm using a brand new 3DR power module. I did go through the steps on the voltage and adjusted the settings based on my readings. I've not done this step for amperage, I'm just not sure where and when to take the amp reading with my multimeter. I've updated my mah from 0 to 600 though based on your suggestion.
On the GPS, I did some due diligence and found out that I was way to high on my HDOP and should have stayed out of GPS modes. I just tossed a cheap tablet running Tower on my TX so that I can always have a good view of my stats.
I've adjusted the Loiter time as per your instructions. Thanks so much for the insight. I greatly appreciate it!
Your welcome Mike.
If you haven't seen this video yet, it explains in good detail on power module adjustments. For amperage you have to hook-up meter leads in series and have motors running at around 40 % power with props installed. In the video he flips props around, I prefer to leave props in place and just anchor the copter to a heavy weight that I am sure will not be able to lift nor budge. Task is easier if you have a Wattage power tester thus don't have to bother with a multimeter.
Maybe your battery is not rated high enough ( C rating ) to handle your power requirements and thus dipping in voltage or is damaged. MAX charge for a three cell lipo is 12.6, I say this because your max was only 11.35 Volts and as soon as you went airborne your voltage dropped to approximately 10.6
I think I might have located the source of the fluctuations. I landed yesterday and went to take the battery out and the positive wire pulled right off the plug, the only thing that was holding it to the plug was heat shrink wrap. The solder joint was completely broken. That could have been a bad day in a hurry. Going to head out today and give it all a go. Logs looked good yesterday even with the battery issue.