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Permalink Reply by Michael Krader on April 26, 2012 at 7:49am

is the esc making any noise when this happens.

 

Mike

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Permalink Reply by Vernon Barry on April 26, 2012 at 7:54am

I'm seeing this too in my Hexa with APM 2.0.  It seems to be that the ESCs are jumping into program mode on boot, and then depending on how log it takes the APM to start sending PWMs out, some of the ESCs get hung up. APM 2.0 has a known problem they require a reset to boot when first powering up which contributes to my delay but again, the other part of the problem is the firmware sequence happing inside of the ESCs.

For example, yesterday:

Attempt 1: plug in battery, hit reset, leds blink normally, arm it, red LED solid, motors do not spin. Unplug battery.

Attempt 2: plug in battery, hit reset faster, arm it, only 2 of the six motors spin

Attempt 3: plug in battery, wait for ESCs to beep, then hit reset, arm, fly normally

I know I have APM 2.0 and you have APM 1 but the common thing is these 20AMP ESCs and I can see already the firmware is not optimal for our use. We really need a set it once firmware for the ESC and not have this bootup training sequence for normal flights. I have to think this same bug could occur even in normal RC usage. I know APM 1 and 2 are slightly different but I have strong feeling our problems are very related because it's the way the ESC firmware boots. There is a very short time window and the APM has to output just the right signal at the right time or else the ESCs will not work.

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Permalink Reply by Bradley J Carr on April 26, 2012 at 8:33am

I unplugged and did everything to get it to work.  Now I was just getting back to work and thought I would try it before and it worked just fine. 

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Permalink Reply by Bradley J Carr on April 26, 2012 at 11:08am

Well made it out to fly and was really bad. 

Would not really takeoff by it self and then when switched to auto it took off torwards the targed overshot and then started to come back.  Needless to say it hit a power line.  But when it when to the first target it took off faster than I have ever seen it go and it took a large dip.

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Permalink Reply by Vernon Barry on April 26, 2012 at 11:28am

That sucks!!! Safety first though, I wouldn't fly near power lines anyway. I also wouldn't test waypoints in an area where you could hit something on the way or with overshoot.

This brings up a problem I have seen with my GPS. If I just let the machine sit, not flying at all, with telemetry (Xbees) via MP, the GPS is reporting all over the place. I probably get 30 foot errors from where it is sitting and it's tracking 8-9 sats!!! My goal is to make 4 waypoints and fly around my neighborhood down the streets in a loop around the block. Being that trees and houses are a major problem here (no overhead power lines but there are some street light poles) I cannot have it attempting to hit a 30 foot radius around a waypoint and that's assuming the PIDS can keep it within a few feet of where the GPS "thinks" it is. I should really post some images, but the movement is slow considering the GPS is updating at 10hz, but still, the error factor here means I cannot execute what should be a rather simple mission. I need to add, I also cannot really hit high altitude as we are in the flightpath. It's not bad and we're not next to the airport, but close enough I won't be flying over 100 feet as my own self imposed limit.

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Permalink Reply by Vernon Barry on April 26, 2012 at 11:41am

Another fine example of where not to fly. This local parking lot has lots of strategically placed lightpoles garanteed to take you out when going between waypoints. Sure, it's abandond and the few cars there are from those who carpool, but those lightpoles are the extreme hidden danger. You only see it right before you hit it.

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Permalink Reply by Bradley J Carr on April 26, 2012 at 11:44am

I am limited on space right now with all the spray planes and farmers getting into the feilds.  This was really my last resort.  But it overshot so fast.  I need to set the speed in the MP so that id does not go so fast and then I think the overshoot will be alot less.  I can understand some but that was way out of control.  Its all good though.  One broken motor and arm I will be back in action in a couple days.  Just waiting for my FPV camera and goggles to get here.

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Permalink Reply by Vernon Barry on April 26, 2012 at 11:55am

Do yourself a favor and see how much GPS error you are actually getting using mission planner. I could see that much error if  I only had 3 satellites but with 8-9, 30 feet is pretty unusable. I'm just curious if others are seeing that much error. Over a 10 minute timespan, i'm up to 3 houses down the block, across the street in the trees and then nearly to the pond all while the GPS never physically moved and is in clear sky view. It's no wonder people complain about loiter, how could you fault the PID settings if the GPS "thinks" it's in the right spot but is really moving all over.

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Permalink Reply by Bradley J Carr on April 26, 2012 at 12:17pm

very true.  How do you run that test?

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Permalink Reply by Vernon Barry on April 26, 2012 at 12:29pm

Not a "test", just an observation. Simply park the quad outside, with the APM powered and mission planner attached via computer. I have radio (Xbee telemetry) but you can just power the APM via USB and a laptop and connected mission planner. Wait for GPS lock and again, just let the whole rig sit for several minutes watching the GPS. On MP, it tracks a line where the heli has been over time so I expected some small movement but it was really bad in my area. The line goes all over my block, across the street, etc..  Obviously if that's where the GPS "thinks" it is, then how can your GPS waypoint be accurate? I'm thinking it's not a loiter code problem, it's GPS not knowing where it is!

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Permalink Reply by Bradley J Carr on April 26, 2012 at 12:37pm

well I think I am going to run out and set in the car and see what happens while I am working.  Be right back

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Permalink Reply by Bradley J Carr on April 26, 2012 at 1:11pm

The GPS test did rather well.  I had 10-11 sats the whole time.  I think it just went way to fast and overshot and with me trying to correct it and get it back didn't help.  Next test will be in the open field.

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