Hi, Ardupilot 2.6 (still with thermopiles) did a pretty good job in handling our solar drone (seriously, http://diydrones.com/forum/topics/lusa-low-cost-unmanned-solar?id=7...), now we bought APM2.0 to improve the results thanks to the ultra-precise IMU and other things such as the built in compass that can help controlling such a weird-handling plane like that.
But we also noticed that ardupilot code&hardware has grown so much in complexity, and this is kinda scaring us, since it will be in charge of a $1000+ 2000hrs of labor plane...
All what it will be required to do is to keep the plane loitering with excellent precision, nothing else for the moment, our main concerns are:
- Are there some timers or counter that may overflow or something causing errors after a long period of continuative use? It will probably be around 4 hrs?
-Are there known issues for APM2.0 operating in a pretty hot enviroment? (around 50 / 60 celsius)
-Are there known issues with partially-configured autopilots? (we will not explore, at least for a while, the ardupilot`s advanced functions)
-Are there any known failsafe failures? I keep the radio in my hand for the whole flight, ready to swith to manual mode if somethings goes wrong, but is the failsafe chip really bombproof or if the APM starts rebooting or something I`m screwed?
-What other things should we take great care of to ensure the APM will work realiabily?
Even Attopilot uses the main flight control microprocessor to perform the RC pass-through function. If the micro hangs, then you might not be able to switch over to RC to recover the aircraft. Having said that, Attos do have an excellent reputation for NOT hanging.
The only way to determine answers to Ludovico's questions is with data. Reports from users (even me) are not data but anecdotal information. (this is why the developers ask for logs after an event)
We need to take 10 or so APM2 units, ready to fly, and see what kind of extremes they can handle.
The road to this knowledge will be paved with dead APM2 units but if the experiments are set up well and the data collected well, everyone will benefit from the data; developers, engineers, 3DR especially.
Without data, all we have are stories, debates, mysteries and arguments. This is generally called 'ignorance'.
So Jordi, how about 3DR teaming up with some of the schools there in the Golden State and doing NDT or other reliability testing on the APM2? I see several excellent papers and projects on this subject.
We might even settle some differences of opinion. (OK, I am a dreamer at times)
We made a board that allows to transfer the control to the pilot, bypassing the APM via logic gates, we`ll post schematics and pictures soon. At a flick of a switch on the TX the APM gets cut out of the loop.
Still, we have a question: if our RX dies and stop outputting anything on any channel (after 3hrs of flight in a hot enviroment this is a hard but not impossibile scenario) our board gets in the "ardupilot in the loop" condition (for sure better than no control at all lol) in order to have the Ardupilot land the plane. Sounds a bit of over engineering but on a plane like ours isn`t. But do we need to update the ppm software to be able to set APM to consider zero input on all its channel as a call to go in RTL mode?