Hi all,
I am working on a design for a reasonable size plane. At this point it is all on paper, so I like to approach everything from a theoretical point of view. I’ve been out of the RC world for quite some time and it has changed to say the least. So I consider myself a newbie at this point. I was still playing around with analog transmitters and crystals. Anyway, I have some (maybe noobish) questions about the Navio and some other general questions, mostly related to fail-over. I have an aviation and IT background and if I send a plane up which I have designed myself, I’d like to have a very acceptable safety margin in place (comparable with commercial drone rules and regulations).
I’ve flown Airbus in real life and what I learned is: electronics will fail. IRS’s will fail, autopilots will fail, mechanical parts will fail. That’s OK though, because there is double or sometimes triple redundancy in place. Sometimes, a simple reboot will fix a flight computer, sometimes there is an abnormal checklist to be followed. With that in mind, I’d like to design my plane. I don’t really like the idea of a rebooting Pi in mid air (I have a Pi which fails under high load lying around here somewhere…). So I’m thinking about the following: I’d like to fly the plane by joystick with APM, with FPV, artificial horizon and telemetry. I am creating a list with all components that could fail and I try to figure out what the bare minimum of flight controls is (including mechanical failures). I’d like to focus on telemetry and the Navio for the time being. Also, I like to consider out of range situations as a precaution.
My basic questions are:
- What if I use 2 Navio’s, 2 Raspberry Pi’s and let them talk to each other in a master-slave configuration (working together would be even better). If the link fails for whatever reason (power issues, pi failure, navio failure, software failure), they switch to the backup. I don’t think I can hook up a servo to Navio 2 boards at the same time, so I probably have to design a circuit board to allow for this. Any tips on how to achieve this? Has it been done before? Worst case scenario: I lose signal, autopilot takes over and then the Navio or Pi fails. Is it possible to connect 2 Navio’s via the UART bus and write software to let them work together?
- Manual control with a receiver? What happens when the Navio fails (including power failures)? Will the receiver be able to control the servo’s? If it is out of range it will be useless…?
- Maybe use only one autopilot and use a fully independent Pi with Piface and 3G in which case I can disable the electric system of the autopilot and deploy a parachute in case of emergency. This adds weight and I don’t like this option (only when the wings fall off :P).
Maybe I’m thinking too much. However, “Autopilot fail drone” on YouTube tells me otherwise.
Any help, tips etc. would be greatly appreciated! Thanks in advance!