Servers by jDrones

SBUS Failsafe Flag(s)


(Paul) #1

Does ArduPlane read the SBUS failsafe flag(s) in its failsafe logic?

Where in the parameters list would I set this capability?

Thanks,

Paul


(wkf94025) #2

I would like to second Paul’s request for SBus failsafe support. I am setting up Arduplane 3.8.1 on Pixhawk2.1 with Dragonlink v3 and Futaba 14SG. The Dragonlink Rx is speaking SBus to the Pixhawk’s RCIN. I was quite surprised to see the system ignore radio off, staying happily in Manual or FBWA mode, during bench testing. I researched the docs, and have implemented throttle-based failsafe, but believe SBus failsafe is better. I believe other flight controllers are SBus-failsafe-aware.

Kelly


(peterbarker) #3

I would like to second Paul’s request for SBus failsafe support. I am
setting up Arduplane 3.8.1 on Pixhawk2.1 with Dragonlink v3 and Futaba 14SG.
The Dragonlink Rx is speaking SBus to the Pixhawk’s RCIN. I was quite

Notionally we do support s.bus failsafe flag.

https://github.com/ardupilot/ardupilot/blob/master/libraries/AP_HAL_PX4/RCInput.cpp#L32

https://github.com/ArduPilot/PX4Firmware/blob/master/src/modules/px4iofirmware/controls.c#L322

surprised to see the system ignore radio off, staying happily in Manual or
FBWA mode, during bench testing. I researched the docs, and have implemented
throttle-based failsafe, but believe SBus failsafe is better. I believe
other flight controllers are SBus-failsafe-aware.

… problem being some receivers don’t actually set the s.bus failed bit.
I believe some of the OrangeRX receivers are in this category.

Kelly

Yours,


(wkf94025) #4

Peter,

Thanks for your responses. Is there some combination of settings on my Arduplane system that won’t activate RTH if the aircraft is on the bench? I don’t recall that conditions necessary for “isflying” to be true. If system thinks it’s landed, or otherwise not in the air, is it refusing to go RTH because that might not make sense? Unless bench testing RTH of course!

Kelly


(peterbarker) #5

Thanks for your responses. Is there some combination of settings on my
Arduplane system that won’t activate RTH if the aircraft is on the bench? I
don’t recall that conditions necessary for “isflying” to be true. If system
thinks it’s landed, or otherwise not in the air, is it refusing to go RTH
because that might not make sense? Unless bench testing RTH of course!

No. If you turn your transmitter off, your vehicle should enter failsafe;
short-failsafe (circle) followed by long-failsafe (rtl), usually. It is
independant of isflying.

This is a really good check to do if you’ve fiddled with your aircraft.

I suggest you investigate setting up “throttle failsafe”. Usually
receivers will do special things if they don’t have signal from the
transmitter. Often this is “send values seen at bind time”, but it does
vary FWIU. If it is “send values seen at bind time”, then you can ensure
that those values will put the plane into throttle failsafe, even if the
S.BUS error bit thing isn’t working.

Kelly

Peter


(wkf94025) #6

Thanks Peter. Glad to know it should enter FS/RTH even on the bench. An important test before chucking it aloft. When I realized SBus FS wasn’t triggering RTH, I went into the documentation and followed the throttle FS method, which works fine (I have used throttle FS on other aircraft + FCs in the past). The Rx is Dragonlink 1W Advanced Rx. It has several options as to how to respond in case of loss of Tx connection, but setting FS bits in the stream is not one of the [obvious] options. I have set Rx failsafe to insure neutral control surfaces and zero throttle, in case FC does not take over and bring my bird home. Though thinking about that, perhaps modest throttle, slight rudder, and level elevator would be a better setting. i.e., circle until battery exhausted, in hopes something good comes along before then.

I will check with Dragonlink on SBus FS bits.

Kelly