Support off board commands

[LorenzMeier]

Offboard roll / pitch / yaw or motor commands seem super popular, but are right now not implemented / enabled. Contributions welcome - please comment if you are willing to work on this and need some guidance in exchange for a pull request for the main project.

Tasks:

• Parse offboard control message in MAVLink
• Accept off board control commands in controller @DrTon
• Log offboard control messages in sdlog2 app
• Support an auto-arming strategy once these messages are received (e.g. using a circuit breaker, Add circuit breakers for key system components #961)

[LorenzMeier]

Please contact @thomasgubler for questions on this 8).

[thomasgubler]

There exists some old code which is sitting around until the navigator rewrite is done ;)

[andre-nguyen]

Team Elikos from Polytechnique Montreal is in!
I can get a team of 4 guys on this.
1 undergraduate student in electrical engineering
2 undergraduate students in computer engineering
and 1 masters student in aerospace engineering - avionics and controls

[DrTon]

Yes, ad Thomas said there is some work already. Look offboard2 branch.

[andre-nguyen]

Branch offboard2 isn't listed.

[DrTon]

Ah, sorry, it was in my repo (DrTon), pushed to PX4 now. Going to merge master to it now.

[DrTon]

@LorenzMeier, we need to discuss the following offboard questions:

• How mode switching should be done? Do we need OFFBOARD switch on RC (e.g. may be useful for manual recovery if something goes wrong)?
• How should we handle failsafe?
  • In OFFBOARD state, offboard signal gone, RC is ok: should we RTL / LAND or switch to MANUAL?
  • In manual (MANUAL/ALTCTL/POSCTL) state, RC switched off and offboard signal available: should we switch to OFFBOARD or RTL / LAND?
• Do we really need auto arm/disarm? As latest expirience shown, it is easier to use mavlink command for this: if user doesn't use RC he need to switch to OFFBOARD state somehow, in the same command he can put arming flag. Auto-arming may conflict with set_mode commands.

[DrTon]

WIP already :) #968

[andre-nguyen]

I can see that the quad swarm packets are transformed into an ORB topic registered as an offboard_control_setpoint, which is then picked up by the commander module. From what I understand, contrary to the manual_control_setpoint, this is where it stops and the data isn't transferred to any other modules.

I'm a bit at a loss as to what to do with the offboard setpoints next. Should I register it in the different controllers or should I transform it into a manual setpoint? Also, should the quad swarm packets be dropped in case the MAV is not in offboard control mode?

[LorenzMeier]

@andre-nguyen What you need to do is to publish an attitude_setpoint in the mavlink app receiving the off board control packet. The system will already switch modes correctly, so you just need to get the setpoint from the mavlink module to the controller.

Do not use the manual control setpoint - the system is designed properly to have individual layers and this has nothing to do with manual control.

[DrTon]

Working on it...

[DrTon]

Initial support for offboard attitude and rates added, ready to test. See #968

[andre-nguyen]

https://dl.dropboxusercontent.com/u/13822870/VID_20140524_232745.mp4

Finally got around to testing this out. Was able to fiddle around with some throttle values, looks good!

[mhkabir]

Now that the SET_POSITION_CONTROL_SETPOINT message is in MAVLink, I think we can use it instead of the hacky yaw pitch roll message.

[andre-nguyen]

I'd be willing to close #1058 and redo it with the new messages as they are a big improvement but as I understand it, they haven't officially been merged yet and there's that navigator rewrite going on, so I guess it will have to wait.

[LorenzMeier]

Probably done when this is done: #1983

[mhkabir]

Also this : #1856

[LorenzMeier]

Implemented on master and according to testing currently operational.

[mandelyoni]

Is offboard working also for yaw and yaw rate commands?
any examples?

thanks