Configuring Retractable Landing Gear On Cube Orange With Herelink Running Solex TX

HereLink
1

Please forgive my ignorance here. I was just getting comfortable with all of this (Pixhawk 2.1/Cube, Here GPS, RC TX basics in general, etc…) a couple of years ago when I put it away for a while. I’ve broken it back out and I am determined to complete the heavy lift hexacopter I started. To say a LOT has changed is an understatement. Actually, advanced is probably the better word. Regardless, I feel like a stroke patient learning to talk again. So much I have forgotten and simply don’t comfortably grasp again.

Before even starting to go at this again, I upgraded from the Cube Black with Edison Board to the Cube Orange with ADS-B Board to be at the current standard. I upgraded both HERE GPS units to HERE 3 Units for dual UAVCAN GPS units. I also upgraded the video and controller to Herelink. Now starts the re-learning. Starting goal is to get the basic hex with no camera or extras on it in the air and operating correctly. The only upgrade on it is the large retracts that will be required, so they’re on there to start with.

Probably my biggest problem is button mapping. I’m having trouble wrapping my head around not just the difference between Herelink button mapping and Soles TX button mapping, but when and where each one should be used. My general understanding is as follows:

  1. Mapping buttons from within the Herelink Settings maps buttons to the SBUS control channels.

  2. Mapping buttons from within the Solex TX Settings maps buttons to functions in MavLink, not the RC channels. (honestly, I may not really understand this even though I can say it… I never did get very fluent in Mission Planner & MavLink)

  3. You CAN, but as a general rule, you SHOULDN’T map the same button in both settings area?

  4. Aircraft Modes MUST be mapped from within Solex TX, and NOT from the Herelink Settings area. (FLTMODE_CH must be set to 0)

I have been going through everything I can find on setting up retractable gear with Herelink running Solex TX. My head hurts, and I’m not even close to feeling I have it right. My goal is as follows:

Have the Herelink D button configured to toggle the landing gear up or down with every long press. However, I also want the Cube to be able to automatically raise and lower the gear based on altitude, on all RTL activations, etc. I don’t want to program the D button to work, but do it in such a way that I prevent the Cube from activating the landing gear safety functions it can employ.

I currently have a button mapped in Herelink Settings for Toggle, on a Long Press of “D”. 1100 is the default value (gear down/deployed). 1900 is the toggle value (gear up/retracted). Mapping to SBUS CH9, on Bus 1.

I have my signal line to the gear servo(s) on the AUX 1 output on the Cube carrier board. I also have both SERVO9 and RC9 FUNCTION set to 29 for Landing Gear. Pictures are below to show other SERVO9 and RC9 settings:

RC9 Settings
RC9 Settings1917×567 237 KB
SERVO9 Settings
SERVO9 Settings1920×829 298 KB

On the surface, it appears to work correctly. A long press on button D toggles the gear up and down. Radio Calibration screen in MP confirms gear goes up when CH9 toggles to 1900, and gear deploys down when toggling CH9 to 1100. I’m just not sure if I’m losing safety functions the flight controller offers for taking control of the gear and deploying/retracting in appropriate situations (like RTL or specific altitudes).

Any help, advice, or reassurance would be greatly appreciated.

Chuck

2
  1. Mapping buttons from within the Herelink Settings maps buttons to the SBUS control channels.
  2. Mapping buttons from within the Solex TX Settings maps buttons to functions in MavLink, not the RC channels. (honestly, I may not really understand this even though I can say it… I never did get very fluent in Mission Planner & MavLink)
  3. You CAN, but as a general rule, you SHOULDN’T map the same button in both settings area?

Yes. You point 1 and 2 are correct. For point 3, system allows you to set in both ways, but may cause conflict if you set both.

  1. Aircraft Modes MUST be mapped from within Solex TX, and NOT from the Herelink Settings area. (FLTMODE_CH must be set to 0)

This is not true. It depends on what you want. Flight modes can be set in both ways.
If you set flight mode in Solex, the command have already been packed in mavlink message and will directly change the mode.
If you set in sbus, you need to go to ground control station to map the corresponding channel to change flight mode.

Have the Herelink D button configured to toggle the landing gear up or down with every long press. However, I also want the Cube to be able to automatically raise and lower the gear based on altitude, on all RTL activations, etc. I don’t want to program the D button to work, but do it in such a way that I prevent the Cube from activating the landing gear safety functions it can employ.

https://ardupilot.org/copter/docs/common-landing-gear.html
As mentioned in ardupilot wiki,

For later firmware versions, the LGR_OPTIONS bitmask can selectively enable or disable these operations… The manual switch, if programmed, can change the deploy/retract state of the gear at any time.

It should be possible to have it automatic while manually controllable at the same time.

3

Hi @Alvin,

Regarding flight mode buttons: The Herelink user guide is quite clear that those buttons must be mapped within Solex or QGC as it is the more safe way. Is the user guide still correct? You seem to say that we could also map the flight modes in the Herelink settings (without risks?).

Many thanks for your support in advance.

Regards,

Sven

image
image750×1334 190 KB

4

Buttons can be mapped in App (QGC/Solex) or Herelink Setting App.
Setting flight mode with mavlink button is a more preferred way because it is more straight forward. Also, it require less steps to set up.

Also, mavlink button have more functionality. If you need those function, you will need to stick with it.

Sbus button is for those who need to stick with sbus. If you don’t have any special reasons, we usually recommend using mavlink button which is set in Solex.

1 Like
5

Hello @Alvin,
Thank you for taking the time to reply. I’m a little confused as to setting flight modes. I understand that we are capable of setting flight modes through both Herelink (SBus) and Solex TX (MavLink), but the documentation is very specific, to the point of instructing to disable FLTMODE_CH, to ensure we don’t use Herelink to set flight modes. I understood this to be a precaution against an unexpected change of flight modes as a result of an unexpected reboot or signal loss? Is there a specific condition where we would want to disregard this safer procedure of only changing flight modes through MavLink commands?

1 Like
6

On the button mapping the reason Sbus is not advised for modes is because these are soft buttons and not physical switches. In the event of a crash of the RC or some other random event the position of the Sbus outputs has the potential to fall to another setting and as such change you flight mode without you knowing, this could be catastrophic.

The reason Mavlink buttons is recommended is you simply can not have a random Mavlink command sent even on a crash or it’s very VERY unlikely.

There is nothing stopping you mapping the Sbus for modes but you have to be aware there is this possible behaviour, it may be very unlikely for a crash to happen the overall safety choice was to not recommend it at all.

I actually wrote that part of the wiki and the wording was chosen to specifically push people away from doing it.

Nothing on this has changed and will change as there is no physical switches on the remote.

As for mapping both Mavlink commands and Sbus commands on the same button it can absolutely be done however you need to play with caution on that one as you could easily get into deep water.

For modes the ideal setup would be a failsafe like RTH on one of the Sbus buttons then mode selection on Mavlink buttons. That way you have the best of both.

Again technically nothing stopping mode selection on Sbus but it comes with great caution.

As for what to map to what other than modes your pretty much fine mapping to what ever you feel suits it best.

You landing gear setup looks correct, what have you mapped the servo output for the landing gear too ? Just make sure that’s set to landing gear and not the RC SBus channel directly.

1 Like