The Ardurover First time setup / radio control configuration page ( Radio Control Calibration — Rover documentation)
decribes a generic radio control channel configuration that is applicable to air vehicles (copter, plane) but is wrong for ardurover.
-Pitch channel : useless for ardurover. this page provides a extensive explanation how channel 2 (pitch) should be reversed on the radio tx. This is valid for air vehicles, not for ardurover.
-the most important change should be about the Throttle channel (RC3) : for Ardurover this channel shoud not be controlled by the usual stick on the radio that is used for in the case of air vehicles. In the case of air vehicles, the throttle stick is springless and covers a continuous range from 1000us to 2000us. This throttle stick in air vehicles must be set down to the minimum position before turning on the radio and vehicle (for obvious reason that it would be dangerous to start up/arming an air vehicle with a non zero throttle value.)
But for Ardurover it is another situation : an ardurover is a ground vehicle that should move forward and backward with a stop position that is located in the middle of the throttle range (1500us). So if you set your arudrover throttle channel to the usual throttle stick of your radio, you start in full speed reverse speed ! This is dangerous.
It is also not practical to have to guess manually the middle position of your springless throttle stick on the radio (it could be a little bit above or under the 1500us position).
So it is much more practical to set your RC3 throttle channel to use a spring loaded stick such as the Ele stick (which is usually used for pitch channel). Knowing that the pitch stick is useless anyway for Ardurover. If needed the pitch channel can be controlled anyway by the springless throttle stick on the radio.
Shouldn’t we adapt the documentation for these specific Ardurover points ?
A window will appear with the prompt, “Ensure all your sticks are centered and throttle is down and click ok to continue”. Move the throttle to the center and press “OK”.
By this ardupilot learns that the center position of the stick is zero throttle and not the down position as usual for copter/plane version.
Ok and will ardurover accept to arm if the throttle is down then ? (meaning full speed reverse direction)
But in any case, it is not ideal to have the throttle stick for ardurover on the usual springless stick on the radio. Much afvides to use a spring loaded stick such as the usual Ele stick on the radio. It gives another advantage : you can control forward/reverse and left /right turns with a single stick on the radio.
Most modern radios can have the centre spring reinstated by turning a screw in the radio. I don’t use a spring throttle on my boats when running rover.
I use a locking arming switch on the radio that needs lifted to move to avoid accidental arming/disarming.
@Hugues, your perspective is slightly myopic, focusing on your own transmitter setup and preferences.
As others have stated, spring centered sticks are often employed on both sides of the transmitter. In other cases, trigger and wheel radios are used. For non-3D Planes and Copters, throttle gets calibrated with a trim value at the low end to get full range throttle (and in Dave’s case where a reversing mix is used on the transmitter itself).
The RCMAP parameters allow for configuring control how you desire, and the radio calibration routine is flexible enough to compensate.
ArduPilot is extremely flexible. It’s a challenge to convey that concept in the documentation and various UIs. That said, it appears that @eosbandi can ignore my comment regarding a warning in mission planner to return sticks to their trim positions before completing calibration because it already exists!
EdgeTx and Ardurover allows any customisations and mapping you may dream of.
My point of this post is not to debate this but rather to improve the documentation wiki on the First time setup / radio control configuration page ( Radio Control Calibration — Rover documentation ) to remove the inadequate /useless descriptions (about reversing pitch for example) and to add all of the ardurover good practices everyone contirbutes here (about springless and springloaded options, about arming switch options, etc)
You are specialists and experts. For you it is obvious. But documentation should be made for newbies as well. The recurrence of similar questions across this forum and others about ardurover, more specifically about reverse/forward issues (which is also linked to how you configure your radio control channels), points toward the necessity to improve the documentation as explained above.
It is equally impractical to empirically set the throttle trim position to the exact calculated midpoint automatically in Mission Planner, as the intent of calibration is to capture the exact where the throttle rests. If you’re using less than ideal hardware that has no spring center or center detent, that’s on you, not the software.
And one better - the completion dialog in MP actually changes based on config. I just tested. For a config where the throttle is non-reversing, it asks for 0 throttle, otherwise, it says to center sticks.
That said, I’ll tag @eosbandi one more time because maybe there’s a compromise here that doesn’t even require more documentation - a second warning that pops up after the initial “center the sticks” dialog if it appears that a stick is significantly off-center, requiring confirmation that an off-center calibration is actually desired.
My point here is on the side of the radio TX, not about how ardurover calibrates the neutral point. Which is working prefectly as you mentioned already.
And sorry to reframe the discussion on the intial purpose of this post : wiki/documentation.
So either the wiki should never mention any advice/instructions on how to configure your radio TX side, either it should be exact, clear and improved.
@Hugues i’m running Ardurover on my 1:5 scale rc with a Radiomaster MT12. Getting the channels right, and RC_MAP right was a pain. I’m using typical RC channels; 1 for steering and 2 for throttle. I’m arming with steering channel. I have a servo for braking that only moves in the “reverse” direction of the trigger. So, I can help with something
I submitted a pull request for documentation change but I do not know what the process is afterwards to validate/accept the proposed documentation changes. Anyone knows about this github/pull request/process ?
