Pixhawk flight modes

[violetwolf]

I was typing at the same time as CrayFellow..

You need to find out why it won't arm in Stabilize mode. This is a safety function... if it finds something is wrong it won't arm.. something is wrong here. You could lose your craft or hurt someone. My suspicion is GPS issues as Alt Hold does not use GPS it will arm in that mode. You must have a decent number of satellites locked in (7-8 or more) and and HDOP below 2. Anything outside these parameters you risk a fly-away.

Also, as mentioned by Old Man above, Stabilize is your primary mode. You should take off and land in Stabilize and always be ready to switch back to it if something screwy happens.

There is also a "Land" mode if you are a beginner and feel uncomfortable landing on your own. But as Old Man mentioned landing in any of the auto modes can lead to possible injuries or craft damage.

 

[violetwolf]

landing with confidence in Loiter is completely fine.

While I would agree with the rest of your post, I would not advise this for beginners. You and I as more experienced pilots can recognize issues but the novice may panic.

For instance it can be reflex to manually disarm the motors upon touchdown. This (stick action) can be disastrous while in Loiter and just having landed... ask me how I know lol

 

[crayfellow]

While I would agree with the rest of your post, I would not advise this for beginners. You and I as more experienced pilots can recognize issues but the novice may panic.

hence 'with confidence' only once the confidence is there to take off and land should one rely on the more automated modes.

For instance it can be reflex to manually disarm the motors upon touchdown. This (stick action) can be disastrous while in Loiter and just having landed... ask me how I know lol

Trust me I know as well!! Nice scar on my hand to prove it in fact... Some advocate for using motor kill switch or the new motor interlock switch as a manual override, but I personally feel it would be a massive safety issue to have any switch on your tx set to kill motors with impunity. Jumping to Stabilize while it's writhing on the ground has the same effect at 0 throttle.

(@Chalagi, a sidenote just to get this out there: ) for what it's worth, the flipping due to failed landing detector thing is not exclusive to Pixhawk. It's simply a reality when there is no absolute determinant for altitude. As range finding sensors such as LIDAR Lite become commonplace, it will be a nonissue.

 

[Old Man]

Don't fly Drift with a gimbal attached.....

 

[crayfellow]

Don't fly Drift with a gimbal attached.....

why do you say that? It's pretty much just Loiter without the speed limitation and with yaw/roll combined. Depending on how you fly, it's be no different than flying in PosHold. Do you mean due to the braking effect? If so, PHLD_BRAKE_ANGLE or PHLD_BRAKE_RATE can dial it back.
(BTW I am keen to fork both APM and Mission Planner so more of those effects can be applied to tx sliders. I'd also like to adjust Loiter speed. I am sure others would benefit from it as well)

 

[Old Man]

Some advocate for using motor kill switch or the new motor interlock switch as a manual override, but I personally feel it would be a massive safety issue to have any switch on your tx set to kill motors with impunity.

Not that long ago I flew a lot of giant scale fixed wing 3D. One often uses several rate and mode switches on a transmitter for that kind of flying. A friend of mine always liked to have me try out his planes. Unfortunately he preferred having an engine kill switch to shut down the engine after landing. Didn't matter what switch he selected for the feature, if I was flying his plane I would flip that switch a some point in the flight. I became quite adept at landing his planes dead stick. Any multirotor that loses power while in the air instantly becomes a brick.

 

[Old Man]

why do you say that? It's pretty much just Loiter without the speed limitation and with yaw/roll combined. Depending on how you fly, it's be no different than flying in PosHold. Do you mean due to the braking effect? If so, PHLD_BRAKE_ANGLE or PHLD_BRAKE_RATE can dial it back.
(BTW I am keen to fork both APM and Mission Planner so more of those effects can be applied to tx sliders. I'd also like to adjust Loiter speed. I am sure others would benefit from it as well)

I flew my X8 a few times in Drift with a GoPro and 2D gimbal. When flying in Drift mode I fly it pretty hard (3D airplane roots) and the post flight video clearly showed the bank angles far exceeding the capability of the gimbal. Since rudder is slaved to aileron in Drift it's really easy to over bank, over "G" a gimbal, Bouncing gimbal stops can't be a good thing.

Adjusting Loiter speed is very easy. After adjusting Loiter speed remember that when in Loiter mode the FC will accelerate at 1/2 the set Loiter speed.

 

[crayfellow]

right. Exactly the kinds of things I think would be useful to adjust via sliders in flight (including the banking coefficient for Drift). Part of the challenge with APM for beginners is that there is so much you 'could' do, and on the forums there is always someone asking for a new adjustable property. So for me I have considered just forking it specifically for AP/survey/mapping just to see where it goes.

 

[Old Man]

Best to start with what's provided in the basic flight modes and set up and learn. As one learns they can slowly start exploring the various options available. Kind of like computers. Should someone first getting exposed to one jump right in and try to reprogram it? I know MR people do that kind of stuff all the time and we get to read all about it in the numerous posts relating their tale of woe. With APM one can adjust just about everything. The problem is doing some or a lot of that wrong brings disaster for the aircraft. Because someone "wants" does not mean they should "get".

IMO it's better to build an aircraft to fit generally specific tasks. A camera ship should not be an FPV racer or aerobat. The aerobat should not also be intended to double for handle heavy lift tasks. A maximum stability platform is inherently better for some uses than others. If something does something extremely well why would anyone desire to reduce that functionality? Tools function best when used for the job they were designed for.

 

[Chalagi]

The next time I go out I will try and arm in stable mode. I tried that once on the bench and it says "Arming mode not allowed". My problem is that I have always flown with Naza and its kinda hard to get thing together on the pixhawk. But on the altitude pid's my guess is that I would need to lower them to get a some what steady altitude correct?

 

[violetwolf]

Don't worry, you will soon love the Pixhawk it just takes a while for it all to sink in.

For stronger altitude hold you raise the number higher. I usually find about + .5 (point five) is a good increment to try.. I usually end up around point six increase. An easy way to find the right amount is to assign the pid to channel 6 and use a knob on the radio to set it while test flying. Then land without changing the knob and look in mission planner to see where its set. Then make that setting permanent and disable the chanel six.

 

[Chalagi]

Well right now my altitude pid number is 1.00 and I"m trying to figure out assigning a channel to the altitude pid.

 

[Old Man]

You're flying a 680 if I recall correctly. The PID's in an out of the the box Pixhawk are very close to right for most quads in this size. I would fly it and see how it is before changing anything. I would also dig deep to find the reason for not arming in Stabilized mode. That is one of the three modes even 3DR suggests being available all the time. The other two are Loiter and RTL. Everything else is an option.

Violetwolf;
In some ways Pixhawk and Vector share amazing similarities. Assigning a PID to a dial or slider to adjust on the fly is one of them. Nice thing about Pixhawk is you don't need an active OSD to see the changes made, you just keep the power on and look at the feed in MP from the telemetry radio or connect Pixhawk to a laptop and view it in MP there. It's too bad the Vector loiter mode is far less stable than Pixhawk's.

 

[Chalagi]

I'll check out the arming in stable mode and see what happens.

Update: I just got the hexa to arm and disarm in stable mode neat

 

[crayfellow]

you probably just hadn't hit the safety button or didn't have the radio on. With 3.3 there are tones to indicate "failed prearm checks" as well. Also since 3.3rc11 (and with what will become the release for 3.3) you will have specific text on Mission Planner indicating the prearm check that is failing.

Chalagi, I will get you my Taranis setup probably tomorrow when I am porting some settings over to another craft. I have them set up in the Flight Modes section and the mix ends up pretty simple. Then you have speech indications for each mode as well.

Also, with the way I am using logic to setup two switches to enumerate flight modes, pulling down the main switch will override the other and trigger RTL no matter what. I find this to be extremely useful and a good safety measure.

 

[violetwolf]

I think you mentioned that it wouldn't arm in Stab when you were bench testing.. My guess is that you might not have had enough satellites due to being indoors.

 

[Chalagi]

Well right now mission planner will show the text to indicate whatever alarm if any. Right now I can't remember what I did or what went wrong that time it did not arm in stable mode. Thanks crayfellow

 

[JoeBob]

Don't worry, you will soon love the Pixhawk it just takes a while for it all to sink in.
.

Welcome to the Darkside...

 

[Chalagi]

Darkside is putting it lightly

 

[Chalagi]

Also guys I'm not new to the RC world I have flown rc heli's for more than 6 years and rc quads and hexa's for more than 2 years. And in my early teen days I flew .049 and bigger engines planes on the land line and that makes for a screwed up head depending on how big your gas tank was lol.