Reply to topic  [ 6 posts ] 
gliding with throttle off 
Author Message

Joined: Mon Sep 05, 2011 10:26 pm
Posts: 66
Post gliding with throttle off
Hey,

is it possible to change the code so that the QS would be able to glide (motors off) and still stabilize itself using elevons (mode 2)?
if the throttle is off, the QS's elevons do not move at all. Actually the QS is dead.

This feature would be very useful in mode 2 and 3, should the QS is too high, the user could just kill the throttle and the QS would glide like a "normal" airplane. Of course, also motors can contribute to the stabilization.
I found it difficult to pay atention to keep throttle just a little bit off the "kill zone" when geting the QS closer to the ground.

Thnx,

David

As soon as I solve all the problems and learn to fly the QS I will start to hack the code, but for now, it's more or less nervous flying and repairing damage.


Wed Oct 24, 2012 6:58 pm
Profile

Joined: Wed Jun 22, 2011 5:24 pm
Posts: 148
Post Re: gliding with throttle off
That is due to preference. There are many options for these features. The benefit to the way it currently is, is that the elevons will not add to the instability during a vertical, tail first descent, and that the pilot can instantly turn the motors back on without thought: the normal reaction is to just add power and pull up. With stabilization with the throttle all of the way down, it is dangerous to touch the QS while it is just sitting there on the ground. The moment you move it, it will bite you. So, a kill switch must be used. But, we found that most people either hit that switch on accident while flying, and/or forget to hit that switch again while flying to regain control.


Wed Oct 24, 2012 8:49 pm
Profile

Joined: Tue Jun 21, 2011 7:34 pm
Posts: 116
Post Re: gliding with throttle off
It is indeed possible to change the kill behavior of the throttle. Please look at AUTOPILOT_INSTANT_START_WITH_SAFETIES in paparazzi/sw/airborne/firmwares/rotorcraft/autopilot.c
Note that this block has fewer and different safety features that the default kill/unkill behavior (AUTOPILOT_THROTTLE_INSTANT_START_WITH_SAFETIES) so you might need to add the safety features or be careful during startup operations.


Wed Oct 24, 2012 8:52 pm
Profile

Joined: Mon Sep 05, 2011 10:26 pm
Posts: 66
Post Re: gliding with throttle off
Perhaps we didn't understand each other. :)

So mode 1 is hoovering
mode 2 is "simple flying"
mode 3 is aerobatic

When I kill throttle in mode 2, the QS stops moving at all (motors or elevons). There is no movement even if I apply some roll or pitch command. I also tested it on the ground (holding in my hand while switching to mode 1 or two and applying throttle/pich/roll combinations)

Therefore in flight I have to descent the QS with a little throttle added to keep it alive.

Hope I was a bit more clear :)

Regards,

David


Thu Oct 25, 2012 8:05 pm
Profile

Joined: Wed Jun 22, 2011 5:24 pm
Posts: 148
Post Re: gliding with throttle off
I understood that. I guess that I did not make my post clear. The QS does not react when the throttle is at zero so that you can turn it off instantly. Most pilot's reactions during a crash is to lower the throttle all of the way, so we used the same method to turn off the QS. Also it makes for cleaner landings, rather than having to reach for a switch.

You are right though, even without throttle active it would be helpful to have control of the elevons. I think we didn't implement that because the QS is not very stable without the motors on anyways. And it benefits from no elevon response during vertical, tail first descent. The elevons do not respond below a certain low throttle setting.


Thu Oct 25, 2012 8:40 pm
Profile

Joined: Mon Sep 05, 2011 10:26 pm
Posts: 66
Post Re: gliding with throttle off
Oh, ok. :) Got it.
Good point.

Thanks,

David


Fri Oct 26, 2012 6:02 am
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 6 posts ] 

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by ST Software for PTF.