I am developing an unpowered paraglider system that will return the payload from a weather balloon to one of a few clear/open landing areas. The idea is that depending on where the balloon bursts the Pixhawk will autonomously choose the best landing point (based on a pre-calculated prediction from software before ascent). There are two main problems: the parafoil lacks any controls other than ailerons, and path planning to avoid being carried away by the wind.
Ideally, the Pixhawk would know to point itself into the wind, reducing ground speed to burn off excess altitude with minimal change in horizontal travel (basically keep heading into wind and GPS track towards target). As I understand it, the autopilot would instead try to head directly to the landing point and loiter down to it, pitching down to fight any overpowering wind. This is a problem since there is no elevator and the parafoil would get carried away if the wind speed is greater than its cruise airspeed.
Are there any options within Mission Planner to achieve this result? I assume I will need to edit the firmware to implement this new model, but I am unsure of where to start in the code.
I’m new to Ardupilot so any help is greatly appreciated!
Replies
Um, what?
What is a twist dive and what does it have to do with anything? I am talking about a spiral dive, see here:
https://xcmag.com/news/dive-dive-dive/
one of the most basic rapid descent tricks any paraglider pilots learns.
As to how much control one can have over the exit, please have a look at the following video:
https://www.youtube.com/watch?v=nH__8UbK1S8
(don't try this at home, chances are, you don't have enough space)
Not sure what you mean by deleting comments but I had been using the forward and back button in my browser before replying so that might have had unintended results. If that is the case, sorry, won't happen again.
" can exit whenever you feel like
you are not correct
twist dive can be controlled at low speed only
https://www.bing.com/images/search?q=twist+dive&form=HDRSC2&...
BTW
deleting comments turns this thread into time-waster
Increase. Higher weight -> higher speed.
Spiral dive is never uncontrolled or it wouldn't be used as a standard descent manoeuvre in paragliding so your risk of failure is damn small. What you don't have control over is direction while doing it (you are just going in circles), since you are in a spiral so you drift with the wind (like you would with a normal parachute). However, you can exit whenever you feel like and then you have your foil's forward speed to point wherever you want to.
A complication you might have is deployment at altitude. Deployment from a stationary platform in the troposphere is no big deal, check out videos for paraglider D-bagging. However, trying it in super thin air, is an unknown. You might need to consider a pilot chute for stability until you are low enough to deploy the foil.
@Andreas Gazis
", another way to increase your speed is to increase your wing loading,
increase or decrease the speed ?
To solve the M$M worth problem how to save a payload in case weather balloon bursts
I work with operation research, heuristics, AI and live weather/ jet stream data.
Spiral dive is always uncontrolled, so a risk of failure is 99%
what may work and is reliable is built in stratospheric parachute
If your fly your weather balloons over unpopulated regions you don't need to care for clear/open landing area since you get landing place geolocated remotely.
Try to collect burst altitude for a type of weather balloons you fly
https://www.bing.com/search?q=weather+balloon+burst&qs=n&fo...
Always use recovery parachute, as advised below
https://www.basicairdata.eu/knowledge-center/design/introduction-to...
"The parachute will slow down the payload descent when the balloon explodes, during the ascent, the parachute is already exposed and hangs from the rigging.
If you want to burn altitude using a parafoil, use a spiral dive (look for paraglider spiral dive on youtube). You will drift with the wind but will get to lower altitudes where wind speeds will be less extreme. Depending on the conditions and your flight envelope, it might be best to drift but spend less time in the high wind region than to waste time fighting against it. Of course, another way to increase your speed is to increase your wing loading, if your payload is reasonably robust, just use a small parafoil.
Regarding the software, have a look here. I don't think there is any stock firmware that handles parafoils but, if you feel like coding a bit, you might be able to just use an Arduino with GPS without needing a full blown Pixhawk.
Since weather balloons fly against jet streams it's a good chance to have aerodynamic cell structure of your parafoil inflated by the wind.
You can read wind speed from GPS tracker coming with every weather balloon but need to precalculate safe descent trajectories to work for you if the balloon bursts.
Reversing your concept may give good results.
Hi Colin !
I'm currently working on a similar project, have you had any luck with your project ?
I'd be really interested discussing any progress you've made.
Jim
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