I know that people have discussed this before, but I have yet to see anyone declare that they built a worthwhile system or create any documentation.  I did see some youtube videos using pyro charges, but that makes me nervous.  I want to use CO2.  If anyone has any information or observations I would love to hear it as I start this project.  I am throwing all my ideas out there to see what people would do differently, or to find out if it is a pipe dream (pun intended).  So here we go!

Goal:

Develop a lightweight and independent failsafe system for multicopters.

Idea Summary:

Use an Arduino micro with an accelerometer to trigger the ejection of a parachute.  The system will have to be independent of all other power and mechanical systems on board so it will have it's own power source.

Detail:  

This would be primarily designed for multicopters carrying a large and expensive payload like a DSLR.  The goal is to slow the copter down enough so that the payload is less likely to be damaged if an emergency occurs.  The independent power source must be small and light weight.

I researched different methods to see if anyone had tried to worked with Arduino and pressurized CO2.  Unfortunately, there were only unanswered questions or some hypothesis with no follow up.  While brainstorming I thought about paintball and thought that a solution might exist there since they use electric triggers in many of the markers.

I picked the CO2 system from the Tippman Tipx pistol because it was built around CO2 cartridges, instead of a refillable bottle system.  I think I can use the puncture valve assembly from this marker to interface with the CO2 cartridge.  I need to figure out if the puncture valve assembly will actually act as a valve, or if it only provides the breach.  I also need to find out if the an e-trigger solenoid provides enough force to puncture the cartridge, or if it has to be manually punctured.

The Solenoid will be triggered by an e-trigger assembly, this assembly will be hooked up to an arduino micro with an accelerometer.  The accelerometer will trigger the solenoid when either the multicopter tips past a certain point or the rate of descent reaches a specified velocity.

The gas from the CO2 cartridge will travel through a pipe into the adjacent tube that is packed with wadding and a parachute.  I will need to run some tests to see how big the chute needs to be, but I am sure it will be significant.

Reference:

Tipx Exploded Diagram: http://www.tippmann.com/pdfs/manuals/TiPX%20Schematic%208-11.pdf

Valve Puncture Assembly: https://www.pbsports.com/Tippmann-TiPX-Puncture-Valve-Complete.html

Solenoid & e-trigger: https://www.pbsports.com/Virtue-Redefined-Tippmann-A5-Upgrade-Board...

Arduino Micro: https://www.adafruit.com/products/1086

Accelerometer: https://www.adafruit.com/products/1018

Here is a really rough draft of what I am thinking:

So lets hear what you think!

Views: 6222

Comment by Gary McCray on November 30, 2012 at 2:01pm

Hi, I've given the chute use problem a lot of thought for multicopters.

Multicopters have one problem regular planes don't, spinning blades everywhere, I presume you are addressing this by trying to shoot the chute (couldn't help myself) away from the blades.

But even here, if the completely aerodynamically unstable multicopter happens to be more or less upside down, it will just fall into or at least tangle its own chute anyway.

A ballistic chute will work better than a conventional self deploying chute on a multicopter, but it is still subject to complete failure.

Aside from that, your system is intrinsically heavy, the size solenoid required to actually pierce a CO2 cartridge reliably is almost certainly on the order of a pound in weight, much better would be a spring loaded CO2 cartridge puncturer with the solenoid or a servo controlling the trigger. Aside from that, a satisfactory "chamber to hold the CO2 cartridge and its puncturer would have to withstand 200PSI and be heavy also.

Estes rockets use a small explosive charge in the top of their rocket motor to launch chutes for rocket recovery and these are a lot smaller, simpler and lighter and only require a simple igniter circuit.

And you still have the potential upside down multicopter falling on the chute problem.

I came up with something a little different, 4 thin flexible fiberglass rods mounted inside the 4 corners of the quad copter inside the propellor wash zone but outside the main filght control and battery bay and angled to the outside. These rods are flexible enough to all be bent over to the center and back down to the top of the multicopter. At the top end they are fastened to the corners of a Square chute which can be folded up and stuck into a box on the top of the multicvopter. A servo releases the box top and the chute "deploys" immediately and cannot get stuck in the prop blades. It will also provide sufficient drag to immediately right the multicopter. In theory this should work for recovery at altitudes as low as 10 or 15 feet. The box could even be freely suspended above the copter and everything could be constructed of non-RF interfering or absorbing materials so it wouldn't interfer with GPS or radio.

I came up

Comment by Patrick Davis on November 30, 2012 at 2:10pm

Hmm, that is an interesting idea.  I am going to see if I can incorporate that.  Can you post some pictures of what yours looks like?

Comment by wilfrid.babilas on November 30, 2012 at 2:52pm
Hi, Every drone need something like this !
Good luck, i follow you works....
Comment by Ned Stojadinovic on November 30, 2012 at 5:30pm
Howabout a water rocket to drag the chute out - that's how some full sized systems do it. Easy enough to seal the rocket nozzle into an electronically actuated plug using a seer like the trigger assy of a gun
Comment by Ned Stojadinovic on November 30, 2012 at 5:33pm
Oh yes, don't forget a safety lock out so it can't fire into your face!
Comment by Jean on November 30, 2012 at 6:12pm

Wouldn't a water rocket be inherently heavy?  I'm imagining a rocket with at least a litre of water = 1kg of dead weight.

Comment by Patch Thompson on November 30, 2012 at 7:30pm

Don't attempt a CO2 system; IMHO, it's the wrong approach. Check out Rouse-Tech co2 systems for deployment; we use those in place of FFFF black powder systems, when employed in High Power Rockets exceeding 30,000' AGL. The rest of the time, it's a small black powder charge. Honestly, a well packed chute with a properly compressed spring(or simple mechanical ejector), on a micro servo-latch release, is your best bet. 

Comment by Ned Stojadinovic on November 30, 2012 at 8:35pm

Hi Jean-Baptiste. Water rockets for the job that small are tiny. Look up aircraft ballistic recovery chutes (eg. Second Chantz), they use less than a liter for a full size chute. At any rate, the Youtube demos are pretty interesting!

I might sit down and do some maths, but I suspect that it would come out fairly similar to the C02 system in that the propellant would be an insignificant part of the system weight.

BTW, I don't know that an emergency deployment system like this is very similar to a rocket 'chute. Rockets can be assumed to have a good long time to deploy their chute, whereas an emergency system will ideally deploy right now because there may be no later.

Comment by Michael Johnston on November 30, 2012 at 9:17pm

worth having a look at the installations used by RC warships that fire ball bearings at each other. 

MJ

Comment by Scott Berfield on December 1, 2012 at 12:36am
I agree with Patch. A simple mechanical system with a properly packed chute would be the simplest/most reliable. Chutes inflate fast once in the open. The sizing might be an issue for the quads, but be interesting to give it a try.

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