Multirotor Emergency Parachute?

[chaos23]

Yeah its great discussion because of the unknowns

 

[andybenton]

I like to think that progression is made here on the forums threw engaging conversation like this.
With any luck at all, even if they don't make an episode of it, someone may decide to prototype it.


although a multirotor may be a bit ambitious. the icon a5 does use a ballistic chute IRL. maybe we need to look more closely at fixed wing chute systems before we try to tackle the multirotor side of things. I don't know if there would be much useable knowledge to be gained, but it would be a place to start...

it would be realitivley easy to build a stand in for a quad, replicate the weight, size shape, maybe put props on it, and drop it from various heights to see how quickly we can count on the chute to deploy...

also with the same arduino unit, and a simple altimeter, we could program an airbag system to deploy if the loss of control happens under a certain altitude... however as said before, the bags require the craft to land in its normal orientation....

on another note, it may be possible to use a much smaller "drag" chute, to orient the craft properly to fix the orientation issue of the airbag... but again, some altitude would be required... this may be best left to building a system that would save you in a certain circumstance.... as in the chute for those of us that fly mostly at higher altitudes... and the bags for those of us that fly lower altitudes.


all in all im afraid combining them may over complicate things,making the system likely to fail.


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random thought, anyone know or want to speculate as to whether or not you can auto-rotate the Curtis Youngblood stingray 500???

maybe there would be something to cp quads... granted in the event of radio lock out your still screwed, but in a loss of motor power, it could be savable with a practiced pilot....

 

[Craftydan]

From the video, he talked about pulling the throttle down and building head speed, but before touchdown he juiced the motors with he last bit of remaining charge, instead of bleeding off the head speed.

I imagine with his blades being so very light they make terrible flywheels. While the freewheeling props can act as an airbrake and give a controled descent, they can't build up enough energy to cancel the momenum.

However, if his ESC was regenerative . . .

 

[chaos23]

May I just point out that the airbags can deploy ontop and below the craft orientation is a none issue. And as the would be like big fat pillows they would protect and stop your rotors spinning in decent. .. but first a simple Co2 system using party balloons should serve to test the concept using a mockup deadweight

 

[rcspaceflight]

it would be realitivley easy to build a stand in for a quad, replicate the weight, size shape, maybe put props on it, and drop it from various heights to see how quickly we can count on the chute to deploy...

Yeah, that's what I was thinking. Just a simple mock up with free rotating props.

This is a great discussion and I want to raise a question: What would the goal of the system be? Is it to save the majority of the craft, or just a few components? Basically, would it even be worth trying to save the motors? I know the props are out, who cares about those? but aren't motors rather cheap too? Or would you want to save those?

I think the nice thing about airbags is that you can wait until the last minute to deploy them. And actually if an airbagged quad lands on someone, the airbags would still be taking the majority of the impact. It wouldn't hurt that much.

The chute would have to be deployed quickly for best effect... and chutes tend to drift with the wind. Just saying. But a 10mph impact does a lot less damage than a 30mph impact. So even just slowing the craft down would help a lot. It doesn't have to be a big chute.

I think the problem with the airbags is the complexity of them.

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This kind of reminds me of the classic engineering school project of preventing an egg from breaking when dropped from the third floor. lol.

 

[andybenton]

May I just point out that the airbags can deploy ontop and below the craft orientation is a none issue. And as the would be like big fat pillows they would protect and stop your rotors spinning in decent. .. but first a simple Co2 system using party balloons should serve to test the concept using a mockup deadweight

this is true, but im not sure its the end all correct answer. the mechanics required to pop the co2 would be complex, and probably require a servo, so a servo driver would be in order, IE a receiver, or a servo drive on the arduino, something similar...

then the durability of the bags is also an immediate concern.

on the other hand I do see the value in the bags. however I do think that there will be a continuous division regarding which system would be most desirable. And ultimately its going to come down to the pilot and there preferences.

 

[andybenton]

Yeah, that's what I was thinking. Just a simple mock up with free rotating props.

This is a great discussion and I want to raise a question: What would the goal of the system be? Is it to save the majority of the craft, or just a few components? Basically, would it even be worth trying to save the motors? I know the props are out, who cares about those? but aren't motors rather cheap too? Or would you want to save those?

I think the nice thing about airbags is that you can wait until the last minute to deploy them. And actually if an airbagged quad lands on someone, the airbags would still be taking the majority of the impact. It wouldn't hurt that much.

The chute would have to be deployed quickly for best effect... and chutes tend to drift with the wind. Just saying. But a 10mph impact does a lot less damage than a 30mph impact. So even just slowing the craft down would help a lot. It doesn't have to be a big chute.

I think the problem with the airbags is the complexity of them.

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This kind of reminds me of the classic engineering school project of preventing an egg from breaking when dropped from the third floor. lol.

In my mind, and that's all that this is, my own mind.
The goal would be to save basically everything minus the props... sensitive data logging equipment, the camera, volatile lithium batteries, fpv transmitters... I guess the props are really about the only thing I wouldn't care to save.

it would also depend on what material you plan on building the quad from... mainly wood vs CF... cf is expensive and in a crash, I personally would like to minimize damage to the frame as well. wood on the other hand, you could focus more on the equipment onboard... however I do think a multirotor designed to carry this payload, of which I have no earthly conception of the weight, would benefit from being made of carbon fiber.


yeah, it is really an issue with wind drift.... theres not much you can do about it. again, in my mind, the craft is already equipped with gps, and the arduino board, so getting a buzzer or something similar to help you locate it, would require a minimal amount of work and weight.


like I said, no one system will be right for everyone, and I think that it really speaks to the creativity of the human mind, getting to read everyones ideas, input, modifications, concerns and general chatter on the subject really does meet at least one part of the Flite test mission statement... elevating, or inspiring the world of flight.

 

[chaos23]

this is true, but im not sure its the end all correct answer. the mechanics required to pop the co2 would be complex, and probably require a servo, so a servo driver would be in order, IE a receiver, or a servo drive on the arduino, something similar...

then the durability of the bags is also an immediate concern.

on the other hand I do see the value in the bags. however I do think that there will be a continuous division regarding which system would be most desirable. And ultimately its going to come down to the pilot and there preferences.

absolutely a pilots preference, the system for the airbags is easier then you think, literally buy the ones they put in your steering wheel. the release would be a 2 stage system, arduino alt and speed sensor and if that fails ie dead system total failure, a mechanical proximity trigger, like curb feelers that release when there is a system failure, I/O magnetic release. so they dont go off when your just making a harder then normal landing.

for me the goal is to prevent total destruction. i fully expect a boom arm to break in the worst case, so long as 80% is safe and ok its as the swede says "landed" lol.

 

[andybenton]

absolutely a pilots preference, the system for the airbags is easier then you think, literally buy the ones they put in your steering wheel. the release would be a 2 stage system, arduino alt and speed sensor and if that fails ie dead system total failure, a mechanical proximity trigger, like curb feelers that release when there is a system failure, I/O magnetic release. so they dont go off when your just making a harder then normal landing.

for me the goal is to prevent total destruction. i fully expect a boom arm to break in the worst case, so long as 80% is safe and ok its as the swede says "landed" lol.

car airbags are VIOLENT, and a late deployment would probably do more damage than good...

that being said, there are issues with the parachute also.IE entanglement in props, late deployment, not deploying, etc...

unfortunately, what I had assumed was an original idea, has officially been done

http://fruitychutes.com/uav_rpv_dro...er-rc_aircraft_recovery_and_rescue_chutes.htm


although, different representations and iterations are just waiting.

 

[chaos23]

new airbag systems are normally fully self contained and developments have made them more "gentle" without sacrificing speed of deployment, they dont contain the gas very well in order to divert the kinetic velocity difference of to objects (car-face) or in this case (ground-rotor). hence the need for late deployment, deploy them to early and they will deflate enough to be useless.

also a rotor can take way more Gs then a human and with the weight difference the deceleration would be much greater whilst spreading the force across the frame.

another more dangerous idea is to have spikes or rods at least a half meter long used as landing gear mainly but at velocity would penetrate the ground (assuming your in like a field) to create the same deceleration needed. a very low tech solution they used on the lander legs for the moon landings, thin spikes that would either crumple or penetrate the surface and remove the initial shock load on landing.

 

[rcspaceflight]

To prevent the chute from getting tangled in the rotors, I think an umbrella will be needed. By that I mean to only use wire instead of string, except for a shock cord to take the initial stress of the chute going one way and the craft going another. And I also mean to have wires inside of the chute to keep it apart. Although, maybe just wires to force the chute to stay away from the rotors is enough.

I'm just thinking that you may get locked out with one rotor at full speed. Constantly over rotating the craft. The system would be almost useless if it can't cover everything. Well, not "useless", you know what I mean.

You know those tents that you take out of the bag and shake them and they instantly pop up? I'm thinking something like that. They also make frisbees like that. Maybe a horizontal "frisbee" and a vertical "frisbee" intersecting at the CG of the multirotor would be enough. It would both create drag and take some of the impact. It couldn't get tangled in the props. And it would be lightweight. Although, you'd need rather large frisbees to slow the craft down to a reasonable speed and to take a lot of the impact. Not sure how to actually mount them to not hit the props while unfolding.

 

[chaos23]

My dad had good idea when I told him about this. He suggested to fire the chute from one or two of the boom arms. This would force the blades to angle away from the chute

 

[rcspaceflight]

Okay, this is weird, but strapping this TMNT tent to a mock up quad would be a great proof of concept for a pop up style chute/airbag. http://www.amazon.com/Playhut-Teena...F8&qid=1389042560&sr=1-3&keywords=pop+up+tent

I think one half the size on both the top and bottom could save a good portion of a quad. Unless it landed right on the boom. But if the airbags are tall like the tent is, then the drag would, hopefully, force it to land right on top of either bag.

 

[xuzme720]

Just strap one of these to each boom! http://www.amazon.com/Ball-Bounce-Sport-TOYS-Teenage/dp/B00D9TDZLA/ref=pd_sim_t_5

 

[chaos23]

We have left the realm of sanity. "Face palms"

 

[rockets4kids]

First time chiming in on this thread...

First off, I have seen parachute deployment as an option on a number of commercial fixed-wing UAV products. I believe the idea here is to make "landings" easier for non-pilots. An autopilot needs merely to return to a fixed point at several hundred feet of altitude and deploy the parachute. So in principle, the concept is completely viable.

I can think of at least two cases where automatic parachute deployment could do more harm than good:

1. At high altitudes on windy days, parachute recovery could lead to substantial drift, possibly into an inaccessible area.

2. A parachute could make recovery from a tree much more difficult. A multi-rotor stuck in a tree could probably be brought down with some good shaking. With a parachute, it is stuck up there for good.

If you want to go the parachute route, be aware that it often takes several hundred feet for the parachute to deploy and slow descent to safe speed levels.

In terms of implementation, I would strongly suggest investigating how parachutes are deployed in the amateur rocketry community. In almost all cases, a small pyrotechnic charge is used to deploy the parachute. This method is simple, reliable, lightweight, and inexpensive.

Compressed air deployment is only used for high-altitude deployment. CO2 systems are complex, expensive, heavy, and prone to failure.

Servo-activated spring deployment systems are common in the water-rocket community. I have seen a number of designs that appear relatively simple, inexpensive, and can be constructed with common tools, but I do question the reliability of deployment.

Regardless of how the parachute is deployed, careful packing is required for successful deployment and quick inflation.

You are going to want to stop (and ideally brake) the motors before ejecting the parachute to avoid fouling.

 

[Tritium]

Just strap one of these to each boom! http://www.amazon.com/Ball-Bounce-Sport-TOYS-Teenage/dp/B00D9TDZLA/ref=pd_sim_t_5

O yea, 16 lbs of landing gear. Where do I sign up?

Thurmond

 

[chaos23]

First time chiming in on this thread...

First off, I have seen parachute deployment as an option on a number of commercial fixed-wing UAV products. I believe the idea here is to make "landings" easier for non-pilots. An autopilot needs merely to return to a fixed point at several hundred feet of altitude and deploy the parachute. So in principle, the concept is completely viable.

I can think of at least two cases where automatic parachute deployment could do more harm than good:

1. At high altitudes on windy days, parachute recovery could lead to substantial drift, possibly into an inaccessible area.

2. A parachute could make recovery from a tree much more difficult. A multi-rotor stuck in a tree could probably be brought down with some good shaking. With a parachute, it is stuck up there for good.

If you want to go the parachute route, be aware that it often takes several hundred feet for the parachute to deploy and slow descent to safe speed levels.

In terms of implementation, I would strongly suggest investigating how parachutes are deployed in the amateur rocketry community. In almost all cases, a small pyrotechnic charge is used to deploy the parachute. This method is simple, reliable, lightweight, and inexpensive.

Compressed air deployment is only used for high-altitude deployment. CO2 systems are complex, expensive, heavy, and prone to failure.

Servo-activated spring deployment systems are common in the water-rocket community. I have seen a number of designs that appear relatively simple, inexpensive, and can be constructed with common tools, but I do question the reliability of deployment.

Regardless of how the parachute is deployed, careful packing is required for successful deployment and quick inflation.

You are going to want to stop (and ideally brake) the motors before ejecting the parachute to avoid fouling.

Great information. But the reason for this thread is for when the bovine excrement impacts the aero propoltion device. So its not going to be planned or expected, motor breaking will be the last thing on your mind.

 

[rcspaceflight]

So its not going to be planned or expected, motor breaking will be the last thing on your mind.

Not unless the chute/bag system also jams something into the motors to stop them. A burnt out motor/ESC is better than a motor powering the craft into an uncontrollable spin. Actually, a servo could be used to unplug one wire from each motor to turn it off. But that's probably not necessary.

 

[xuzme720]

O yea, 16 lbs of landing gear. Where do I sign up?

Thurmond

Is that too heavy? I may have to rethink this one then!

You know I was only kidding on the bouncy ball thing, right?