Servers by jDrones

Autonomous parafoil flyback for high powered rocket recovery

(Randy Steck) #1

After a bit of research, it appears that you folks are probably the most conversant to give advice for a project that’s a bit out of the ordinary.

I fly high powered rockets and we go for speed and altitude with these launches. Our best is altitude of 75,000 feet with a max speed of mach 2.2. This was a three stage rocket. Recovery is by parachute; first a small drogue at high altitude (apogee) and then a main chute at low altitude (1000 feet). The problem is that we have no control over where the rocket lands. We’ve found stages of rockets as close as 1/2 mile and as far away as 12 miles.

We want to deploy a parafoil at reasonable altitude for each stage to fly the rocket (fin can, nosecone, body tubes) back to the launch point (or a designated recovery point). We have the mechanical design mostly figured out; the challenge being that we have to get the chute out without tearing it or the rocket apart since we cannot always guarantee low velocity deployment (but that’s figured out).

Our parafoil design is 12 sq ft to recover about a 12 lb load, and the control lines require about a 5 lb pull. To get the required torque we will need to gear down motors, which leads to slower response than you’d find with a plane. I don’t have much experience with the guts of autopilots.

Several questions:

  1. Can Ardupilot be configured for this sort of control given the slow control and directional response?
  2. How can Ardupilot be set up as a glider toward a pre-designated landing site?
  3. What sensors are required in addition to the standard package if we want to compensate for wind deviation to get a straight line back to the landing point? I would seem we need either forward airspeed or a precise compass to figure out the wind vector to allow compensation.

Thanks in advance for thinking about this. Happy to address this to a different category if there’s something more appropriate.

(cthill24) #2

Its really cool to see someone working on this. I tinkered around with making a mini JPADS setup with a parafoil some time ago with hopes of using rally points to bring a disabled drone down. I strongly feel what you are wanting to do is very possible with Ardupilot. There are ways you can set this up without having heavily modify the code, but a more tailored approach would be ideal.

You will likely need to incorporate a pitot tube. I would think you could use heavy duty servos with sailing winches, or micro linear actuators like Actuonix with pwm control for the control lines. Of course, you will have to be really selective with your hardware to keep your weight down.

(Jimbo Franz) #3

I am working on this as well. My concern is the action of the autopilot before it goes into Glide mode. “Level” would have to be set perhaps an hour early, the unit disabled from running servos and then reengaged while very likely upside down and near vertical. Basically, if you went up to a tall building, while the autopilot was not controlling, but keeping track of itself, the you switch it’s controls on and drop the plane off the roof any old which way, it must still recover.
Thanks for your time.

(Randy Steck) #4

This may be a very important insight and one that I was hoping to get on the forum. My intention was to deploy the parafoil into a default glide configuration and then initialize the autopilot. I am trimming the parafoil for the descent rate and only wanted the autopilot to control heading. I figured this would make it much easier to get through all the high impact and high G portions of the flight into the controlled phase. Of course, the GPS lock needs to remain working throughout the flight as the reference for autonomous flight back to the recovery point.

Do you think the ardupilot system would allow such a deployment?

I’m glad to see someone else working on this also!

(Rathe) #5

Hi Randy !
I’m also working on a similar project, have you had any success yet ?
I would be really interested to discuss any progress you’ve made.
Jim

(Dave) #6

I wonder if one of these relatively cheap powered parasails could be used for development purposes? Mount a Flight Controller on it and see what can be achieved!