I could use just a little guidance

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Arpak

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Those are "tufts" that I put on to try and spot vortices from the canards. I thought I might see something that correlated with the spin can movement.

Jim
Ah gotcha, it almost looks like there's some correlation in where it's pointing but it's subtle so who knows.
 

Grog6

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I built a stabilized design over 50 years ago that was made up of three hobby motors mounted to use speed up down accelleration to move the rocket around the CG.

A friend of my dad's with the batf told me it was too close to being a guidance system, with only simple controls.
An arduino with a gps and 3 axis control would make it a weapon to the wrong people.
 

boatgeek

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I built a stabilized design over 50 years ago that was made up of three hobby motors mounted to use speed up down accelleration to move the rocket around the CG.

A friend of my dad's with the batf told me it was too close to being a guidance system, with only simple controls.
An arduino with a gps and 3 axis control would make it a weapon to the wrong people.
This issue has been discussed ad nauseum here (I think) and in other threads. Making a system that points the rocket up and/or at angles to stay within the waiver is all OK. IIRC, NAR and TRA said that controlling a parachute (or a rocket-boosted RC glider) to land in a spot is also fine as long as that spot is in a safe location. Making a guidance system that aims at a target is Not OK. Doing anything intentionally destructive is Not OK. There is a big gray area in the middle that we prefer not to test.
 
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CoyoteNumber2

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An arduino with a gps and 3 axis control would make it a weapon to the wrong people.
I worked on a counter-UAS development program, and I can promise you that turning a model rocket into a target-seeking missile is not as easy as everyone seems to think. The "wrong people" would better spend their time finding some Stingers on the black market.
 

MJW

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My senior capstone project was sponsored by the University's rocketry club. While my work was not directly tied to the navigation system, I can tell you with certainty that all the CS, EE, and CompE students, faculty, and industry volunteers involved saw no possibility of making a 6-DoF guidance algorithm run on an Atmel 328 MCU. If anyone wants to go down that rabbit hole, find an University team to partner with. The complexity, cost, access to appropriate GPS hardware is next to impossible for a hobbyist to do on their own--not to mention compliance with applicable regulations.

Stabilization, roll control, etc... Sure. Guidance under thrust... Not a chance.
 

JimJarvis50

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My system attempts to control the orientation of the rocket, i.e., a specified tilt and bearing. It generally follows those instructions, but is affected by the ability of the rocket aerodynamically to hold the desired orientation, errors in the cumulative tilt and bearing calculations over time, and wind. The powers-that-be are OK with this. But, add gps or targeting and all bets are off.

Jim
 

MJW

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All of that can be done with an IMU based system. No need for GPS at all in the compensation loop. If you're using active control though, simulation of your loop parameters is key. Error on the low side of each parameter for the first flight. It's much safer to have an over damped system.
 

JimJarvis50

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All of that can be done with an IMU based system. No need for GPS at all in the compensation loop. If you're using active control though, simulation of your loop parameters is key. Error on the low side of each parameter for the first flight. It's much safer to have an over damped system.
I'm about 25 flights into the operation of my system. Check out videos earlier in this thread (the "Infinity" flight was pretty good).

Jim
 

JimJarvis50

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So, at last report, I crashed the test rocket at AirFest. The only significant damage was to knock two fins off the spin can. It has been repaired. It's a pita to take off the residual tip-to-tip carbon and redo it, but it's now completed (except that I need to add the fin tips like those used in the last flight). I'm hoping to conduct another flight with a slightly different profile perhaps early next year.

Jim
 

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