Q3 2016 Rocket active stabilization system update, complete hardware redesign of fin drive system with bonus sketches and a needed disclaimer

The old and new designs, massive improvements to the overall design

Update time has rolled around again now that a good chunk of progress is completed on the Arduino based rocket stabilization system. This has taken a while since I've been busy with not only work but also getting the A+ certification in computer repair and completely reworking my current workstation. After much discussion with several other rocket tinkerers, the conclusion was reached that stresses on the servo spline itself would be quite considerable and may result in damage or inoperability. Based on force distribution I surmised that flanged bearings embedded in the system shroud tube would function as not only supports but also as smooth rotation points. With the challenge of a new fin drive train in mind, I set to brainstorming. My first thought was to use linkages connecting the servo to the actuation shaft, though it would increase the diameter of the system unless the servos were staggered which would also increase the overall height of the system. Stepper motors were considered, however as I was unable to find suitably sized units and the common 28byj-48 had too low precision and torque this too was eliminated from consideration. After those two ideas were discarded, it was relegated to the back burner while I had work. The breakthrough was about a week later, while browsing patents looking at missile fin drives I noticed an old Raytheon control segment used bevel gears to transfer the motion and that became the seed for the new design. 

Side projects update: Optical/radio telescopes, CAD, new rigs and custom sensor breakouts

Apologies for the radio silence on this blog, work has been continually crazy and some projects have been sidelined for temporary holds due to funding reallocation, however the backlog of completed short term projects has been full for a while and I thought I'd get some posted to tide you over until the next flagship update (Coming soon! Major redesign underway). Details on projects after the break, with a teaser for the flagship redesign at the end. 

8 inch Dobsonian telescope with craptastic eyepiece

Q1 2016 Rocket active stabilization system update, now with fins, nose cone and a mockup

With 2016 well underway it's time for the first update on the state of the stabilization system!

First off, apologies for the massive delays this post has had, was originally slated for mid-Jan launch but between job hunting and other stuff I've been hitting delays and trouble at every turn. Since last semester ended on Dec 18th, I'd been going to TechShop pretty much every day until Jan 18th making massive leaps and bounds of progress along the way. The most obvious of progress is the completion of the demonstration mockup airframe which will be gone into more in-depth after the break. 

The system's current state on the demonstration mockup

Spring break TechShop progress

Near-final fin with correct blending

Over this recent spring break, I'd decided to forgo the archetypal partying of the Senior year and continue work on my projects. My primary objective was to redesign the fin so it could be used with the round metal servo horns for easier integration and sturdier mounting. The main issue I was having was the splines not printing due to the low resolution of the printer which meant the servos are unable to properly engage with the fin.

Christmas break TechShop Day 1 update

Test fit

First day back at TechShop after 3 months away due to the start of school soaking up the vast majority of my time and preventing me from going into DC every day. After arriving I immediately set to work on the new integration cans as the early prototypes are about ready to be phased out. Halfway through modeling the alpha I realize that I would not be able to slot in the middle segment due to it having the fittings on both the top and bottom, preventing the middle section from being able to slide into place.

Working on the fins

Started work on the servo-actuated fins today, Simple extrudes and lofts based around a standard servo arm, will print these before the end deadline

Finally got rid of the cardboard structure! (size of prints is still wrong :[)

At long last, the horrible cardboard vanishes(except the fins). With the print that was completed today the tolerances came closer than ever before to being perfect but they still are wrong (D:). I had to take an exacto knife and shave the notches slightly wider but for some reason one of the plates was not circular but rather an oval which was nearly imperceptible except when they are stacked on one another(:/).

3D printing plates

Started printing plates to replace the crappy cardboard demo model. First time(black plastic) I had the slots for the servos too small; fixed it and am now printing it again(red plastic)
The initial print had issues with the quality of filament bead as is seen in the partially completed picture

printed revised prototype