|Motor control testbed using TB6612FNG motor driver|
Tuesday, April 25, 2017
Q1 2017 Rocket active stabilization system update; Finally have working PID for positional control of a DC motor! New gear, livestreams and the first program sponsor!
After nearly 4 and a half months of late nights, caffeine fueled jam sessions, one livestream(more on that later!) and more frustration than anticipated I FINALLY figured out implementation of PID for positional control of a DC motor with an encoder. More details after the break including a breakdown of problems I ran into, some shiny response graphs and most importantly; SOURCE CODE!?!?!
In working towards a positional control system, the first order of business was to go for the most basic of controllers; Bang-Bang. Dead simple to implement but not without numerous shortcomings. Several of these removed it from even consideration of the flight unit due to possibility of overcontrol or destructive airframe resonance. Airframe resonance would start as a flutter in the fins but spread to the stabilizer oscillating on the front of the rocket before finally leading to a full half of the body wobbling about the split for parachute deployment and snapping the rocket in half mid-flight. Another nightmare scenario is overcontrol, where the system attempts to correct course changes but turns itself into a kinetic hazard as it passes the +- 5 degrees off vertical allowable range for safe flight or worse goes sideways and WAY off course.
Monday, January 30, 2017
Yes you read that right, as of January 30th I am working at NASA Goddard as a student researcher in the earth sciences wing, specifically on the 4U Laser Hetrodyne Radiometer cubesat as a hardware/software engineering intern.
Thursday, December 29, 2016
Happy Hackerdays readers! Since the last update I've been absolutely slammed between life and projects which had a drastic balance change that took more time and energy away from the blog than I'd have liked but thanks to a few alterations it is looking like I'll be back on track to get updates out more frequently and have an increase in project progress.
|Hackertree 2016, with even better gear and Wi-Fi LEDs!|
Wednesday, August 17, 2016
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.
Tuesday, June 14, 2016
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|
Friday, March 11, 2016
You've probably had this problem before; Writing code late at night trying to get new features to work but the bright white of the default IDE is burning your eyes and giving you a headache even with F.Lux installed, and/or you've mistaken a "l" for a "1". Well, there are solutions to those problems, but not the other well known problems (autocomplete, not enough debugging features, etc etc) after the break.
|Original on left, rethemed and refonted on right|
Sunday, February 14, 2016
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|