Home on Robot Daycare

It's somehow already been over a month since I last posted motor dyno documentation, so a lot has happened in the meantime.

Enjoy this unprecedented two posts in one day.

Where "Small" means around 6-7 kW.

With the mechanical bits out of the way, it's time to go through the process of controlling the inverted pendulum.

This is a relatively quick little project, but one that's been on my mind for more than a year now, and finally got around to building.

I've been saying I'll post my design files and such online for a while now, so here it is.

One more jumping leg post.

Last night I reworked all the communication to happen directly over serial, and hooked the leg up to a more capable power supply.

After 2 days of debugging (and only partially fixing) a mysterious SPI communication bug that appeared out of nowhere, here's a jumping leg: A few things to note:   - This is with current limited to 40 amps on the motor side.

Not really, but a sideways leg is basically a SCARA arm, right?

I promised more science, so here it is.

Another fairly unsubstantial post (as far as technical details are concerned), but pretty pictures.

I finally put the finishing touches on the 2nd revision of motor control boards, and sent them out to get made.

I made a little single-stage 6:1 planetary gearbox for one of the motors.

Over winter break I finished EAGLE-ing up a first revision of motor control hardware, and sent out for boards from 3PCB first week in January.

Snow Bike was more or less finished Saturday night, just in time for playing in several inches of snow before it all got plowed and salted.

After the absurd amount of snow Massachusetts got last winter, I decided to prepare myself for the next winter by grabbing a pair of small snow blower treads on Ebay.

In Part 1, I documented quadrature-encoder-ing with the Nucleo boards, and talked about some ways to sense speaker cone velocity.

a.k.a.

I've been using the STM32F4 Nucleo dev boards for everything lately, and needed to do high speed (edges at MHz frequency) quadrature decoding with one.

I like taking my gourd ukulele with me when I leave school for more than a week or so, but it's a little annoying to travel with, since it takes up pretty much an entire backpack and is somewhat fragile.

After stumbling upon the bed, carriage, and tailstock from a Taig lathe, I rebuilt the lathe, making all the parts I didn't have already.

Here's a pile of tiny lathe pictures: Since taking these, I've also re-cut the spindle taper in place to eliminate runout, mounted an encoder to the back of the motor for closed-loop spindle speed control, and leveled the tailstock.

After great struggles with the lathe electronics, the lathe is finally working.

I recently stumbled across a neat design for a ball turner on youtube, and ebay-rage-ordered all the parts to build one.

l spent way too long agonizing over how to mount the motor.

A tiny tool post for the tiny lathe.

I'm back from the left coast, and for once I'm not busy building giant wooden contraptions for orientation.

Machining the spindle turned out to be kind of a disaster, but I was mostly able to salvage things.

The making of the handwheels involved a few revisions and many mistakes before producing something acceptable.

I considered buying a little metric rack gear for the lathe on SDP-SI, but it would have cost around $30.

School's over, so it's time to catch up on documentation.

Man am I behind on documenting the mini lathe.

As previously indicated,  my longboard (can it be called that?

A new innovation in silly electric vehicle battery technology: More to come soon.

Since I only have one of the original taig cross slides, but want both a cross slide and compound on the mini lathe, I had to make a new cross slide from scratch.

Back over the summer, while exploring some dusty top shelves at MITERS, I found what appeared to be they ways, carriage, and cross slide from a tiny lathe.

First, some photos taken with one of Bayley's magical cameras: Sorry I didn't focus it well enough to achieve the full 25 megapixels of resolution, Bayley After last round, the only thing left to make was a ring to separate the two halves of the rotor.

I've been thinking about this kind of motor since I started playing with the ServoDisc's for the robot arm.

The Big Scooter (version 2) has existed for a year and a half now, and I've finally gotten around to doing some long needed updates to it.

There's an old safe at the EC front desk that hasn't been opened in a while, and no one knows either the combination or what's in it.

I finally made it back to Atlanta this December, and while I was there I was given this beautiful little block plane.

Since working on the rotating climbing wall last year, I've been interested in trying to revive the East Campus roller coaster.

Winter break means it's time to finally finish up roller coaster documentation.

Because why not.

Finally back to the robot arm!

While I wrote about designing the shape of the track a while back, the shape design and detailed mechanical design actually happened somewhat simultaneously.

Two summers ago I bought an iPad 3 LCD off ebay.

The East Campus Roller Coaster happened, and was a great success.

You may be wondering what's been happening with that extremely shiny hub motor I built ages ago.