First steps for Super Mega Microbot

[KevinO]

I will check it out.
I'm using a raspberry Pi right now for compute so all the code I wrote in python.

My last robot Charlotte ran a raspberry pi. Great platform. Looking forward to watching your progress.

[jpieper]

I will check it out.
I'm using a raspberry Pi right now for compute so all the code I wrote in python. I have the commands to control the serves done. Also got basic start sequence which clears the serves, turns the torque on and puts it into a default stance. Now been playing with a single leg swing to get a good idea for leg lift, swing etc.

The promised python gait engine and development tool is now posted:

http://forums.trossenrobotics.com/sh...p?7021-legtool

[nvrdunn]

The promised python gait engine and development tool is now posted:

http://forums.trossenrobotics.com/sh...p?7021-legtool

jpieper, thank you for posting the app!

[jpieper]

While we know there still isn't any large competition in the near future, we made up a "qualification" video just to prove to ourselves that we at least had everything working end to end. The long dimension in the room we were shooting in was 13ft, so only a little shorter than a full arena.

[jpieper]

And now, some more upgrades in progress... a prototype gyro stabilized turret. This is just a proof of concept video, with a hacked up aluminum gimbal frame and an off the shelf Martinez gimbal controller with its code slightly modified to stabilize about the pitch and yaw axes instead of pitch and roll.





The upshot is, even while walking, it keeps the video plenty usable and keeps the turret aimed about as well as any of us can aim it against a moving target.

Now I'm tweaking the controller's firmware to use the Dongbu servo protocol, so that we can aim it instead of just stabilizing. If that works out, I'll probably build a more suitable turret bracket, and possibly switch to a custom controller that has two IMUs for even better stabilization.

[jwatte]

keeps the turret aimed about as well as any of us can aim it against a moving target

OK, now I'm scared! Move-and-shoot was effective for your guys already. (As was your two-person piloting team set-up.)

[jpieper]

Next up I'm working on a new chassis and an integrated odroid daughterboard to go with it.



No one seems to go with mammal style bodies, but I wanted to experiment with it for other reasons. I also figured out the "right" way to mount the HerkuleX servos, so now there are zero washers, lock washers, spacers, or nuts in the entire assembly and half the total screws.

The odroid daughterboard integrates what was 6 separate boards/modules on the old mech:

1. The 5V regulator for the odroid
2. Power and serial data distribution for servos, fuse, and main power switch
3. Drivers for AEG and agitator
4. Shore power connector
5. Weapon power switch and indicator
6. The stock IO shield for the odroid (we were using the I2C level shifters and AVR, and had built on it serial level shifters, a laser pointer driver, and IMU)

It also has a pass-through JST-style USB connector on top for the turret webcam.





The daughterboard and all the main structural components mount to the top plate, which has slots where the connectors from the daughterboard for top-side things protrude. I think you should be able to take it apart in nearly any order without needing to carefully thread cables through like on our old chassis.

The daughterboard is sent off to macrofab now, the 3d parts to shapeways, and the chassis plates I'm sitting on sending out because they aren't nearly as long of lead time as the other pieces.

[jwatte]

Speaking of Macrofab, I sent the files for an Onyx Fire II to Macrofab to test them out. Just got the envelope, so now I need to hook it up and see whether it actually works :-)

[jpieper]

I got my first boards from macrofab back for a second rev of the scoring system a week or so back and they seem to be working out just fine.

Also, some minor progress to report on the mech itself. A prototype mammal style leg, with a 3D printed bracket to hold the final leg segment:



And a 3D printed gimbal bracket that permits full range of motion vertically:

[jwatte]

Shiny!

The IK for that mammal leg seems interesting. You CAN reach a reasonable envelope, but the angle to ground will be... varying.
I'm wondering whether a good use of a fourth leg servo is to define the contact angle with ground, and then use wider feet to get less tilt while walking. This would make for a more stable gait so stabilization is less necessary.
Might need a fifth servo, for orientation, even...

(In other news: I got the Onyx Fire II back from Macrofab, and it did, indeed, work. Who needs Seeed now? :-)