Let's Make Robots!

MegaQuad MKII

Obstacle avoidance via ping, hand tracking (eventually)

The old bot had 3DOF per leg using 9g servos :( I'm using Inverse kinematics for his movement. I just started programming him and got the IK working for one leg. The ping((( is just stuck in the mega2560 for now. I'll be adding a tilt/pan head when I get more servos, and the wiring needs some cleaning up :p I just found out about LMR last week and so far it's awesome! The thing underneath him in the picture is a stand I made with my 3d printer to get his legs working correctly, very handy. More to come.


    ****    UPDATE    9 - 23 - 12    ****

 
 
 
     Well the little guy above is no more, as you can see in the picture below, he went through the disassemble process. The reason for this was I thought I had a pile of bad servos. Upon powering the servos the bot would go into an epileptic fit. At first I thought that the pots were dirty, but a teardown revealed that they were fine.
     My original intentions were to build a V2 bot when I got the code working for the V1 bot, but things change and you just have to adapt sometimes. As it turns out, it wasn't the servos that were bad, it was the cheap oxidized jumpers that were the bots untimely demise. This wasn't realized until it was time to center the new SG-5010's for the leg assemblies, and THOSE were acting erratic and having convulsions as well.
     At the end of the day at least I have a small pile if micros' for future bots, and a good start on V2. I'm currently prototyping a power distribution board while waiting for the Mega PotoShield to show up from Adafruit Industries. I tried etching my own board for powering all of those servos, but most of the traces ended up being open and overall it just wasn't worth trying to save. I'll show some pics just to try to justify the long slow updates . :P

The carcass of MegaQuad Mk1
 
The parts needed to assemble a leg.
 
When you don't have the right tools, sometimes you have to make the right tools.
 
I put a pivot on the back of the servos in this design.
 
Here is a size comparison with the old bot.
 
More parts printed and almost ready for assembly.
 
All the legs attached pretty nicely.
 
Ahh, that's better, now he can see where he's going.
 
Still needs the servo board I'm putting together and lots more programming.
 
Eye level view.
 
Well, that's all I have for now. Thanks for stopping by, And I'll have some video on the next update. Hopefully it will be sooner than later....
 Oh wait, here are those pics of the servo power board fail. :P I guess I owe it to ya if you made it this far through the post. :)
The board before etching, all sharpied up, or so it appears :( 

View of the board mostly populated (no signal jumpers, yet), but not soldered. Hence the dangling screw-terminal. :P

View of the back, notice the over-etched traces.
 
Thanks again and be sure to click on the collect link above.

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Nice! are you using 9g servos? is there any videos?

The 9g servos only have one mounting hole per side. These servos have two.

I second the call for a video. Very nice looking bot!

The bot looks great I should put my microservos to some use :)

But the sharpie PCB remainds me of one of my first drivers :) I would suggest a redo on that with toner transfer or exposure as it will cause great pains in the near future.

Just my 2c ;)

Yeah, I have no intentions of using this particular board, it was mostly an example of. "If it looks like you got it all with the sharpie, give it another coat." I actually have a Mega ProtoShield that I decided to go with until my eagle skills improve. It was included because I think fails can offer some good "what not to do" information. Thanks for your good suggestion.

that's a nice looking quad ! :)

Thanks for your comment. This robot was actually inspired by your hexapod, which is what brought me here to LMR in the first place.

i am doing a quadruped robot soon, hope we can share some idea on the IK and gait sequence... :-)

Very cool design , looking forward to see it walk !

3d printing enables such great builds!

How thick are the various parts ? (I usually consider any print with a thickess > 3 mm to be robust enough at 50 % infill , but I wonder if  it is thick enough for these "leg parts")

The parts are generally 3mm thick, printed at 20% infil. They are quite strong. I printed the bot with PLA so it is quite rigid at this thickness. I could definately see a servo horn tear off before a leg broke, and it is still quite light. ~300g of PLA for the whole bot.

I think that is the reason I can't get this to show up as updated. Hmm, guess I'll have to bump it. But anyway, finally after a month and a half, an update!