Quadbot 17 - Quadruped robot designed in Autodesk Fusion 360

[jwatte]

FWIW: The AX18 don't have a lot more torque, just a lot more speed. Weight/carrying capacity is mostly about torque, not directly speed.
Yes, the AX18 have slightly more torque, but it's not night-and-day. But it's really fast!

Also, Robotis has pretty much put the AX and MX series into maintenance mode now. They have the new XL320 (last year) and XL430 (this year) servos as replacements. The 430 is nice, because it has a more precise encoder, and otherwise very similar specs to the AX12 at about the same price.

Most of the 'mechs at Mech Warfare (see other threads) are quadropeds built on AX12, btw. There are many different approaches to how to design those legs, so look through the videos to see what you'd like.

Regarding m3atsauc3's legs: There are three vertical servos that all have essentially the same amount of torque acting on them. Given that that's created by gravity, I imagine that some torsion springs could be added to those joints to reduce the load.

[m3atsauc3]

Thanks jwatte, I was going to say the same!
The XL320 is good if you want something significantly cheaper. I was gutted to see the newer X-series this year and not have them now!
If you see the page description of the x-series, most are prohibitively expensive, but the XL430 stands out as the cheap and viable option:
http://www.robotis.us/x-series/


Trossen has a useful comparison chart here:
http://www.trossenrobotics.com/dynam...30-w250-t.aspx

[m3atsauc3]

Torsion springs are definitely on the TODO list.
The robot can currently hold its home position with torque off, but more weight is going to be added (battery being the heaviest).
Fans and heat sinks will also improve things...

[jwatte]

Note that reducing load on the motors not only makes them overheat less, but it also draws less battery current, and thus gives you a longer runtime!