View Full Version : How I made my DARwIn-OP clone is now a Instructable!

02-13-2013, 04:24 PM
I submited a instructable on how I printed out a DARwIn-OP.



09-04-2013, 06:07 PM
Updated my progress with a new video. Getting close now.



09-05-2013, 03:19 PM
As much as I enjoy the merits of 3D printing, it seems that printing brackets that were designed for 5052 sheet aluminum is not ideal.

You'd either want to use specially designed brackets with trusses of some sort, or simply use metal as they're weight bearing structures that need to be as rigid as possible.

Evidence in this is how wobbly it is even standing- I can tell you that my own all metal-framed Darwin is MUCH more rigid and stable in standing up/moving around. This is going to be even more problematic with walking, as rigidity in your leg frame is super important. You already have gear backlash to combat, adding in flexible framing can't help the situation.

09-05-2013, 05:02 PM
Sure, never said that I was done working on my clone, it is still a work in process. I will keep posting as I make improvements to it.

09-05-2013, 05:02 PM
While I can imagine a completely printed plastic bipedal robot on the scale of the DARwIn-OP, I really do not think that the DARwIn-OP is a good design to use as a starting point. The servos are rather heavy for an all plastic body, the design of the mount points on the servo and horn are intended for thin and stiff shell-like structural members, and the gait engine assumes a perfect match between the expected and actual positions of all joints/limbs. It does not use any feedback except a little bit from the IMU on the CM-730, and even a little bit of weight added away from the COG of the bot, or slightly bent frames or loose screws, can cause repeated failures in walking until the damage is repaired and the motion offsets are all reconfigured.

Also, have I mentioned recently that the servos are sufficiently strong to bend the aluminium frames and break gearsets under some loading conditions? If it can bend aluminium, it will easily cause permanent distortion or fracture of plastic.

09-05-2013, 05:09 PM
For a simpler option, I'm actually working on a 3D printed version of Little Walker :-)
(TwitchMX was of course also at least partially 3D printed, and bipedal...ish)