Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

3DOF Mini Quadruped

by tmbg, published

3DOF Mini Quadruped by tmbg Feb 13, 2013
3 Share
Download All Files

Thing Apps Enabled

Order This Printed View All Apps



Liked By

View All

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag.

Print Thing Tag


Thing Statistics

22913Views 5274Downloads Found in Robotics


I printed TheCase's excellent mini-quadruped design, and I love the simplicity of the parts, but I wanted a third degree of freedom in the leg for more complete kinematics, so I slightly redesigned the leg parts.

This also results in a slightly less bulky leg.

For now, I've left off the servo buttons at the coxa joint, but I may go back and add them back in for smoother motion.

If there's interest, I may workup a PCB which carries a Teensy 2.0 microcontroller board and provides power and support for twelve servos.

Update: Video of its first gait!


Parts needed:

1 backbone
2 hips
2 coxa_right
2 coxa_left
4 femur
4 tibia

12 9g servos. Design is optimized for Turnigy TG9e servos: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=22928

However, any 9g servo will work, but the printed parts may need to be tweaked a bit.

More from Robotics

view more

All Apps

Auto-magically prepare your 3D models for 3D printing. A cloud based 3D models Preparing and Healing solution for 3D Printing, MakePrintable provides features for model repairing, wall thickness...

App Info Launch App

Kiri:Moto is an integrated cloud-based slicer and tool-path generator for 3D Printing, CAM / CNC and Laser cutting. *** 3D printing mode provides model slicing and GCode output using built-in...

App Info Launch App
KiriMoto Thing App

With 3D Slash, you can edit 3d models like a stonecutter. A unique interface: as fun as a building game! The perfect tool for non-designers and children to create in 3D.

App Info Launch App

Print through a distributed network of 3D printing enthusiasts from across the US, at a fraction of the cost of the competitors. We want to change the world for the better through technology, an...

App Info Launch App

Quickly Scale, Mirror or Cut your 3D Models

App Info Launch App

3D Print a wide range of designs with Treatstock. Easy to use tools to get the perfect result. The global 3D printing network that connects you with high-quality and fast working print services nea...

App Info Launch App

where can I find the code at? thanks.

Hello, print files of 2 coxa_right 2 coxa_left, and noticed that one of the thighs not Coincide with the design of its assembly.

Can you share your code and wiring diagrams?

Can you share your code? if you have any, i love the design.

Can you post a Youtube video of it in action? I would love to see how it moves.

Here you go :) https://www.youtube.com/watch?v=VsHNA3oLXC8https://www.youtube.com/watch?...

Mind you, this is my first shot at walking bots, and the gait is kinda naive, but it works!

In my opinion, that is an awesome start! It looks to me like you have the basic timing down for a 4 legged bot. My initial impression is to put some "shoes" on the bot for better grip. I suggest Sugru. There might be a better choice though. Here is one source: https://www.adafruit.com/products/436https://www.adafruit.com/produ...
I teach an engineering course at a community college and have been looking for a cheap, open source, easy to replicate quadruped design for my students to build. Yours is very impressive. I look forward to see how it progresses. Awesome work.

I don't have anything yet. I'm working on IK now, and I'm basically teaching it to myself from scratch, so it's taking some time :) I'll certainly put up videos as soon as I have something.

That looks great! Let me know about your power source and how many servos you can power with it at the same time. And I like that direct connection of two servos without the clamp bracket. The servo's gears are powerful. But can the servo's axis handle the weight without a clamp?

For the moment I'm running off USB, and it's plenty of power. I haven't tried measuring draw yet. The servos handle the static weight of the bot without issue. It's designed such that the force is mostly up from the foot through the tibia directly into the femur, and not much twisting moment. If you twist the tibia, it will pop the horn off over the screw, but for normal motion it's plenty strong enough.

With this many servos it would be extremely advantageous to use a switching regulator in conjunction with a 2S Lipo. This would greatly reduce weight over conventional batteries and provide ample power without straining the servos.

Right now I have a simple 7805 regulator on the board, and I can power it from a 2S lipo. If I end up spinning a board for it, I will likely do a small switcher for efficiency. Honestly, right now I'm just powering it off USB, and these little servos require little enough power that it's plenty.

Good to know, I only suggest the switching regulator as you can power an chip and the servos from a single switch in most cases. Otherwise with a linear regulator voltage dropout will occur well before the battery is drained.

Thanks for the tip on USB, are you powering from a 1+ amp charger or from a 500ma computer output?

off a powered hub, and I'm not sure what it supplies. I'll try to rig up a current measuring rig here soon.

If it is a powered hub then you are getting much more power than what a PC USB port can supply. Typically 1 amp unless you are using a larger than normal wall adapter for the hub.

Exactly what I had in mind for getting a 3rd servo on each leg, thanks for making this.