Let's Make Robots!


4WD vehicle with a 3D printed ball link


Four wheel drive vehicles have always excited my imagination, and this time I joined two Farrusco (Dagu's) chassis in front to front as you can see in the picture below:


This way both chassis are fixed on each other (is this correct to say in english??) and I thought it would be cool to have them articulated in some way, so I started to design a ball link and this is the first output (oh, did I mention I have a 3D printer at the office? :D



It still need a bit of work because the link needs some kind of lock to prevent the vehicle to bend itself and touch the ground (gosh!! what a crappy english!!)



I used OpenSCAD to design the piece, it is a great tool to use because everything is made with simple commands and you can design pretty much everything!! You can download the OpenSCAD files in Thingiverse.

Screen shot 2011-05-05 at 11.07.32 PM

Screen shot 2011-05-05 at 11.05.23 PM

In the next chapter, the redesign!



6 - MAY - 2011

List of things to try:

- Try to implement springs, speccially on the Z axis

- This possibilities were given by MaskedRetriever on Thingiverse:


  - Zero z-freedom answer: Change the geometry from sphere to cylinder. That eliminates the ability to rotate entirely.  

  - More sophisticated answer: cut away part of the sphere on the ball top and bottom, then fill in /slightly less/ of the socket top and bottom. This will yield a maximum angle of "vertical" rotation. 

  - Even more elegant answer: just have the sphere wrap around more of the ball joint. The closer it goes to fully locking, the less rotation you get. To have more rotation in one dimension than the other, just make the hole elliptical. 




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I never thought of doing anything like that.  I might have to make a robot like that except with more sections.  Right now I am working on a robot with an off road chassy that I will post when I get more done on it.  I need more time for robotics....

available time is an issue for me too!  I have a couple of unfinished bots getting dust.. maybe I will just post them around, and you should do the same maybe? :p

and that one I did post. (Beverage Bot) But I also have another project that I am going to be starting but there is a school science project inbetween me and my robot project.  The school science fair project is going to be a hand tracker and I have most of that done and once thats finished I am going to have tons of time over summer break for robotics =)  I think I will post the hand tracker soon. 

When English is your first language, then you can worry about how bad it is. Until then, don't worry. Your English is just fine. As long as it doesn't look like something a software translator tried to convert using Yoda speak we are in good shape. :D

EDIT: On topic, lucky you for having a 3D printer to play with at work, and, your chassis looks pretty sweet.

thanx for the comfort! post edited! 

The brass standoff looks like a great place to mount an elastic band, four short standoffs mounted below the centerline would equalize the ball to the center. This would reduce the load on the shaft holding the ball. It could also tend to straighten out the bot without the need for servos.

Yeah that might be a good solution! Thanks!

One thing I have in the office and want to try is soft PLA, I will have to change the design a bit..