First prototype build

A project log for Landbeest walking robot

Terrain-going quadruped. 3D printable. Two servo drive.

Dejan RisticDejan Ristic 01/31/2019 at 04:040 Comments

I want to start the project with immediately building a working prototype, even though I havn't got all the details worked out yet. I'm calling it "Landbeest Zero". 

The main thing I want to try out with Zero is leg movement for simple locomotion along a straight line. I'm not worrying too much about the intricacies of the drivetrain at this point, as long as the legs move like they're supposed to. And I'm not above stealing parts of the design if it means getting the prototype done quicker.

The main thing I want to "steal" is a linear actuator to use with the two servo motors. After a little browsing I found this design by [fastmike75] on Thingiverse. It's compact, rugged and easy to print —just what I need.

I imported the linear actuator model into Tinkercad and designed the rest of the prototype around it. I probably should learn how to use a real CAD suite at some point, but Tinkercad is pretty much perfect for small tasks like this. 

When modelling mechanical parts for 3d printing I prefer to print a very flimsy first draft since I usually have to change something and print it over again anyway. But this time most parts came out serviceable enough on first try —hence the exposed infill here and there.

Next I attach the hinge parts that connects one side of each leg directly to the chassis. Note how they aren't symmetrically placed on each corner. (I'll go into why in a later post.)

And no, I didn't sneeze on the lower-right hinge. It broke and I had to fix it with hot glue.

Finally there's the two slidy things, which connects two legs to each linear actuator:

Landbeest Zero is a mess of hot glued ill-fitting parts and it barely holds together. But it works dammit, and I feel very encouraged to start on round two of this project.