Bob Krause, Inventor Studios
(The following information was first posted on Sawppy's Hackaday.io project discussions section here)
Our focus at this point is to increase the configurability of the design, as you can see in the list of changes we’ve made so far that’s included below.
Wheel width can be changed
- Wheel width changeable
- Steerable knuckle width varies with wheel width
- Fixed knuckle width varies with wheel width
Wheel rim and tire can be printed as separate parts of a dual-extrusion printer job
Beam width & height can be changed
- All 3D printed components that accept beams varies based on beam dimensions
LX-16A brackets now accept heat-sets so that servos are held more tightly
The geometry of the LX-16A bracket changed.
- The orientation of the servo is rotated 180 degrees to fit narrow knuckles and narrow tires.
The area we’re focusing on next is support for drive-train and control systems that will move the bot much (much) faster than the LX-16A servos currently allow. The first step in that direction is to design in FTC-compatible (First Technical Challenge) components, which we have an almost endless supply of parts laying around the lab. Driving a bogie suspended robot around on rough terrian at high speeds will likely require adding shock dampeners to the suspension.
Our longer-term aspiration is to create a more flexible robot design tool that allows designers to create robots with different dimensions, drive-trains, suspensions, control systems, and accessories.
We’ve made our copy of the OnShape document public. It’s named SawppyRover.neobobkrause. You can link to it here https://cad.onshape.com/documents/aaa3eec885d174f48744d770/w/a9ccb2ae8a9fa3bfab65a3f5/e/02e39956ce53a7a4a720a4aa
Here are some shots of some wheels and knuckles we've printed that are narrower (65mm). One wheel has a TPU tire on a PLA rim. The other rim was printed using transparent PETG. The third photo shows the narrow fixed knuckle from the inside. Also note that the orientation of the servo has been rotated 180 degrees.