I had a very busy build session today involving a trip to the hardware store for some more hardware. I found I had less play in everything if I used a bolt with an unthreaded shank on it. After retrofitting a few, I built the box chassis with a cross member for the rocker arm. This is a component that lends itself to the name Rocker – Bogie Suspension. I mounted the suspension arms and rocker and gave it a wiggle. It worked great!
Next, on with the wheels. For now, all I need is a simple wooden wheel, so, I re purposed a painted pine plank I had laying around and cut out six four inch diameter wheels. After a little sanding, I installed them on the legs and gave it good look. I put it in a few different configurations in an attempt to simulate what it might go through in a boulder strewn terrain. It performs quite well and deals with a wide range of positions thanks to the way the rocker links the two suspension arm assemblies.
Of course, when you start looking at a prototype, things pop up you didn’t expect. That’s part of the process though so I pay attention in those moments even though my builder ego may be bruised. Ego schmego… work the problem. Anyway, you start to think “what if a drive motor failed on one of the two bogie wheels? What keeps it from just snagging on something and rotating 360 degrees and ending up useless?? ” Yeah.. what if? So now I’m thinking a limit of travel is in order, but I would need some data on maximum angles and such, hence, this prototype.
So now I can collect suspension angle data , operating parameters, and continue forward to the next phase, powered locomotion.