Background work

A project log for Sophie Robot

A next generation home robot with a omni directional drive unit and 6 axis collaborative robot arm

Apollo TimbersApollo Timbers 07/28/2022 at 12:420 Comments

I have been pretty busy with the project still, though it has mostly now swapped to power system design and for a little extra fun I made a nicer gripper design. (It also so happens to fit around a standard aluminum can) :)  It will need some tweaking when the arm gets here, though I did discover a nice PA12 nylon infused with Glass Beads on Shapeways. Fusion 360 (*amazing program*) is stating the two fingers and silicon inserts should weigh around 15grams. The CAD may be lying a bit though,  I did set the materials of the gripper, and they are hollow...

I'm also starting to really flesh out the base design and where everything will be going, I will soon be designing a sheet metal power panel to hold switches, circuit breakers and main battery cutoff. 

Power requirements are being laid out, I'm sorting with primary and secondary loads. I will likely spec over on the DC-DC converters for inrush current and longevity. Took some internet searching, though I have found some nice (railroad spec'd) power versions from Meanwell. Will likely be a dedicated DC-DC for the arm, computer , and drive units. 

Primary loads:

  1. Nvidia Jetson TX2   12v @ ~2 amps
  2. 6 axis arm 24v @ ~3 amps
  3. Motor drives 24v @ ~1.5 amps
  4. Liner actuator 24v @ ~unknown 
  5. Medical grade air pump 24v @ ~unknown (for neck tilt soft air muscles, and possibly a gripper down the road)

Secondary loads:

  1. Powered USB 3.0 hub 24v @ ~2amps
  2. Pi Pico 5v (powered by hub)
  3. Lidar (powered by hub)
  4. Indicator LED's (meh)
  5. Solid state relays for "low power mode" (meh)