Robot Arm

Sixi Robot developments 2019-07-16

New OSHPark PCBs arrived

With this we can finally finish the hardware preparation for shipping units, after which we can also get a final bill of materials and start to package DIY kits.  There will be two flavors:

  • DIY kits with all the non-printable parts.
  • DIY kits with everything, including the printed parts.

Collision detection

The software only lets each joint of the robot move within a safe range to prevent wire twisting or other potential damage.  That piece of code does not consider the angle of joint A in relation to the value of some other joint B.  So it was still possible to make the arm hit itself.

This new collision detection code prevents each bone of the arm from colliding with other bones of the arm.  At present it is a crude collision detection system, using only the box around each joint.

Also now that these boxes have been calculated, the center of each box is known.  the mass of each bone can be pulled from the Fusion360 model, and then a point-mass physics model can be created to simulate forces like gravity.  This gets us closer to dynamics like push-to-teach and telling the arm “please push on this item with a force of N newtons”

Next

Next we’ll be assembling the new shoulder design with the PCBs that should allow us to unplug the umbilical from the arm and the control box.  I’m thinking Twitch stream?  Maybe just a Youtube Live, given the recent Amazon protests.  Choice of evil companies… hmm…