Did they ever say how heavy their robot ended up being?
Over–about 135lbs all in. The elevator is overbuilt though and weight loss would be relatively simple (but not the best use of our time for Ri3D, so we’re not worried about it besides keeping people informed)
Any chance you have links to suppliers/distributors or a part number?
What was the weight of you manipulator? (Everything past the wrist)
I’ll also add here that we recommend putting a little more time into the design to ensure there is no risk of the cylinder rods bending (i.e. use the force of the cylinder, but not the rod itself to do the lifting).
Weight of the gripper past the wrist is ~12 lb. There are multiple weight savings opportunities, including reducing the thickness of the plastic in several locations and swiss cheesing the aluminum frame.
Ben, it seems like with more stroke on the cylinders (and adjusted geometries) you guys might make it up to the top step. Could you comment on the ease of turning 90 degrees on Level 2? It seems easy enough.
I personally believe it may be possible to “stair step” your way up. We were able to turn 90 degrees on the second level. Adjustments would be needed to the current design though–see below to see how our bumpers would conflict with the 2nd level platform:
We’ve released our Github for the 3-day build, which includes trapezoidal motion profiling on each subsystem. Happy to take any questions!
Were the axles on the drive train equally spaced, or did you end with a slightly longer spacing between the two middle axles? My team is planning on running a very similar set up.
Equally spaced, but some implementations could certainly have unequally-spaced axles.
You guys mention in one of your videos that you decided to use the 2 stage elevator plus the 4 bar to get to the heights you required. Was there any thought put into mounting the 4 bar pivot up higher on a single stage elevator? Would you be able to go into further detail on why you chose a 2 stage elevator?
Four bar on a 1-stage elevator would probably work. We had the 2 stage elevator design ready to go, and for a 3-day build we wanted to go ‘overkill’ to make sure we would for sure reach the height. At the end of day 1 we were planning to go single stage, but we were nervous the next morning and decided to take the safe route.
Special thanks to Adam Wolnikowski (225 alumni) for making the video.