We on 95 wanted to do something to help with the Covid-19 crisis like anyone else. However, we did not want to create a solution for a problem that did not exist, or worse: potentially spread infection under the guise of being safe.
So we waited.
We did not have to wait too long though. A local doctor from DHMC got in touch with us through the grape vine. She had an idea for a robot that could reduce risk to their staff and conserve PPE usage and wanted help turning her idea into reality. We were absolutely thrilled at the opportunity. We named the effort “Project Semmelweis” after Ignaz Semmelweis, one of the pioneers in the field of antiseptic practices.
-Deliver and retrieve mobile tablet stands to and from patient rooms without exposing the patient to hospital staff (and vice-versa)
Tablets are commonly used in telehealth to allow patients to talk with their doctors, nurses, and family.
-Robot is easy to sanitize with wipes
-Navigate a potentially cluttered isolation room (IV stands, bedside monitoring equipment, etc.)
-Precisely place tablet stand
-Navigate linoleum flooring with minor defects/obstacles without damage
-Multi-hour run time
-Little or no risk of contaminating the patient room
-Easy to maintain
-Drive at walking pace for longer hallway trips
-8-hour run time (one full shift)
-Awesome paint job
… okay, so I made up that last one.
Here are some pictures of the development, without any context.
We have a lot less than our normal level of documentation owing to the fact that most testing was conducted in an active hospital and we were not comfortable taking any pictures or video for the sake of privacy.
The short version of the development story is…
*We brainstormed and sketched out a bunch of different approaches as a team over slack.
*We settled on using a switchable permanent magnet device, in this case an inspection magnetic block, to grapple with a magnetic target we could install on the stand. No moving parts outside of the robot besides the wheels dramatically reduced our chance of tangling with anything.
*Mk1 was a box shape with belt drive using NEO motors and Colson wheels. The drive part of the hardware worked, but was clunky to package. It was what we had on-hand and we learned a lot by building something really fast (we failed early and failed well). We had plenty of time to react.
*Mk2 was powder-coated for easier cleaning and triangular-ish to improve turning clearance in the room. We also put a simple suspension in our magnetic target to handle slight flooring imperfections more robustly. We ran into some assembly and service annoyances with this design. We also identified the velcro-down lid as a decontamination nightmare.
*Mk3 features improved service access, thru-lid charger port, a smooth magnetic lid seal, and a slight tilt in the magnetic target that causes weight to be shifted from the tablet stand to the robot’s drive wheels, improving robot traction and mobility. This is the version we have delivered.
Team members worked as they wanted to through Slack. Manufacturing was donated by one of our big sponsors, Progressive Manufacturing. Powder coating was donated by a local shop called Race Metalsmiths. Assembly was conducted at Grasshopper Machine Werks (my garage/side business). Team alumni primarily handled assembly at GMW, we were not comfortable asking team members/minors to go out and about. @kaszeta, a former 95 coach, handled all of the programming and will be publishing a Git Repo (right?) in a little bit. My day-job, FujiFilm Dimatix, covered basically all of my time on this project too, which was just awesome.
We got parts donations from numerous FRC suppliers: AndyMark, CTRE, and Rev. We used parts from the above and Vex.
Our BOM is here.
OnShape model is here, including a whole lot of scratch work.
More documentation is forthcoming.
As usual for 95 our design is open. Please feel free to copy it, modify it, and use it. Just let us know and credit your source. Please contact me via PM for any special requests.
Any questions and comments are welcome. I know this is a little light on detail for one of my build posts, time is tight these days!