Project Hercules (lifting shoulder harness)

This page describes a voice-controlled shoulder-harness lift to help with transfers to/from my wheelchair.  I have advanced MS with some remaining leg strength and use the lift for independent pivot transfers.  Besides featuring hands-free control, the design loops under the arms and pulls up with controlled force, much like a human assistant.

As of this writing, I built (with help of a good handyman) two of them at home (bed & bath).  The lifts have done their job over 200 times with only a few software glitches due to since-fixed bugs.  Why build your own?  Even the doctor told me not to:  Those things never work.  But they do and I'm unaware of  commercial options that allow hands-free voice control.  Further benefits are flexibility, precise trajectories, and wall-mounting.  In an earlier life I invented, designed, and built sophisticated equipment for others.  There is satisfaction in using the skill for a personal need.

I'll try to document the lifts better, but for now show a video, some pix, and notes/drawings/code.  Let me know if you have ideas for improvement or are interested in the design!

"Hercules Pegasus" activates the system. "Pegasus" by itself slowly lowers. "Ascend" slowly raises. In the video it's running in low speed mode for pre-positioning. For actual transfers I put one belt under each shoulder and say "Hercules" to activate torque which pulls harder (maybe 100 lb). That's enough help to stand and rotate onto the bed via hand hold and arm strength. "Release" lets go. Keyword detection is via Porcupine on a Raspberry Pi 4B. The high-torque motor is from GRIN, driven by a VESC 6 EDU.

The shelf brackets are attached to wood studs (our ceiling lacks joists that could support weight).

On the bench:

Design drawing of shelf (excluding rope guide):

Laser-cut plywood spacers, 0.472" thick:

• Parts list (possibly incomplete)

• Prepare shelf

• Setup electronics

• Source code

• Log file