Arm exosuit part 1

My first attempt at an exosuit is going to be based on a cheap compression shoulder brace and elbow sleeve. These will be attached together with nylon webbing ensuring the load path travels past my shoulder. Actuation will consist of bowden cables attached to both the top and bottom of my elbow. Acting like a replacement for my bicep and tricep muscles.

This is based on the device in my second reference below. However they used a very complicated motor and pulley system that I believe is unnecessary. Instead I will use two springs, one for each bowden cable.

The A-gear, see below, also uses two springs. In fact it is my inspiration. From the A-gear I discovered two springs can statically balance 4 degrees of freedom.

These devices also share another similarity, they are the exact same device! Think about it, one is fabric, the other is aluminum but look closer and you will see. They both pull on the same points on the arm and forces are redirected in the same manner. Achieving the same goal with different materials.

The main problem with a passive spring based approach is it may be too late for me. A decade ago I would have had enough strength but now I have almost nothing. I tried the compression sleeves and the friction was noticeable. I have a backup plan for motor assistance just in case.

References:

1. A-gear dynamic arm support

2. Soft wearable assistive robotics: exosuits and
supernumerary limbs