An adaptive grip-strengthening device for people with rheumatoid arthritis, by Katie Le, S.B. '26.
Many people with rheumatoid arthritis (RA) struggle to keep up with physical therapy, especially during flare-ups, when pain and fatigue spike. Grip trainers and stress balls offer fixed resistance and can't adapt to how someone's hands feel on a given day.
For her ES 100 engineering capstone, Bioengineering student Katie Le built a device that measures grip force in real time and adjusts its resistance to match the user's current strength. It combines springs, sensors, motors and 3D-printed parts.
I served as Katie's advisor through the year-long capstone. When the first design, which used motors to compress the springs, didn't have enough holding torque, she pivoted to limiting the spring's maximum compression. She went on to build three successive versions of the device and ran validation tests along the way. Watching a student learn to pivot, iterate and trust her own engineering judgment is one of my favorite parts of this work.