As progress continues on the hardware behind bionic prosthetics, the need for robust and safe control systems increases. The challenge is that the researchers working on these systems often are limited to testing in simulation or spending the time and money to build their own prosthetics for testing. To accelerate development, University of Michigan bioengineer Elliott Rouse, director of the neurobionics lab, and colleagues created the Open Source Leg. They report that the Open Source Leg costs $10,000 to $30,000 to build, compared to $100,000 for similar commercial products. Additionally, the design uses high-torque, lightweight motors developed for drones, that make "it easier to walk with less fatigue, and the batteries onboard the prosthetic could be smaller." From IEEE Spectrum:
Accompanying the artificial limb are free-to-copy step-by-step guides meant to assist researchers looking to assemble it or order parts for it. The Michigan group has also produced videos illustrating how to build and test the hardware, and has developed code for programming the prosthetic to walk using a preliminary control system.
The scientists focused on keeping the Open Source Leg relatively easy to assemble, control, and maintain by reducing the number of parts and suppliers needed. The knee and ankle joints can operate independently, allowing research in patients with above-knee and below-knee amputations. In addition, each joint has on-board batteries and its own set of sensing and control systems, enabling test outside the laboratory. Also, a number of the Open Source Leg's design and control features can be customized to fit specific research needs, such as the foot type and the knee elasticity.
"An Open-Source Bionic Leg" (IEEE Spectrum)