Design and Validation of a Novel Partially Powered Knee Prosthesis

This work presents the design, development and validation of a partially powered knee prosthesis that enhances key features of energetically passive microprocessor-controlled knees (MPKs). We introduce a novel mechatronic architecture which combines a compact electro-hydrostatic actuation (EHA) unit with a controllable hydraulic valve. The design rationale is focused towards the support of swing-related activities and, as such, does not require large amounts of torque. Furthermore, the proposed solution retains the backdrivability properties of conventional MPKs and enhances the versatility through a highly integrated actuation unit (active and passive sides share the same motion transmission system), which may lead to improved walking capabilities. To this end, a prototype is designed, built and validated experimentally on a test bench to verify its active and passive functionalities. Results highlight comparable passive features with respect to state of the art MPKs with the possibility to inject active power at the joint to support swing related activities during level ground walking and stairs ascent tasks.