Feasibility of Triboelectric Energy Harvesting and Load Sensing in Total Knee Replacement

Abstract

The main goal of this paper is to investigate the feasibility of a triboelectric mechanism to harvest electrical energy for powering a knee implant load measurement sensor under walking activity of daily living. A triboelectric energy harvester is proposed to be placed in between the tibial tray and the UHMWPE bearing of the TKR. To characterize the triboelectric generator, the walking tibiofemoral axial load is approximated as a 1 Hz sine wave signal. An MTS 858 II servo-hydraulic load frame setup is used to transfer the axial load to the triboelectric generator. The optimal resistance is extracted experimentally and found to be 58MΩ. With an applied cyclic load of 2.3 kN at 1 Hz, which is equivalent to the load from normal walking, the generator generated a maximum output of 18 V, and 6 μW of power at the optimal resistance. A power management and digitization circuit is designed based on the harvester output that consumes about 4.74 μW power, which is less than the generated power. Thus, the power harvested from the triboelectric energy harvester can power the load sensing circuitry.