Design and fabrication of rotary magnetostrictvie energy harvester for knee-joint wearable applications

Purpose This paper aims to present the design and fabrication of a rotary magnetostrictive energy generator, using to harvest the rotation energy of human knee joint. Design/methodology/approach A rotary magnetostrictive energy generator is presented in this paper. The harvester consists of six movable flat Terfenol-D rods, surround by the picked-up coils respective, and alternate permanent magnet (PM) array fixed in the upper cover of the stator. The harvester rotates like as a stepper motor, which has rotary electromagnetic power generating effect and impacted magnetostrictive power generating effect in its rotation. Modeling and simulation are used to validate the concept. A prototype of harvester is fabricated and subjected to the experimental characterization. Findings The size of proposed structure is control as 77 cm3, and its mass is about 0.21 kg. Huge induced voltage generated in the short-time impact situation, and that induced voltage in the harvester can up to 18.6 V at 0.32 s stepper rotation. Also, the presented harvester has good harvesting effects at low frequency human walking situation, which is suitable to be used for future researches of wearable knee joint applications. Originality/value A new concept of magnetostrictive harvester is presneted, which will be benefit for the application of human knee joint wearable. Also, this concept will give us more idea for collection of human movement energy.