Design and Evaluation of a Quasi-Passive Variable Stiffness Prosthesis for Walking Speed Adaptation in People With Transtibial Amputation

The biological ankle joint adjusts stiffness to adapt changing walking speed, terrain, and load carriage. most commonly used passive transtibial prostheses are unable adjust device therefore do not maximize potential energy storage peak prosthesis power across speeds. We present a quasi-passive variable ankle–foot with discrete adjustment from 352 479 Nm/radian, corresponding the range of quasi-stiffness exhibited during level ground at speeds 0.75 1.5 m/s for 77 kg person. implement novel parallel leaf spring mechanism that utilizes custom solenoid-driven linear actuators constrain sliding springs relative mechanical in order control bending stiffness. is lower mass than all existing prostheses, 945 g. initial results pilot study one participant unilateral amputation, demonstrating an increase motion, power, return, decrease contralateral knee external adduction moment This demonstrates improve biomechanics through design low-mass, prosthesis.