• variable impedance control
• lower limb prostheses
• knee prosthesis control
• ankle prosthesis control

Lower limb amputation is a global health challenge, affecting millions of individuals and necessitating the development of advanced technologies to improve mobility and quality of life for amputees. Active lower limb prostheses have the potential to restore a more natural and efficient gait, restoring different locomotion activities and improving the quality of life of amputees. However, the development of active lower limb prostheses encounters challenges in the development of sophisticated control systems. This thesis presents the development of a unified variable impedance controller for walking at different inclines and velocities. A data-driven optimization approach was employed to model the physiological impedance of the knee and ankle joints as a function of the stride phase. The resulting controller does not necessitate either for subjects’ specific tuning or gait segmentation, modulating continuously the impedance to reproduce the kinematic and kinetic behavior of the human joints. The control algorithm was tested on an ankle prosthesis and a knee prosthesis on three different able-bodied subjects and benchmarked against a finite state machine controller. The presented control strategy outperformed the finite state machine control in achieving physiologically accurate kinematic and kinetics profiles for different locomotion activities.