Design and Manufacture of an Intelligent Prosthetic Ankle-foot for Walking and Running Modes via Optimization of Power and Energy Consumption

Human ankle-foot gait is the result of a complex interaction between nerves and muscles. A significant number of prosthetic ankle-foots (passive, semi-active, active) have been designed to restore an identical function of a real limb. Excluding passive and semi-active prosthesis who couldn’t generate any positive work, one of the biggest challenges in creating these prostheses is providing the needed power and energy during movement. Supplying this power and energy, requires a high-torque and high-power actuator having high weight, thereby causing a dramatic increase in the weight and size of that prostheses. In this paper, a combination of an active actuator (an electrical motor) and an passive stimulus (a spring) is utilized, which decrease the needed power and energy, and in addition to walking mode can also support running mode up to 2.5m/s. Accordingly, The first stage of this article includes mechanical modeling of the ankle and evaluation of efficiency and power consumption in all presented models. Then the structure of Series Elastic Actuator differed with the previous structures is selected as the best combination.  In this opted structure, power and energy consumption is dramatically declined up to 58% and 26% in walking mode and 64% and 57% in running mode. Consequently, a lighter motor and battery can supply the required power, so the prosthesis chr(chr('39')39chr('39'))s weight is subtracted.