Development of a Passive and Slope Adaptable Prosthetic Foot

Abstract

Historically, users of prosthetic ankles have relied on actively operated systems to provide effective slope adaptability. However, there are many drawbacks to these systems. This research builds upon work previously completed by Hansen et al. as it develops a passive, hydraulically operated prosthetic ankle with the capability of adapting to varying terrain in every step. Using gait cycle data and an analysis of ground reaction forces, the team determined that weight activation was the most effective way to activate the hydraulic circuit. Evaluations of the system pressure and energy showed that although the spring damper system results in a loss of 9J of energy to the user, the footplate stores 34J more than a standard prosthesis. Therefore, the hydraulic prosthetic provides a 54% increase in stored energy when compared to a standard prosthesis. The hydraulic circuit manifold prototype was manufactured and tested. Through proof of concept testing, the prototype proved to be slope adaptable by successfully achieving a plantarflexion angle of 16 degrees greater than a standard prosthetic foot currently available on the market.

Volitional control of an active prosthetic ankle: a survey

“…Their experiments showed that the subjects felt less fatigued when using the prototype. Very recently, Amiot et al 9 developed a passive hydraulic design ( Figure 4) for a prosthetic ankle as a proof of concept. Their design allowed the ankle to change foot angles according to the slopes.…”

“…Similar to, 8 Amiot et al 9 used a flexible foot to make their version of the ankle slope adaptable. Their use of hydraulic components in the system is just like.…”

A passive dorsiflexing ankle prosthesis to increase minimum foot clearance during swing

“…The clutch mechanism can be either purely mechanical (often weight-activated) or electromechanical in nature (microcontroller-activated based upon sensor signals). Several research prototypes utilize this design approach (Nickel et al, 2014 ; Amiot et al, 2017 ; Holgate et al, 2017 ; Lee et al, 2017 ; Heremans et al, 2019 ). These clutch-based devices are typically intended to also adapt to varying ground slopes, and as such, are typically heavier and more complex than is necessary to solely achieve the swing phase dorsiflexion functionality.…”

A Semi-Powered Ankle Prosthesis and Unified Controller for Level and Sloped Walking

“…In order to provide slope adaptation, some researchers have developed passive devices that alter the ankle stiffness set-point as a function of ground slope [37][38][39]. These devices incorporate mechanical or hydraulic locking mechanisms to lock the ankle joint at various ankle angles as a function of ground slope.…”