Bionic Foot Research Articles

Advances in Propulsive Bionic Feet and Their Actuation Principles

In the past decades, researchers have deeply studied pathological and nonpathological gait to understand the human ankle function during walking. These efforts resulted in the development of new lower limb prosthetic devices aiming at raising the 3C-level (control, comfort, and cosmetics) of amputees. Thanks to the technological advances in engineering and mechatronics, challenges in the field of prosthetics have become an important source of interest for roboticists. Currently, most of the bionic feet are still on a research level but show promising results and a preview of tomorrow's commercial prosthetic devices. In this paper, the authors present the current state-of-the-art and the latest advances in propulsive bionic feet with its actuation principles. The context of this review study is outlined followed by a brief description of the basics in human biomechanics and criteria for new prosthetic designs. A new categorization based on the actuation principle of propulsive ankle-foot prostheses is proposed. Based on simulations, the general principles and benefits of each actuation method are explained. The corresponding latest advances in propulsive bionic feet are presented together with their main characteristics and scientific outcomes. The authors also propose to the reader a comparison analysis of the presented devices with a discussion of the general tendencies in new prosthetic feet.

Assessment of the effects of carbon fiber and bionic foot during overground and treadmill walking in transtibial amputees

ObjectiveTo determine the energy cost of walking (ECW) of a bionic foot (Proprio-Foot®) during ambulation on floor and on treadmill (at different slopes) compared to walking with a dynamic carbon fiber foot (DCF). We evaluated transtibial amputees (TTAs) perceived mobility with the prosthesis and their walking ability on stairs and ramps. MethodTTAs were enrolled. The ECW tests were conducted on a regular floor surface and on treadmill with −5%, 0% and 12% slopes. In all conditions, TTAs were asked to walk at their own self-selected speed. Metabolic and cardiac data were collected using a portable gas analyzer. Tests were performed at six data collection points: first with a standard suction system (SSS) and the DCF; second, with the DCF after 7 weeks of using a hypobaric suspension system (HSS) with the DCF; third, after 1h of Proprio-Foot® use together with the HSS; three more testing sessions were carried out at 30-day intervals, i.e., after 30, 60 and 90 days of Proprio-Foot® use together with the HSS. TTAs perceived mobility using the prosthesis and walking ability on stairs and ramps were assessed. ResultsTen TTAs completed the measurements. ECW with the Proprio-Foot® obtained in the final floor-walking test was significantly lower than ECW with the DCF (p=0.002). No significant improvements were observed for perceived mobility or walking ability. ConclusionsResults suggest that use of the Proprio-Foot® can lower the ECW for TTAs in spite of its added weight compared to DCF.

Mechanics of the West Point Bionic Foot During Walking: A Case Study

PURPOSE: To investigate the differences in walking gait kinematics and kinetics when using passive versus active (West Point Bionic Foot) foot-ankle prosthetic devices in a transtibial amputee. METHODS: Kinematic (step length, step time) and kinetic (passive peak and active peak forces) variables were measured during treadmill walking in a male transtibial amputee (age 26 years, height 185.0 cm, mass 72.4 kg). A Kistler Gaitway treadmill was utilized to collect kinematic and kinetic data. Prior to data collection, the subject underwent a 30 min treadmill walking familiarization session using both his passive foot and the active foot. He then performed 10-15 min walking trials for each of three conditions: 1) passive foot, self-selected speed (5.6 km/h), 2) active foot, matched speed with passive foot (5.6 km/h), and 3) active foot, self-selected speed (6.0 km/h). RESULTS: There were significant (p < 0.0001) decreases in step length, step time, and passive peak and active peak forces in the prosthetic leg as compared to the unaffected leg in all three conditions. While there were no differences in step length and step time between the passive foot and active foot during the matched speed condition, there were significantly (p < 0.0001) smaller active peak forces when using the active foot. The results for the prosthetic leg are presented in the table below (mean ± SD).TableCONCLUSION: The West Point Bionic Foot allowed the subject to achieve a faster, self-selected comfortable walking speed. In addition, the active foot permitted the subject to maintain a given walking speed while producing smaller active peak forces with no concurrent changes in step length and step time. Supported by AMEDD Advanced Medical Technology Initiative Grant 2008011723.

BIONic WalkAide for correcting foot drop

The goal of this study was to test the feasibility and efficacy of using microstimulators (BIONs) to correct foot drop, the first human application of BIONs in functional electrical stimulation (FES). A prototype BIONic foot drop stimulator was developed by modifying a WalkAide2 stimulator to control BION stimulation of the ankle dorsiflexor muscles. BION stimulation was compared with surface stimulation of the common peroneal nerve provided by a normal WalkAide2 foot drop stimulator. Compared to surface stimulation, we found that BION stimulation of the deep peroneal nerve produces a more balanced ankle flexion movement without everting the foot. A three-dimensional motion analysis was performed to measure the ankle and foot kinematics with and without stimulation. Without stimulation, the toe on the affected leg drags across the ground. The BIONic WalkAide elevates the foot such that the toe clears the ground by 3 cm, which is equivalent to the toe clearance in the unaffected leg. The physiological cost index (PCI) was used to measure effort during walking. The PCI is high without stimulation (2.29 +/- 0.37; mean +/- S.D.) and greatly reduced with surface (1.29 +/- 0.10) and BION stimulation (1.46 +/- 0.24). Also, walking speed is increased from 9.4 +/- 0.4 m/min without stimulation to 19.6 +/- 2.0 m/min with surface and 17.8 +/- 0.7 m/min with BION stimulation. We conclude that functional electrical stimulation with BIONs is a practical alternative to surface stimulation and provides more selective control of muscle activation.