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Review
. 2014:2014:867869.
doi: 10.1155/2014/867869. Epub 2014 Apr 30.

Mechanism and design analysis of articulated ankle foot orthoses for drop-foot

Morshed Alam  1 , Imtiaz Ahmed Choudhury  1 , Azuddin Bin Mamat  1
Affiliations
Review

Mechanism and design analysis of articulated ankle foot orthoses for drop-foot

Morshed Alam et al. ScientificWorldJournal. 2014.

Abstract

Robotic technologies are being employed increasingly in the treatment of lower limb disabilities. Individuals suffering from stroke and other neurological disorders often experience inadequate dorsiflexion during swing phase of the gait cycle due to dorsiflexor muscle weakness. This type of pathological gait, mostly known as drop-foot gait, has two major complications, foot-slap during loading response and toe-drag during swing. Ankle foot orthotic (AFO) devices are mostly prescribed to resolve these complications. Existing AFOs are designed with or without articulated joint with various motion control elements like springs, dampers, four-bar mechanism, series elastic actuator, and so forth. This paper examines various AFO designs for drop-foot, discusses the mechanism, and identifies limitations and remaining design challenges. Along with two commercially available AFOs some designs possess promising prospective to be used as daily-wear device. However, the design and mechanism of AFO must ensure compactness, light weight, low noise, and high efficiency. These entailments present significant engineering challenges to develop a new design with wide consumer adoption.

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Figures

Figure 1
Figure 1
Different phases of normal gait cycle.
Figure 2
Figure 2
A schematic diagram of the ankle joint of AFO with oil damper [34].
Figure 3
Figure 3
Free and constraint mode of passive pneumatic element [37].
Figure 4
Figure 4
(a) Posterior and lateral view of a power harvesting AFO (b) engaging and disengaging of cam lock during gait cycle [10].
Figure 5
Figure 5
(a) Different components and (b) pneumatic driving circuit of a power harvesting AFO [39].
Figure 6
Figure 6
The intelligent AFO with MR fluid damper [40].
Figure 7
Figure 7
(a) Schematic of MR brake cross section of MR brake, (b) linkage mechanism [41].
Figure 8
Figure 8
Halmstad University AFO with MR fluid damper; here α is the adjustable ankle angle [32].
Figure 9
Figure 9
(a) Passive AFO with four-bar mechanism [43]. (b) An AFO with insertion point eccentricity control [9].
Figure 10
Figure 10
(a) An articulated AFO with SEA, (b) a series elastic actuator [42].
See this image and copyright information in PMC

References

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