Method and system for determining occurrence of slips leading to falls
First Claim
1. A method for predicting a macroslip on a walkway surface, comprising:
- determining a characteristic of the walkway surface;
determining an anthropometric constant;
determining a relationship between a walking speed and a stride length in terms of the characteristic of the walkway and the anthropometric constant; and
plotting a curve of the relationship between the walking speed and stride length, wherein the macroslip is predicted to occur at a position on or above the curve of the relationship between the walking speed and stride length.
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Abstract
The present invention provides a system and method for the prediction of macroslip on walkway surfaces. The slip prediction is based on a viscous shear model and incorporates anthropometric characteristics of an individual or substantially similar grouping of individuals as well as properties of the walkway surface. In the shear model, the prediction of slip is a function of walking speed, stride length and other anthropometric factors which affect gait, as well as the friction (shear) forces that develop at the shoe-floor interface. Mathematical relationships are developed relating the forward walking speeds to the stride lengths necessary for the onset of macroslip. Curves are then plotted which enable the prediction of macroslip for various footwear and walkway surface combinations under both wet and dry conditions.
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Citations
20 Claims
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1. A method for predicting a macroslip on a walkway surface, comprising:
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determining a characteristic of the walkway surface;
determining an anthropometric constant;
determining a relationship between a walking speed and a stride length in terms of the characteristic of the walkway and the anthropometric constant; and
plotting a curve of the relationship between the walking speed and stride length, wherein the macroslip is predicted to occur at a position on or above the curve of the relationship between the walking speed and stride length. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for determining a slip at heel strike on a dry walkway surface, comprising:
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determining an anthropometric constant, Cdi, for the dry walkway surface;
determining the occurrence of macroslip, wherein the macroslip occurs when wherein V is a forward walking speed of a center of mass of an individual, L is a stride length of the individual, g is an acceleration due to gravity, and μ
i is a relevant dynamic coefficient of friction. - View Dependent Claims (13)
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14. A method for determining a slip on a wet walkway surface having a fluid contaminant thereon, comprising:
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determining an anthropometric constant, Cwi, for the wet walkway surface;
determining the occurrence of slip, wherein the slip occurs when wherein M is a mass of an individual, h* is a depth of the fluid contaminant at a point of maximum pressure, {dot over (x)} is a horizontal shoe (foot) speed, τ
y is a shear stress necessary to commence shearing in the fluid contaminant, Ac is an area of shoe contact with the interface at the commencement of macroslip, L is a stride length of the individual, and η
is an absolute viscosity of the fluid contaminant. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification