Shoe-Floor Interactions During Human Slip and Fall: Modeling and Experiments

Shoe-floor interactions such as friction force and deformation/local slip distributions are among the critical factors to determine the risk for potential slip and fall. In this paper, we present modeling, analysis, and experiments to understand the slip and force distributions between the shoe sole and floor surface during the normal gait and the slip and fall gait. The computational results for the slip and friction force distribution are based on the spring-beam networks model. The experiments are conducted with several new sensing techniques. The in-situ contour footprint is accurately measured by a set of laser line generators and image processing algorithms. The force distributions are obtained by combining two types of force sensor measurements: implanted conductive rubber-based force sensor arrays in the shoe sole and six degree-of-freedom (6-DOF) insole force/torque sensors. We demonstrate the sensing system development through extensive experiments. Finally, the new sensing system and modeling framework confirm that the use of required coefficient of friction and the deformation measurements can real-time predict the slip occurrence.