A system for force distribution measurement beneath the feet

Abstract

Objective methods for assessing the performance of the postural control system may be helpful in identifying persons with an increased risk of falling. Postural performance is often characterized using center of pressure, but force distribution under the feet may provide additional information on the state of the postural control system. Foot position and orientation can also be extracted from force distribution without the need for manually tracing footprints. A low-cost force distribution measurement system is being developed to complement an existing dual force-plate platform. The system's sensing module contains 1024 1-cm by 1-cm force sensing resistors (FSRs). Interface electronics were designed to convert the FSR outputs to digital data. Continuously sampling the FSR outputs allows one to monitor force distribution over time. A system controller mediates the data acquisition process and transfers the result to a PC for post processing. An apparatus was developed to calibrate the FSRs in order to reduce error caused by inter-sensor variability. Although the system is still under development, preliminary tests show that the system can quantitatively measure force distribution beneath the feet.