Static and dynamic response of a multiplexed-array piezoresistive contact sensor

Multiplexed piezoresistive sensor arrays hold great potential for measuring contact stress distributions for orthopedic research applications. However , their acceptance has been handicapped by output drift and the fact that t heir dynamic response has not been well characterized. In this report, the static and dynamic responses of one device of this class (the K-Scan piezor esistive contact stress sensor) are formally characterized using a speciall y made pressure vessel that provides spatially homogeneous contact stress. Drift was predominant early in static loading, reaching relative errors of approximately 30 percent over a 10-min period. During loading, first-order dynamic analysis showed that the time constant land time lag) was nearly ze ro and there was little attenuation of the output up to 20 Hz. A deconvolut ion algorithm proved capable of compensating for the great majority of stat ic drift.