Force Estimation with a Non-Uniform Pressure Sensor Array

Embedding pressure sensors into household fixtures enables unobtrusive occupant health and safety monitoring at home. To monitor bathroom grab bar use, the force applied to a grab bar is desired from the output of three embedded pressure sensors. We examine the measurement of applied force in a non-uniform pressure sensor array, where forces are distributed with spatial nonlinearity to the pressure sensors. Two methods that ignore the spatial nonlinearities are compared to two methods that incorporate them. These include a polynomial response curve, a theoretical model, a lookup table, and an artificial neural network. When many calibration points can be taken and location estimates are accurate, the location-based lookup table presented the lowest error. However, when calibration time is limited, the theoretical model performs best, while an artificial neural network is preferred when location inputs are inaccurate.