Non-linear modeling of the steady-state disturbance term in isometric force

The analysis of isometric force may provide early detection of certain types of neuropathology such as Parkinson´s disease. Our long term goal is to determine if there are detectable differences between model parameters of healthy and unhealthy individuals. In this study we evaluate nonlinear dynamic system models of isometric force using Hammerstien models. The experiments involved subjects exerting isometric force over a range from 5% to 95% of maximal voluntary contraction. The findings suggest that the Hammerstien models provide adequate fit, reducing the number of nonlinear difference equations of higher order that were determined in our earlier work.