Identification of nonlinear passive devices for haptic simulations

This paper describes a method for identifying models of a class of nonlinear passive devices, such as switches, knobs, and buttons. A general nonlinear impedance model is presented, which accounts for dynamics that change with both position and direction. Exponentially-weighted least-squares is used to fit the nonlinear model to experimental data from a specially designed physical 1-DOF test device with inherent nonlinearities. The data are obtained using an instrumented linear probe.