A Lumped-Parameter Model for Dynamic MR Damper Control

The dynamic behavior of a small-scale magnetorheological damper intended for use in a tremor-suppression orthosis is characterized through experimental analysis and finite element simulation. The combined frequency response of both the electromagnetic coil and the fluid particles is modeled by a second-order transfer function. The output of this function is an effective current that, combined with piston velocity, is empirically related to resistance force of the damper. The derived model demonstrates high-fidelity to experimental testing of the damper under variable piston velocity and applied current within the expected frequency range of pathological tremor. The model is thus deemed suitable for use in a control algorithm for the mechanical suppression of tremor.