SCHURER ET AL . 1 Comparison of Three Methods for Linearization ofElectrodynamic

|Based on a simpliied nonlinear lumped element model of the electrodynamic loudspeaker, three nonlinear controllers are derived, simulated and implemented on a DSP. First the Volterra series expansion, a well known functional expansion to model nonlinear systems, is used to derive an open-loop controller to cancel out nonlinearities. Second method is based on direct inversion of the nonlinear part of the diierential equation. Finally, the diierential geometric theory of nonlinear control systems is used to develop an exact input-output linearizing controller. All three linearizing controllers are compared with respect to ee-ciency, computational complexity and eeectiveness for the case of a low frequency test loudspeaker in a closed cabinet. Digital implementation is realized on a general purpose TMS320C30 DSP development board using automatic code generation from schematic entry, by means of the Alta-Group SPW software.