Model Following Approach for Plant-Input-Mapping Discretization of a Current Regulator for Stepping Motors

The paper presents a model following approach for the plant input mapping (PIM) discretization of the stepping motor current regulator. The PIM method can derive a digital form of the underlying feedback system while preserving its stability for any non-pathological sampling interval. However, the method cannot take the local block property into account, such as an integrator, which is the fatal issue in the motor current regulation problem. We solve this issue through incorporating the model following structure to the prescribed PIM digital controller. Through an experiment using a commercial stepping motor and driver, the proposed model following scheme of the PIM discretization is verified.