Improved PIM digital driver with dead-zone compensation for a stepping motor

The present paper is concerned with an improvement of the so-called plant-input-mapping (PIM) discretization as applied to an analog controller that is used in a high-performance commercial driver for stepping motors. The controller employs a linearizing compensator to cancel out the effect of dead-zone nonlinearity that exists in a pulse-width-modulation circuit of the driver, which has been one of the major limiting factors in the design of linear PIM digital drivers. The experiments show that the proposed digital driver has the performance that is closer to that of the analog one, even at the low sampling rate of 4 kHz, than the existing PIM driver which approximates the dead-zone as a simple gain.