Initial Position Estimation for Closed-loop Linear Hybrid Stepping Motor Drives using DC Current Excitation

This paper demonstrates a simple and economical way to accurately estimate an initial position for linear hybrid stepping motor (LHSM) drives by utilizing dc current excitation. In order to detect an absolute position of the mover, two preliminary tests are carried out under two different dc current conditions: single-phase and two-phase dc current excitation. The proposed algorithm has been successfully applied to a practical system with a rated initial load and stiction without causing any mechanical damage. The proposed scheme is not affected by the harmonic force ripple of the LHSM and its benefits are much more significant for multi-axis systems. Experimental results are presented to prove the effectiveness of the proposed initial position estimation scheme