Determination of the optimum parameter tolerances for a permanent magnet-step motor: a sensitivity approach

The permanent magnet step motor (PM step motor) is one of the most important control elements used in the process control industry. In this study, a method is proposed by the use of the sensitivities of the transfer function to determine the optimum parameter tolerances of such motors. These tolerances keep the deviation of the output of the PM step motor due to parameter variations, in the tolerance region. Furthermore a sensitivity measure is defined to be used to improve the sensitivity performance of a PM step motor and to compare various PM step motors with different sets of design parameter values which realize the same transfer function.