State and parameter estimation for step motors under actual working conditions

Abstract

A method of measuring the dynamic behavior and characteristics of step motors without attaching mechanical sensors is described. Friction load torque and motor torque constant, as well as rotor position and velocity, are estimated by a sequential least square filter driven by sensed back electromotive force and current. The validity of the proposed filter is confirmed in detail by comparing the estimated results with direct measurements in both steady and transient state.<>