Inertia moment identification in the average speed‐type instantaneous speed observer

Abstract

AbstractIn recent servomotor control systems using highspeed microprocessors, it is difficult to obtain accurate speed information by using a low‐resolution shaft encoder because encoder pulses are very sparse in the low‐speed range. To overcome this problem, the instantaneous speed observer is proposed, system stability is improved, and strong disturbance rejection control is realized. However, when the inertia moment changes, the estimated instantaneous speed has error because the observer uses the nominal value of the inertia moment to calculate the instantaneous speed. For this reason, the identification method of the inertia moment for the “position input‐type” speed observer is proposed but it operated at about 50 rpm speed command. This paper proposes some novel identification methods for the “average speed‐input type” instantaneous speed observer and identifies the inertia moment in the very low speed range below 1 rpm.