Tape Transport Control and Estimation of Reel Inertia for Magnetic Tape Drives

Abstract

The moment of inertia of the tape reel of VTR varies depending on the reel size and the volume of the tape winding around the reel. Due to the variation, the tension control of the tape in the reel-to-reel drive is difficult.
To overcome this problem, the paper presents a new method to identify the tape reel without using additional sensors. Based on this identification scheme, the tape transport control is also presented to achieve the precise tension/speed control.
This real-time identification approaches are presented for spinning and running. When the tape reels start spinning up, the tape speed is changed stepwise, by which the inertia of the reel can be estimated using the variation of the tape tension at each reel. The process is repeated to improve the accuracy of identification. Under running condition, the changing inertia can be calculated from the tape radii of two reels. The changing tape radius can be detectable with the speed of capstan.
The validity of the proposed method has been approved by experiments using VTR.