In -plane and transverse vibration of axially-moving media with advanced guiding and actuation elements

This thesis is motivated by the need for further and fundamental engineering science advances in guiding and actuation technologies that facilitate large increases in volumetric storage density for magnetic tape. Advanced guiding and actuation technologies have been developed to enable significant increases in the storage density. Three advanced path technologies are considered in this thesis, and their effectiveness and technical feasibility is analyzed in the context of reducing lateral tape vibration and improving servo bandwidth. The specific issues addressed in this thesis are listed below:;Vibration with edge weave. Externally-pressurized porous air bearing guides control the tape's position by biasing the tape's edge against a datum surface. The constant tape-datum contact is less detrimental to the tape's edge relative to the intermittent contact and impacts that are characteristic of self-pressurized guides having rigid or compliant flanges. While the guides effectively control the low frequency components of the tape's vibration, with this form of edge guiding, lateral motion can be influenced by imperfections or weave in the shape of the tape's edge, that arise during the manufacturing process. This edge weave can excite vibration as the material convects over and interacts with the guide's flanges. The free and forced vibration response are obtained through modal analysis, and parametric studies are presented to identify opportunities to optimize the path for reduced vibration.;High-frequency vibration reduction with friction guiding. Friction guiding eliminates edge contact between the guide and the tape by applying the guiding forces to the media's wider face. Sub-ambient pressure features on the surface of the distributed guide can be used to increase the contact pressure, and friction force, well beyond that generated by wrap pressure alone. The higher friction forces are effective in reducing the tape's problematic high-frequency vibration. In addition, by applying the guiding force over the wider backcoat of the tape, rather than its fragile edge, the guiding pressure and tape wear are reduced, thereby enabling the use of thinner media.;Parametric excitation with laterally-moving elastic foundation. Narrow-width head designs, that do not span the entire tape's width, can reduce the mass of the read/write head assembly and thereby, in principle, increase the servo's bandwidth. However, with such a head design, the tape's edges are not supported, and may undergo excessive out-of-plane vibration as the head slews across the tape's width. (Abstract shortened by UMI.).