High-speed orthogonal power effect actuator for recording at over 10000 TPI

Modal Testing and Finite Element Modelling of Subsystem in Hard Disk Drive

“…. At this moment the measured QR mode shape is the same as that predicted by Aruga et al [5]. However, there are significant offset in the lateral motion among different arms, indicating HAA rotation about the longitudinal axis.…”

“…The mode is usually located in the frequency range 3-6 kHz dependent on a particular drive. Aruga et al [5] first presented that the HAA has a quasirigid lateral translation motion on arm/suspension at the lateral QR mode vibration. Stricklin and Blanks [6] described the vibrations of HAA at about 2 kHz was the in-plane bending of the arm.…”

“…Radwan and Whaley [9] and Aruga et al [5] established two finite element models of actuator without suspension and slider, respectively. Jiang and Miles [7] built an HAA FE model in which the VCM was not included.…”

Fem and Experimental Analysis of the Actuator ‘Butterfly Mode’ in a Hard-Disk Drive

“…In the past, this assumption was used and accepted as long as the mass of the actuator was high [4,5,8,9]. However, with the shrinking form factor, the stiffness-to-mass ratio becomes higher rendering the rigid body assumption invalid, as both the bearing stiffness and the actuator stiffness are not infinite.…”

“…In order not to excite this mode, solutions such as using a dual flat coil was introduced, in which the actuator was driven by a force approximately orthogonal to the seek direction [4]. In theory, the butterfly mode would not be excited.…”