ABSTRACT
This chapter discusses the system modeling from the first principle of actuators. A hard disk drive includes five major parts: baseplate and cover, spindle and motor assembly, actuator assembly, disk, head/suspension assembly, and electronics card. The seek time is a measure of how fast the disk drive actuators can move the read/write (R/W) head to a desired location. In a disk drive, the positioning information or servo information is embedded in each disk surface. Vibration in disk drives causes the deviation of the R/W head positioning from the desired track center. Vibration modeling that is based primarily on the spectral decomposition of the error signal measured in a closed-loop system. The models of a voice-coil motor actuator and a piezoelectric zirconate titanate microactuator have been derived on the basis of their physical operations. The chapter addresses the modeling of uncertainties in high frequency and nonlinearities such as actuator pivot friction.
