Single-Stage Actuated Servo Systems

Abstract

In this chapter, we proceed to address one of the key issues of this book — the design of complete single-stage HDD servo systems that meet the two most important requirements for HDDs, i.e., a high-speed seeking performance, and a highly accurate head-positioning/settling performance. We will utilise the nonlinear control techniques reported in Chapter 5 and the linear techniques reported in Chapter 4 to carry out the design of three different types of servo system for a Maxtor HDD with a single VCM actuator. More specifically, we will design the servo systems using the conventional PTOS approach, the CNF control technique, and the MSC system with PTOS and RPT controllers. As will be seen shortly, the CNF technique will yield the best performance compared with those of the other two approaches. This is due to the fact that there is no switching element involved in the CNF design.