Computational Aspect Analysis of Real-Time Systems: Application to HDD Servo Control

Abstract

Co-simulation for a hard disk drive (HDD) servo system and its microcontroller control system was developed to analyze computational aspects of the control system such as memory use and calculation load on processors. The microcontroller was modeled with its instruction set simulator that executed the binary codes of control commands. The model also incorporated the peripheral functions of timer units, an interrupt controller, an analog-to-digital converter, and so forth. The plant model of the HDD mechanism and its control algorithms were adopted from a study on HDD servo controls. The microcontroller and HDD models communicated with each other periodically to realize co-simulation. The control algorithms, which were originally written in Matlab®, were converted to C codes and eventually to binary codes by an automated code generation tool to eliminate manual programming and to guarantee fair comparison. The proposed co-simulation method compared different control algorithms, as well as different microcontrollers, for selection. The accuracy of the co-simulation was investigated, and the potential use of co-simulation approach was discussed. A synchronization adaptor was proposed to improve the timing accuracy of the control system simulation.