Abstract
In various servo positioning systems, both fast transient and precise positioning are required. To meet these demands, Mode-Switching Control (MSC) scheme has been used widely. A MSC will include several controllers with different structures, and a switching function that will switch from one controller to another according to a certain condition. Consequently, each controller of the MSC can be optimally designed to meet specifications. This thesis presents a Mode-Switching Control applied to the focusing and tracking servo system of an optical disk drive. In addition, an initial value compensation (IVC) method is adopted to improve transient characteristics after switching. Establishing the master development environment based on the embedded Digital Signal Processor (DSP), assembly language is adopted to realize control law of the system in order to perform algorithms more efficiently, while the embedded Complex Programmable Logic Device (CPLD) is treated as a slave device, utilizing the Hardware Description Language (HDL) to implement other essential digital circuit modules, including servo signal acquisition and logic determination. By fusing the high-speed computation ability of a DSP and the powerful logic capability of a CPLD, a Mode-Switching control law design can achieve a fast and precise position control task. Experiments were performed to further validate its efficiency.