الصفحة 1
الصفحة 1
Hard Disk Drive Servo Systems
The second edition of this monograph provides a systematic treatment of the design of modern hard disk drive servo systems updated with the latest research results to reflect recent improvements in spindle speed and bit density and other changes in this fast-moving field. In particular, it focuses on the applications of some newly developed results in control theory, i.e., robust and perfect tracking control and composite non-linear feedback control which are suitable for track following and seeking respectively. Emphasis is placed on hard disk drive servo systems with single- or dual-stage actuation using a voice-coil-motor actuator enhanced in the latter case by the addition of a micro-actuator providing faster responses and therefore higher bandwidth in track following. Other issues such as modeling and compensation of nonlinearities and friction in microdrives, disturbance rejection and resonance compensation are also addressed.
Creating Web-based Laboratories
Remote web-based experimentation, enabling students and researchers to access the laboratory anytime via the Internet, is becoming an increasingly attractive way to complement or even replace traditional laboratory sessions. Placing a video camera & microphone before the equipment and apparatus to capture what is actually happening in the laboratory allows the images and audio data to be streamed to the client side. Researchers in different countries can share equipment and conduct research cooperatively and remotely. The authors summarise their research and discuss the development of the 5 web-based laboratories launched from the National University of Singapore. The principles, structure, and technologies required for the creation of Internet remote experimentation systems are discussed with particular emphasis on the integration of hardware and software systems. Also highlighted is the design and development of interfaces and components for use in typical web-based laboratories or similar web-control applications.
