Abstract: Conventionally, the variable structure control is investigated in the time domain. However, this paper xplore the properties of robust stability for variable structure control in frequency domain. Here, it can be shown that the variable structure control can be transformed into a Lur’e problem. If the uncertainties of system and input matrices satisfy the “matching conditions”, then the zero dynamics of sliding surface will not changed; For robust stability, it can be shown that from frequency domain point of view, the variable structure control possesses phase margin and infinity gain margin. With this point of view, the sliding mode control reveals superior robust properties. Finally, according to circle criterion, a formula is presented that with suitable boundary layer, the sliding mode control can achieve absolute stability of overall system.

Brief Biography of the Speaker:
Chingyei Chung is a professor in the Department of Electronic Engineering, Ming Shin University of Science and Technology, Taiwan Prior to this position, he held various academic positions at Feng Chia University Taiwan and San Francisco State University, USA respectively. He received B.S. from Natl. Chiao Tung University, Taiwan ROC and M.S. degree in electrical engineering from San Jose State University, U.S.A. Also He finished his Ph.D degree in Mechanical Engineering from University of California, Berkeley, USA.
He has four Patents granted by the United State Patent and Trademark Office. In 2003, he is an Distinguished Research Advisor in ABI (American Biographic Institute). His research interests include nonlinear control, nonlinear circuit theory and etc.