Dynamic Voltage Scaling for Digital Control System Implementation

For real-time computer-controlled systems, control performances of tasks as well as energy consumption of overall system must be optimized. A control task does not have a fixed period but a range of periods in which the control performance varies. Hence, when more than one control tasks are scheduled on a single processor, an optimization problem appears. Furthermore, when an energy saving technique such as dynamic voltage scaling is used, its properties affect the control performance.Using a performance index that involves control performance and energy consumption, a static solution is proposed to obtain the optimal processor speed and a set of periods for given control tasks in O(k). Also a dynamic solution is proposed to utilize system services of real-time operating systems to overcome unavoidable deficiencies of the static solution and to further reduce the energy consumption of the overall system. The performances of proposed solutions are revealed via simulation studies.Hyung Sun Lee received his B.S. and M.S. degrees in electronics engineering from Korea Advanced Institute of Science and Technology (KAIST) in 2000 and 2002, respectively. He is currently a Ph.D. student in the Department of Electrical Engineering and Computer Science (EECS) at KAIST. His research interests include real-time control and power-aware real-time embedded systems.Byung Kook Kim received his B.S. degree in Electronics Engineering from Seoul National University in 1975, and his M.S. and Ph.D. degrees from KAIST in 1977 and 1981, respectively. Dr. Kim was a manager and founder of the Calibration Laboratory, Woojin Instrument Co. Ltd, in 1981. He performed his postdoctoral research at the University of Michigan, Ann Arbor, Michigan, from 1982 to 1983. He returned to Woojin Instruments as a chief researcher of the R&D Department from 1984 to 1986. He joined the faculty of the Department of Electrical Engineering at KAIST in 1986, where he is currently a professor. His research interests include real-time systems, parallel and distributed systems, fault-tolerant computing, mobile robot sensing and navigation, and manipulator control.