Control-scheduling codesign of real-time systems: The control server approach

Issue title: Real-Time Systems (Euromicro RTS-03)

Article type: Research Article

Authors: Cervin, Anton | Eker, Johan

Affiliations: Department of Automatic Control, Lund Institute of Technology, SE-221 00 Lund, Sweden | Ericsson Mobile Platforms, SE-221 83 Lund, Sweden

Note: [] Corresponding author. E-mail: anton@control.lth.se

Abstract: The paper presents the control server, a real-time scheduling mechanism tailored to control and signal processing applications. A control server creates the abstraction of a control task with a specified period and a fixed input-output latency shorter than the period. Individual tasks can be combined into more complex components without loss of their individual guaranteed fixed-latency properties. I/O occurs at fixed predefined points in time, at which inputs are read or controller outputs become visible. The control server model is especially suited for codesign of real-time control systems. The single parameter linking the scheduling design and the controller design is the task utilization factor. The proposed server is an extension of the constant bandwidth server, which is based on the earliest-deadline-first scheduling algorithm. The server has been implemented in a real-time kernel and has also been validated in control experiments on a ball and beam process.

Keywords: Feedback control, real-time scheduling, design methodology, real-time components, constant bandwidth server

Journal: Journal of Embedded Computing, vol. 1, no. 2, pp. 209-224, 2005