ARTES – A network for Real - Time research and graduate Education in Sweden 1997 – 2006

ion 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 espe-cially 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.