Control-Scheduling Codesign of Real-Time Systems: The Control Server Approach

• The paper presents the control server, a real-time schedulingmechanism tailored to control and signal processing applications. Acontrol server creates the abstraction of a control task with aspecified period and a fixed input-output latency shorter than theperiod. Individual tasks can be combined into more complexcomponents without loss of their individual guaranteed fixed-latencyproperties. I/O occurs at fixed predefined points in time, at whichinputs are read or controller outputs become visible. The controlserver model is especially suited for codesign of real-time controlsystems. The single parameter linking the scheduling design and thecontroller design is the task utilization factor. The proposedserver is an extension of the constant bandwidth server, which isbased on the earliest-deadline-first scheduling algorithm. Theserver has been implemented in a real-time kernel and has also beenvalidated in control experiments on a ball and beam process.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Reglerteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Control Engineering (hsv//eng)

Keyword

constant bandwidth server

real-time components

design methodology

Feedback control

real-time scheduling

Publication and Content Type

art (subject category)

ref (subject category)