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Embedded control systems are subject to conflicting demands: end-users ask for devices with better capabilities while strong industrial competition impose tight cost constrains that results in devices with limited resources. Current research in the multidisciplinary embedded systems discipline indicates that by combining real-time and control systems it is(More)
In this paper, we first identify the potential violations of control assumptions inherent in standard real-time scheduling approaches (because of the presence of jitters) that causes degradation in control performance and may even lead to instability. We then develop practical approaches founded on control theory to deal with these violations. Our approach(More)
—In network-based control systems (NCSs), plant sensor–controller–actuator nodes in closed-loop operation drive principal network traffic. The quality-of-control (QoC) in an NCS, i.e., the performance delivered by each closed-loop operation, depends not only on the controller design but also on the message scheduling strategy. In this paper, we show that(More)
Closed-loop control systems are dynamic systems subject to perturbations. One of the main concerns of the control is to design controllers to correct or limit the deviation that transient perturbations cause in the controlled system response. The smaller and shorter the deviation, the better the achieved performance. However, such controllers have been(More)
In many application areas, including control systems, careful management of system resources is key to providing the best application performance. Most traditional resource management techniques for real-time systems with multiple control loops are based on open-loop strategies that statically allocate a constant CPU share to each controller, independent of(More)
—In many application areas, including control systems, careful management of system resources is key to providing the best application performance. Traditional control systems with multiple control loops statically allocate a fixed portion of the system resources to each controller based on their average or worst-case resource requirements. However,(More)
—In recent years, approaches to control performance and resource optimization for embedded control systems have been receiving increased attention. Most of them focus on theory, whereas practical aspects are omitted. Theoretical advances demand flexible real-time kernel support for multitasking and preemption, thus requiring more sophisticated and expensive(More)
In real-time multitasking systems, feasible periodic tasks execute within their periods. However, the exact time at which each task executes vary due to other task interferences. For control tasks, this produces irregular sampling and varying time delays, which may degrade system performance and bring the system to instability. In this paper we present(More)
− − − − The increasing application of flexible and powerful real-time distributed control systems is presently characterizing the industrial automation field. Such systems involve three main disciplines: control systems, real-time systems, and communication systems. Control systems, due their stringent timing constraints, demand real-time computing(More)