| 1. |
- Cervin, Anton, et al.
(författare)
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Feedback Scheduling of Control Tasks
- 2000
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Ingår i: Proceedings of the 39th IEEE Conference on Decision and Control, 2000.. - 0780366387 ; 5, s. 4871-4876
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The paper presents a feedback scheduling mechanism in the context of co-design of the scheduler and the control tasks. We are particularly interested in controllers where the execution time may change abruptly between different modes, such as in hybrid controllers. The proposed solution attempts to keep the CPU utilization at a high level, avoid overload, and distribute the computing resources evenly among the tasks. The feedback scheduler is implemented as a periodic or sporadic task that assigns sampling periods to the controllers based on execution-time measurements. The controllers may also communicate feedforward mode-change information to the scheduler. As an example, we consider hybrid control of a set of double-tank processes. The system is evaluated, from both scheduling and control performance perspectives, by co-simulation of controllers, scheduler, and tanks.
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| 2. |
- Cervin, Anton
(författare)
-
The Real-Time Control Systems Simulator -Reference manual
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A Matlab / Simulink-based simulator for real-time control systems is described. The simulator facilitates co-simulation of plant dynamics, controller code execution, and real-time scheduling. Three examples are given. The kernel primitives are described in detail.
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| 3. |
- Cervin, Anton
(författare)
-
Towards the Integration of Control and Real-Time Scheduling Design
- 2000
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis deals with scheduler and controller co-design for real-time control systems. The overall goal is higher resource utilization and better control performance. One goal is to minimize the performance loss due to jitter and control delays. Another goal is to relax the nominal requirements on hard deadlines and fixed worst-case execution times. A third goal is to provide a co-simulation environment for real-time control systems.
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| 4. |
- Persson, Patrik, et al.
(författare)
-
Execution-Time Properties of a Hybrid Controller
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We are interested in gaining more knowledge about the execution-time requirements of real-time control tasks, and this paper presents a system for gathering statistics of the execution times of real-time tasks. The system allows real-time code to be instrumented in order to gather, analyze, and present execution-time statistics. It has been used to instrument an existing hybrid controller to gather execution-time statistics. These statistics indicate that the worst-case execution times of the controller occur in conjunction with reference and mode changes, and that a scheduling based on that worst-case execution time leads to poor CPU utilization.
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| 5. |
- Årzén, Karl-Erik, et al.
(författare)
-
An Introduction to Control and Scheduling Co-Design
- 2000
-
Ingår i: Proceedings of the 39th IEEE Conference on Decision and Control, 2000.. - 0780366387 ; 5, s. 4865-4870
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The paper presents the emerging field of integrated control and CPU-time scheduling, where more general scheduling models and methods that better suit the needs of control systems are developed. This creates possibilities for dynamic and flexible integrated control and scheduling frameworks, where the control design methodology takes the availability of computing resources into account during design and allows on-line trade-offs between control performance and computing resource utilization.
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