realtidskontroll

Realtidskontrol is a discipline within automation and control engineering that concerns systems designed to perform sensing, computation, and actuation within strict temporal constraints. In real-time control, tasks must complete within predetermined deadlines, and the correctness of the system depends not only on the logical outcome but also on the time at which the outcome is produced. Real-time control can be classified as hard real-time, where missed deadlines are unacceptable, and soft real-time, where occasional deadline misses may be tolerable but degrade performance.

A typical realtidkontrol system comprises sensors to measure the process, actuators to influence it, and controllers that determine control actions. The processing can take place on PLCs, embedded controllers, or real-time capable industrial PCs, often running a real-time operating system or a deterministically scheduled software stack. Key control strategies include proportional–integral–derivative (PID) control, state-feedback control, and model predictive control. Deterministic timing, sampling rates, and reliable communication are essential, and time synchronization (for example, with Precision Time Protocol) is commonly required across distributed components.

Applications of realtidkontrol span manufacturing automation, process industries, robotics, power systems, and traffic or building automation. Design considerations focus on latency, jitter, end-to-end cycle time, and robust fault handling. Safety and reliability standards frequently influence architecture and validation, with standards such as IEC 61508, IEC 62061, and ISO 13849 playing a role in functional safety. Challenges include integrating heterogeneous equipment, ensuring fail-safe behavior, verifying real-time performance, and maintaining security in networked environments.