Rhythmic Tasks: A New Task Model With Continually Varying Periods for Cyber-Physical Systems
Traditional mechanical subsystems in automobiles are being replaced by electronically controlled systems, often with no mechanical backup. This trend towards "Drive-by-wire" systems is becoming increasingly popular. In these cyber-physical systems, a critical task not meeting its timing deadline can lead to a safety violation and damage to life and/or property. Classical real-time scheduling techniques such as RMS and EDF can be used to guarantee the schedulability of periodic tasks. However, certain critical tasks like the engine control task are activated by engine events such as pulses generated by sensors at the engine crankshaft. The periods of these engine tasks vary continually and even dramatically depending on the engine speed.