Sufficient Real-Time Analysis for an Engine Control Unit with Constant Angular Velocities

Abstract

Abstract-Engine control units in the automotive industry are particular challenging real-time systems regarding their real-time analysis. Some of the tasks of such an engine control unit are triggered by the engine, i.e. the faster the angular velocity of the engine, the more frequent the tasks are executed. Furthermore, the execution time of a task may vary with the angular velocity of the engine. As a result the worst case does not necessarily occur when all tasks are activated simultaneously. Hence this behavior cannot be addressed appropriately with the currently available real-time analysis methods. In this paper we make a first step towards a real-time analysis for an engine control unit. We present a sufficient real-time analysis assuming that the angular velocity of the engine is arbitrary but fixed.

Schedulability tests for tasks with Variable Rate-dependent Behaviour under fixed priority scheduling

“…Some preliminary steps have previously been taken to analyse VRB tasks under fixed priority scheduling: In 2013 [26] Pollex et al considered systems where the rotational speed is arbitrary, but fixed; however, this simple first step does not account for the important effect of transitions between different execution modes. Pollex et al [25] subsequently provided a simple analysis for systems with angular acceleration, but considering only the maximum execution time and the minimum inter-arrival time that could be obtained in the analysis interval, starting from different engine speeds.…”

Rate-adaptive tasks: Model, analysis, and design issues

“…Pollex et al [18] also presented a sufficient schedulability analysis under fixed priorities, but they assumed that all the tasks with a variable rate depend on the same angular velocity, which can be arbitrary, but fixed. Moreover, the analysis is formulated using continuous intervals, hence it cannot be immediately translated into a practical schedulability test, whose complexity has not been evaluated.…”

Uniprocessor EDF scheduling of AVR task systems

“…Some early work on understanding the scheduling of AVR tasks was done by [17] on a simplified model, where only a single task, that is assigned highest priority, is analyzed. Pollex et al [22] later considered systems with multiple tasks, but constant engine speed. This work was later extended to the case with angular acceleration in [21] -by considering the maximum execution time and the minimum inter-arrival time starting from different speeds, sufficient schedulability conditions were derived.For the preemptive uniprocessor fixed-priority scheduling of AVR tasks, Davis et al [13] present an Integer Linear Programming (ILP) based sufficient dynamic schedulability test; Biondi et al [10] have recently proposed a search tree based method based on a Brute-Force approach with pruning rules.…”