An Adaptive Fuzzy Scheduling and Fuzzy-PID Perfomance Control Model Being Suitable to Soft Real-Time Systems

Abstract

Considering the unsteadiness and unpredictability of a practical task running environment due to the unsteadiness of network communication and the estimation deviation, it is necessary to introduce fuzzy concept and theory to the scheduling and performance control of the soft real-time application systems oriented communication and network fields. In this paper, a new adaptive soft real-time task scheduling model with the fuzzy-PID feedback controller was presented. In this model, we used the fuzzy scheduling algorithm in which the scheduling turn of a ready task is decided by the fuzzy inference result of its criticality and deadline distance. Meanwhile,in the adaptive control part, we used the fuzzy-PID controller that combines the fuzzy feedback controller and PID controller instead of traditonal PID controller. The simulation test shows that our presented model can enable a soft real-time systems which has the mulit-level service characteristic reach the steady state faster and has less miss ratio to more important tasks.