Study On The Scheduling Algorithm Of CPS Events Based On PTIDES

Cyber-physical system(CPS) is a kind of integrated system, which is consisted of computational process, communication process and physical process. The difference between CPS and usual distributed embedded system is that CPS has open network and time-space coherence. So, study of events scheduling in CPS is a severe challenge. Programming Temporally-Integrated Distributed Embedded System(PTIDES) provides a time programming semantic, which is PTIDES semantic for short. PTIDES semantic guarantees the time-space coherence in open network environment. Hence, study events scheduling in CPS integrating PTIDES semantic is of great significance.First of all, the usage of PTIDES semantic in CPS events scheduling is stated and what is PTIDES semantic is interpreted. The exiting scheduling algorithms integrated PTIDES semantics: simple PTIDES scheduling algorithm, parallel PTIDES scheduling algorithm and ZSFPTIDES scheduling algorithm are analyzed, at the same time the advantages and disadvantages are stated briefly. To improve the disadvantage of stated algorithms, this thesis advanced a new scheduling algorithm integrated PTIDES semantic: MPEDFPTIDES. The new scheduling algorithm took into consideration various factors, such as the events’ absolute deadline, the rest of execution time and the rest time of events. The new scheduling algorithm not only adapts the high concurrency of CPS, but also improves the rate of deadline meet.Finally, considering the fact that there are period and acyclic events in CPS and the probability of CPU in CPS break down, this thesis advanced a period/acyclic mixed fault-tolerant scheduling algorithm. The period events are scheduled by RM algorithm and the acyclic events are scheduled by MPEDFPTIDES. At the same time, to improve the fault-tolerant performance the events sub-edition mechanism is used. The algorithm is suitable for CPS period and acyclic events scheduling by experiment proving. The CPU number needed in the system is reduced and CPS scheduling efficiency is improved.