Optimal Scheduling Algorithm for Messages in Networked Control Systems Based on Token-Bus

For scheduling messages in networked control system (NCS), the characters of messages in NCS are analyzed firstly in this paper. The message models are given and the relationship of messages is studied. Non pre-emptive EDF (earliest deadline first) is selected for scheduling messages and the method for realizing the scheduling algorithm is presented based on token control. The schedulability of messages is investigated and schedulable condition is given. According to the relationships of submessages, the submessage deadlines are optimized to increase the maximal utilization of network and the algorithm for computing optimal deadlines is prevented. The simulation results show that the algorithms prevented in this paper are effective.