Intelligent Dynamic Scheduling Strategy Of Networked Control Systems With Resource Constraints

Networked control system is a closed-loop feedback control system by the components such as sensors,controllers and actuators in the system connected through the network.This kind of control system is widely attention with high reliability,less connection and easy to extend,etc.But the networked control system also inevitably raises a lot of problems:network-induced delay,packet dropout and network congestion etc.These problems impact the system control performance and the stability of the system.Therefore,the study of network control system indeed has practical significance.Aiming at the characteristics of randomness,instability and nonlinear induced delay of networked control system,a delay prediction algorithm of modified ensemble empirical mode decomposition-permutation entropy and wavelet neural network optimized by cuckoo search is proposed.Firstly,modified ensemble empirical mode decomposition(MEEMD)is used to decompose the original delay sequence,then the permutation entropy values of each sub sequence are calculated and recombination of new sub sequences to reduced the non-stationary characteristics of the delay sequence and amount of calculation.And then predict the new sub sequences by the wavelet neural network optimized by the cuckoo search algorithm.The final results of network delay are calculated by superimposing the prediction of the sub models.Simulation results show that the method has the advantages of better prediction accuracy,reflecting the overall trend of the delay sequence,effectively reducing the impact of outliers.Aiming at networked control system of the limited resources,a variable sampling period scheduling algorithm based on the model of whale optimization algorithm-relevance vector machine is proposed.The network bandwidth and packet transmission delay is obtained by the monitoring module,which are predicted by the model of whale optimization algorithmrelevance vector machine;Fuzzy dynamic weight coefficient and the predictive value of network bandwidth and data transmission delay is used for constantly changing the sampling period of the system control subsystem,to realize the dynamic adjustment of the sampling period.Simulation results show that the proposed scheduling algorithm guarantees the real-time performance and control performance of the system under the condition of limited resources.