Delay Compensation Strategy Research Of The Network Control Systems

Networked control systems are distributed feedback control systems whose sensors,it allows for reduced wiring,as well as a lower installation cost.It also permits greater agility in diagnosis and maintenance procedures. But due to the existence of network delay, network control system control commands and transmit information often cannot promptly executed, thus cause the system performance, even affect the stability of the system. In order to solve the problem, improve the network delay the stability of the network control system, this paper analyzed the characteristics of delay in network is proposed, based on the two kinds of delay compensation strategy.Aiming at the network delay which are less than one sampling period in networked control systems, according to the characteristics of dynamic matrix control in predictive control, a new compensating strategy is proposed in this paper based on the dynamic matrix control method. This strategy can predict the future situation of the delay signals in the networked control systems, using dynamic matrix control algorithm to compensate for the delay in network transmission. Aiming at the problem of undetermined time delay in network control system,the strategy based on neuron controller for compensating time delay is proposed in accordance with the characteristic analysis of time delay in cyclic service network and random contention network.In this strategy,the influence of undetermined delay in NCS is overcomed by using the excellent learning ability of neuron.Connecting with the concrete examples, this paper does some simulation experiments, and the simulation results verify the validity of the proposed strategy by comparison with the traditional PID control.In order to take simulation of networked control systems better,the paper introduces an ideal simulation tool of networked control systems-TrueTime toolbox, which can give an synthetic simulation for network delay, network parameters, system performance, control method and so on. By using the TrueTime toolbox, a testing platform for networked control systems is proposed, and then, connecting with the concrete examples, the simulation of ethernet network and token ring network is carried out. The simulation results show that this toolbox is an effective tool to realize simulation for networked control systems and the characteristics of ethernet network and token ring network are verified significantly.