The Research Of Delay Compensation Control Strategy On Networked Control Systems

Networked control systems (NCSs) invovling many communities, such as computer sciences, communications and automatic control, have been an active research area in the past several years. Consequently, NCSs have been applied in a broad range of areas such as manufacturing systems, real-time command and control of traffic system, aircraft systems, teleportation of robot systems, etc.It is known that the network induced delay generally brings negative effects on NCS stability and performance. For example, due to the existence of the network delay in feedback channel, the state observer can only receive delayed measurements, which may affect the accuracy of state estimation. Similarly, the control input signal cannot be received by the actuator timely since the network delay exists in forward channel. The network delays in the forward and feedback channels may degrade the control system performance or even make the system unstable.This thesis considers the delay compensation problems in NCSs. First of all, we propose the delay compensation control strategy to compensate the effects of the forward channel network delay. By viewing the difference between the current input and the delayed input as a special disturbance, and using the active disturbance rejection control (ADRC) technique, the extended state observer is constructed to estimate both the state and the disturbance simultaneously, and the composite control laws are synthesized to actively compensate the input delay by using the state and disturbance estimates. Secondly, we concern with the problem of delay compensation for the discrete- and continuous-time NCSs with feedback channel network delay. With the delayed measurement, the asymptotic state observers are designed, which implies that the influence of the delay in feedback channel has been weakened or eliminated. In the last, the function observer and networked predictive controller are integrated to deal with the NCSs with both feedback and forward channel delays, and the output tracking control problem of NCSs is considered. Besides, the integral extended state observer is also designed to estimate both the state and the disturbance induced by the difference between the current input and the delayed input, and with the state and disturbance estimates, the composite control laws are synthesized to ensure the stability of the system. The simulations are provided to illustrate the effectiveness and applicability of the developed techniques.