The Study Of Deadband In NCS Based On Sensor And Controller

Networked control system is a distributed control system that transmit signal through network between sensor, controller and actuator. It has many advantages, such as good flexibility, convenient for system installation and maintenance and so on. On the other hand, it leads to time delay, packet loss and other issues. The rational design of scheduling strategy can reduce the network conflicts and improve the overall performance of the system when the network bandwidth resources are limited.Two kinds of deadband scheduling method using different scheduling strategies in sensor nodes and controller nodes was presented for networked control system that multiple loops share the same network.The first method of deadband scheduling:In the sensor, it was determined whether the sensor sent packet to the controller based on the absolute value of the difference between current sampling signal and the previous transmission signal, and scheduling based on the difference between two adjacent sampled signals; In the controller, combined with human-simulated intelligent method, the controller scheduling based on the deviation and the deviation change rate of the system.The second method of deadband scheduling:In the sensor, it was determined whether the sensor sent packet to the controller based on the absolute value of the difference between current sampling signal and the previous transmission signal, and the sensor sent the packet to the controller at regular intervals; In the controller, combined with human-simulated intelligent method, scheduling based on the deviation and the deviation change rate of the system.Truetime1.5simulation toolbox was used to carry out the simulation research. First of all, the proposed scheduling method was discussed from the aspect of the system output response, time delay, network scheduling, and network packet traffic. Then, the performance of the proposed scheduling method was analyzed through the comparison of various parameters obtained by simulation. Finally, the proposed scheduling method was studied in the case of packet loss or step interference.The simulation results show that using the proposed deadband scheduling method in this paper can improve the utilization rate of network bandwidth resources and the control performance of quality. Two kinds of deadband scheduling method are simple to implement, with great engineering application value.