Research On GPC Performance Compensation In Time-delayed Networked Control Systems

As convenience and efficiency were brought to our daily lives with the Network Control Systems'(NCS) application, both opportunities and challenges also subsequently came to the controlling field. As the result of combination of control technology and network information technology, geographic limitation was broken in network control systems in a certain range, tremendous changes and transformation also has been happened in the control field. However, as the limitations of network speed and network bandwidth, network delay has been brought to the system inevitably, the delay can not be eliminated, and it may cause packet losses, and then degrade the performance of control systems and even would make the system destabilize as the network burden aggravation. The network delay is the most important problem in the NCS if you want to increase the performance of control systems.With the subsidization of the key project of the National Natural Sciences fund. According to the compare and analyses the present situation of the networked digital control theory and key technology in domestic-overseas. The network time-delay compensate algorithmic was researched in both theory and practice sides.Theoretically, the network time-delay was tested and simulated between the two computers, the properties of different time-delay was compared and analysed. According to study the different time-compensate algorithms, an improved GPC algorithmic was introduced-Queue-select stair-like GPC algorithm. With the stair-like factor was introduced in the stair-like strategy, the dimension of the biorthogonal matrix and the algorithmic complexity was reduced efficiently; The received packets were be queued by time slice in Queue-strategy, and the newest packet was used to participate the operate, with this strategy the problems of large time-delay,packets loses and packets worse were solved efficiently. At last, the machine tool feed moving system was selected as the research object to modeling and simulation by matlab. The simulation results of the new algorithm was compared with the literature twenty-three. It shows that the control performance of improved GPC algorithm is much better than the GPC's especially when the delay is big in some degree.The feasibility and effectiveness of the algorithm was proved theoretically.Finally, in the practice sides, The implementation process of improved GPC algorithm was detailed introduced. Based on CNC milling machine, the network control system platform was built by Microsoft Visual Basic 6.0.Because of the data acquisition loop, the speed control loop and the debug of algorithm need to be further improved. More profound research on this part is expected.