Research And Development On Embedded Controllers For The Dynamic Network Systems

With the rapid development of network, the size of the network is gradually increasing, and the amount of network data transmission is also increasing. The problems of network congestion are worsening, people`s requirements for the network transmission quality are also improving. Network congestion and network transmission delay are the two major research focuses in network transmission problems. Active Queue Management (AQM) algorithm is very effective and widely used as a better method in network congestion control, by maintaining the desired queue length, AQM could achieve reducing packet loss and queuing delay in router, improving network performance service quality.This paper using nonlinear theory proposes three kinds of active queue management algorithm to control the network instantaneous queue lengths and maintain the desired queue length, in order to improve network congestion and delay, and guarantee the nonlinear TCP dynamic network systems stability. The contents and conclusions of the study are as follows:First of all, this paper presents a robust control scheme for a class of nonlinear TCP dynamic network systems. There are interferences in the actual network operation environment, by introducing the interference to improve the nonlinear TCP dynamic network systems model. Using proper coordinate transformation, evaluation signal and energy storage function, obtain the robust controller which is satisfied nonlinear L 2 gain and realize the effective suppression of system interferences.Second, this paper presents a robust control scheme for a class of nonlinear TCP time-delay dynamic network systems. By comparing the existing models, the paper improves the nonlinear TCP dynamic network systems model which is obtained from Jacobsion's algorithm, and designs the nonlinear robust controller with interference. According to the simulation, the controllers can maintain the desired queue size and guarantee asymptotic stability under the time-delay and external interference.Third, this paper presents an adaptive robust control scheme for a class of nonlinear TCP dynamic network systems. Considering the uncertainty of the various parameters in the running environment, this paper designs an adaptive robust controller. The controller can update parameters in real time, and the parameters can online change by the adaptive control law during operation changes, the controller can greatly improve the network performance.Finally, this paper uses embedded box to design an adaptive robust router.