时滞TCP网络的自适应滑模控制

针对具有输入时滞和状态时滞的TCP网络的拥塞控制问题,提出了一种基于自适应滑模控制的主动队列管理算法。通过引入一个特殊变换将原时滞系统转化为无时滞系统,从而消除时滞带来的影响。考虑到网络系统不确定性上界很难获得,提出了一种自适应律以适应系统的不确定的上界,并根据此自适应律设计了一个滑模控制器,所设计的控制器不仅可以使队列长度快速收敛到设定值,而且维持较小的队列振荡。仿真结果表明,该算法可以获得良好的暂态和稳态响应,该方法优于传统的PI控制和滑模控制。

Adaptive Sliding Mode Control for TCP networks with Time-delay

For the problem of congestion control in TCP networks with input-delay and state-delay, an active queue management algorithm is presented based on an adaptive sliding mode control. A particular linear transformation is used to turn the original time-delay system into a delay-free system and to eliminate the impact of time-delay. Considered the upper bound of the network system uncertainties may not be easily obtained, a simply adaptive law for the upper bound of system uncertainties is presented and a sliding mode controller is designed according to that adaptive law. The controller not only enables the queue length to converge to set value quickly but also keeps the queue oscillation small. Simulation results demonstrate that this algorithm can obtain good transient and steady state responses, and the algorithm is superior to the traditional PI control and sliding mode control.