不确定时滞TCP/AQM系统的滑模控制

针对具有非匹配不确定项和输入时滞的TCP线性化动态系统进行特殊线性变换,将原不确定时滞系统转化为无时滞系统.在新坐标下,基于滑模控制(SMC)设计了一种主动队列管理(AQM)算法.根据滑模到达条件设计了一种控制策略,基于LMI技术给出线性滑动超平面的设计方法,通过Lyapunov函数证明了系统的稳定性.仿真结果表明,该算法可以使队列长度快速收敛到设定值,同时维持较小的队列振荡,尤其是在网络条件变化的情况下,该方法优于传统的滑模控制,能实现准确的跟踪,具有良好的鲁棒性.

On the Sliding Mode Control of Uncertain Time-Delay TCP/AQM System

For the transmission control protocal(TCP) linear dynamic systems with input time-delay and unmatched uncertainties,a special linear transformation was done to transform an uncertain time-delay system into a delay-free system.Then,an active queue management(AQM) algorithm based on sliding mode control(SMC) was designed in the new coordinate system.A new SMC strategy is proposed satisfying the sliding mode reaching conditions,and LMI-based method was given to design the robust sliding hyperplane so as to verify the system stabilization via Lyapunov function.Simulation results showed that the algorithm enable the queue length to converge to its set value quickly and keep the queue oscillation small.The simulation also showed that the algorithm outperforms the conventional SMC strategies with its high robustness and accurate trackability in case the network conditions change.